U.S. patent application number 16/799536 was filed with the patent office on 2020-12-24 for novel rnai molecule delivery platform based on single-sirna and shrna nanocapsules.
The applicant listed for this patent is THE REGENTS OF THE UNIVERSITY OF CALIFORNIA. Invention is credited to Irvin S.Y. CHEN, Masakazu KAMATA, Min LIANG, Yunfeng LU, Jing WEN, Ming YAN.
Application Number | 20200397712 16/799536 |
Document ID | / |
Family ID | 1000005064667 |
Filed Date | 2020-12-24 |
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United States Patent
Application |
20200397712 |
Kind Code |
A1 |
LU; Yunfeng ; et
al. |
December 24, 2020 |
NOVEL RNAi MOLECULE DELIVERY PLATFORM BASED ON SINGLE-siRNA AND
shRNA NANOCAPSULES
Abstract
Novel siRNA and shRNA nanocapsules and delivery methods are
disclosed herein. These siRNA and shRNA nanocapsules and delivery
methods are highly robust and effective. This invention provides a
platform for RNAi delivery with low toxicity and long intracellular
half-life for practical therapeutic applications.
Inventors: |
LU; Yunfeng; (Culver City,
CA) ; CHEN; Irvin S.Y.; (Palos Veerdes Estate,
CA) ; YAN; Ming; (Encino, CA) ; LIANG;
Min; (Encino, CA) ; KAMATA; Masakazu; (Los
Angeles, CA) ; WEN; Jing; (Culver City, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
THE REGENTS OF THE UNIVERSITY OF CALIFORNIA |
Oakland |
CA |
US |
|
|
Family ID: |
1000005064667 |
Appl. No.: |
16/799536 |
Filed: |
February 24, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15721501 |
Sep 29, 2017 |
10568844 |
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16799536 |
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14385430 |
Sep 15, 2014 |
9782357 |
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PCT/US2013/032615 |
Mar 15, 2013 |
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15721501 |
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61612178 |
Mar 16, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 48/00 20130101;
A61K 47/42 20130101; C12N 15/111 20130101; C12N 2320/32 20130101;
A61K 9/5192 20130101; A61K 47/14 20130101; A61K 9/5123 20130101;
A61K 47/18 20130101; A61K 47/20 20130101; A61K 9/5138 20130101;
C12N 2310/14 20130101; A61K 31/7105 20130101; A61K 31/713 20130101;
C12N 15/87 20130101; A61K 47/6925 20170801; A61K 47/22 20130101;
A61K 47/6933 20170801 |
International
Class: |
A61K 9/51 20060101
A61K009/51; A61K 47/69 20060101 A61K047/69; C12N 15/11 20060101
C12N015/11; A61K 31/7105 20060101 A61K031/7105; C12N 15/87 20060101
C12N015/87; A61K 31/713 20060101 A61K031/713; A61K 47/14 20060101
A61K047/14; A61K 47/18 20060101 A61K047/18; A61K 47/20 20060101
A61K047/20; A61K 47/22 20060101 A61K047/22; A61K 47/42 20060101
A61K047/42 |
Goverment Interests
GOVERNMENT RIGHTS
[0002] This invention was made with Government support under Grant
Number HDTRA1-09-1-0001, awarded by the Dept of Defense/Defense
Threat Reduction Agency and under Grant Number AI069350, awarded by
the National Institutes of Health. The Government has certain
rights in the invention.
Claims
1. A method of treating a subject having a disease or disorder or
at risk of developing a disease or disorder, wherein the disease or
disorder is characterized by over expression of a gene, the method
comprising administering to a subject in need thereof, a polymer
nanocapsule comprising a polymer shell and a nucleic acid selected
from the group consisting of: an siRNA, an shRNA expression DNA
cassette, and a dsRNA, wherein the polymer shell comprises a. one
or more positively charged monomers selected from the group
consisting of:
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)acrylamide,
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)methacrylamide,
N-(3-((4-aminobutyl)amino)propyl)acrylamide,
N-(3-((4-aminobutyl)amino)propyl)methacrylamide,
N-(2-((2-aminoethyl)(methyl)amino)ethyl)acrylamide,
N-(2-((2-aminoethyl)(methyl)amino)ethyl) methacrylamide,
N-(piperazin-1-ylmethyl)acrylamide,
N-(piperazin-1-ylmethyl)methacrylamide,
N-(2-(bis(2-aminoethyl)amino)ethyl)acrylamide,
N-(2-(bis(2-aminoethyl)amino)ethyl)methacryl amide,
(3-acrylamidopropyl) trimethylammonium hydrochloride, and
2-aminoethyl methacrylate; b. one or more crosslinkers selected
from the group consisting of: 1,3-glycerol dimethacrylate, glycerol
1,3-diglycerolate diacrylate, N,N'-bis(acryloyl)cystamine,
bis[2-(methacryloyloxy)ethyl]phosphate,
N,N'-Methylenebisacrylamide, bisacryloylated polypeptide, and c.
one or more neutral monomers selected from the group consisting of:
N-(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)acrylamide,
acrylamide, N-(hydroxymethyl)acrylamide, 2-hydroxyethyl acrylate,
2-hydroxyethyl methacrylate, and wherein the polymer shell
encapsulates the nucleic acid.
2. The method of claim 1 wherein the siRNA, shRNA expression DNA
cassette, or dsRNA knocks down or decreases expression of the
gene.
3. The method of claim 1, wherein the one or more crosslinkers
comprise: a. a degradable crosslinker selected from the group
consisting of: 1,3-glycerol dimethacrylate, glycerol
1,3-diglycerolate diacrylate, N,N'-bis(acryloyl)cystamine,
bis[2-(methacryloyloxy)ethyl]phosphate and bisacryloylated
polypeptide; and b. a non-degradable crosslinker, wherein the
non-degradable cross linker is N,N'-methylenebisacrylamide, wherein
the ratio of degradable crosslinker to non-degradable crosslinker
is selected from the ratios comprising 1:0, 3:2, 2:3, or 1:4.
4. The method of claim 1, wherein all of the crosslinkers are
selected from the group consisting of: 1,3-glycerol dimethacrylate,
glycerol 1,3-diglycerolate diacrylate, N,N'-bis(acryloyl)cystamine,
bis[2-(methacryloyloxy)ethyl]phosphate and bisacryloylated
polypeptide.
5. The method of claim 1, wherein the one or more positively
charged monomers is selected from the group comprising
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)methacrylamide,
N-(3-((4-aminobutyl)amino)propyl)acrylamide,
N-(3-((4-aminobutyl)amino)propyl)methacrylamide,
N-(2-((2-aminoethyl)(methyl)amino)ethyl)acrylamide,
N-(2-((2-aminoethyl)(methyl)amino)ethyl) methacrylamide,
N-(piperazin-1-ylmethyl)acrylamide,
N-(piperazin-1-ylmethyl)methacrylamide,
N-(2-(bis(2-aminoethyl)amino)ethyl)acrylamide, and
N-(2-(bis(2-aminoethyl)amino)ethyl)methacrylamide.
6. The method of claim 1, wherein the polymer shell comprises
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)acrylamide;
1,3-glycerol dimethacrylate; and
N-(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)acrylamide.
7. The method of claim 1, wherein the polymer shell comprises
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)acrylamide;
glycerol 1,3-diglycerolate diacrylate; and acrylamide.
8. The method of claim 1, wherein the polymer shell comprises
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)acrylamide;
1,3-glycerol dimethacrylate; and
N-(1,3-dihydroxy-2-(hydroxymethyl)propan-2-yl)acrylamide.
9. The method of claim 1, wherein the polymer shell comprises
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)acrylamide;
glycerol 1,3-diglycerolate diacrylate; and acrylamide.
10. The method of claim 1, wherein the polymer shell has a diameter
of approximately 20 nm to 250 nm.
11. The method of claim 1, wherein the polymer nanocapsule is
conjugated to a targeting agent.
12. The method of claim 1, wherein the disease or disorder is a
cellular proliferative and/or differentiative disorder, an immune
or immunodeficiency disorder, a viral infection, a neurological or
neurodegenerative disorder.
13. The method of claim 12, wherein the disease or disorder is
cancer, pachyonychia congenital, age-related macular degeneration,
choroidal neovascularization, metastatic melanoma, metastatic
melanoma without CNS metastases, chronic myeloid leukemia, solid
tumors, advanced solid tumors, optic atrophy, non-arteric anterior
ischemic optic neuropathy, pancreatic cancer, pancreatic ductal
adenocarcinoma, diavetic macular edema, hypercholesterolemia,
colorectal cancer with hepatic metastases, pancreatic cancer with
hepatic metastases, gastric cancer with hepatic metastases, breast
cancer with hepatic metastases ovarian cancer with hepatic
metastases, preeclampsia, neuroblastoma, ocular hypertension, open
angle glaucoma, glaucoma, ocular pain, dry eye syndrome, kidney
injury, acute renal failure, delayed graft function, complications
of kidney transplant, TBX3 overexpression, and diabetic
retinopathy.
14. The method of claim 1, wherein the disease or disorder is
cancer.
15. The method of claim 1, wherein the disease or disorder is a
viral infection.
16. The method of claim 15 wherein the viral infection is a
retroviral viral infection.
17. The method of claim 1, wherein the retroviral infection is HIV
or AIDS infection.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 15/721,501 filed Sep. 29, 2017, now U.S. Pat. No. 10,568,844,
which is a Continuation of U.S. application Ser. No. 14/385,430
filed Sep. 15, 2014, now U.S. Pat. No. 9,782,357 which is a 371
U.S. application of PCT International Application No.
PCT/US2013/032615 filed Mar. 15, 2013 which claims, under 35 U.S.C.
.sctn. 119(e), the benefit of U.S. Patent Application 61/612,178
filed Mar. 16, 2012, the disclosures of which are incorporated
herein by reference in their entireties for all purposes.
FIELD OF THE INVENTION
[0003] This invention relates to the effective delivery of RNA and
DNA molecules into cells by use of novel nanocapsules.
Specifically, this invention relates to a novel DNA cassette and
siRNA nanocapsule technology wherein DNA molecules or siRNA are
encapsulated within a small polymer nanocapsule to facilitate
delivery to cells.
BACKGROUND
[0004] RNA interference is is a powerful tool to target and silence
specific gene expression. The term "RNA interference" (RNAi) was
coined after the discovery that injection of double stranded RNA
(dsRNA) into C. elegans leads to specific silencing of genes that
are highly homologous in sequence to the delivered dsRNA (Fire et
al., 1998). RNAi is closely linked to the post-transcriptional
gene-silencing (PTGS) mechanism of co-suppression in plants and
quelling in fungi (Catalanotto et al., 2000; Cogoni and Macino,
1999; Dalmay et al., 2000, Ketting and Plasterk, 2000; Mourrain et
al., 2000; Smardon et al., 2000).
[0005] RNAi was discovered when researchers were attempting to use
antisense RNA to inactivate a C. elegans gene. The researchers
found that injected sense-strand RNA was equally as effective as
antisense RNA at inhibiting gene function (Guo et al. (1995) Cell
81: 611-620). Further investigation revealed that the active agent
was modest amounts of double-stranded RNA (dsRNA) that contaminated
in vitro RNA preparations. Researchers further determined that exon
sequences are required and that introns and promoter sequences,
while ineffective, did not appear to compromise RNAi.
[0006] RNAi can act systemically. This systemic potency was
demonstrated by Timmons and Fire (1998 Nature 395: 854). Timmons
and Fire performed a simple experiment that produced an astonishing
result. They fed to nematodes bacteria that had been engineered to
express double-stranded RNA corresponding to the C. elegans unc-22
gene. The transgenic nematodes developed a phenotype similar to
that of unc-22 mutants. The results of this and variety of other
experiments, in C. elegans and other organisms, indicate that RNAi
acts to destabilize cellular RNA after RNA processing.
[0007] Double-stranded RNAs (dsRNAs) can provoke gene silencing in
numerous in vivo contexts including Drosophila, C. elegans,
planaria, hydra, trypanosomes, fungi and plants. Furthermore, short
interfering RNA (siRNA), possessing the unique capability to
specifically knock down an undesired expression of gene, holds
great promises for therapeutics of diversified human diseases. In
fact, in it was reported in 2009 that there were 12 ongoing
clinical trials using siRNA to treat diseases. Cheng et al., siRNA
Delivery and Targeting, Molecular Pharmaceutics, 2009,
6(3):649-650. Of the 12 ongoing trials, 8 trials used naked siRNA
for local treatment of ocular and respiratory diseases. Castanotto,
et al., The promises and pitfalls of RNA-interference-based
therapeutics, Nature, 2009, 457(7228):426-433. In February 2013,
there were 28 siRNA clinical trials reported by the National
Institute of Health. See National Institute of Health Clinical
Trials website. Many of the 28 trials appear to use naked
siRNA.
[0008] The clinical application of siRNA is constrained by
inefficient delivery systems. Specifically, there is a lack of
delivery vehicles that are safe, stable, and efficient. To date,
various delivery systems have been proposed. Such systems include
cationic liposomes, cell-penetrating peptides (CPPs) and cationic
polymers. Tseng et al., Lipid-based systemic delivery of siRNA,
Advanced Drug Delivery Reviews, 2009, 61(9):721-731 and Lewis et
al., Systemic siRNA delivery via hydrodynamic intravascular
injection, Advanced Drug Delivery Reviews, 2007,
59(2-3):115-123.
[0009] Cationic liposomes and cationic lipids, such as
Lipofectamine.RTM. and lipid-like materials, are used widely for in
vitro studies with high effectiveness; however, the toxicity and
low efficiency still restrain their in vivo applications.
[0010] For the CPPs-based approaches, RNAi molecules are assembled
with CPPs or CPP bioconjugates into complexed particles with
significantly improved delivery efficiency. Crombez et al., A New
Potent Secondary Amphipathic Cell-penetrating Peptide for siRNA
Delivery Into Mammalian Cells, Molecular Therapy, 2009,
17(1):95-103 and Davis et al., Evidence of RNAi in humans from
systemically administered siRNA via targeted nanoparticles, Nature,
2010, 464(7291):1067-U140. Nevertheless, the formation of such
assembled structure was driven by weak noncovalent interactions and
these particles were generally unstable, particularly against serum
nucleases which leads to degradation and poor targeting of the
RNAi.
[0011] For the cationic-polymer-based approaches, siRNA are
assembled with cationic polymers is mainly through the
electrostatic interactions. The unique proton sponge effect of the
cationic polymers provides the complexes with improved
intracellular delivery efficiency. However, similar to the
CPPs-based approach, such assembled systems are unstable and
readily dissociate and release their siRNA payload before they
reach the cytoplasm of the target cells.
[0012] Accordingly, in spite of such intensive efforts, the design
and synthesis of an effective delivery vehicle for siRNA remains
challenging. Thus, there is an ongoing need to develop novel
siRNA-delivery methods that are highly robust and effective.
Success of this work will provide a general delivery platform with
low toxicity and long intracellular half-life for practical
therapeutic applications.
BRIEF SUMMARY OF THE INVENTION
[0013] In certain embodiments, this invention comprises a polymer
nanocapsule comprising a polymer shell and a RNAi molecule. In
certain embodiments, the polymer shell comprises one or more
positively charged monomers selected from FIG. 23, one or more
crosslinkers selected from FIG. 24, and one or more neutral
monomers selected from FIG. 25. In certain embodiments, the RNAi
molecule is siRNA or an shRNA DNA cassette.
[0014] In certain embodiments, one or more crosslinkers comprise a
ratio of degradable crosslinker to non-degradable crosslinker. In
certain embodiments, the ratio of degradable crosslinker to
non-degradable crosslinker is selected from the ratios comprising
1:0, 3:2, 2:3, or 1:4. In certain embodiments, all of the
crosslinkers are degradable crosslinkers. In certain embodiments,
all the degradable crosslinkers are glycerol 1,3-diglycerolate
diacrylate.
[0015] In certain embodiments, the one or more positively charged
monomers is acryl-spermine. In certain embodiments, the one or more
positively charged monomers is selected from the group comprising
N-(3-Aminopropyl) methacrylamide hydrochloride, Dimethylamino ethyl
methacrylate, (3-Acrylamidopropyl) trimethylammonium hydrochloride,
and (3-Acrylamidopropyl) trimethylammonium hydrochloride. In
certain embodiments, the one or more positively charged monomers is
selected from the group comprising
N-(3-((4-((3-aminopropyl)amino)butyl)amino)propyl)methacrylamide,
N-(3-((4-aminobutyl)amino)propyl)acrylamide,
N-(3-((4-aminobutyl)amino)propyl)methacrylamide,
N-(2-((2-aminoethyl)(methyl)amino)ethyl)acrylamide,
N-(2-((2-aminoethyl)(methyl)amino)ethyl) methacrylamide,
N-(piperazin-1-ylmethyl)acrylamide,
N-(piperazin-1-ylmethyl)methacrylamide,
N-(2-(bis(2-aminoethyl)amino)ethyl)acrylamide, and
N-(2-(bis(2-aminoethyl)amino)ethyl)methacrylamide.
[0016] In certain embodiments, the polymer nanocapsules comprises
acryl-spermine, tris-acrylamide, and crosslinker selected from FIG.
24.
[0017] In certain embodiments, the one or more positively charged
monomers has 3 protonable amines. In certain embodiments, the one
or more positively charged monomers has 2 protonable amines. In
certain embodiments, the one or more positively charged monomers
has 1 protonable amines.
[0018] In certain embodiments, the polymer nanocapsules are
approximately 20 nm to 250 nm in diameter.
[0019] In certain embodiments, the polymer nanocapsules is
conjugated to a targeting agent. In certain embodiments, the
targeting agent is selected from the group comprising cyclodextrin,
adamantine, CD4, CD8, CD45, aHLA, and transferrin. In certain
embodiments, the targeting agent delivers the polymer nanocapsules
to a specific cell type, wherein the cell type is selected from the
group comprising immune cells, blood cells, cardiac cells, lung
cells, optic cells, liver cells, kidney cells, brain cells, cells
of the central nervous system, cells of the peripheral nervous
system, cancer cells, cells infected with viruses, stem cells, skin
cells, intestinal cells, and/or auditory cells. In certain
embodiments, the cancer cells are cells selected from the group
comprising lymphoma cells, solid tumor cells, leukemia cells,
bladder cancer cells, breast cancer cells, colon cancer cells,
rectal cancer cells, endometrial cancer cells, kidney cancer cells,
lung cancer cells, melanoma cells, pancreatic cancer cells,
prostate cancer cells, and thyroid cancer cells.
[0020] In certain embodiments, the polymer nanocapsule further
comprises a pharmaceutically acceptable carrier.
[0021] In certain embodiments, this invention comprises a
pharmaceutical composition comprising one or more polymer
nanocapsule described above.
[0022] In certain embodiments, this invention comprises a method of
treating a disease characterized by over expression of a gene with
a pharmaceutical composition of a nanocapsules described herein,
wherein the siRNA or shRNA knocks down or decreases expression of
an over expressed gene, thereby treating the disease.
[0023] In certain embodiments, this invention comprises a method of
making a siRNA polymer nanocapsules. In certain embodiments, the
siRNA is dissolved in RNase-free water. In certain embodiments, one
or more positively charged monomers selected from FIG. 25 and one
or more crosslinkers selected from FIG. 24 in deoxygenated and is
dissolved in deionized water to create a monomer mixture. In
certain embodiments, the dissolved siRNA as described above is
combined with the monomer mixture. In certain embodiments, ammonium
persulfate and N,N,N',N'-tetramethylethylenediamine is added to the
mixture. In certain embodiments, the mixture is incubated in
serum-free medium.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1A-FIG. 1D depicts an illustration of the synthesis and
delivery of DNA cassette nanocapsules: 1) self-assembly of
hydrophilic monomer A, positively charged monomer B, degradable
crosslinker C and non-degradable crosslinker D around DNA cassette;
2): formation of DNA cassette nanocapsules through in situ
polymerization; 3): delivery; IV): release of DNA cassette and
expression of siRNA.
[0025] FIG. 2 depicts a schematic illustration of the synthesis and
delivery of single siRNA nanocapsules. Step I of the schematic
depicts a positively charged, polymerizable monomer that interacts
with the negatively charged siRNA. Step II of the schematic depicts
the polymerization of pH-degradable crosslinkers and hydrophilic
monomers to create a polymer network that that wraps each siRNA
molecule. Step III of the schematic depicts crosslinked shell
protecting the cored siRNA from hydrolysis. Step IV of the
schematic depicts the stability of the polymer nanocapsules in
serum (pH.about.7.4) and their ability to escape from the endosomes
upon the degradation of the shell that releases the siRNA to the
cytoplasm.
[0026] More specifically, Step I depicts: starting with a
positively charged, polymerizable monomer, acryl-spermine (1),
electrostatic interactions enrich 1 around the surface of the
negatively charged siRNA. Step II depicts: subsequent
room-temperature polymerization in an aqueous solution, which
contains the pH-degradable crosslinkers (2) and hydrophilic
monomers (3), wraps each siRNA molecule with a thin shell of
polymer network. Step III depicts: a crosslinked shell well
protects the cored siRNA from hydrolysis; while tuning the ratio of
1 and 3 allows precise control of the surface charge ensuring the
effective cellular transduction of the polymer nanocapsules. Step
IV depicts: (2) is stable in neutral pH but is rapidly degraded in
acidic environment, such as late endosomes with pH.about.5.4. It is
believed that this unique responsive design will provide the
polymer nanocapsules with outstanding stability in serum
(pH.about.7.4), while enabling their escape from endosomes upon the
degrading of the shell that releases the siRNA to the cytoplasma.
Furthermore, this synthetic approach allows for the immobilization
of targeting components (e.g., antibody) to the polymer
nanocapsules surface, allowing targeted delivery of siRNA.
[0027] FIG. 3A-FIG. 3C depicts images and representations of DNA
cassettes and nanocapsules. FIG. 2A depicts a gel electrophoresis
image of DNA cassette. Lane a is CCR5 shRNA and lane b is EGFP
shRNA. FIG. 2B depicts a TEM image of DNA cassettes (Scale bar=100
nm). FIG. 3C depicts a TEM image of DNA cassette nanocapsules
(molar ratio of DNA to 3 reactants shown in FIG. 1 and Example 1
and Example 2 s A,B,C=1:750:750:30).
[0028] FIG. 4A-FIG. 4D depicts the polymer nanocapsules and their
ability to prevent degradation. FIG. 4A depicts a TEM image of
siRNA nanocapsules. FIG. 4B depicts florescence and optical images
of HEK-293 T cells transducted with FITC-labeled siRNA
nanocapsules.
[0029] FIG. 4C depicts florescence images of HEK-293 T cells
transducted with si1005 siRNA nanocapsules targeted to CCR5 (right)
showing knockdown of CCR5-mCherry fusion protein (control siRNA
nanocapsules as control (left)). FIG. 4D depicts CCR5-mCherry
knock-down by siRNA nanocapsule (1,3,5,7) and siRNA
Lipofectamine.RTM. (Invitrogen.RTM.) (2,4,6,8) in the absence or
presence of active human serum.
[0030] FIG. 5A-FIG. 5D depicts HEK-293T cells transduced with
Alexa592-labelled DNA cassette nanocapsules. FIG. 5A depicts an
optical image of the cells. FIG. 5B depicts a fluorescent image of
the cells. FIG. 5C depicts a flow cytometry graph of the cells.
FIG. 5D depicts the knockdown of CCR5-luciferase by CCR5-shRNA DNA
cassette nanocapsules (100 ng DNA per 2.5.times.104 cells in 100
uL). In these experiments, the cells were dosed with
Alexa592-labelled DNA cassette nanocapsules at 100 nM for 4 hours.
Then nanocapsules were removed and cells were washed 3 times with
PBS. After trypsinization, cells were pictured with Leica Zeiss
Axio Observer and also analyzed by a flow cytometer.
[0031] FIG. 6A-FIG. 6B depicts the sensitivity of DNA cassette to
Dnase I and siRNA to nuclease and human serum. FIG. 6A depicts the
sensitivity of native DNA cassette and DNA nanocapsules to Dnase I.
DNA cassette complexed with Lipofectamine.RTM. and DNA nanocapsules
were incubated for 1 hour without Dnase I and with Dnase I,
respectively. Samples were run on 2% agarose gel and imaged with
ImageQuant LAS4000. FIG. 6B depicts the sensitivity of siRNA to
Nulcease and serum. siRNA complexed with lipofectamine and siRNA
nanocapsules were incubated for 1 hour with nuclease (up) and human
serum (down), respectively. Then siRNAs were extracted from
lipofectamine and nanocapsules with chloroform/0.1% SDS-0.5 M NaCl.
Samples were run on 4% agarose gel and imaged with ImageQuant
LAS4000.
[0032] FIG. 7 depicts the viability of HEK-293T cells transduced
with CCR5 DNA cassette nanocapsules. HEK-293T cells were treated
with DNA cassette nanocapsules at 0, 0.1, 0.2 and 0.4 pmol for 4 h
at 37.degree. C. in serum-free medium. Then mediums were changed to
DMEM with 10% Bovine Fetal Serum. After 24 h, cell viability was
determined through CytoToxGlow kit using a 96-well plate
reader.
[0033] FIG. 8A-FIG. 8B depicts knockdown of CCR5-Luciferase in
HEK-293T cells. FIG. 8A depicts knockdown of CCR5-Luciferase in
HEK-293T cells transduced with CCR5 DNA cassette nanocapsules. FIG.
8B depicts knockdown of CCR5-Luciferase in HEK-293T cells
transduced with CCR5 siRNA Lipofectamine.RTM. complex. HEK-293T
cells were treated with DNA cassette nanocapsules at 0, 0.1, 0.2
and 0.4 pmol and siRNA Lipofectamine.RTM. complex at 0, 50, 100 and
200 pmol for 4 h at 37.degree. C. in serum-free medium. Then
mediums were changed to DMEM with 10% Bovine Fetal Serum. After 48
h, the luciferase activity was determined using a 96-wells plate
reader.
[0034] FIG. 9A-FIG. 9B depicts the degradation rates of CCR5-shRNA
DNA cassette nanocapsules. FIG. 9A depicts the degradation rates of
CCR5-shRNA DNA cassette nanocapsule prepared with cocktails of
degradable and non-degradable crosslinkers. FIG. 9B depicts the
stability of CCR5-shRNA DNA cassette nanocapsule monitored by DLS
in water. The initial shell thickness of the polymer nanocapsules
was estimated from R.sub.0-R*, where R.sub.0 is the initial
diameter of DNA nanocapsules and R* is the diameter of a DNA
molecule (the final diameter after degradation). The degradation
degree was calculated as [R.sub.0-R.sub.t]/[R.sub.0-R*].times.100%,
where R.sub.t is the diameter of nanocapsules.
[0035] FIG. 10 depicts the down-regulation of CCR5 in HEK293 cells
by sh1005 DNA cassette nanocapsules with different ratios (5:0;
3:2; 2:3 and 1:4) of degradable crosslinker (Glycerol
1,3-diglycerolate diacrylate, GDGDA) to non-degradable crosslinker
(N,N'-methylenesbisacrylamide, BIS). On day 0 of culture cells were
transduced with DNA cassette nanocapsules for 4 hours. On day 3, 5
and 9 of culture cells were labeled with anti-CCR5 and analyzed by
flow cytometry.
[0036] FIG. 11 depicts the ability of nanocapsules prepared with
positively charged monomers #1-#14 from FIG. 23 to knockdown
luciferase gene expression in luciferase-expressing CWR cells. As
can be seen from the figure, the best knockdown of luciferase
expression was achieved with nanocapsules prepared with positively
charged monomers #1, #2, #7 and #8.
[0037] FIG. 12 depicts the ability of nanocapsules prepared with
crosslinkers #1-#5 from FIG. 24 to knockdown luciferase gene
expression in luciferase-expressing CWR cells. As can be seen from
the figure, the best knockdown of luciferase expression was
achieved with nanocapsules prepared with crosslinker #1 (i.e.,
2-hydroxyethyl methacrylate).
[0038] FIG. 13 depicts the ability of neutral monomers to affect
the size of the siRNA nanocapsules. As can be seen in the figure,
N-(1,3-dihydroxy-2-(hydroxymethyl) propan-2-yl) acrylamide produced
the smallest nanocapsules (less than 25 nm) and acrylamide produced
the largest nanocapsules (greater than 200 nm).
[0039] FIG. 14A-FIG. 14B depicts the knockdown of luciferase gene
expression by using luciferase siRNA nanocapsules. FIG. 14A depicts
the knockdown of luciferase gene expression in CWR cells using
luciferase siRNA nanocapsules and control siRNA nanocapsules. FIG.
14B depicts the cell viability after treatment of siRNA
nanocapsules. CWR cells were treated with siRNA nanocapsules at 0,
20, 50, 100, 200 and 300 nM for 4 h at 37.degree. C. in serum-free
medium. Then mediums were changed to DMEM with 10% Bovine Fetal
Serum. After 48 h, the luciferase activity was determined using a
96-wells plate reader.
[0040] FIG. 15 depicts the pH titration curve of nanocapsules and
confirms that one of the polymer nanocapsules has about 60% of
buffer capacity of PEI25K between pH 7.3 and 5.5. The buffering
capacity of the nanocapsule was measured by acid-base titration.
The nanocapsule solutions (8.3 mM in terms of total molar
concentration of ioniziable amine groups), which were initially
adjusted to pH 10, were titrated with 0.01 M HCl. The pH profiles
were recorded at room temperature.
[0041] FIG. 16 depicts the TEM picture of BSA control nanoparticle.
It is synthesized using the same formulation as that of siRNA
nanocapsules and does not show the dark cores in the image. BSA was
dissolved in 20 uL Rnase-free water at 20 uM. Then a specific
amount of acryl-spermine, tris-acrylamide and glycerol
dimethacrylate (molar ratio=5:5:1) dissolved in 0.5 mL deoxygenated
and deionized water was mixed with BSA in the microcentrifuge tube
(final molar ratio of BSA to acryl-spermine=1:220). Radical
polymerization from the surface of BSA was initiated by adding 2 uL
of 1% ammonium persulfate solution and 1 .mu.L of 5%
N,N,N',N'-tetramethylethylenediamine (final molar ratio of BSA to
acryl-spermine=1:240). The reaction was allowed to proceed for 60
min in a nitrogen atmosphere.
[0042] FIG. 17 depicts the surface charge of one of the siRNA
nanocapsules determined by dynamic light scattering.
[0043] FIG. 18 depicts the size and size distribution of one of the
siRNA nanocapsules determined by dynamic light scattering. The
average diameter of 24.6 nm obtained by light scattering is
consistent with the average diameter of 20 nm obtained by TEM.
[0044] FIG. 19 depicts the knockdown of luciferase by one of the
siRNA nanocapsules in the presence and absence of serum.
[0045] FIG. 20 depicts the degradation profile of siRNA
nanocapsules under pH 5.4 or pH 7.4.
[0046] FIG. 21 depicts the absorption change of siRNA after
self-assembling with monomers. The absorption of siRNA (top)
decreased after formation of siRNA-monomers complex (bottom).
[0047] FIG. 22A-FIG. 22B depicts the targeting delivery of siRNA to
293 cells expressing CD4 receptors. FIG. 22A shows the flow
cytometry graph of 293 cells expressing CD4 receptors after
incubation with FITC-labeled siRNA nanocapsules conjugated with
anti-CD4 antibody for 4 hours. FIG. 22B shows the flow cytometry
graph of regular 293 cells without CD4 receptors after incubation
with FITC-labeled siRNA nanocapsules conjugated with anti-CD4
antibody for 4 hours. 100 uL of anti-CD4 antibody dissolved in
pH=8.7 HEPES buffer at 1 mg/mL reacted with 10 uL of
2-Iminothiolane (Trout's reagent) at lmg/mL for 30 minutes. The
modified anti-CD4 antibody will be then incubated with 100 uL of
FITC-labeled siRNA nanocapsules at 10 uM overnight.
[0048] FIG. 23A-FIG. 23B depicts Non-Limiting Examples of
Positively Charged Monomers For RNAi Molecule Polymer Nanocapsules
(* monomers are not commercially available and were specifically
synthesized for the manufacture of these nanocapsules).
[0049] FIG. 24 depicts Non-Limiting Examples of Crosslinkers for
RNAi molecule Polymer Nanocapsules.
[0050] FIG. 25 depicts Non-Limiting Examples of Neutral Monomers
for RNAi Molecule Polymer Nanocapsules.
DEFINITIONS
[0051] For convenience, the meaning of certain terms and phrases
used in the specification, examples, and appended claims, are
provided below.
[0052] As used herein, the terms "target" refers to a section of a
DNA or RNA strand of a double-stranded DNA or an RNA that is
complementary to a section of a DNA or RNA strand, including all
transcribed regions, that serves as a matrix for transcription. A
target gene, usually the sense strand, is a gene whose expression
is to be selectively inhibited or silenced through RNA
interference.
[0053] As used herein, the term "polymer nanocapsules" refers to a
composition comprising a "polymer shell" and a "RNAi molecule."
[0054] As used herein, the term "polymer shell" refers to the
polymer portion of the RNAi polymer nanocapsules comprising one or
more positively charged polymer monomers, one or more crosslinkers,
and optionally one or more neutral polymer monomers. Examples of
positively charged monomers, crosslinkers, and neutral monomers are
provided in FIG. 23, FIG. 24, and FIG. 25.
[0055] As used herein, the term "RNAi molecule" refers to a RNA or
DNA molecule that plays a role in RNA interference. Specifically,
an RNAi molecule refers to a shRNA, siRNA, or dsRNA as disclosed
herein. A small hairpin RNA (shRNA) is a RNA sequence that forms a
tight hairpin turn that can be used to silence gene expression by
RNA interference. shRNAs can be delivered to target cells using DNA
plasmids, viral vectors, or bacterial vectors. As used herein,
shRNA can be delivered to cells using DNA cassettes.
Double-stranded RNAs (dsRNA) comprise a broad group of viruses.
Small interfering RNA (siRNA) is a class of double stranded RNA
molecules. siRNAs are short, generally around 20-25 base pairs in
length. siRNA can be used to silence gene expression by RNA
interference. Furthermore, siRNA can also act in RNAi-related
pathways such as viral and retroviral infection.
[0056] As used herein, the terms "degradable polymer" and
"nondegradable polymer" refer to the ability of the polymers
described herein to degrade into smaller fragments. In certain
embodiments of this invention, degradable polymers can break down
at physiological pH. In certain embodiments, degradable polymers
can break down at approximately pH 7.4. In certain embodiments, a
mixture of degradable and nondegradable polymers can yield a
degradable polymer mixture. In certain embodiments, a mixture of
degradable and nondegradable polymers can break down at
physiological pH. In certain embodiments, a mixture of degradable
and nondegradable polymers can break down at approximately pH
7.4.
[0057] As used herein, the terms "mutant gene" and "target mutant
gene" refer to a gene comprising at least one point mutation
relative to the corresponding normal, non-mutated cellular gene
(referred to herein as the "corresponding wild-type gene"). The
terms mutant gene and target mutant gene specifically encompass any
variant of a normal cellular gene or gene fragment whose expression
is associated with a disease or disorder (e.g., an oncogene).
[0058] As used herein, the term "conjugate" or "conjugate agent" or
"surface-conjugated targeting agent" or "polymer nanocapsule
conjugates" refers to any moiety, such as a protein or effective
portion thereof, that is conjugated to the polymer nanocapsules and
provides specific targeting of the polymer nanocapsules to the
surface of a specific cell type thereby providing directed delivery
of the siRNA or shRNA to a specific cell type. For example, the
conjugate agent can binding to a cell-specific cell surface
receptor, thereby bringing the polymer nanocapsules into immediate
proximity to the target cell. In certain embodiments, the
conjugates used to achieve specific targeting of the polymer
nanocapsules include CD4, CD8, CD45, CD133, aHLA, and transferrin.
In other embodiments, the conjugates can be cell-specific
antibodies or fragments thereof. Additional examples of conjugates
used to target specific cell types are described below in the
Detailed Description.
[0059] The term "complementary RNA strand" (also referred to herein
as the "antisense strand") refers to the strand of a dsRNA which is
complementary to an mRNA transcript that is formed during
expression of the target gene, or its processing products. As used
herein, the term "complementary nucleotide sequence" refers to the
region on the complementary RNA strand that is complementary to a
region of an mRNA transcript of the target mutant gene (i.e., "the
corresponding nucleotide sequence" of the target gene). "dsRNA"
refers to a ribonucleic acid molecule having a duplex structure
comprising two complementary and anti-parallel nucleic acid
strands. Not all nucleotides of a dsRNA must exhibit Watson-Crick
base pairs. The maximum number of base pairs is the number of
nucleotides in the shortest strand of the dsRNA. The RNA strands
may have the same or a different number of nucleotides. The
complementary nucleotide region of a complementary RNA strand is
less than 25, preferably 19 to 24, more preferably 20 to 24, even
more preferably 21 to 23, and most preferably 22 or 23 nucleotides
in length. The complementary RNA strand is less than 30, preferably
fewer than 25, more preferably 21 to 24, and most preferably 23
nucleotides in length. dsRNAs comprising a complementary or
antisense strand of this length (known as "short interfering RNA"
or "siRNA") are particularly efficient in inhibiting the expression
of the target mutant gene. "Introducing into" means uptake or
absorption in the cell, as is understood by those skilled in the
art. Absorption or uptake of dsRNA can occur through cellular
processes, or by auxiliary agents or devices. For example, for in
vivo delivery, dsRNA can be injected into a tissue site or
administered systemically. In vitro delivery includes methods known
in the art such as electroporation and lipofection.
[0060] As used herein, "selective inhibition of expression" means
that a dsRNA has a greater inhibitory effect on the expression of a
target mutant gene than on the corresponding wild-type gene.
Preferably, the expression level of the target mutant gene is less
than 98%, less than 95%, less than 90%, less than 80%, less than
70%, less than 60%, less than 50%, less than 40%, less than 30%,
less than 20%, or less than 10% of the expression level of the
corresponding wild-type gene.
[0061] As used herein and as known in the art, the term "identity"
is the relationship between two or more polynucleotide sequences,
as determined by comparing the sequences. Identity also means the
degree of sequence relatedness between polynucleotide sequences, as
determined by the match between strings of such sequences. Identity
can be readily calculated (see, e.g., Computation Molecular
Biology, Lesk, A. M., eds., Oxford University Press, New York
(1998), and Biocomputing: Informatics and Genome Projects, Smith,
D. W., ed., Academic Press, New York (1993), both of which are
incorporated by reference herein). While there exist a number of
methods to measure identity between two polynucleotide sequences,
the term is well known to skilled artisans (see, e.g., Sequence
Analysis in Molecular Biology, von Heinje, G., Academic Press
(1987); and Sequence Analysis Primer, Gribskov, M. and Devereux,
J., eds., M. Stockton Press, New York (1991)). Methods commonly
employed to determine identity between sequences include, for
example, those disclosed in Carillo, H., and Lipman, D., SIAM J.
Applied Math. (1988) 48:1073. "Substantially identical," as used
herein, means there is a very high degree of homology (preferably
100% sequence identity) between the sense strand of the dsRNA and
the corresponding part of the target gene. However, dsRNA having
greater than 90% or 95% sequence identity may be used in the
present invention, and thus sequence variations that might be
expected due to genetic mutation, strain polymorphism, or
evolutionary divergence can be tolerated. Although 100% identity is
preferred, the dsRNA may contain single or multiple base-pair
random mismatches between the RNA and the target gene.
[0062] As used herein, the term "treatment" refers to the
application or administration of a therapeutic agent to a patient,
or application or administration of a therapeutic agent to an
isolated tissue or cell line from a patient, who has a disorder,
e.g., a disease or condition, a symptom of disease, or a
predisposition toward a disease, with the purpose to cure, heal,
alleviate, relieve, alter, remedy, ameliorate, improve, or affect
the disease, the symptoms of disease, or the predisposition toward
disease.
[0063] As used herein, a "pharmaceutical composition" comprises a
pharmacologically effective amount of a dsRNA and a
pharmaceutically acceptable carrier. As used herein,
"pharmacologically effective amount," "therapeutically effective
amount" or simply "effective amount" refers to that amount of an
RNA effective to produce the intended pharmacological, therapeutic
or preventive result. For example, if a given clinical treatment is
considered effective when there is at least a 25% reduction in a
measurable parameter associated with a disease or disorder, a
therapeutically effective amount of a drug for the treatment of
that disease or disorder is the amount necessary to effect at least
a 25% reduction in that parameter.
[0064] The term "pharmaceutically acceptable carrier" refers to a
carrier for administration of a therapeutic agent. Such carriers
include, but are not limited to, saline, buffered saline, dextrose,
water, glycerol, ethanol, and combinations thereof. The term
specifically excludes cell culture medium. For drugs administered
orally, pharmaceutically acceptable carriers include, but are not
limited to pharmaceutically acceptable excipients such as inert
diluents, disintegrating agents, binding agents, lubricating
agents, sweetening agents, flavoring agents, coloring agents and
preservatives. Suitable inert diluents include sodium and calcium
carbonate, sodium and calcium phosphate, and lactose, while corn
starch and alginic acid are suitable disintegrating agents. Binding
agents may include starch and gelatin, while the lubricating agent,
if present, will generally be magnesium stearate, stearic acid or
talc. If desired, the tablets may be coated with a material such as
glyceryl monostearate or glyceryl distearate, to delay absorption
in the gastrointestinal tract.
DETAILED DESCRIPTION OF THE INVENTION
Introduction
[0065] RNA interference is a powerful tool to silence specific gene
expression and a variety of RNAi-based therapies are being
considered for human diseases. However, the major impediment to the
effective use of RNAi for applications in humans is its effective
delivery into cells. For example, transduction of short hairpin
shRNA into hematopoietic stem cells by lentiviral vector has shown
to allow endogenous synthesis of siRNA and is able to provide
sustainable gene silencing. However, the toxic myeloablative
regimens used in the transplant procedure and the limited
engraftment of gene-modified cells currently constrains wide
application.
[0066] A variety of non-viral siRNA delivery systems have been
proposed, including cationic liposomes, cell-penetrating peptides
(CPPs) and cationic polymers. Cationic lipids, such as
Lipofectamine.RTM. and lipid-like materials, are widely used for in
vitro studies and have shown potential for in vivo gene silencing
especially in the liver. As an example of the CPPs-based approach,
siRNA can be assembled with CPPs or CPP bioconjugates into
complexed particles to generate significantly improved delivery
efficiency. Nevertheless, the formation of such structures is
driven by weak non-covalent interactions and these particles were
generally unstable, particularly, against serum nucleases.
[0067] For the cationic-polymer-based approach, siRNA can be
assembled with cationic polymers mainly through electrostatic
interactions. For example, cationic polymer-based nanoparticles
with transferrin as a targeting agent have been shown to deliver
siRNA molecules to tumors in humans and reduce the expression of
the ribonucleotide reductase sub-unit RRM2, an anti-cancer target.
However, similar to the CPP-based approach, such systems are based
upon non-covalent electrostatic self-assembly, which have
competition from electrolytes and polyions within the bloodstream.
Therefore, in spite of intensive efforts, the design and synthesis
of an effective delivery vehicle for siRNA remains a challenge.
[0068] Despite the challenges described above, siRNA has become one
of the most promising and specific drug candidates with broad
potential for the treatment of diverse human diseases attributed to
their unique ability to regulate specific genes and control the
expression of corresponding proteins. Current commercial products
for in vitro siRNA delivery include lipofection and nucleofection.
Although these two methods are widely applicable in many cell
lines, the delivery efficiency and the toxicity in primary cells
remains a formidable challenge.
[0069] For in vivo delivery of siRNA, siRNA-mediated gene silencing
in mammals through systemic administration was achieved using naked
siRNA. However this administration is not compatible with and has
many limitations for use in human. Several recent studies have
shown improved siRNA delivery in mouse models and nonhuman primates
using positively charged peptide or proteins like arginine peptide,
CpG oligonucleotide and protamine. Crombez et al., A New Potent
Secondary Amphipathic Cell-penetrating Peptide for siRNA Delivery
Into Mammalian Cells, Molecular Therapy, 2009, 17(1):95-103.
Another recent study demonstrates the presence of an RNAi mechanism
in humans through systemic administration of siRNA a nanoparticles
targeted to melanoma cells. Davis et al., Evidence of RNAi in
humans from systemically administered siRNA via targeted
nanoparticles, Nature, 2010, 464(7291):1067-1070. Nevertheless,
highly effective delivery to targeting sites still persists as a
major obstacle. In addition, potential adverse immune responses
caused by the siRNA remains to be solved.
[0070] As described herein, highly stabilized RNAi molecule polymer
nanocapsules ("polymer nanocapsules") were fabricated through an in
situ polymerization technique, which introduced a protective
crosslinked degradable polymer shell covering the surface of the
RNAi molecules with designed charges and properties. This
crosslinked polymer shell provides protection to the RNAi molecules
from RNase degradation, temperature dissociation and serum
inactivation. Furthermore, degradability of the polymer network
assigns a control-releasing property to RNAi molecules, which
results in a less intracellular immune response. By adjusting the
charge of the polymer nanocapsules, delivery efficiency of RNAi
molecules into human cells was achieved. Furthermore, efficient
RNAi molecule delivery into a broad variety of cells including
293T, Hela, CEM, and PBMCs was achieved with highly
positive-charged nanocapsules.
[0071] Furthermore, surface-conjugated targeting agents on
optimized nanocapsules provided successful targeted delivery of
RNAi molecules into cells of interest, such as T-cells. The
diversified and controllable nontargeting and targeting abilities
provided to the RNAi molecule delivery will have important
implications for many in vitro tests and clinical applications
using RNAi molecules to knock down any desired gene
expressions.
Polymer Nanocapsules
[0072] This invention provides a novel strategy through
self-assembly and in situ polymerization technology to imprint RNAi
molecules into crosslinked polymer nanocapsules. In certain
embodiments, the polymer nanocapsules are approximately 20-100 nm
in diameter. The small diameters of the polymer nanocapsules
maximize the protection of the RNAi molecules from external RNase
attack and serum neutralization.
[0073] In specific embodiments, the polymer nanocapsules are 10
nm-20 nm, 20-25 nm, 25 nm-30 nm, 30 nm-35 nm, 35 nm-40 nm, 40 nm-45
nm, 45 nm-50 nm, 50 nm-55 nm, 55 nm-60 nm, 60 nm-65 nm, 70-75 nm,
75 nm-80 nm, 80 nm-85 nm, 85 nm-90 nm, 90 nm-95 nm, 95 nm-100 nm,
or 100 nm-110 nm. In specific embodiments, the polymer nanocapsules
are approximately 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm,
17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, 26
nm, 27 nm, 28 nm, 29 nm, 30 nm, 31 nm, 32 nm, 33 nm, 34 nm, 35 nm,
36 nm, 37 nm, 38 nm, 39 nm, 40 nm, 41 nm, 42 nm, 43 nm, 44 nm, 45
nm, 46 nm, 47 nm, 48 nm, 49 nm, 50 nm, 51 nm, 52 nm, 53 nm, 54 nm,
55 nm, 56 nm, 57 nm, 58 nm, 59 nm, 60 nm, 61 nm, 62 nm, 63 nm, 64
nm, 65 nm, 66 nm, 67 nm, 68 nm, 69 nm, 70 nm, 71 nm, 72 nm, 73 nm,
74 nm, 75 nm, 76 nm, 77 nm, 78 nm, 79 nm, 80 nm, 81 nm, 82 nm, 83
nm, 84 nm, 85 nm, 86 nm, 87 nm, 88 nm, 89 nm, 90 nm, 91 nm, 92 nm,
93 nm, 94 nm, 95 nm, 96 nm, 97 nm, 98 nm, 99 nm, 100 nm, 101 nm,
102 nm, 103 nm, 104 nm, 105 nm, 106 nm, 107 nm, 108 nm, 109 nm, 110
nm, 111 nm, 112 nm, 113 nm, 114 nm, 115 nm, 116 nm, 117 nm, 118 nm,
119 nm, or 120 nm in diameter. In specific embodiments the polymer
nanocapsules are 120 nm-130 nm, 130 nm-140 nm, 140 nm-150 nm, 150
nm-160 nm, 160 nm-170 nm, 170 nm-180 nm, 180 nm-190 nm, 190 nm-200
nm, 200 nm-210 nm, 220 nm-230 nm, 230 nm-240 nm, 240 nm-250 nm, or
larger than 250 nm in diameter.
[0074] In certain embodiments, additional advantages of the polymer
nanocapsules disclosed herein include nontargeting and targeting
ability, higher efficiency, and lower adverse immune response. For
example, the higher efficiency may result from increased uptake and
more directed delivery.
[0075] Furthermore highly stabilized RNAi molecules inside the
protective nanocapsule is able to be fully released once the
nanostructured polymer shell is degraded in endosomes and
lysosomes. In certain embodiments, a nontargeting polymer
encapsulated RNAi molecules can be transduced into primary cells
such as PBMCs in vitro with superior efficiency and noncytoxicity
compared to the low efficiency and high toxicity resulting from
liposome transduction.
[0076] Importantly, by choosing and designing appropriate polymer
charge, the method of RNAi molecule delivery to specific purposes
(such as targeting by conjugating moieties to the polymer
nanocapsules as described herein) can be modulated.
[0077] In certain embodiments, the ratio of degradable crosslinker
to non-degradable crosslinker is 1:1, 1:2, 2:1, 1:3, 2:3, 3:1, 3:2,
4:1, 1:4, 4:3, 3:4, 5:1, 1:5, 2:5, 5:2, 5:3, 3:5, 4:5, 5:4, 6:1,
1:6, 1:7, 7:1, 2:7, 7:2, 3:7, 7:3, 4:7, 7:4, 5:7, 7:5, 6:7, 7:6,
8:1, 1:8, 3:8, 8:3, 5:8, 8:5, 7:8, 8:7, 9:1, 1:9, 2:9, 9:2, 4:9,
9:4, 5:9, 9:5, 7:9, 9:7, 8:9, 9:8, 10:1, 1:10, 3:10, 10:3, 7:10,
10:7, 9:10, 10:9 or any other ratio that one of skill in the art
would know to use.
[0078] In certain embodiments, the degradable crosslinkers are one
or more of crosslinker 1, 2, 3, 4, or 6 in FIG. 24. In certain
embodiments, the non-degradable crosslinkers are crosslinker 5 in
FIG. 24.
[0079] In certain embodiments, the polymer nanocapsules are
designed to degrade in 1 hour, or 2 hours, or 3 hours, or 4 hours,
or 5 hours, or 6 hours, or 7 hours, or 8 hours, or 9 hours, or 10
hours, or 11 hours, or 12 hours, or 13 hours, or 14 hours, or 15
hours, or 16 hours, or 17 hours, or 18 hours, or 19 hours, or 20
hours, or 21 hours, or 22 hours, or 23 hours, or 1 day, or 2 days,
or 3 days, or 4 days or 5 days, or 6 days, or 1 week, or 2 weeks,
or 3 weeks, or 1 month or any combination thereof. In certain
embodiments, the polymer nanocapsules are designed to degrade at
any of the above rates at a physiological pH. In specific
embodiments, the polymer nanocapsules are designed to degrade at
any of the rates above post-administration to a subject in need
thereof.
[0080] In specific embodiments, RNAi molecules can be effectively
delivered to specific sites in vivo. In certain embodiments, a
targeting agent (i.e., a conjugate or conjugate agent) is
conjugated to the polymer nanocapsule. In certain embodiments the
conjugation prevents the dissociation of the targeting agent from
the polymer particle. In specific embodiments, cyclodextrin and
adamantane can be used for targeting agent conjugation.
[0081] In one embodiment, the invention is practiced using
nontargeted and targeted polymer nanocapsules RNAi molecule
delivery with high efficiency and low toxicity for in vitro testing
and in vivo targeting to specific tissues and organs via
intravenous injection.
[0082] The enhanced stability of RNAi molecules attributed to the
cross-linked polymer also ensures its long-lasting circulation in
body before it reaches the targeting sites. Overall, the novel RNAi
molecule delivery technology described herein has a notable
efficiency, augmented stability, and minimal toxicity both in vitro
and predicted in vivo.
Monomers and Cross Linkers
[0083] Different monomers and crosslinkers can be used to
encapsulate the RNAi molecules by in situ polymerization.
[0084] In certain embodiments, the positive monomer have the
structure:
##STR00001## [0085] wherein [0086] R.sup.20 is unsubstituted
C.sub.1-C.sub.6 alkyl [0087] R.sup.21 is selected from the group
consisting of:
[0087] ##STR00002## [0088] wherein m is an integer from 1 to 5;
[0089] R.sup.22 is H or unsubstituted C.sub.1-C.sub.6 alkyl or
C.sub.1-C.sub.6 alkyl substituted with NR.sup.25R.sup.26, wherein
[0090] R.sup.25 and R.sup.26 are independently selected from H or
unsubstituted C.sub.1-C.sub.6 alkyl or C.sub.1-C.sub.6 alkyl
substituted with amino or C.sub.1-C.sub.6 alkyl substituted with
NR.sup.27R.sup.28, wherein [0091] R.sup.27 and R.sup.28 are
independently selected from H or unsubstituted C.sub.1-C.sub.6
alkyl or C.sub.1-C.sub.6 alkyl substituted with amino [0092]
R.sup.23 is H or unsubstituted C.sub.1-C.sub.6 alkyl or
C.sub.1-C.sub.6 alkyl substituted with amino or C.sub.1-C.sub.6
alkyl substituted with NR.sup.29R.sup.30, wherein [0093] R.sup.29
and R.sup.30 are independently selected from H or unsubstituted
C.sub.1-C.sub.6 alkyl or C.sub.1-C.sub.6 alkyl substituted with
amino or C.sub.1-C.sub.6 alkyl substituted with NR.sup.31R.sup.32,
wherein [0094] R.sup.31 and R.sup.32 are independently selected
from H or unsubstituted C.sub.1-C.sub.6 alkyl or C.sub.1-C.sub.6
alkyl substituted with amino [0095] and R.sup.22 and R.sup.23 are
optionally combined to form a 5-7 membered heterocycloalkyl ring;
and [0096] R.sup.24 is a lone pair of electrons or unsubstituted
C.sub.1-C.sub.6 alkyl.
[0097] In certain embodiments, the crosslinkers have the
structure:
##STR00003## [0098] wherein R.sup.1 is unsubstituted
C.sub.1-C.sub.6 alkyl, [0099] R.sup.4 is unsubstituted
C.sub.1-C.sub.6 alkyl, [0100] and A is selected from the group
consisting of:
[0100] ##STR00004## [0101] wherein R.sup.10 is unsubstituted
C.sub.1-C.sub.6 alkylene; [0102] an amino acid; [0103] a peptide
consisting of from 2 to 10 amino acids;
[0103] ##STR00005## [0104] wherein R.sup.11 is unsubstituted
C.sub.1-C.sub.6 alkylene and R.sup.12 is unsubstituted
C.sub.1-C.sub.6 alkylene;
[0104] ##STR00006## [0105] wherein n is from 1 to 10; and
[0105] ##STR00007## [0106] wherein R.sup.13 is unsubstituted
C.sub.1-C.sub.6 alkylene and R.sup.14 is unsubstituted
C.sub.1-C.sub.6 alkylene.
[0107] In certain embodiments, the neutral monomers have the
structure:
##STR00008##
wherein R1 is unsubstituted C1-C4 alkyl and R2 is amino or amino
substituted with hydroxy substituted alkyl or OR.sup.3, wherein R3
is hydroxy alkyl.
[0108] Non-limiting examples of monomers are presented in FIGS. 23
and 25. Non-limiting examples of crosslinkers can be found in FIG.
24. Targeting agents, such as antibodies, peptides, or growth
factors can be covalently or noncovalently conjugated with the
polymer as described in the Figures.
Polymer Nanocapsule Conjugates
[0109] In certain embodiments, targeted delivery of RNAi molecules
into cells is achieved using surface-conjugated targeting agents on
optimized nanocapsules. Of particular interest, the polymer
nanocapsule conjugates can be used to target immune, pulmonary,
lung, optic, liver, kidney, brain, central nervous system,
peripheral nervous system, cardiac, cancer, proliferative, virally
or retrovirally infected, stem, skin, intestinal, and/or auditory
cells.
[0110] In certain embodiments, the conjugates used to achieve
specific targeting of the polymer nanocapsules include CD4, CD8,
CD45, CD133, aHLA, and transferrin. In certain embodiments, the
conjugates used to achieve specific targeting of the polymer
nanocapsules include any one or more of the cluster of
differentiation or cluster of designation (CD) markers. For
example, the CD markers include CDX wherein X can be any one of
1-340. As described herein, the term "CD1", for example, means all
CD1 variants and subtypes. This applies to all CD markers described
herein.
[0111] In certain embodiments, the conjugates used to achieve
specific targeting of the polymer nanocapsules include any one or
more of AFP, beta-Catenin, BMI-1, BMP-4, c-kit, CXCL12, SDF-1,
CXCR4, decorin, E-Cadherin, Cadherin 1, EGFR, ErbB1, Endoglin,
EpCAM, TROP-1, Fc epsilon RI A, FCER1A, L1 CAM, LMO2, Nodal,
Notch-1, PDGFRB, Podoplanin, PTEN, Sonic Hedgehog, STAT3,
Syndecan-1, Tranferrin Receptor, and Vimentin.
[0112] In certain embodiments, the conjugates used to achieve
specific targeting of the polymer nanocapsules include any one or
more of ALK, AFP, B2M, Beta-hCG, BCR-ABL, BRAF, CA15-3, CA19-9,
CA-125, Calcitonin, CEA (Carcinoembryonic antigen), CD20,
Chromagranin A, Cytokeratin or fragments thereof, EGFR, Estrogen
Receptor, Progesterone Receptor, Fibrin, Fibrinogen, HE4, HER2/neu,
IgG variants, KIT, lactate dehydrogenase, Nuclear matrix protein
22, PSA, thyroglobulin, uPA, PAI-1, and Oval.
[0113] Any marker described herein or known to one of skill in the
art can be used alone, or in combination with one or more
additional markers, to achieve the desired targeting of specific
cells.
[0114] All other cell and/or tissue specific markers known to one
of skill in the art here incorporated by reference.
Methods of Treating Diseases Caused by Expression of a Target
Gene
[0115] In one embodiment, the invention relates to a method for
treating a subject having a disease or at risk of developing a
disease caused by the expression of a target mutant gene. In
certain embodiments, the polymer nanocapsules described herein can
act as novel therapeutic agents for controlling one or more of
cellular proliferative and/or differentiative disorders. In certain
embodiments, the polymer nanocapsules can act as novel therapeutic
agents for controlling one or more immune or immunodeficiency
disorders. In certain embodiments, the polymer nanocapsules can act
as novel therapeutic agents for preventing viral replication or
viral infection. In certain embodiments, the polymer nanocapsules
can act as novel therapeutic agents for controlling one or more
neurological or neurodegenerative disorders. In certain
embodiments, the polymer nanocapsules can act as novel therapeutic
agents for treating or preventing cancer.
[0116] In certain embodiments, the polymer nanocapsules can act as
novel therapeutic agents for treating advanced cancers,
pachyonychia congenital, age-related macular degeneration,
choroidal neovascularization, metastatic melanoma, metastatic
melanoma without CNS metastases, chronic myeloid leukemia, solid
tumors, advanced solid tumors, optic atrophy, non-arteric anterior
ischemic optic neuropathy, pancreatic cancer, pancreatic ductal
adenocarcinoma, diavetic macular edema, hypercholesterolemia,
colorectal cancer with hepatic metastases, pancreatic cancer with
hepatic metastases, gastric cancer with hepatic metastases, breast
cancer with hepatic metastases ovarian cancer with hepatic
metastases, preeclampsia, neuroblastoma, ocular hypertension, open
angle glaucoma, glaucoma, ocular pain, dry eye syndrome, kidney
injury, acute renal failure, delayed graft function, complications
of kidney transplant, TBX3 overexpression, and diabetic
retinopathy.
[0117] In specific embodiments, the polymer nanocapsules can act as
novel therapeutic agents for treating viral infections. In specific
embodiments, the polymer nanocapsules can act as novel therapeutic
agents for treating retroviral viral infections. In specific
embodiments, the polymer nanocapsules can act as novel therapeutic
agents for treating HIV or AIDS infections. In specific
embodiments, the polymer nanocapsules can act as novel therapeutic
agents for suppressing retroviral viral infections. In specific
embodiments, the polymer nanocapsules can act as novel therapeutic
agents for blocking, preventing, or downregulating retrovirus or
virus replication.
[0118] In certain embodiments, the polymer nanocapsules described
herein can be administered by intravitreal injection,
intravenously, by injection into the callus on the bottom of one
foot, by oral administration, subcutaneously, and by any other mode
of pharmaceutical administration known to one of skill in the
art.
[0119] In certain embodiments, the method comprises administering a
pharmaceutical composition of the invention to the subject, such
that expression of the target mutant gene is silenced or down
regulated. In certain embodiments the subject is a mammal. In
certain embodiments the mammal is a human. Because of their high
specificity, the polymer nanocapsules of the present invention
specifically target the mutant genes of diseased cells and tissues,
as described herein.
[0120] In the prevention of disease, the target gene may be one
which is required for initiation or maintenance of the disease, or
which has been identified as being associated with a higher risk of
contracting the disease. In the treatment of disease, the polymer
nanocapsules can be brought into contact with the cells or tissue
exhibiting the disease. As one non-limiting example, polymer
nanocapsules are substantially identical to all or part of a
mutated gene associated with cancer, or one expressed at high
levels in tumor cells may be brought into contact with or
introduced into a cancerous cell or tumor gene. As another
non-limiting example, polymer nanocapsules are substantially
identical to all or part of a mutated gene associated with a viral
or retroviral disease. Specifically, a non-limiting example of a
retroviral disease that can be treated with the polymer
nanocapsules described herein is HIV (see FIGS. 3, 4, and
6-10).
[0121] Non-limiting examples of cellular proliferative and/or
differentiative disorders include cancer, e.g., carcinoma, sarcoma,
metastatic disorders or hematopoietic neoplastic disorders, e.g.,
leukemias. A metastatic tumor can arise from a multitude of primary
tumor types, including but not limited to those of prostate, colon,
lung, breast and liver origin. As used herein, the terms "cancer,"
"hyperproliferative," and "neoplastic" refer to cells having the
capacity for autonomous growth, i.e., an abnormal state of
condition characterized by rapidly proliferating cell growth. These
terms are meant to include all types of cancerous growths or
oncogenic processes, metastatic tissues or malignantly transformed
cells, tissues, or organs, irrespective of histopathologic type or
stage of invasiveness. Proliferative disorders also include
hematopoietic neoplastic disorders, including diseases involving
hyperplastic/neoplatic cells of hematopoietic origin, e.g., arising
from myeloid, lymphoid or erythroid lineages, or precursor cells
thereof
[0122] Mutations in cellular genes that directly or indirectly
control cell growth and differentiation are considered to be the
main cause of cancer. There are approximately thirty families of
genes, called oncogenes, which are implicated in human tumor
formation. Members of one such family, the RAS gene family, are
carried in a broad range of eukaryotes and are frequently found to
be mutated in human tumors. Polymer nanocapsules of this invention
can be used to target such oncogenes to knock down or prevent their
expression.
[0123] In addition to oncogenes, the methods and compositions of
the invention can be applied to other disease-related target genes
having a point mutation. Gene mutations have been reported in more
than 1000 different human genes. Data on these mutations and their
associated phenotypes have been collated and are available online
through two major databases: Online Mendelian Inheritance in Man in
Baltimore and the Human Gene Mutation Database in Cardiff. For
example, there is a high frequency of CG to TG or CA mutations in
the human genome due to deamination of 5' methyl-cytosine. Short
deletions or insertions of less than 20 nucleotides are also very
common mutations in humans. See, e.g., Antonarakis, S. E., Eur.
Pediatr. (2000) 159(3):5173-8.
[0124] Furthermore, Sachidanandam et al. describes a map of human
genome sequence variation containing 1.42 million single nucleotide
polymorphisms, which is useful for identifying biomedically
important genes for diagnosis and therapy (Sachidanandam, R., et
al., Nature (2001) 409(6822):821-2 and Nature (2001)
409(6822):822-3). The map integrates all publicly available SNPs
with described genes and other genomic features. An estimated
60,000 SNPs fall within exon (coding and untranslated regions), and
85% of exons are within 5 kb of the nearest SNP. Clifford et al.
provides expression-based genetic/physical maps of
single-nucleotide polymorphisms identified by the cancer genome
anatomy project (Clifford, R., et al., Genome Res (2000)
10(8):1259-65). In addition to SNP maps, Sachidanandam et al.
provide maps containing SNPs in genes expressed in breast, colon,
kidney, liver, lung, or prostate tissue.
[0125] Accordingly, RNAi molecule polymer nanocapsules of this
invention can be used to target such mutant genes to knock down or
prevent their expression
Methods of Inhibiting Expression of a Mutant Gene
[0126] In yet another aspect, the invention relates to a method for
inhibiting the expression of a mutant gene in subject. The method
comprises administering a composition of the invention to the
subject such that expression of the mutant gene is silenced as
compared to the corresponding wild-type gene. In certain
embodiments the subject is a mammal. In certain embodiments the
mammal is a human.
[0127] Because of their high specificity, the siRNA nanocapsules of
the present invention specifically target RNAs (primary or
processed) of target mutant genes, and at surprisingly low dosages.
Compositions and methods for inhibiting the expression of a target
gene using polymer nanocapsules can be performed as described
herein.
[0128] In one embodiment, the invention comprises administering a
composition comprising polymer nanocapsules, wherein the polymer
nanocapsules comprise a nucleotide sequence which is substantially
complementary to an RNA transcript of the target mutant gene and
partially complementary to the corresponding wild-type gene. When
the subject to be treated is a mammal, such as a human, the
composition may be administered by any means known in the art
including, but not limited to oral or parenteral routes, including
intravenous, intramuscular, intraperitoneal, subcutaneous,
transdermal, airway (aerosol), rectal, vaginal and topical
(including buccal and sublingual) administration. In preferred
embodiments, the compositions are administered by intravenous or
intraparenteral infusion or injection.
[0129] The methods for inhibition the expression of a target gene
can be applied to any mutant gene one wishes to silence, thereby
selectively inhibiting its expression. Non-limiting examples of
human genes which can be targeted for silencing include oncogenes
cytokinin gene, idiotype protein genes, prion genes, genes that
expresses molecules that induce angiogenesis, genes that encode
adhesion molecules, genes that encode cell surface receptors, genes
of proteins that are involved in metastasizing and/or invasive
processes, genes of proteases as well as of molecules that regulate
apoptosis and the cell cycle, genes that express the EGF receptor,
genes that encode the multi-drug resistance 1 gene (MDR1 gene),
genes that allow viral uptake and replication, genes that cause
neurodegenerative disorders, genes that cause protein aggregation
and/or accumulation, genes that cause up-regulation or down
regulation of hormones, genes that cause neurological disorders,
genes that cause cardiac disorders, and genes that cause
psychological disorders. One of skill in the art would understand
which genes are encompassed by the broad categories of exemplary
genes described above.
Methods of Manufacture
[0130] In certain embodiments, the polymer nanocapsules described
herein are manufactured to achieve a specific size, to target a
specific site for gene downregulation, and to downregulate a
specific gene. The size of the polymer nanocapsules described
herein can be determined based on the polymer:crosslinker ratio as
described herein. Targeted delivery can be achieved, for example,
using conjugate agents that are attached (i.e., conjugated) to the
exterior of the polymer nanocapsules as described herein.
Furthermore, the specific binding of an RNAi molecule of a polymer
nanocapsules described herein to a specific gene (thereby
decreasing specific gene expression) can be achieved by designing
the RNAi molecule using methods known to one of skill in the art.
See, e.g., Birmingham et al., "A protocol for designing siRNAs with
high functionality and specificity," Nature Protocols, 2007;
2(9):2068-78. Furthermore, the ability of the polymer nanocapsules
to deliver the RNAi molecules to the target site can be optimized
and determined by adjusting the ratios of degradable:nondegradable
polymers as described herein.
Methods of Administration
[0131] The pharmaceutical compositions encompassed by the invention
may be administered by any means known in the art including, but
not limited to oral or parenteral routes, including intravenous,
intramuscular, intraperitoneal, subcutaneous, transdermal, airway
(aerosol), rectal, vaginal and topical (including buccal and
sublingual) administration. In preferred embodiments, the
pharmaceutical compositions are administered by intravenous or
intraparenteral infusion or injection.
EXAMPLES
Example 1. Manufacture of Nanocapsules
[0132] Highly stabilized siRNA polymer nanocapsules were fabricated
through an in situ polymerization technique as described in Example
1 and FIGS. 1 and 2. The manufacture of a siRNA nanocapsule
platform depicted in FIG. 1, starts with a positively charged
monomer A, a crosslinker B, a neutral co-monomer C and enriches
these molecules around the surface of the negatively charged siRNA
through electrostatic interaction and hydrogen bonding. A series of
positively charged monomers FIG. 23), crosslinkers (FIG. 24) and
neutral co-monomers (FIG. 25) were used in the manufacture of the
polymer nanocapsule platform. Different crosslinkers, for example
those listed in FIG. 24, can be used to form copolymer coatings
with tunable composition, structure, surface property, and
functionality.
[0133] This in situ polymerization technique introduced a
protective crosslinked degradable polymer shell covering on the
surface of the siRNA with designed charges and properties. This
crosslinked polymer shell provides protection to the siRNA from
RNase degradation, temperature dissociation and serum inactivation.
Non-liming examples of crosslinkers that can be used in the siRNA
nanocapsules are provided in FIG. 24.
Example 2. Manufacture of Nanocapsules Using Acryl-Spermine
[0134] In this example, the preparation of acryl-spermine was
achieved by reacting spermine with acrylic acid, hydroxysuccinimide
ester (NAS). Briefly, spermine (100 mg) and NAS (80 mg) were
dissolved in 1 mL chloroform, respectively. NAS solution was then
added into spermine solution gradually at room temperature under
vigorous stirring. After overnight reacting, the mixture was
filtered to remove by-products. The filtrate was then dried by
rotary evaporation, followed by re-dispersing with ddH2O. After
removal of insoluble substance, the solution was lyophilized.
Finally, acryl-spermine was purified by process TLC. One of skill
in the art that this is an exemplary method of manufacturing
acryl-spermine and will understand that alternative methods could
be used to reach the same result.
[0135] As illustrated in FIG. 2, the manufacture of a nanocapsules
began with a positively charged, polymerizable monomer. For
purposed of this example, the positively charged, polymerizable
monomer is acryl-spermine which was prepared as described above.
The first step of the process of manufacturing the polymer
nanocapsules required electrostatic interactions enriched around
the surface of the negatively charged siRNA. After the initial
interactions, subsequent room-temperature polymerization in an
aqueous solution took place with the pH-degradable crosslinkers and
hydrophilic monomers. During the room temperature polymerization,
each siRNA molecule was wrapped in a thin shell of polymer network.
Such a crosslinked shell served to protect the cored siRNA from
hydrolysis. Specific tuning of the ration of the acryl-spermine and
the hydrophilic monomers allowed precise control of the surface
charge and ensured the effective cellular transduction of the
polymer nanocapsules. Moreover, 2 is stable in neutral pH but are
rapidly degraded in acidic environment, such as late endosomes with
pH.about.5.4. We believe that this unique responsive design will
provide the polymer nanocapsules with outstanding stability in
serum (pH.about.7.4), while enabling their escape from endosomes
upon the degrading of the shell that releases the siRNA to the
cytoplasma (Step IV). Furthermore, our synthetic approach allows
for the immobilization of targeting components (e.g., antibody) to
the polymer nanocapsules surface, allowing targeting delivery of
siRNA.
Example 3. Ability of Nanocapsules to Protect and Deliver
Encapsulated siRNA
[0136] in order to test the efficacy of the polymer nanocapsules
described herein, a single siRNA nanocapsule platform that
efficiently delivers siRNA was generated. Schematics of how the
polymer nanocapsules are made are depicted in FIG. 1 and FIG. 2.
These nanocapsules of this platform were designed to protect the
encapsulated siRNA from nucleases and can effectively deliver siRNA
into cells.
[0137] In order to test the ability of the polymer nanocapsules to
protect the encapsulated siRNA and effectively deliver the siRNA
into cells, the well known siRNA1005 was used in the preparation of
the polymer nanocapsules. siRNA1005 is a short hairpin RNA (shRNA)
that targets the HIV-1 co-receptor CCR5. The well-characterized
potency of siRNA1005 made it an ideal candidate for demonstrating
CCR5 knockdown by applying the single molecule nanocapsule delivery
technology. Exemplary images of nanocapsules with siRNA1005 are
presented in FIG. 4 and FIG. 5.
[0138] As proof of concept we showed that CCR5 RNA can be
effectively knocked down by nanocapsules of siRNA1005. One unique
advantage of this nanocapsule platform is the ability to modify the
polymer nanocapsules by selecting monomers and crosslinkers which
alter the chemical properties of size, charge, and reactivity of
the particles. Non-limiting examples of monomers and crosslinkers
can be found in FIG. 23 and FIG. 24.
[0139] The ability of the polymer nanocapsules to effectively
protect encapsulated materials from degradation, was also
demonstrated by encapsulating proteins. For example, EGFP, HRP, and
caspase 3 were encapsulated and protected in the polymer
nanocapsules. Furthermore, the polymer nanocapsules were also used
to encapsulated quantum dots and siRNAs such as siEGFP,
siLuciferase, and si1005 as described above.
Example 4. Delivery of siRNA Using DNA that Encodes shRNA
[0140] Delivery of siRNA was accomplished using DNA that encodes
shRNA transcriptional units. For example, plasmid and viral vectors
were used because they provide high levels and long term expression
of the siRNA.
[0141] In this example, the polymer nanocapsule technology was
further extended to nanocapsules of DNA encoding shRNA1005. As
described in Example 3, shRNA1005 is an RNAi that targets and
knocks down the expression of CCR5 RNA expression. This DNA
nanocapsule technology is more challenging than the above described
RNAi nanocapsule because DNA transcription units are much larger
than siRNA.
[0142] The formulation of polymer nanocapsules platform for
encapsulation of DNA cassettes was modified by tuning monomers and
crosslinkers which alter the size, charge, and degradability of the
particles. Non-limiting examples of monomers and crosslinkers are
provided in FIG. 23 and FIG. 24.
[0143] Of particular interest, the polymer nanocapsules were
engineered for delayed release using crosslinkers that degrade at
different rates, enabling effective siRNA activity over several
days or weeks. This is a big advantage over current small molecule
drugs that are required daily administration
Example 5. Synthesis and Delivery of DNA Nanocapsules
[0144] As illustrated in FIG. 1, starting with the monomer A and B,
crosslinker C, these molecules self-assembled along the surface of
the DNA cassettes through electrostatic interaction and hydrogen
bonding (Step 1). Then a thin network of polymer shell was formed
around the DNA cassette by subsequent in situ polymerization (Step
2), which effectively conferred new surface properties that protect
the DNA. Crosslinker C was a non-degradable crosslinker.
Acid-degradable crosslinkers D were stable in neutral pH but were
rapidly degraded in acidic environment, such as late endosomes with
pH around 5.4.
[0145] This unique responsive design provided the polymer
nanocapsules with outstanding stability in the physiological pH of
serum (pH-7.4). It also led to effective endosomal escape due to
the "proton-sponge" effect resulting from the positive charges of
monomers B and enabled controllable release of the DNA cassette
into the cytoplasm upon the degradation progress of the shell. The
DNA cassette then entered the nucleus and allowed the endogenous
generation of siRNA (Step 4).
Example 6. DNA Nanocapsule Incorporating Short Linear DNA
Cassettes
[0146] As proof of concept, we designed a model DNA nanocapsule
incorporating a short linear DNA cassette with H1 expressed sh1005
shRNA and H1 expressed anti-EGFP shRNA as control. Delivery of a
large DNA plasmid, consisting of shRNA transcriptional units and
antibiotic resistance genes, was hindered by delivering barriers at
the cell membrane and nucleopore. Accordingly a second DNA cassette
was manufactured using a minimized linear DNA cassette of only 395
base pairs that was produced by PCR. The DNA cassette of only 395
base pairs, was able to transfer nucleopores more efficiently.
[0147] Gel electrophoresis image of these two DNA cassettes was
shown in FIG. 3A.
[0148] Interestingly, the TEM image of linear naked DNA cassette
stained with tungsten agent appeared as a dark half circular arc
with a diameter about 50 nm. In contrast, the DNA cassette
nanocapsules had a round morphology with a much smaller size of
approximately 30 nm. This is likely a result of DNA condensation
through complexing with polymers.
[0149] Compared to previously reported nanoparticles that contain
plasmid DNA (approximately 150-300 nm), the size of DNA cassette
nanoparticles is remarkably 1/10 to 1/5 the size. This small size
of the DNA cassette nanocapsules likely leads to a high diffusional
rate and improve the delivery efficiency.
Example 7. DNA Cassette Nanocapsules are Efficiently Delivered to
Cells
[0150] DNA cassette nanocapsules of this invention can be
effectively delivered to cells. The optical and fluorescent images
of HEK-293T cells after incubation with Alexa592-labeled DNA
cassette nanocapsules for 4 hrs is shown in FIG. 4 and FIG. 5. The
intense green fluorescence demonstrates delivery of the
FITC-labeled siRNA nanocapsules (FIG. 4 and FIG. 5).
[0151] Flow cytometry of HEK-293 T cells transduced with
Alexa592-labeled DNA cassette nanocapsules confirmed the results of
the fluorescence imaging and demonstrated successful delivery of
fluorescence-labeled siRNA nanocapsule (FIG. 5C).
[0152] RNAi activity of the DNA nanocapsule in 293T cells
expressing a fusion of CCR5 and luciferase reporter gene sequence
with CCR5-shRNA (sh1005) was also examined (FIG. 5D). The
CCR5-shRNA DNA nanocapsules down-regulated about 80% of the
bioluminescence intensity reflecting the knockout of the
CCR5-luciferase fusion mRNA while cells treated with control DNA
cassette nanocapsules did not exhibit significant decreases in the
luciferase activity.
[0153] To investigate the sensitivity of DNA nanocapsules against
Dnase I, DNA complexed with Lipofectamine.RTM. and DNA nanocapsules
were incubated with Dnase I for 1 hour (FIG. 6A).
[0154] After acid treatment and DNA extraction, agarose gel
electrophoresis showed such nanocapsules were able to proted and
maintain the integrity of the encapsulated DNA. In contrast,
non-encapsulated DNA in the native state and non-encapsulated DNA
that was formulated with Lipofectamine.RTM. degraded. The DNA
nanocapsules did not show obvious cytotoxicity at the concentration
of DNA cassette below 0.4 pmol. At 0.4 pmol, the viability of cells
treated with DNA nanocapsules was slightly reduced to about 85%
(FIG. 7).
Example 8. siRNA Nanocapsules are Efficiently Delivered to Cells
and Target Specific Sequences
[0155] FIG. 4A shows a representative TEM image of the
double-stranded siRNA nanocapsules which target CCR5 sequence
3'-gagcatgactgacatctac-5' with an average diameter of 25 nm.
Interestingly, within each nanocapsule, a dark core with diameter
around 5 nm was clearly observed, which is due to preferred
complexation of siRNA with the tungsten-staining agent used for TEM
observation. Since a double-stranded siRNA (21 base pairs) has an
average molecular weight of 12 kDa and size of 3-5 nm, each of the
polymer nanocapsules appears to only contain one siRNA molecule.
FIG. 4B shows a fluorescent image of HEK-293 T cells after
incubation with FITC-labeled siRNA for 4 hrs. The intense green
fluorescence proves the effective delivery of the siRNA
nanocapsules.
[0156] As proof of concept, CCR5-siRNA was used to target and
down-regulate CCR5 expression. It has been well demonstrated that
individuals born with naturally existing mutations in the CCR5
chemokine receptor are protected from HIV infection and disease
progression. CCR5-siRNA holds great promise as a therapeutic drug
to downregulate CCR5 expression and to develop HIV resistance in
patients. To prove this concept, FIG. 4C shows flourescence images
of HEK 293 cells transducted with siRNA nanocapsules targeted to
CCR5 sequence (left panel of image in FIG. 4C) and EGFP sequence
(right panel of image in FIG. 4C). Clearly, delivery of the
CCR5-siRNA nanocapsules effectively down-regulates the CCR5-mCherry
fusion protein expression. This demonstrates the effectiveness of
siRNA nanocapsules delivery and function.
[0157] Luciferase-expressing CWR cells stably expressing luciferase
were used to test the gene-silencing efficacy of single siRNA
nanocapsules (FIG. 14A). Cells treated with luciferase siRNA
nanocapsules showed a significant decrease in the luciferase
activity especially at concentrations above 50 nM, while cells
treated with control siRNA nanocapsules did not exhibit significant
decrease in the luciferase activity. The siRNA nanocapsules did not
show obvious cytotoxicity at the concentration of siRNA below 200
nM. At 300 nM, the viability of cells treated with siRNA
nanocapsules was slightly reduced to about 75% (FIG. 14B).
[0158] Furthermore, without human serum, nanocapsules and
Lipofectamine.RTM. (Invitrogen.RTM.) silenced expression of
CCR5-mCherry expression to 8% and 15%, respectively. But in the
presence of human serum, CCR5 siRNA nanocapsules still knocked down
more than 85% of CCR5-mCherry expression while siRNA delivered
through Lipofectamine.RTM. only made a number at 45%. Therefore,
nanocapsules can provide extra protection and stabilization to
siRNA inside against attacking of human serum nucleases compared
with Lipofectamine.RTM..
Example 9. DNA Cassette Nanocapsules Efficiently Knockdown Gene
Expression in Cells
[0159] The knockdown efficacy of DNA cassette nanocapsule was
compared to standard Lipofectamine.RTM. siRNA transduction to HEK
293T cells expressing CCR5-luciferase fusion protein (FIG. 8).
[0160] After 48 hours, 0.1 pmol of sh1005 DNA cassette nanocapsule
silenced the expression of CCR5-luciferase to 45%. In stark
contrast, 100 pmol (1000.times. the amount) of
siRNA-Lipofectamine.RTM. complex was required to knock down the
level of CCR5-luciferase to 47%. On a molar basis, the sh1005 DNA
cassette nanocapsule is over 1000-fold more effective at
downregulating CCR5 than si1005 siRNA formulated with
Lipofectamine.RTM. (FIG. 7 and FIG. 8). This result is likely due
to de novo transcription of shRNA within transduced cells.
Example 10. Delayed Release and Degradable Nanocapsules
[0161] Because of the high potency of the DNA cassette
nanocapsules, DNA cassette nanocapsules can be used in applications
where sustained activity is beneficial. To accomplish this, DNA
cassette nanocapsules were engineered for delayed release using
crosslinkers that degrade at different rates.
[0162] The DNA nanocapsules prepared with 100% degradable
crosslinkers (e.g., Glycerol 1,3-diglycerolate diacrylate, GDGDA)
(5:0) was degraded completely after 10 hours. The DNA nanocapsules
prepared with a mixture of one part degradable crosslinker to four
parts non-degradable crosslinker (e.g., N,N'-methylene
bisacrylamide, BIS) was completely degraded after 150 hours (FIG.
9). The slopes of the degradation profiles consistently increase
with the percentage of degradable crosslinkers. This confirms that
a higher percentage of the degradable crosslinkers leads to a
higher degradation rate.
[0163] Using 100% of degradable crosslinker, the downregulation of
CCR5 reached 70% at day 3 and 5 following transduction and
decreased to 23% at day 9 (FIG. 10).
[0164] When the ratio of degradable crosslinker to non-degradable
crosslinker is 3:2, the knockdown of CCR5 increased from 58% at day
3 to 70% at day 5 and then decreased to 42%.
[0165] The DNA nanocapsule with the ratio of degradable crosslinker
to non-degradable crosslinker at 2:3, the silencing percentage of
the CCR5 increased from 53% to 64% and further increased to 73%. By
using 20% degradable crosslinker, the down regulation of CCR5 was
as low as 20% at day 3 and reached 80% at day 9.
Example 11. Visualization Nanocapsules
[0166] IR spectra of the polymer nanocapsules were obtained on a
PerkinElmer Paragon 1000 FT-IR spectrometer. UV-Visible spectra
were acquired with a GeneSys 6 spectrometer (Thermo Scientific).
Fluorescence spectra were obtained with a QuantaMaster
Spectrofluorimeter (Photon Technology International). TEM images of
nanocapsules were obtained on a Philips EM120 TEM at 100000.times.
(see, e.g., FIG. 3, FIG. 4, and FIG. 5).
[0167] Before observation, siRNA nanocapsules were negatively
stained using 1% pH 7.0 phosphotungstic acid (PTA) solution. Zeta
potential and particle size distribution were measured with a
Malvern particle sizer Nano-ZS. SEM images of nanocapsules were
obtained with a JEOL JSM-6700F SEM. Dry samples on a silicon
surface were sputter-coated with gold before measurement.
Fluorescent images of cells were obtained with either Zeiss Axio
Observer.Z1 fluorescence microscope or Leica TCS SP MP Inverted
Confocal Microscope. Cellular fluorescent intensity distribution
was determined with Becton Dickinson FACScan Analytic Flow
Cytometer. A 488 nm argon laser was used as the excitation
light.
Example 12. Synthesis of siRNA Nanocapsules
[0168] In situ polymerization and the process of manufacturing
siRNA nanocapsules with different types and ratios of siRNA was
optimized. Specifically, positively charged monomer, hydrophilic
monomer and degradable crosslinkers were used to optimize the siRNA
nanocapsules.
[0169] The effects of buffer salt, ion types, ionic strength and
solvent composition on the morphology and yield of siRNA
nanocapsules was assessed.
[0170] Varieties of targeting components were conjugated to the
siRNA nanocapsules to achieve targeted delivery of the siRNA. For
example, targeting conjugates used in these experiments included
CD4, CD8, CD45, aHLA, and transferrin. These exemplary conjugates
can be used alone or in combination to achieve specific targeting
of the polymer nanocapsules. FIG. 22 depicts the targeting delivery
of siRNA to 293 cells expressing CD4 receptors. FIG. 22A shows the
flow cytometry graph of 293 cells expressing CD4 receptors after
incubation with FITC-labeled siRNA nanocapsules conjugated with
anti-CD4 antibody for 4 hours. FIG. 22B shows the flow cytometry
graph of regular 293 cells without CD4 receptors after incubation
with FITC-labeled siRNA nanocapsules conjugated with anti-CD4
antibody for 4 hours.
Example 13. Characterization of the Nanocapsules
[0171] TEM and dynamic light scattering were used to determine the
size and size distribution of single-siRNA nanocapsules.
Furthermore, electrophoresis and electrophoretic light scattering
was used to investigate the surface charge and the interaction
between siRNA and nanocapsules. Specifically, size, surface charge,
and encapsulation yield were investigated.
[0172] The stability of siRNA and single-siRNA nanocapsules in the
presence of nuclease and serum was compared. Degradability and
releasing profile of siRNA nanocapsules has been investigated in
the buffer of pH 7.4 and 5.4. siRNA complexed with lipofectamine
and siRNA nanocapsules was incubated with nuclease and human serum
for 1 hour. After RNA extraction, agarose gel electrophoresis
showed such nanocapsules could maintain the integrity of siRNA
inside (FIG. 6B), while siRNA is degraded at the same time in the
native state or when formulated with lipofectamine.
Example 14. Intracellular Delivery of the siRNA Nanocapsules
[0173] The siRNA delivery efficiency of the siRNA nanocapsules was
tested in a broad variety of cells. Examples of these cells include
HEK-293 T, Hela, CEM, PBMCs, and MSCs.
[0174] Fluorescence-labeled siRNA was used to investigate the
endocytosis pathway using endocytosis inhibitors. The efficiency
and toxicity of siRNA delivery by nanocapsules was compared with
those by the commercial liposome agents. Different types of siRNA
including, CCR5, EGFP, Gaussia luciferase was used to
quantitatively assess specificity of gene silencing.
Example 15. In Vitro Cellular Internalization
[0175] Cellular internalization studies were performed via
fluorescence microscopic technique and fluorescence-activated cell
sorting (FACS). HeLa cells were cultured in Dulbecco's modified
Eagle's medium (DMEM) supplemented with 10% bovine growth serum
(BGS) and 1% penicillin/streptomycin. Cells (20000 cells/well,
24-well plate) were seeded the day before adding the siRNA
nanocapsules.
[0176] siRNA nanocapsules with different concentrations were added
into the cell medium. After incubation at 37.degree. C. for 2 to 4
hrs, the cells were washed three times with PBS and either
visualized with a fluorescent microscope or trypsinized,
centrifuged, and re-suspended in PBS and analyzed via FACS.
Example 16. Cell Proliferation Assay
[0177] The toxicity of the polymer nanocapsules was assessed by the
MTT assay using native proteins as control. HEK 293T cells (7000
cells/well) were seeded on a 96-well plate the day before exposure
to the polymer nanocapsules. Nanocapsules with different
concentrations were incubated with the cells for 2-4 hrs, removed
from the mixture, and incubated with fresh media for 24 hrs. The
MTT solution (20 .mu.L) was added to each well and incubated for 3
h. The medium was then removed and 100 .mu.L DMSO was added onto
the cells. The plate was placed on a shaking table, 150 rpm for 5
min to thoroughly mix the solution, and then absorbance readings
were measured at 560 nm. Untreated cells were used as the 100% cell
proliferation control.
Example 17. Synthesis of Positively Charged Monomers for siRNA
Nanocapsules
[0178] The preparation of N-(3-((4-aminobutyl) amino) propyl)
acrylamide, N-(2-((2-aminoethyl)(methyl) amino) ethyl) acrylamide,
N-(piperazin-1-ylmethyl) acrylamide, and N-(2-(bis(2-aminoethyl)
amino) ethyl) acrylamide (i.e., positively charged monomers) was
achieved by reacting amine-containing precursor (N-(3-aminopropyl)
butane-1,4-diamine/N-methylpropane-1,3-diamine/piperazin-1-ylmethanamine/-
N,N'-bis(2-aminoethyl)ethane-1,2-diamine) with acrylic acid,
hydroxysuccinimide ester (AHS). Briefly, amine-containing
precursors and AHS were dissolved in chloroform at 0.5 mol/L,
respectively. Then, acrylic acid, hydroxysuccinimide ester was
added into each of the amine-containing precursors at the molar
ratio of 1:1 gradually at room temperature under vigorous stirring.
After overnight reaction, the mixture was filtered to remove
by-products. The filtrate was then dried by rotary evaporation,
followed by re-dispersing in water. After removal of insoluble
substance, the solution was lyophilized. Finally, the product was
purified by thin layer chromatography. The yield was from 37% to
63%. .sup.1HNMR was performed to confirm the final products.
[0179] .sup.1H NMR for N-(3-((4-aminobutyl) amino) propyl)
acrylamide produced the following peaks at 400 MHz, D.sub.2O: 6.46
(m, 1H, CH.sub.2.dbd.CHCO), 5.65 (m, 2H, CH.sub.2.dbd.CHCO), 3.27
(m, 2H, CONH--CH.sub.2), 2.78 (m, 10H, CH.sub.2--NH--CH.sub.2 and
CH.sub.2--NH.sub.2), 1.75 (m, 4H, NH--CH.sub.2--CH.sub.2), 1.23 (m,
4H, NH--CH.sub.2--(CH.sub.2).sub.2--CH.sub.2--NH)
[0180] .sup.1H NMR for N-(piperazin-1-ylmethyl) acrylamide produced
the following peaks at 400 MHz, D.sub.2O: 6.53 (m, 1H,
CH.sub.2.dbd.CHCO), 5.69 (m, 2H, CH.sub.2.dbd.CHCO), 3.91 (m, 2H,
CONH--CH.sub.2--N), 2.28 (m, 4H, CH.sub.2--NH--CH.sub.2), 2.75 (m,
4H, CH.sub.2--NH--CH.sub.2).
[0181] .sup.1H NMR for N-(2-((2-aminoethyl)(methyl) amino) ethyl)
acrylamide (400 MHz, D.sub.2O): 6.39 (m, 1H, CH.sub.2.dbd.CHCO),
5.58 (m, 2H, CH.sub.2.dbd.CHCO), 3.18 (m, 2H, CONH--CH.sub.2--N),
2.54 (m, 2H, CH.sub.2--NH--CH.sub.3), 3.22 (m, 3H,
NH--CH.sub.3)
[0182] .sup.1H NMR for N-(2-(bis(2-aminoethyl) amino) ethyl)
acrylamide produced the following peaks at 400 MHz, D.sub.2O: 6.41
(m, 1H, CH.sub.2.dbd.CHCO), 5.62 (m, 2H, CH.sub.2.dbd.CHCO), 3.14
(m, 2H, CONH--CH.sub.2--N), 2.48 (m, 6H, N--(CH.sub.2).sub.3), 2.65
(m, 4H, CH.sub.2--NH.sub.2).
Example 18. Synthesis of Positively Charged Monomers for siRNA
Nanocapsules
[0183] The preparation of N-(3-((4-((3-aminopropyl) amino) butyl)
amino) propyl) methacrylamide, N-(3-((4-aminobutyl) amino) propyl)
methacrylamide, N-(2-((2-aminoethyl)(methyl) amino) ethyl)
methacrylamide, N-(piperazin-1-ylmethyl) methacrylamide, and
N-(2-(bis(2-aminoethyl) amino) ethyl) methacrylamide (i.e.,
positively charged monomers) was achieved by by reacting
(N,N'-(butane-1,4-diyl) bis (propane-1,3-diamine)/N-(3-aminopropyl)
butane-1,4-diamine/N-methylpropane-1,3-diamine/piperazin-1-ylmethanamine/-
N,N-bis(2-aminoethyl) ethane-1,2-diamine)) with methacrylic acid,
hydroxysuccinimide ester. Briefly, amine-containing precursors and
methacrylic acid, hydroxysuccinimide ester were dissolved in 1 mL
chloroform at 0.5 mol/L, respectively. The MAHS was then added into
one of the amine-containing precursor at the molar ratio of 1:1
gradually at room temperature under vigorous stirring. After
overnight reacting, the mixture was filtered to remove by-products.
The filtrate was then dried by rotary evaporation, followed by
re-dispersing with ddH2O. After removal of insoluble substance, the
solution was lyophilized. Finally, the product was purified by thin
layer chromatography. The yield was from 32% to 61%. .sup.1HNMR was
performed to confirm the final products.
[0184] .sup.1H NMR for N-(3-((4-((3-aminopropyl) amino) butyl)
amino) propyl) methacrylamide produced the following peaks at 400
MHz, D.sub.2O: 1.89 (m, 3H, CH.sub.2.dbd.C(CH.sub.3)CO), 5.72 (m,
2H, CH.sub.2.dbd.C(CH.sub.3)CO), 3.27 (m, 2H, CONH--CH.sub.2), 2.78
(m, 10H, CH.sub.2--NH--CH.sub.2 and CH.sub.2--NH.sub.2), 1.75 (m,
4H, NH--CH.sub.2--CH.sub.2), 1.23 (m, 4H,
NH--CH.sub.2--(CH.sub.2).sub.2--CH.sub.2--NH).
[0185] .sup.1H NMR for N-(3-((4-aminobutyl) amino) propyl)
methacrylamide produced the following peaks at 400 MHz, D.sub.2O:
1.92 (m, 3H, CH.sub.2.dbd.C(CH.sub.3)CO), 5.75 (m, 2H,
CH.sub.2.dbd.C(CH.sub.3)CO), 3.27 (m, 2H, CONH--CH.sub.2), 2.78 (m,
10H, CH.sub.2--NH--CH.sub.2 and CH.sub.2--NH.sub.2), 1.75 (m, 4H,
NH--CH.sub.2--CH.sub.2), 1.23 (m, 4H,
NH--CH.sub.2--(CH.sub.2).sub.2--CH.sub.2--NH).
[0186] .sup.1H NMR for N-(piperazin-1-ylmethyl) methacrylamide
produced the following peaks at 400 MHz, D.sub.2O: 1.90 (m, 3H,
CH.sub.2.dbd.C(CH.sub.3)CO), 5.72 (m, 2H,
CH.sub.2.dbd.C(CH.sub.3)CO), 3.91 (m, 2H, CONH--CH.sub.2--N), 2.28
(m, 4H, CH.sub.2--NH--CH.sub.2), 2.75 (m, 4H,
CH.sub.2--NH--CH.sub.2).
[0187] .sup.1H NMR for N-(2-((2-aminoethyl)(methyl) amino) ethyl)
methacrylamide produced the following peaks at 400 MHz, D.sub.2O:
1.94 (m, 3H, CH.sub.2.dbd.C(CH.sub.3)CO), 5.62 (m, 2H,
CH.sub.2.dbd.C(CH.sub.3)CO), 3.18 (m, 2H, CONH--CH.sub.2--N), 2.54
(m, 2H, CH.sub.2--NH--CH.sub.3), 3.22 (m, 3H, NH--CH.sub.3).
[0188] .sup.1H NMR for N-(2-(bis(2-aminoethyl) amino) ethyl)
methacrylamide produced the following peaks at 400 MHz, D.sub.2O:
1.93 (m, 3H, CH.sub.2.dbd.C(CH.sub.3)CO), 5.67 (m, 2H,
CH.sub.2.dbd.C(CH.sub.3)CO), 3.14 (m, 2H, CONH--CH.sub.2--N), 2.48
(m, 6H, N--(CH.sub.2).sub.3), 2.65 (m, 4H, CH.sub.2--NH.sub.2).
Example 19. Synthesis of siRNA Nanocapsules
[0189] siRNA was dissolved in 20 uL RNase-free water at 20 uM. Then
a specific amount of positively charged monomers, tris-acrylamide
and glycerol dimethacrylate (molar ratio=5:5:1) dissolved in 0.5 mL
deoxygenated and deionized water was added to the microcentrifuge
tube. Radical polymerization from the surface of the acryloylated
protein was initiated by adding 0.02 mg of ammonium persulfate
dissolved in 2 .mu.L of deoxygenated and deionized water and 0.4
.mu.L of N,N,N',N'-tetramethylethylenediamine. The reaction was
allowed to proceed for 60 min in a nitrogen atmosphere.
Example 20. Effect of Positively Charged Monomers on siRNA
Knockdown of Gene Expression
[0190] To test the effect of the positively charged monomers
provided in FIG. 23, siRNA nanocapsules were prepared with siRNA
against luciferase gene expression with each of the 14 individual
positively charged monomers in FIG. 23. These knockdown experiments
were conducted in luciferase expressing CWR cells.
[0191] To prepare the polymer nanocapsules, siRNA was dissolved in
20 uL Rnase-free water at 20 uM. Then a specific amount of a
positively charged monomer selected from FIG. 23, tris-acrylamide
and glycerol dimethacrylate (total number of protonable amines of
positively charged monomer:tris-acrylamide:glycerol
demethacrylate=15:5:1) were dissolved in 0.5 mL deoxygenated and
deionized water was added to the microcentrifuge tube. Radical
polymerization from the surface of the acryloylated protein was
initiated by adding 0.02 mg of ammonium persulfate dissolved in 2
.mu.L of deoxygenated and deionized water and 0.4 .mu.L of
N,N,N',N'-tetramethylethylenediamine. The reaction was allowed to
proceed for 60 min in a nitrogen atmosphere.
[0192] CWR cells were treated with siRNA nanocapsules at 50 nM for
4 h at 37.degree. C. in serum-free medium. Then mediums were
changed to DMEM with 10% Bovine Fetal Serum. After 48 h, the
luciferase activity was determined using a 96-wells plate reader
(FIG. 11).
Example 21. Effect of Different Crosslinkers on siRNA Knockdown of
Gene Expression
[0193] To test the effect of the crosslinkers provided in FIG. 24
on gene knockdown, siRNA nanocapsules were prepared with siRNA
against luciferase gene expression with 1,3-glycerol
dimethacrylate, Glycerol 1,3-diglycerolate diacrylate,
N,N'-bis(acryloyl)cystamine, bis[2-(methacryloyloxy)ethyl]
phosphate, or N,N'-Methylenebisacrylamide (FIG. 24). These
knockdown experiments were conducted in luciferase expressing CWR
cells.
[0194] To prepare the polymer nanocapsules, siRNA was dissolved in
20 uL Rnase-free water at 20 uM. Then a specific amount of
acryl-spermine, tris-acrylamide and a crosslinker from FIG. 24
(total number of protonable amines of positively charged
monomer:tris-acrylamide:crosslinker=15:5:1) were dissolved in 0.5
mL deoxygenated and deionized water was added to the
microcentrifuge tube. Radical polymerization from the surface of
the acryloylated protein was initiated by adding 0.02 mg of
ammonium persulfate dissolved in 2 .mu.L of deoxygenated and
deionized water and 0.4 .mu.L of
N,N,N',N'-tetramethylethylenediamine. The reaction was allowed to
proceed for 60 min in a nitrogen atmosphere.
[0195] CWR cells were treated with siRNA nanocapsules at 50 nM for
4 h at 37.degree. C. in serum-free medium. Then mediums were
changed to DMEM with 10% Bovine Fetal Serum. After 48 h, the
luciferase activity was determined using a 96-wells plate reader
(FIG. 12).
Example 21. Effect of Different Neutral Monomers on siRNA
Nanocapsule Size
[0196] To test the effect of the neutral monomers provided in FIG.
25 on nanocapsules size, siRNA nanocapsules were prepared with
1N-(1,3-dihydroxy-2-(hydroxymethyl) propan-2-yl) acrylamide,
acrylamide, N-(hydroxymethyl)acrylamide, 2-hydroxyethyl acrylate,
or 2-hydroxyethyl methacrylate (FIG. 25).
[0197] To prepare the polymer nanocapsules, siRNA was dissolved in
20 uL Rnase-free water at 20 uM. Then a specific amount of
acryl-spermine, a neutral monomer selected from FIG. 25, and
glycerol dimethacrylate (total number of protonable amines of
acryl-spermine:neutral co-monomer:glycerol demthacrylate=15:5:1)
were dissolved in 0.5 mL deoxygenated and deionized water was added
to the microcentrifuge tube. Radical polymerization from the
surface of the acryloylated protein was initiated by adding 0.02 mg
of ammonium persulfate dissolved in 2 .mu.L of deoxygenated and
deionized water and 0.4 .mu.L of
N,N,N',N'-tetramethylethylenediamine. Once the siRNA nanocapsules
were formed, the size of the polymer nanocapsules were measured
(FIG. 13).
* * * * *