U.S. patent application number 15/956409 was filed with the patent office on 2018-10-25 for recombinant cancer therapeutic cytokine.
The applicant listed for this patent is Virginia Commonwealth University. Invention is credited to Praveen Bhoopathi, Swadesh K. Das, Luni Emdad, Paul B. Fisher, Devanand Sarkar, Upneet Sokhi.
Application Number | 20180305429 15/956409 |
Document ID | / |
Family ID | 52008547 |
Filed Date | 2018-10-25 |
United States Patent
Application |
20180305429 |
Kind Code |
A1 |
Fisher; Paul B. ; et
al. |
October 25, 2018 |
RECOMBINANT CANCER THERAPEUTIC CYTOKINE
Abstract
Recombinant therapeutic cytokines ("therakines") for the
treatment of cancer are provided. The recombinant therakines
include a truncated region of MDA-7/TL-24 ("M4") not normally found
in nature that has anti-cancer activity and a secretory signal
which causes secretion of the therakine from plasmid/virus
transduced normal and cancer cells and interaction of the therakine
to MDA-7/IL-24 receptors on adjacent, neighboring and distant
cancer cells. Therakine interaction results in bystander killing of
the target cancer cell as well as adjacent, neighboring and distant
cancer cells.
Inventors: |
Fisher; Paul B.; (Richmond,
VA) ; Bhoopathi; Praveen; (Richmond, VA) ;
Das; Swadesh K.; (Richmond, VA) ; Emdad; Luni;
(Richmond, VA) ; Sarkar; Devanand; (Richmond,
VA) ; Sokhi; Upneet; (Richmond, VA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Virginia Commonwealth University |
Richmond |
VA |
US |
|
|
Family ID: |
52008547 |
Appl. No.: |
15/956409 |
Filed: |
April 18, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14895138 |
Dec 1, 2015 |
9951114 |
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PCT/US14/40793 |
Jun 4, 2014 |
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15956409 |
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61830814 |
Jun 4, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07K 14/54 20130101;
C07K 2319/055 20130101; C07K 14/5428 20130101; A61K 38/00
20130101 |
International
Class: |
C07K 14/54 20060101
C07K014/54 |
Claims
1-5. (canceled)
6. A nucleic acid sequence encoding a recombinant cytokine
comprising: i) a fragment of MDA-7/IL-24 that has antitumor
activity and interacts with MDA-7/IL-24 receptors on the surface of
cancer cells; and ii) a heterologous secretory leader sequence.
7. The nucleic acid sequence of claim 6, wherein said fragment of
MDA-7/IL-24 comprises SEQ ID NO: 1.
8. (canceled)
9. The nucleic acid sequence of claim 6, wherein said heterologous
secretory leader sequence comprises SEQ ID NO: 3.
10. The nucleic acid sequence of claim 6, wherein the nucleic acid
sequence comprises SEQ ID NO: 6.
11. A recombinant vector comprising the nucleic acid of claim 6,
wherein said nucleic acid sequence is operably linked to a
promoter.
12.-15. (canceled)
16. The recombinant vector of claim 11, wherein said promoter is a
cancer specific or cancer selective promoter.
17. The recombinant vector of claim 11, wherein said recombinant
vector is a viral vector.
18.-19. (canceled)
20. The recombinant vector of claim 11, wherein the promoter is
selected from the group consisting of: a truncated CCN1 promoter,
an mda-9/syntenin promoter, a PEG-Prom, an AEG-1-Prom, and a CMV
promoter.
21. A nanoparticle comprising a nucleic acid sequence encoding a
recombinant cytokine comprising: i) a fragment of MDA-7/IL-24 that
has antitumor activity and interacts with MDA-7/IL-24 receptors on
the surface of cancer cells; and ii) a heterologous secretory
leader sequence, wherein: a) said heterologous secretory leader
sequence comprises SEQ ID NO: 3, or b) said recombinant cytokine
comprises SEQ ID NO: 5, wherein said nucleic acid sequence is
operably linked to a promoter.
22. A method of treating or preventing cancer and/or cancer
metastasis in a subject in need thereof, comprising administering
to said subject a recombinant cytokine comprising: i) a fragment of
MDA 7/IL-24 that has antitumor activity and interacts with
MDA-7/IL-24 receptors on the surface of cancer cells; and ii) a
heterologous secretory leader sequence.
23. The method of claim 22, wherein said recombinant cytokine
comprises SEQ ID NO: 1.
24. The method of claim 22, wherein said recombinant cytokine is
administered as a protein.
25. The method of claim 22, wherein said recombinant cytokine is
administered by administering a vector comprising a nucleic acid
sequence that encodes said recombinant cytokine.
26. The method of claim 24, wherein said protein comprises SEQ ID
NO: 1.
27. The method of claim 25, wherein said nucleic acid sequence
comprises SEQ ID NO: 2.
28. The method of claim 22, wherein said cancer is selected from
the group consisting of osteosarcoma, ovarian carcinoma, breast
carcinoma, melanoma, hepatocarcinoma, lung cancer, brain cancer,
colorectal cancer, hematopoietic cell cancer, prostate cancer,
cervical carcinoma, retinoblastoma, esophageal carcinoma, bladder
cancer, neuroblastoma, renal cancer, gastric cancer, and pancreatic
cancer.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
[0001] The invention generally relates to novel recombinant
therapeutic cytokines ("therakines") for the treatment of cancer.
In particular, the invention provides recombinant cytokines which
include i) an "M4" region of MDA-7/IL-24 that has anti-cancer
activity and ii) a secretory signal which permits the therakine to
be secreted from plasmid/virus transduced normal or cancer cells
and then bind to and exhibit a bystander cell-killing effect in
neighboring cancer cells.
BACKGROUND OF THE INVENTION
[0002] IL-10 gene family member melanoma differentiation associated
gene-7/Interleukin-24 (MDA-7/IL-24) displays profound
broad-spectrum anti-cancer therapeutic activity, both in vitro in
primary and established human cancer cells lines, in vivo in nude
mouse and transgenic animal models and in a Phase I/II clinical
trial in patients with advanced cancers (including carcinomas and
melanomas). A major contributing factor in the ability of
MDA-7/IL-24 to show such robust anti-cancer activity in viva is its
profound "bystander" antitumor activity upon secretion from
plasmid/virus transduced cells. During secretion from transduced
cell, a 47 amino acid secretory signal is cleaved from MDA-7/IL-24.
The secreted form of the protein interacts with dimeric receptors,
e.g. IL-20R1/IL-20R2, IL-22R/IL-20R2 and IL-20R1/IL-22R on the
surface of neighboring cancer cells it encounters after secretion,
thereby directly inducing growth suppression, apoptosis and toxic
autophagy in the tumor cells. Secreted MDA-7/IL-24 protein also
induces secondary anti-tumor effects by inhibiting tumor
angiogenesis and promoting an anti-tumor immune response.
Remarkably, MDA-7/IL-24 lacks harmful effects on normal cells or
tissues.
[0003] There is a need in the art to further extend knowledge
concerning the mechanism of action of MDA-7/IL-24 and to develop
alternative forms of this protein. Especially desirable would be
forms of the protein that retain full bystander activity, and which
are readily administrable as proteins/polypeptide, or amenable to
incorporation into recombinant constructs (e.g. vectors) for
administration to cancer patients.
SUMMARY OF THE INVENTION
[0004] This disclosure describes a novel bioactive synthetic
cytokine, a "therakine", which unexpectedly displays potent
"bystander" anti-cancer activity in tumor cells containing dimeric
MDA-7/IL-24 receptors. This new cytokine was discovered as a result
of mutational analysis that was performed to elucidate the role of
specific regions of MDA-7/IL-24 in promoting cancer cell death. The
investigations resulted in identification of "M4", a region of
MDA-7/IL-24 containing amino acids 104 to 206 of the MDA-7/IL-24
protein (103 amino acids total). Notably, M4 lacks 103 amino
terminal amino acids, including the 47 amino acid secretory region
(secretory motif) of MDA-7/IL-24. This truncated, mutant form of
the MDA-7/IL-24 was as potent as the full-length protein in
inducing cancer-specific cell death in cells in which it is
produced (Dash et al. Cytokine & Growth Factor Reviews; 21
(2010) 381-391). Although this observation was exciting, the
utility of the M4 mutant as a therapeutic for cancer was assumed to
be limited because it lacks 103 amino terminal amino acids,
including the 47 amino acid secretory region. M4 is thus not
secreted and is therefore incapable of exhibiting classical
"bystander" antitumor activity on its own. Instead, the use of M4
as an anticancer agent would require direct delivery of the
molecule to the interior of a cancer cell in order to benefit from
its anti-cancer activity.
[0005] The "bystander" antitumor activity of MDA-7/IL-24 depends
critically on cytokine signaling through receptors on the surface
of cancer cells. Productive interaction between MDA-7/IL-24 and
receptors requires a particular three-dimensional configuration of
MDA-7/IL-24 that results in precise positioning of residues on the
surface of the protein. While in theory M4 could be modified to be
secreted, it was believed that the resulting polypeptide, lacking
103 amino acids of the native MDA-7/IL-24, would surely lack the
preferred shape to interact with surface receptors and hence would
not be capable of exhibiting the bystander effect. However, when
this hypothesis was tested, the results were surprising and
unanticipated in that addition of a secretory signal to M4 resulted
in a recombinant molecule, which displayed "bystander" activity
equivalent to that of full length MDA-7/IL-24. Like full length
MDA-7/IL-24, this truncated and modified recombinant polypeptide
exhibits direct and distant killing of cancer cells, both in vitro
and in vivo; activity in animal models shows that the recombinant
secreted protein is active and can reach distant tumors through the
circulation. In contrast to MDA-7/IL-24, which promotes its own
production in cells, M4 does not induce this effect, but like
MDA-7/IL-24, M4 does induce production of SARI (Suppressor of AP-1,
regulated by Interferon) (Su et al., Proc Natl Acad Sci USA; 105
(2012) 20906-20911; Dash et al., Cancer Res; 74 (2014) 563-574),
which is required for cell killing by MDA-7/IL-24.
[0006] This novel "therakine" (therapeutic cytokine) thus
represents a new therapeutic molecule for the treatment of diverse
cancers and is a paradigm shifting observation with respect to
requirements for cytokine activity. In particular, this new
truncated version of MDA-7/IL-24, which does not normally exist
innately in nature, can be readily incorporated into heterologous
constructs designed for targeted delivery to cancer cells, as
described in detail herein. The shorter length of the polypeptide
is advantageous in terms of production and manufacturing, and yet
retains the most desirable characteristics of the natural parent
molecule, MDA-7/IL-24. Other features and advantages of the present
invention will be set forth in the description of invention that
follows, and in part will be apparent from the description or may
be learned by practice of the invention. The invention will be
realized and attained by the compositions and methods particularly
pointed out in the written description and claims hereof.
[0007] It is an object of this invention to provide recombinant
cytokines comprising a fragment of MDA-7/IL-24 that i) has
antitumor activity and ii) interacts with MDA-7/IL-24 receptors on
the surface of cancer cells; and a secretory leader sequence. In
some aspects, the fragment of MDA-7/IL-24 comprises amino acids 104
to 206 of MDA-7/IL-24 (SEQ ID NO: 1). The secretory leader sequence
may be a heterologous secretory leader sequence, for example, the
Flt3 sequence of SEQ ID NO: 3. In some aspects, an amino acid
sequence of the recombinant cytokine is represented by SEQ ID NO:
5.
[0008] The invention further provides nucleic acid sequences
encoding a recombinant cytokine comprising a fragment of
MDA-7/IL-24 that i) has antitumor activity and ii) interacts with
MDA-7/IL-24 receptors on the surface of cancer cells; and a
secretory leader sequence. In some aspects, the fragment of
MDA-7/IL-24 comprises amino acids 104 to 206 of MDA-7/IL-24 (SEQ ID
NO: 1) encoded by the nucleic acid represented by SEQ ID NO: 2. The
secretory leader sequence may be a heterologous secretory leader
sequence such as the Flt3 sequence (SEQ ID NO: 3) encoded by the
nucleic acid represented by SEQ ID NO: 4. In some aspects, the
nucleic acid sequence is represented in SEQ ID NO: 6.
[0009] The invention also provides recombinant vectors comprising a
nucleic acid sequence encoding a recombinant cytokine comprising a)
a fragment of MDA-7/IL-24 that i) has antitumor activity and ii)
interacts with MDA-7/IL-24 receptors on the surface of cancer
cells; and b) a secretory leader sequence, wherein said nucleic
acid sequence is operably linked to a promoter. In some aspects,
the fragment of MDA-7/IL-24 comprises amino acids 104 to 206 of
MDA-7/IL-24 (SEQ ID NO: 1) encoded by the nucleic acid represented
by SEQ ID NO: 2. The secretory leader sequence may be a
heterologous secretory leader sequence such as the Flt3 sequence
(SEQ ID NO: 3) encoded by the nucleic acid represented by SEQ ID
NO: 4. In some aspects, the nucleic acid sequence is represented in
SEQ ID NO: 6. The recombinant vector may further comprise a cancer
specific or cancer selective promoter operationally linked to the
nucleic acid encoding the recombinant cytokine. The recombinant
vector is, in some cases, a viral vector such as, for example, an
adenoviral vector, a lentiviral vector, a herpes simplex virus, a
measles virus, and a vaccinia virus. In other aspects, the
recombinant vector comprises at least one additional gene of
interest encoding one or more of an anticancer agent, an imaging
agent and at least one gene that is required for viral replication.
The at least one additional gene of interest is also generally
operably linked to a promoter. The promoters that are used in the
recombinant vector may be, for example, a truncated CCN1 promoter,
an mda-9/syntenin promoter, a PEG-Prom, an AEG-1-Prom, or a CMV
promoter.
[0010] The invention further provides nanoparticles comprising a
nucleic acid sequence encoding a recombinant cytokine comprising a
fragment of MDA-7/IL-24 that i) has antitumor activity and ii)
interacts with MDA-7/IL-24 receptors on the surface of cancer
cells; and a secretory leader sequence. The nucleic acid sequence
is operably linked to a promoter.
[0011] The invention also provides methods of treating or
preventing cancer and/or cancer metastasis in a subject in need
thereof, comprising
[0012] administering to said subject a recombinant cytokine
comprising a fragment of MDA-7/IL-24 that i) has antitumor activity
and ii) interacts with MDA-7/IL-24 receptors on the surface of
cancer cells; and a secretory leader sequence. In some aspects, the
recombinant cytokine has an amino acid sequence as set forth in SEQ
ID NO: 1. In some aspects, the recombinant cytokine is administered
as a protein, e.g. having an amino acid sequence as set forth in
SEQ ID NO: 1. In other aspects, the recombinant cytokine is
administered by administering a vector comprising a nucleic acid
sequence that encodes the recombinant cytokine, e.g. a nucleic acid
sequence as set forth in SEQ ID NO: 2. In some cases, the cancer is
selected from the group consisting of osteosarcoma, ovarian
carcinoma, breast carcinoma, melanoma, hepatocarcinoma, lung
cancer, brain cancer, colorectal cancer, hematopoietic cell cancer,
prostate cancer, cervical carcinoma, retinoblastoma, esophageal
carcinoma, bladder cancer, neuroblastoma, renal cancer, gastric
cancer, and pancreatic cancer.
[0013] The invention also provides recombinant cDNAs comprising the
nucleotide sequence set forth as SEQ ID NO: 2 The recombinant cDNAs
do not encode full length MDA-7/IL-24.
[0014] The invention also provides isolated recombinant cytokines
comprising a fragment of MDA-7/IL-24 that i) has antitumor activity
and ii) interacts with MDA-7/IL-24 receptors on the surface of
cancer cells. In some aspects, an amino acid sequence of the
isolated recombinant cytokine comprises SEQ ID NO: 1. The isolated
recombinant cytokine may further comprise a secretory leader
sequence. In some aspects, an amino acid sequence of the isolated
recombinant cytokine comprises SEQ ID NO: 3.
[0015] The invention further provides a composition comprising the
isolated recombinant cytokine as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1. Schematic representation of Flt3-Mda-7 and Flt3-M4
construction.
[0017] FIGS. 2A and B. MDA-7/IL-24 and M4 are present in
conditioned medium (CM). (A) Western blot analysis of MDA-7/IL-24
and M4 in total cellular lysates. (B) Western blot analysis of
MDA-7/IL-24 and M4 in CM. Experiment was repeated at least three
times and representative images of Western blots are shown.
[0018] FIG. 3A-C. Secreted MDA-7/IL-24 and M4 induce apoptosis in
DU145 but not in A549 cells. (A) Western blot analysis of DU145 or
A549 cells; (B) TUNEL assay of DU145 or A549 cells; (C) DNA content
of DU145 or A549 cells as measured by FACS. All the experiments
were repeated at least three times and representative images are
shown.
[0019] FIGS. 4A and B. Western blot analysis of pro- and
anti-apoptotic molecules secreted by DU145 and A549 cells after
exposure to MDA-7/IL-24 and M4. A, DU145 cells; B, A549 cells.
Experiment was repeated at least three times and representative
images of Western blots are shown.
[0020] FIGS. 5 A and B. Tumor volume reduction in vivo after
subcutaneous tumor cell implants: secreted MDA-7/IL-24 and M4
promotes profound `bystander` activity in DU145 cells with a
minimal effect on A549 cells. A, DU145 cells implanted on both
sides of mice; B, DU145 cells implanted on the left side and A549
cells implanted on the right side. Tumors were treated as indicated
with Flt3-MDA-7 or Flt3-M4 constructs.
[0021] FIG. 6. TUNEL staining showing bystander effect of secreted
MDA-7 and M4 in untreated receptor positive distant DU145 tumors,
but not in receptor negative A549 tumors.
[0022] FIG. 7. Graphical representation of "bystander" activity of
secreted MDA-7/IL-24 and M4 in tumors arising from implanted DU145
cells, A549 receptor negative cells, and receptor positive A549
(cells reconstituted with IL20 or IL22).
[0023] FIG. 8. Secreted MDA-7/IL-24 and M4 induces apoptosis in
IL-20/IL-22 receptor positive cells. 1M-PHFA (2.times.10.sup.6)
cells were infected with adenovirus expressing either null,
Flt3-MDA-7 or Flt3-M4 (5000 vp) in 10 cm plates for 48 hours.
Conditioned media (CM) was collected as described in FIG. 2. A549
cells (2.times.10.sup.6) (Receptor negative) or A549 IL-20R2/A549
IL-22R1 (receptor reconstituted cells) were plated overnight and
the medium was replaced with 5 nil of either CM collected from
Ad-Null, or Ad-Flt3-M4, or Ad-Flt3-MDA-7 infected cells and
cultured for 72 hours. This media was replaced with fresh
conditioned medium after 48 hours. Cells were then collected and
used for western blotting analysis for TARP cleavage. All the
experiments were repeated at least three times and representative
images are shown.
[0024] FIG. 9. His-M4 or His-MDA-7 pure protein shows
receptor-mediated biological activity in cancer cells. A549
(without a complete dimeric receptor pair) or DU145 cells (dimeric
receptor positive) were cultured for 24 hours (.about.60-70%
confluence), cells were then trypsinized and plated in each well of
96-well plate. 8 wells for each treatment were used for performing
MTT assays. The cells were treated either with His-M4 or His-MDA-7
at the indicated doses (reconstituted lyophilized protein) and
cultured for an additional 96 hours and MTT assays were performed
according to the standard protocol. Experiments were repeated at
least three times and representative line graph are shown. These
results indicate that His-M4 or His-MDA-7 exert equal biological
activity in a receptor-dependent manner in cancer cells.
[0025] FIG. 10. His-M4 or His-MDA-7 pure protein induces PARP
cleavage and ER stress markers. DU145 or A549 cells were cultured
for 24 hours (.about.50-60% confluence), and treated with 10
.mu.g/ml of His-M4 or His-MDA-7 and cultured for an additional 96
hours. Cell lysates were subjected to western blotting analysis for
PARP, GRP-78, Bcl2, GADD45 and GADD153 protein expression using
specific antibodies.
[0026] FIG. 11 A-D. A, amino acid sequence of M4 (SEQ ID NO: 1); B,
nucleotide sequence encoding M4 (SEQ ID NO: 2); C, amino acid
sequence of exemplary secretion signal (from Flt3, SEQ ID NO: 3);
D, nucleotide sequence encoding Flt3 secretion signal (SEQ ID NO:
4).
[0027] FIGS. 12 A and B. A, amino acid sequence of an exemplary
recombinant M4 therakine (SEQ ID NO: 5); B, nucleotide sequence
encoding the exemplary recombinant M4 therakine shown in A (SEQ ID
NO: 6).
DETAILED DESCRIPTION
[0028] Provided herein are new recombinant therapeutic cytokines
("therakines") which are used, for example, in the treatment of
cancer. The recombinant therakines comprise an "M4" region or
fragment or portion of MDA-7/IL-24, e.g. the contiguous amino acid
residues from approximately residue 104 to approximately residue
206, inclusive (e.g. generally about 103 amino acids in total
length). In some aspects, M4 includes amino acids 104 to 206,
inclusive, of MDA-7/IL-24. The molecules are referred to herein as
"recombinant M4 therakines" and/or by equivalent terminology. The
primary amino acid sequence of an exemplary truncated segment of
MDA-7/IL-24 is set forth in SEQ ID NO: 1 (FIG. 11A). In some
aspects, the recombinant M4 therakine includes a leader sequence
that causes secretion of the polypeptide (e.g. a "secretory" or
"signal" sequence) that is attached at the amino terminus of the
polypeptide. The primary amino acid sequence of an exemplary
secretory sequence (that of the Flt3 ligand) is set forth in SEQ ID
NO: 3 (FIG. 11C). The primary amino acid sequence of an exemplary
recombinant therakine comprising M4 and the Flt3 secretory sequence
is presented in SEQ ID NO: 5 (FIG. 12A). Exemplary nucleic acids
encoding the peptides/polypeptides of SEQ ID NOS: 1, 3 and 5 are
set forth in SEQ ID NOS: 2, 4 and 6, respectively (see FIGS. 11 and
12).
[0029] Those of skill in the art will recognize that the primary
amino acid sequence of the peptides and polypeptides of the M4
component of the recombinant M4 therakine need not be the exact
sequence that is set forth in SEQ ID NO: 1. Various modifications
of those sequences can be tolerated in the therakine, so long as
full bystander activity (bystander activity comparable to or equal
to or greater than that of MDA-7/IL-24) is retained by the
translated polypeptide. For example, at least 25, 30, 35, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% of the bystander
activity of MDA-7/IL-24 is retained, and in some cases, the
activity of the recombinant therakine may exceed that of native
MDA-7/IL-24, e.g. may be 25, 30, 35, 40, 45, 50, 55, 60, 65, 70,
75, 80, 85, 90, 95, or 100% (2-fold) greater, or more (e.g. about
2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 6.5, 7.0, 7.5, 8.0, 8.5,
9.0, 9.5 or, 10 or more (e.g. up to 100 or 500 or even 1000 fold
greater, including fold-values of all integers in between these
ranges).
[0030] The recombinant M4 therakines thus not only function to kill
cancer cells in which they are expressed (direct killing), but they
also advantageously exhibit the ability to be secreted from both
normal and cancer cells in which they are produced and to interact
with and kill or damage adjacent, nearby and distant cancer cells,
at least those which display canonical MDA-7/IL-24 receptors. Thus,
the recombinant M4 therakines surprisingly do have the ability to
interact with MDA-7/IL-24 receptors and as a result, they have
"bystander" or "distant killing" activity. However, the anti-cancer
activity of the therakine is not limited to bystander activity, but
typically also includes the ability to induce production of
Suppresssor of AP-1 regulated by interferon (SARI), at the same or
similar level as MDA-7/IL-24, e.g., at least 25, 30, 35, 40, 45,
50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100% or more of the
level of SARI activity induced by MDA-7/IL-24.
[0031] Those of skill in the art are familiar with methods to
measure activity levels of cytokines, e.g. levels of receptor
binding, levels of cancer cell killing, levels of SARI induction,
amount of tumor volume reduction, etc. Exemplary methods are
described in the Examples section below.
[0032] Modifications of the sequences disclosed herein (e.g. of the
M4 component of the recombinant M4 therakine, and/or of a secretory
sequence such as that or SEQ ID NO: 3, and/or of the exemplary
recombinant M4 therakine such as that of SEQ ID NO 5) include but
are not limited to: conservative or non-conservative amino acid
substitutions; changes in the sequence to facilitate manipulation,
production and/or isolation and purification of the polypeptide
(e.g. the addition of tagging sequences such as His tags, or of
detectable residues such as tyrosine); or inclusion of residues
that are introduced as a result of changes in the encoding nucleic
acid sequence for ease of cloning (e.g. introduction of restriction
sites, etc, into the encoding nucleic acid); or amino acid sequence
changes to increase or decrease solubility; changes in sequences
which are susceptible to proteolytic cleavage to promote stability
of the polypeptide; or the introduction of proteolytic cleavage
sites to facilitate or foster desired patterns of cleavage;
addition or removal of from about 1 to about 5 amino acids (e.g. 1,
2, 3, 4, or 5) from the amino and/or carboxyl termini, etc. In
addition, various mutations that can increase the activity of M4
may be introduced, e.g. mutation of lysine at position 123, which
is involved in ubiquitination and consequent degradation, to e.g. R
or another suitable residue to render the protein less susceptible
to degradation but maintain (or even increase) activity or
effective activity [see Tian H, Li L, Zhang B, Di J, Chen F, Li H,
Liu J, Pei D, Zheng J. Critical role of lysine 123 in the
ubiquitin-mediated degradation of MDA-7/IL-24. J Interferon
Cytokine Res. 2012 December; 32(12):575-582]. Generally, a
recombinant M4 therakine variant will be or will comprise an amino
acid sequence that has at least about 50, 55, 60, 65, 70, 75, 80,
85, 90, 95, 96, 97, 98, or 99% sequence identity, or at least about
50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, or 99% sequence
similarity, to the amino acid sequence presented in SEQ ID NO: 1,
when aligned using a known identity/similarity calculating program.
As a caveat, the therakine sequence may be a sequence that is
longer than that which is set forth in SEQ ID NO: 1 but the longer
sequence is not MDA-7/IL-24, although is may have the same number
of amino acids or even more amino acids than MDA-7/IL-24. In
sequences longer than SEQ ID NO: 1, SEQ ID NO: 1 is flanked by one
or more heterologous, non-native amino acids or amino acid
sequences (amino acids or amino acid sequences that do not flank
SEQ ID NO: 1 in nature) at one or both of the amino and carboxyl
termini.
[0033] Other means of increasing the effective activity of the M4
therakine are also contemplated. For example, "small molecule"
stabilizers such as SC144 may be used [see Xu S, Oshima T, Imada T,
Masuda M, Debnath B, Grande F, Garofalo A, Neamati N. Stabilization
of MDA-7/IL-24 for colon cancer therapy. Cancer Lett. 2013 Jul. 28;
335(2):421-30]. While the activity of an individual molecule of M4
therakine may or may not be increased due to such stabilizers
(either mutations of the sequence or by interactions with small
molecules), the effective activity (the amount or level of activity
that is observed or measured) may increase due to the increased
lifetime of the therapeutic molecules.
[0034] With respect to the nucleic acid sequences disclosed herein,
those of skill in the art will recognize that the particular
sequences are exemplary, because, for example, the genetic code is
redundant so that many other sequences would encode both the
recombinant M4 therakine polypeptides that are disclosed explicitly
herein, and the modified active variants described above. For
example, the sequences may be modified according to preferred codon
usages for particular species of animals (e.g. experimental animal
models), or for ease of cloning (e.g. to introduce restriction
sites or sequences which base pair with vector sequences, to
introduce or remove stop and/or start codons, or for any other
reason, e.g. the nucleic acid sequence may be modified to encode
changes to the amino acid sequence as described above, for example,
to decrease degradation through ubiquitination by mutation of Lys
123, or to encode a stabilizing small molecule, etc. Generally,
variants of SEQ ID NO: 2 have at least about 50, 55, 60, 65, 70,
75, 80, 85, 90, 95, 96, 97, 98, or 99% sequence identity, or at
least about 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, or
99% sequence similarity, to SEQ ID NO: 2, when aligned using a
known identity/similarity calculating program. Further, nucleic
acid sequences which are longer than that which is set forth in SEQ
ID NO: 2 are encompassed, so long as at least one region or portion
of the sequence encodes a sequence with the level of homology or
similarity to SEQ ID NO: 2 indicated herein, with the caveat that
such nt sequences do not encode a full length MDA-7/IL-24.
Lengthier sequence may, for example, encode 2 or more copies of a
sequence that encodes the M4 cytokine. All such nucleotide
sequences are encompassed by the present invention, including DNA,
cDNA, mRNA, DNA/RNA hybrids, etc. whether single or double
stranded. mRNA sequences encoding the therakine include at least
one heterologous nucleotide or nucleotide sequence that is not
present in native or natural mRNAs encoding the parent MDA-7/IL-24,
e.g. flanking the coding sequence such as at either or at both the
3' and 5' termini.
[0035] The present invention also provides cDNA sequences encoding
the M4 therakine. The sequences of the cDNAs are fragments
(portions, segments, etc.) of the full-length cDNA that encodes the
parent molecule, MDA-7/IL-24, the parent molecules being encoded by
a gene with multiple introns (Huang et al., 2001. Oncogene 20(48):
7051-63). The M4 start sequence (GAGAGCT) is positioned near the
beginning of exon 5 such that exons 5, 6 and 7 are common between
the parent MDA-7 and M4. The genomic sequence that encompasses M4
thus has 2 introns, one between exons 5 and 6, and the second
between exons 6 and 7. Neither intron is present in the cDNA. One
exemplary cDNA sequence is presented in SEQ ID NO: 1. mRNA
sequences translated from this cDNA are also encompassed by the
invention.
[0036] In one aspect, the secretory signal of the recombinant M4
therakine is the exemplary Flt3 secretory sequence (SEQ ID NO: 3).
However, many other signal sequences may also be used in the
practice of the invention, including but not limited to: secretory
signals from molecules including the melanoma differentiation
associated gene-7/Interleukin-24 endogenous secretory peptide,
interferon gamma (IFN.gamma.), interleukin-8 (IL-8), matrix
metalloproteinase-14 (MMP-14), transforming growth factor beta
(TGF-.beta.), insulin-like growth factor-binding protein 2
(IGFBP2), Dickkopf-related protein 1 (DKK1), secreted protein
acidic and rich in cysteine (SPARC), secreted phosphoprotein 1
(SPP1) and interleukin-12 (IL-12), interleukin-10 (IL-10), signal
peptide Gaussia Luciferase (sp-Gluc), etc. Any secretory leader
sequence may be employed, so long as the final recombinant M4
therakine retains bystander cancer cell killing activity as
described herein.
[0037] The invention also comprises methods of using the
recombinant M4 therakine described herein. Exemplary uses include
but are not limited to its use for treating cancer in a patient or
subject in need thereof, and its use in manufacturing a medicament
for treating cancer. In one aspect, in order to be used for
treatment methods, nucleic acid sequences encoding the therakine
are incorporated into a vector that is suitable for administration
to a subject. Within the vector, the recombinant M4 therakine is
operably linked to at least one element such as a promoter and/or
other expression-related element (e.g. an enhancer, etc.) that
drives expression of the therakine after administration, e.g. that
drives or promotes or causes expression within the subject to whom
the vector is administered, particularly within cancer cells in the
subject. Suitable vectors that may be used for this purpose are
described below, as well as suitable promoters and other elements
that cause (drive, facilitate, etc.) productive transcription and
translation of the recombinant M4 therakine, i.e., transcription
into mRNA that is translated into an active gene product, i.e. a
secretable recombinant M4 polypeptide with bystander activity. In
another aspect, the therakine is administered as a protein.
Vectors
[0038] Vectors which may be used in the practice of the invention
include both viral and non-viral vectors. Exemplary non-viral
vectors that may be employed include but are not limited to, for
example: cosmids or plasmids; and, particularly for cloning large
nucleic acid molecules, bacterial artificial chromosome vectors
(BACs) and yeast artificial chromosome vectors (YACs); as well as
liposomes (including targeted liposomes); cationic polymers;
ligand-conjugated lipoplexes; polymer-DNA complexes;
poly-L-lysine-molossin-DNA complexes; chitosan-DNA nanoparticles;
polyethylenimine (PEI, e.g. branched PEI)-DNA complexes; various
nanoparticles and/or nanoshells such as multifunctional
nanoparticles, metallic nanoparticles or shells (e.g. positively,
negatively or neutral charged gold particles, cadmium selenide,
etc.); ultrasound-mediated microbubble delivery systems; various
dendrimers (e.g. polyphenylene and poly(amidoamine)-based
dendrimers; etc).
[0039] In addition, viral vectors may be employed. Exemplary viral
vectors include but are not limited to: bacteriophages, various
baculoviruses, retroviruses, and the like. Those of skill in the
art are familiar with viral vectors that are used in "gene therapy"
applications, which include but are not limited to: Herpes simplex
virus vectors (Geller et al., Science, 241:1667-1669 (1988));
vaccinia virus vectors (Piccini et al., Meth. Enzymology,
153:545-563 (1987)); cytomegalovirus vectors (Mocarski et al., in
Viral Vectors, Y. Gluzman and S. H. Hughes, Eds., Cold Spring
Harbor Laboratory, Cold Spring Harbor, N.Y., 1988, pp. 78-84));
Moloney murine leukemia virus vectors (Danos et al., Proc. Natl.
Acad. Sci. USA, 85:6460-6464 (1988); Blaese et al., Science,
270:475-479 (1995); Onodera et al., J. Virol., 72:1769-1774
(1998)); adenovirus vectors (Berkner, Biotechniques, 6:616-626
(1988); Cotten et al., Proc. Natl. Acad. Sci, USA, 89:6094-6098
(1992); Graham et al., Meth. Mol. Biol., 7:109-127 (1991); Li et
al., Human Gene Therapy, 4:403-409 (1993); Zabner et al., Nature
Genetics, 6:75-83 (1994)); adeno-associated virus vectors (Goldman
et al., Human Gene Therapy, 10:2261-2268 (1997); Greelish et al.,
Nature Med., 5:439-443 (1999); Wang et al., Proc. Natl. Acad. Sci.
USA, 96:3906-3910 (1999); Snyder et al., Nature Med., 5:64-70
(1999); Herzog et al., Nature Med., 5:56-63 (1999)); retrovirus
vectors (Donahue et al., Nature Med., 4:181-186 (1998); Shackleford
et al., Proc. Natl. Acad. Sci. USA, 85:9655-9659 (1988); U.S. Pat.
Nos. 4,405,712, 4,650,764 and 5,252,479, and WIPO publications WO
92/07573, WO 90/06997, WO 89/05345, WO 92/05266 and WO 92/14829;
and lentivirus vectors (Kafri et al., Nature Genetics, 17:314-317
(1997), as well as viruses that are replication-competent
conditional to a cancer cell such as oncolytic herpes virus NV 1066
and vaccinia virus GLV-1h68, as described in United States patent
application 2009/0311664. In particular, adenoviral vectors may be
used, e.g. targeted viral vectors such as those described in
published United States patent application 2008/0213220. In
addition, various cancer-specific conditionally replication
competent viruses, in which replication is controlled by the
PEG-Prom, may be employed, as may viral (or other) vectors in which
expression is regulated by the tCCN1-Prom, hTERT-Prom, mda-9-Prom,
various cancer subtype-specific promoters, etc., as indicated
below.
[0040] Those of skill in the art will recognize that the choice of
a particular vector will depend on the details of its intended use.
Typically, one would not use a vector that integrates into the host
cell genome due to the risk of insertional mutagenesis, and would
design vectors so as to avoid or minimize the occurrence of
recombination within a vector's nucleic acid sequence or between
vectors. The constructs and vectors may be produced using known
recombinant technology or by synthetic (e.g. chemical) means.
[0041] Host cells which contain the recombinant M4 therakine and
vectors encoding the recombinant M4 therakine are also encompassed,
e.g. in vitro cells such as cultured cells, or bacterial or insect
cells which are used to store, generate or manipulate the vectors,
and the like, and/or cells that are in vivo (e.g. in a recipient to
whom the recombinant M4 therakine or vectors encoding the
recombinant M4 therakine have been administered
Promoters
[0042] The recombinant M4 therakine polypeptides of the invention
are generally produced by vectors which include at least one
transcribable element (e.g., a gene composed of a nucleic acid
sequence that encodes a recombinant M4 therakine) that is operably
connected or linked to one or more elements (such as a promoter,
one or more enhancers sequences, etc.) that drive transcription
and/or translation. "Operably linked" refers to an element being
located or positioned within a recombinant construct so as to
interact with an encoding nucleotide sequence of interest (e.g.,
encoding an M4 therakine) in a manner that results in successful
transcription and/or translation of the nucleic acid. If the vector
is a DNA vector, transcription from the construct into mRNA occurs;
if the vector is an RNA vector, translation occurs from the
construct. In some aspects, one element that drives expression is a
promoter that is specific or selective for driving expression of
the recombinant M4 therakine within cancer cells. Expression of the
transcribable or translatable element may be inducible or
constitutive, and suitable cancer selective/specific promoters (and
or promoter/enhancer sequences) that may be used include but are
not limited to: PEG-PROM (e.g. as described in U.S. patent
application Ser. No. 13/881,777), astrocyte elevated gene 1 (AEG-1)
promoter, survivin-Prom, human telomerase reverse transcriptase
(hTERT)-Prom, hypoxia-inducible promoter (HIF-1-alpha), DNA damage
inducible promoters (e.g. GADD promoters), metastasis-associated
promoters (metalloproteinase, collagenase, melanoma differentiation
associated gene-9, etc.), ceruloplasmin promoter (Lee et al.,
Cancer Res Mar. 1, 2004 64; 1788), mucin-1 promoters such as
DF3/MUC1 (see U.S. Pat. No. 7,247,297), HexII promoter as described
in US patent application 2001/00111128; prostate-specific antigen
enhancer/promoter (Rodriguez et al. Cancer Res., 57: 2559-2563,
1997); .alpha.-fetoprotein gene promoter (Hallenbeck et al. Hum.
Gene Ther., 10: 1721-1733, 1999); the surfactant protein B gene
promoter (Doronin et al. J. Virol., 75: 3314-3324, 2001); MUC1
promoter (Kurihara et al. J. Clin. Investig., 106: 763-771, 2000);
H19 promoter as per U.S. Pat. No. 8,034,914; those described in
issued U.S. Pat. Nos. 7,816,131, 6,897,024, 7,321,030, 7,364,727,
and others; etc., as well as derivative forms thereof. In addition,
the MDA-9-Prom and the CCN1 promoter and/or truncated but active
versions thereof may be employed. Any promoter that is specific or
selective for driving gene expression in cancer cells, or in cells
of a particular type of cancer (so as to treat e.g., prostate,
colon, breast, etc. primary and metastatic cancer) may be used in
the practice of the invention. By "specific for driving gene
expression in cancer cells" we mean that the promoter, when
operably linked to a gene, functions to promote transcription of
the gene only when located within a cancerous, malignant cell, but
not when located within normal, non-cancerous cells. By "selective
for driving gene expression in cancer cells" we mean that the
promoter, when operably linked to a gene, functions to promote
transcription of the gene to a greater degree when located within a
cancer cell, than when located within non-cancerous cells. For
example, the promoter drives gene expression of the gene at least
about 2-fold, or about 3-, 4-, 5-, 6-, 7-, 8-, 9-, or 10-fold, or
even about 20-, 30-, 40-, 50-, 60-, 70-, 80-, 90- or 100-fold or
more (e.g. 500- or 1000-fold) when located within a cancerous cell
than when located within a non-cancerous cell, when measured using
standard gene expression measuring techniques that are known to
those of skill in the art.
[0043] The transcriptional elements may include other transcription
or translation supporting elements such as enhancers, regulatory
elements, response elements, etc. and the promoters may be
heterologous (not associated with the encoded gene of interest in
nature) or homologous (associated with the encoded gene of interest
in nature).
Therapy and Administration
[0044] Targeted cancer therapy is carried out by administering the
constructs, vectors, etc. which encode one or more copies of a
recombinant M4 therakine as described herein to a patient in need
thereof, or alternatively, administering the M4
protein/polypeptide. M4 therakine may synergize with conventional
therapies, including radiation, chemotherapy, monoclonal
antibody-based therapy, etc. Thus, M4 may be administered with or
without such conventional therapies, or other therapies that are
less conventional.
[0045] The vector compositions (preparations) of the present
invention are typically administered systemically, although this
need not always be the case, as localized administration (e.g.
intratumoral, or into an external orifice such as the vagina, the
nasopharygeal region, the mouth; or into an internal cavity such as
the thoracic cavity, the cranial cavity, the abdominal cavity, the
spinal cavity, etc.; or peritumorally) is not excluded. For
systemic distribution of the vector, the preferred routes of
administration include but are not limited to: intravenous, by
injection, transdermal, via inhalation or intranasally, or via
injection or intravenous administration of a cationic polymer-based
vehicle (e.g. in vivo-jetPEI.TM.). Liposomal delivery, which when
combined with targeting moieties will permit enhanced delivery. The
ultrasound-targeted microbubble-destruction technique (UTMD) may
also be used to deliver imaging and theranostic agents (Dash et al.
Proc Natl Acad Sci USA. 2011 May 24; 108(21):8785-90. Epub 2011 May
9]; as may hydroxyapatite-chitosan nanocomposites (Venkatesan et
al. Biomaterials. 2011 May; 32(15):3794-806); and others (Dash et
al. Discov Med. 2011 January; 11(56):46-56. Review); etc. Any
method that is known to those of skill in the art, and which is
commensurate with the type of construct or composition that is
employed, may be utilized.
[0046] Those of skill in the art will recognize that the amount of
a construct or vector that is administered will vary from patient
to patient, and possibly from administration to administration for
the same patient, depending on a variety of factors, including but
not limited to: weight, age, gender, overall state of health, the
particular disease being treated, and other factors, and that the
amount and frequency of administration is best established by a
health care professional such as a physician or oncologist.
Typically, optimal or effective tumor-inhibiting or tumor-killing
amounts are established e.g. during animal trials and during
standard clinical trials. Those of skill in the art are familiar
with conversion of doses e.g. from a mouse to a human, which is
generally done through body surface area, as described by Erdreich
et al. (Cancer Chemother Rep 1966; 50(4):219-244); and see Tables 1
and 2 below, which are taken from the website located at
dtp,nci.nih.gov.
TABLE-US-00001 TABLE 1 Conversion factors in mg/kg Mouse wt. Rat wt
Monkey wt Dog wt Human wt 20 g 150 g 3 kg 8 kg 60 kg Mouse 1 1/2
1/4 1/6 1/12 Rat 2 1 1/2 1/4 1/7 Monkey 4 2 1 3/5 1/3 Dog 6 4 12/3
1 3/2 Man 12 7 3 2 1
For example, given a dose of 50 mg/kg in the mouse, an appropriate
dose in a monkey would be 50 mg/kg.times.1/4=13 mg/kg; or a dose of
about 1.2 mg/kg is about 0.1 mg/kg for a human.
TABLE-US-00002 TABLE 2 Representative Surface Area to Weight Ratios
Body Weight Surface Area Km Species (kg) (sq. m.) factor Mouse 0.02
0.0066 3.0 Rat 0.15 0.025 5.9 Monkey 3.0 0.24 12 Dog 8.0 0.4 20
Human, child 20 0.8 25 Human, adult 60 1.6 37
To express the dose as the equivalent mg/sqm. dose, multiply the
dose by the appropriate factor. In adult humans, 100 mg/kg is
equivalent to 100 mg/kg.times.37 kg/sqm.=3700 mg/sqm.
[0047] In general, for treatment methods, the amount of a vector
such as a plasmid will be in the range of from about 0.01 to about
5 mg/kg or from about 0.05 to about 1 mg/kg (e.g. about 0.1 mg/kg),
and from about 10.sup.5 to about 10.sup.20 infectious units (IUs),
or from about 10.sup.8 to about 10.sup.13 IUs for a viral-based
vector. In general, for therapy plus imaging methods, the amount of
a vector will be in the range of from about 0.01 to about 5 mg/kg
or from about 0.05 to about 1 mg/kg (e.g. about 0.1 mg/kg) of e.g.
a plasmid, and from about 10.sup.5 to about 10.sup.20 infectious
units (IUs), or from about 10.sup.8 to about 10.sup.13 IUs for a
viral-based vector, Those of skill in the art are familiar with
calculating or determining the level of an imaging signal that is
required for adequate detection. For example, for
radiopharmaceuticals such as [.sup.124]FIAU, an injection on the
order or from about 1 mCi to about 10 mCi, and usually about 5 mCi,
(i.e. about 1 mg of material) is generally sufficient.
[0048] Further, one type of vector or more than one type of vector
may be administered in a single administration, e.g. a therapy
vector plus an imaging vector, or two (or more) different therapy
vectors (e.g. each of which have differing modes of action so as to
optimize or improve treatment outcomes), or two or more different
imaging vectors, etc.
[0049] In addition, administration of the M4 therakine protein is
also encompassed. The protein that is administered is generally
"purified" (e.g. substantially purified by removal of other
proteins or macromolecules or cellular components or
non-physiologically compatible agents introduced during
purification) and/or "isolated" using standard techniques known in
the art, prior to being combined with the components of an
administrable composition as described above. The dosages that are
used are those that are generally described above for the protein
that is expressed from a vector.
[0050] Typically cancer treatment requires repeated administrations
of the compositions. For example, administration may be daily or
every few days, (e.g. every 2, 3, 4, 5, or 6 days), or weekly,
bi-weekly, or every 3-4 weeks, or monthly, or any combination of
these, or alternating patterns of these. For example, a "round" of
treatment (e.g. administration once a week for a month) may be
followed by a period of no administration for a month, and then
followed by a second round of weekly administration for a month,
and so on, for any suitable period of time, as required to
optimally treat the patient.
[0051] In addition, the compositions may be administered in
conjunction with other treatment modalities known in the art, such
as various chemotherapeutic agents such as Pt drugs and other
chemotherapy agents, substances that boost the immune system,
antibiotic agents, and the like; and/or with detection and imaging
methods (e.g. in conjunction with mammograms, X-rays, Pap smears,
prostate specific antigen (PSA) tests, etc. In particular, agents
that induce ER stress (unfolded protein response) such as
fenretinide and bortezomib (Velcade) may synergize with M4 to
enhance therapeutic outcomes.
[0052] The subjects or patients to whom the compositions of the
invention are administered are typically mammals, frequently
humans, but this need not always be the case. Veterinary
applications are also contemplated.
[0053] The constructs and vectors may also encode one or more
additional therapeutic molecules in addition to a recombinant M4
therakine, including but not limited to various suicide genes,
including genes encoding various enzymes; oncogenes; tumor
suppressor genes; toxins; other cytokines; oncostatins; TRAIL, etc.
Exemplary enzymes include, for example, thymidine kinase (TK) and
various derivatives thereof; TNF-related apoptosis-inducing ligand
(TRAIL), xanthine-guanine phosphoribosyltransferase (GPT); cytosine
deaminase (CD); hypoxanthine phosphoribosyl transferase (HPRT);
etc. Exemplary tumor suppressor genes include p53, Retinoblastoma
tumor suppressor gene (Rb), Wilm's Tumor Gene Product,
Phosphotyrosine Phosphatase (PTPase), AdE1A and nm23. Suitable
toxins include Pseudomonas exotoxin A and S; diphtheria toxin (DT);
E. coli LT toxins, Shiga toxin, Shiga-like toxins (SLT-1, -2),
ricin, abrin, supporin, gelonin, etc. Suitable cytokines include
interferons and interleukins such as interleukin 1 (IL-1), IL-2,
IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-11, IL-12,
IL-13, IL-14, IL-15, IL-18, .beta.-interferon, .alpha.-interferon,
.gamma.-interferon, angiostatin, thrombospondin, endostatin,
GM-CSF, G-CSF, M-CSF, METH 1, METH 2, tumor necrosis factor,
TGF.beta., LT and combinations thereof. Other anti-tumor agents
include: GM-CSF interleukins, tumor necrosis factor (TNF);
interferon-beta and virus-induced human Mx proteins; TNF alpha and
TNF beta; human melanoma differentiation-associated gene-7 (mda-7),
also known as interleukin-24 (IL-24), various other truncated
versions of mda-7/IL-24; siRNAs and shRNAs targeting important
growth regulating or oncogenes which are required by or
overexpressed in cancer cells; antibodies such as antibodies that
are specific or selective for attacking cancer cells; etc. When the
additional therapeutic agent is TK (e.g. viral TK), a TK substrate
such as acyclovir; ganciclovir; various thymidine analogs (e.g.
those containing o-carboranylalkyl groups at the 3-position
[Al-Madhoun et al., Cancer Res Sep. 1, 2004 64; 6280]) is also
administered to the subject. These substrates/drugs act as
prodrugs, which in themselves are not toxic, but are converted to
toxic drugs by phosphorylation by viral TK. Both the TK gene and
substrate are used concurrently to be toxic to the host cancer
cell.
[0054] Alternatively, if the proteinaceous form of M4 is
administered, such agents may be administered together in a
composition as described, or separately, e.g., in separate
compositions, or encoded by a vector that is co-administered with
the protein, etc.
Imaging Plus Treatment
[0055] In some embodiments, the invention provides cancer treatment
protocols in which treating the disease, e.g. killing, destroying,
or otherwise damaging the cancer cells, is combined with imaging of
cancer cells and tumors. These protocols may be referred to herein
as "theranostics" or "combined therapies" or "combination
protocols", or by similar terms and phrases.
[0056] In some aspects, the combined therapy involves administering
to a cancer patient a vector that encodes, in a single construct,
both at least one recombinant M4 therakine (for treating the
disease) and a reporter gene (for imaging) the cancer cells that
are targeted by the construct. In this embodiment, expression of
either a reporter gene or a recombinant M4 therakine gene, or
preferably both, is mediated by a cancer cell specific or selective
promoter as described herein. Preferably, two different promoters
are used in this embodiment in order to prevent or lessen the
chance of crossover and recombination within the construct.
Alternatively, tandem translation mechanisms may be employed, for
example, the insertion of one or more internal ribosomal entry site
(IRES) into the construct, which permits translation of multiple
mRNA transcripts from a single mRNA. In this manner, both a
reporter protein/polypeptide and a recombinant M4 therakine
protein/polypeptide that is lethal or toxic to cancer cells are
selectively or specifically produced within the targeted cancer
cells.
[0057] Alternatively, the polypeptides encoded by the constructs of
the invention (e.g. plasmids) may be genetically engineered to
contain a contiguous sequence comprising a reporter and a
recombinant M4 therakine, e.g., separated with an intervening
sequence that is cleavable within the cancer cell, e.g., a sequence
that is enzymatically cleaved by intracellular proteases, or even
that is susceptible to non-enzymatic hydrolytic cleavage
mechanisms. In this case, cleavage of the intervening sequence
results in production of functional polypeptides, i.e. polypeptides
which are able to carry out their intended function, e.g. they are
at least 50, 60, 70, 80, 90, or 100% (or possible more) as active
as the protein sequences on which they are modeled or from which
they are derived, when measured using standard techniques that are
known to those of skill in the art.
[0058] In other aspects of combined imaging and therapy, two
different vectors may be administered, one of which is an "imaging
vector or construct" as described herein, and the other of which is
a "recombinant M4 therakine vector or construct" as described
herein.
[0059] In other aspects of combined imaging and therapy, the genes
of interest are encoded in the genome of a viral vector that is
capable of transcription and/or translation of multiple mRNAs
and/or the polypeptides or proteins they encode, by virtue of the
properties inherent in the virus. In this embodiment, such viral
vectors are genetically engineered to contain and express genes of
interest (e.g., both a reporter gene and at least one recombinant
M4 therakine) under the principle control of one or more cancer
specific promoters.
[0060] In the "therapy plus imaging" aspect of the invention, the
vectors/constructs include at least one transcribable element that
is either directly detectable using imaging technology, or which
functions with one or more additional molecules in a manner that
creates a signal that is detectable using imaging technology. The
transcribable element is operably linked to is a cancer
selective/specific promoter as described above, and is generally
referred to as a "reporter" molecule. Reporter molecules can cause
production of a detectable signal in any of several ways: they may
encode a protein or polypeptide that has the property of being
detectable in its own right; they may encode a protein or
polypeptide that interacts with a second substance and causes the
second substance to be detectable; they may encode a protein or
polypeptide that sequesters a detectable substance, thereby
increasing its local concentration sufficiently to render the
surrounding environment (e.g. a cancer cell) detectable. If the
gene product of the reporter gene interacts with another substance
to generate a detectable signal, the other substance is referred to
herein as a "complement" of the reporter molecule.
[0061] Examples of reporter proteins or polypeptides that are
detectable in their own right (directly detectable) include those
which exhibit a detectable property when exposed to, for example, a
particular wavelength or range of wavelengths of energy. Examples
of this category of detectable proteins include but are not limited
to: green fluorescent protein (GFP) and variants thereof, including
mutants such as blue, cyan, and yellow fluorescent proteins;
proteins which are engineered to emit in the near-infrared regions
of the spectrum; proteins which are engineered to emit in the
short-, mid-, long-, and far-infrared regions of the spectrum; etc.
Those of skill in the art will recognize that such detectable
proteins may or may not be suitable for use in humans, depending on
the toxicity or immunogenicity of the reagents involved. However,
this embodiment has applications in, for example, laboratory or
research endeavors involving animals, cell culture, tissue culture,
various ex vivo procedures, etc.
[0062] Another class of reporter proteins is those, which function
with a complement molecule. In this embodiment, a construct
comprising a gene encoding a reporter molecule is administered
systemically to a subject in need of imaging, and a molecule that
is a complement of the reporter is also administered systemically
to the subject, before, after or together with the construct. If
administered prior to or after administration of the construct,
administration of the two may be timed so that the diffusion of
each entity into cells, including the targeted cancer cells, occurs
in a manner that results in sufficient concentrations of each
within cancer cells to produce a detectable signal, e.g. typically
within about 1 hour or less. If the two are administered
"together", then separate compositions may be administered at the
same or nearly the same time (e.g. within about 30, 20, 15, 10, or
5 minutes or less), or a single composition comprising both the
construct and the complement may be administered. In any case, no
interaction between the reporter and the complement can occur
outside of cancer cells, because the reporter is not produced and
hence does not exist in any other location, since its transcription
is controlled by a cancer specific/selective promoter.
[0063] One example of this is the oxidative enzyme luciferase and
various modified forms thereof, the complement of which is
luciferin. Briefly, catalysis of the oxidation of its complement,
luciferin, by luciferase produces readily detectable amounts of
light. Those of skill in the art will recognize that this system is
not generally used in humans due to the need to administer the
complement, luciferin to the subject. However, this embodiment is
appropriate for use in animals, and in research endeavors involving
cell culture, tissue culture, and various ex vivo procedures.
[0064] Another exemplary protein of this type is thymidine kinase
(TK), e.g. TK from herpes simplex virus 1 (HSV 1), or from other
sources. TK is a phosphotransferase enzyme (a kinase) that
catalyzes the addition of a phosphate group from ATP to thymidine,
thereby activating the thymidine for incorporation into nucleic
acids, e.g., DNA. Various analogs of thymidine are also accepted as
substrates by TK, and radiolabeled forms of thymidine or thymidine
analogs may be used as the complement molecule to reporter protein
TK. Without being bound by theory, it is believed that once
phosphorylated by TK, the radiolabeled nucleotides are retained
intracellularly because of the negatively charged phosphate group;
or, alternatively, they may be incorporated into e.g. DNA in the
cancer cell, and thus accumulate within the cancer cell. Either
way, they provide a signal that is readily detectable and
distinguishable from background radioactivity. Also, the substrate
that is bound to TK at the time of imaging provides additional
signal in the cancer cell. In fact, mutant TKs with very low Kms
for substrates may augment this effect by capturing the substrate.
The radioactivity emitted by the nucleotides is detectable using a
variety of techniques, as described herein. This aspect of the use
of TK harnesses the labeling potential of this enzyme; the toxic
capabilities of TK are described below.
[0065] Various TK enzymes or modified or mutant forms thereof may
be used in the practice of the invention, including but not limited
to: HSV1-TK, HSV1-sr39TK, mutants with increased or decreased
affinities for various substrates, temperature sensitive TK
mutants, codon-optimized TK, the mutants described in U.S. Pat. No.
6,451,571 and US patent application 2011/0136221, both of which are
herein incorporated by reference; various suitable human TKs and
mutant human TKs, etc.
[0066] Detectable TK substrates that may be used include but are
not limited to: thymidine analogs such as: "fialuridine" i.e.
[1-(2-deoxy-2-fluoro-1-D-arabinofuranosyl)-5-iodouracil], also
known as "FIAU" and various forms thereof, e.g. 2'-fluoro-2'-deoxy-
-D-5-[.sup.125I] iodouracil-arabinofuranoside ([.sup.125I] FIAU),
[.sup.124I]FIAU; thymidine analogs containing o-carboranylalkyl
groups at the 3-position, as described by Al Mahoud et al., (Cancer
Res Sep. 1, 2004 64; 6280), which may have a dual function in that
they mediate cytotoxicity as well, as described below;
hydroxymethyl]butyl)guanine (HBG) derivatives such as
9-(4-.sup.18F-fluoro-3-[hydroxymethyl] butyl)guanine
(.sup.18F-FHBG);
2'-deoxy-2'-[.sup.18F]-fluoro-1-beta-D-arabinofuranosyl-5-iodouracil
(.sup.18F-FEAU),
2'-deoxy-2'-[.sup.18F]-fluoro-5-methyl-1-.beta.-L-arabinofuranosyluracil
(.sup.18F-FMAU),
1-(2'-deoxy-2'-fluoro-beta-D-arabinofuranosyl)-5-[.sup.18F]
iodouracil (.sup.18F-FIAU),
2'-deoxy-2'-[.sup.18F]-fluoro-1-beta-D-arabinofuranosyl-5-iodouracil
(.sup.18F-FIAC, see, for example, Chan et al., Nuclear Medicine and
Biology 38 (2011) 987-995; and Cai et al., Nuclear Medicine and
Biology 38 (2011) 659-666); various alkylated pyrimidine
derivatives such as a C-6 alkylated pyrimidine derivative described
by Muller et al, (Nucl Med Biol. 2012 February; 39(2):235-46); and
others.
[0067] Other exemplary reporter molecules may retain or cause
retention of a detectably labeled complement by any of a variety of
mechanisms. For example, the reporter molecule may bind to the
complement very strongly (e.g. irreversibly) and thus increase the
local concentration of the complement within cancer cells; or the
reporter molecule may modify the complement in a manner that makes
egress of the complement from the cell difficult, or at least slow
enough to result in a net detectable accumulation of complement
within the cell; or the reporter may render the complement suitable
for participation in one or more reactions which "trap" or secure
the complement, or a modified form thereof that still includes the
detectable label, within the cell, as is the case with the TK
example presented above.
[0068] One example of such a system would be an enzyme-substrate
complex, in which the reporter is usually the enzyme and the
complement is usually the substrate, although this need not always
be the case: the reporter may encode a polypeptide or peptide that
is a substrate for an enzyme that functions as the "complement". In
some embodiments, the substrate is labeled with a detectable label
(e.g. a radio-, fluorescent-, phosphoresent-, calorimetric-, light
emitting-, or other label) and accumulates within cancer cells due
to, for example, an irreversible binding reaction with the enzyme
(i.e. it is a suicide substrate), or because it is released from
the enzyme at a rate that is slow enough to result in a detectable
accumulation within cancer cells, or the reaction with the enzyme
causes a change in the properties of the substrate so that it
cannot readily leave the cell, or leaves the cell very slowly (e.g.
due to an increase in size, or a change in charge, hydrophobicity
or hydrophilicity, etc.); or because, as a result of interaction or
association with the enzyme, the substrate is modified and then
engages in subsequent reactions which cause it (together with its
detectable tag or label) to be retained in the cells, etc.
[0069] Other proteins that may function as reporter molecules in
the practice of the invention are transporter molecules which are
located on the cell surface or which are transmembrane proteins,
e.g. ion pumps which transport various ions across cells membranes
and into cells. An exemplary ion pump is the sodium-iodide
symporter (NIS) also known as solute carrier family 5, member 5
(SLC5A5). In nature, this ion pump actively transports iodide
(I.sup.-) across e.g. the basolateral membrane into thyroid
epithelial cells. Recombinant forms of the transporter encoded by
sequences of the constructs described herein may be selectively
transcribed in cancer cells, and transport radiolabeled iodine into
the cancer cells. Other examples of this family of transporters
that may be used in the practice of the invention include but are
not limited to norepinephrine transporter (NET); dopamine receptor;
various estrogen receptor systems), ephrin proteins such as
membrane-anchored ephrin-A (EFNA) and the transmembrane protein
ephrin-B (EFNB); epidermal growth factor receptors (EGFRs);
insulin-like growth factor receptors (e.g. IGF-1, IGF-2 etc.);
transforming growth factor (TGF) receptors such as TGF.alpha.;
glutamate transporters such as excitatory amino acid transporter 2
(EAAT2), etc. In these cases, the protein or a functional modified
form thereof is expressed by the vector of the invention and the
ligand molecule is administered to the patient. Usually, the ligand
is labeled with a detectable label as described herein, or becomes
detectable upon association or interaction with the transporter. In
some embodiments, detection may require the association of a third
entity with the ligand, e.g. a metal ion. The ligand may also be a
protein, polypeptide or peptide.
[0070] In addition, antibodies may be utilized in the practice of
the invention. For example, the vectors of the invention may be
designed to express proteins, polypeptides, or peptides which are
antigens or which comprise antigenic epitopes for which specific
antibodies have been or can be produced. Exemplary antigens include
but are not limited to tumor specific proteins that have an
abnormal structure due to mutation (protooncogenes, tumor
suppressors, the abnormal products of ras and p53 genes, etc.);
various tumor-associated antigens such as proteins that are
normally produced in very low quantities but whose production is
dramatically increased in tumor cells (e.g. the enzyme tyrosinase,
which is elevated in melanoma cells); various oncofetal antigens
(e.g. alphafetoprotein (AFP) and carcinoembryonic antigen (CEA);
abnormal proteins produced by cells infected with oncoviruses, e.g.
EBV and HPV; various cell surface glycolipids and glycoproteins
which have abnormal structures in tumor cells; etc. The antibodies,
which may be monoclonal or polyclonal, are labeled with a
detectable label and are administered to the patient after or
together with the vector. The antibodies encounter and react with
the expressed antigens or epitopes, which are produced only (or at
least predominantly) in cancer cells, thereby labeling the cancer
cells. Conversely, the antibody may be produced by the vector of
the invention, and a labeled antigen may be administered to the
patient. In this embodiment, an antibody or a fragment thereof,
e.g. a Fab (fragment, antigen binding) segment, or others that are
known to those of skill in the art, are employed. In this
embodiment, the antigen or a substance containing antigens or
epitopes for which the antibody is specific is labeled and
administered to the subject being imaged.
[0071] Other examples of such systems include various ligand
binding systems such as reporter proteins/polypeptides that bind
ligands which can be imaged, examples of which include but are not
limited to: proteins (e.g. metalloenzymes) that bind or chelate
metals with a detectable signal; ferritin-based iron storage
proteins such as that which is described by Iordanova and Ahrnes
(Neuroimage. 2012 Jan. 16; 59(2):1004-12); and others. Such systems
of reporter and complement may be used in the practice of the
invention, provided that the reporter or the complement can be
transcribed under control of a cancer promoter, and that the other
binding partner is detectable or can be detectably labeled, is
administrable to a subject, and is capable of diffusion into cancer
cells. Those of skill in the art will recognize that some such
systems are suitable for use, e.g., in human subjects, while other
are not due to, for example, toxicity. However, systems in the
latter category may be well-suited for use in laboratory
settings.
[0072] In yet other aspects, the cancer-specific or
cancer-selective promoters in the vectors of the invention drive
expression of a secreted protein that is not normally found in the
circulation. In this embodiment, the presence of the protein may be
detected by standard (even commercially available) methods with
high sensitivity in serum or urine. In other words, the cancer
cells that are detected are detected in a body fluid.
[0073] In yet other aspects, the cancer-specific or
cancer-selective promoters in the vectors of the invention drive
transcription of a protein or antigen to be expressed on the cell
surface, which can then be tagged with a suitable detectable
antibody or other affinity reagent. Candidate proteins for
secretion and cell surface expression include but are not limited
to: .beta.-subunit of human chorionic gonadotropin (.beta. hCG);
human .alpha.-fetoprotein (APP), and streptavidin (SA).
[0074] .beta. hCG is expressed in pregnant women and promotes the
maintenance of the corpus luteum during the beginning of pregnancy.
The level of .beta. hCG in non-pregnant normal women and men is 0-5
mIU/mL. hCG is secreted into the serum and urine and .beta. hCG has
been used for pregnancy test since the .beta.-subunit of hCG is
shared with other hormones. Urine .beta. hCG can be easily detected
by a chromatographic immunoassay (i.e. pregnancy test strip,
detection threshold is 20-100 mIU/mL) at home-physician's office-
and laboratory-based settings. The serum level can be measured by
chemiluminescent or fluorescent immunoassays using 2-4 mL of venous
blood for more quantitative detection. .beta. hCG has been shown to
secreted into the media when it was expressed in monkey cells.
Human AFP is an oncofetal antigen that is expressed only during
fetal development and in adults with certain types of cancers. AFP
in adults can be found in hepatocellular carcinoma, testicular
tumors and metastatic liver cancer. AFP can be detected in serum,
plasma, or whole blood by chromatographic immunoassay and by enzyme
immunoassay for the quantitative measurement.
[0075] Streptavidin (SA) can also be used as a cell surface target
in the practice of the invention. The unusually high affinity of SA
with biotin provides very efficient and powerful target for imaging
and therapy. To bring SA to the plasma membrane of the cancer
cells, SA can be fused to glycosylphosphatidylinositol
(GPI)-anchored signal of human CD14. GPI-anchoring of SA will be
suitable for therapeutic applications since GPI-anchor proteins can
be endocytosed to the recycling endosomes. Once expressed on the
cell surface, SA can then be bound by avidin conjugates that
contain a toxic or radiotoxic warhead. Toxic proteins and venoms
such as ricin, abrin, Pseudomonas exotoxin (PE, such as PE37, PE38,
and PE40), diphtheria toxin (DT), saporin, restrictocin, cholera
toxin, gelonin, Shigella toxin, and pokeweed antiviral protein,
Bordetella pertussis adenylate cyclase toxin, or modified toxins
thereof, or other toxic agents that directly or indirectly inhibit
cell growth or kill cells may be linked to avidin; as could toxic
low molecular weight species, such as doxorubicin or taxol or
radionuclides such as .sup.125I, .sup.131I, .sup.111In, .sup.177Lu,
.sup.211At, .sup.225Ac, .sup.213Bi and .sup.90Y; antiangiogenic
agents such as thalidomide, angiostatin, antisense molecules, COX-2
inhibitors, integrin antagonists, endostatin, thrombospondin-1, and
interferon alpha, vitaxin, celecoxib, rofecoxib; as well as
chemotherapeutic agents such as: pyrimidine analogs
(5-fluorouracil, floxuridine, capecitabine, gemcitabine and
cytarabine) and purine analogs, folate antagonists and related
inhibitors (mercaptopurine, thioguanine, pentostatin and
2-chlorodeoxyadenosine (cladribine)); antiproliferative/antimitotic
agents including natural products such as vinca alkaloids
(vinblastine, vincristine, and vinorelbine), microtubule disruptors
such as taxane (paclitaxel, docetaxel), vincristin, vinblastin,
nocodazole, epothilones and navelbine, epidipodophyllotoxins
(etoposide, teniposide), DNA damaging agents (actinomycin,
amsacrine, anthracyclines, bleomycin, busulfan, camptothecin,
carboplatin, chlorambucil, cisplatin, cyclophosphamide, cytoxan,
dactinomycin, daunorubicin, doxorubicin, epirubicin,
hexamethylmelamineoxaliplatin, iphosphamide, melphalan,
mechlorethamine, mitomycin, mitoxantrone, nitrosourea, plicamycin,
procarbazine, taxol, taxotere, teniposide,
triethylenethiophosphoramide and etoposide (VP16)); antibiotics
such as dactinomycin (actinomycin D), daunorubicin, doxorubicin
(adriamycin), idarubicin, anthracyclines, mitoxantrone, bleomycins,
plicamycin (mithramycin) and mitomycin; enzymes (L-asparaginase
which systemically metabolizes L-asparagine and deprives cells
which do not have the capacity to synthesize their own asparagine);
antiplatelet agents; antiproliferative/antimitotic alkylating
agents such as nitrogen mustards (mechlorethamine, cyclophosphamide
and analogs, melphalan, chlorambucil), ethylenimines and
methylmelamines (hexamethylmelamine and thiotepa), alkyl
sulfonates-busulfan, nitrosoureas (carmustine (BCNU) and analogs,
streptozocin), trazenes-dacarbazinine (DTIC);
antiproliferative/antimitotic antimetabolites such as folic acid
analogs (methotrexate); platinum coordination complexes (cisplatin,
carboplatin), procarbazine, hydroxyurea, mitotane,
aminoglutethimide; hormones, hormone analogs (estrogen, tamoxifen,
goserelin, bicalutamide, nilutamide) and aromatase inhibitors
(letrozole, anastrozole); anticoagulants (heparin, synthetic
heparin salts and other inhibitors of thrombin); fibrinolytic
agents (such as tissue plasminogen activator, streptokinase and
urokinase), aspirin, dipyridamole, ticlopidine, clopidogrel,
abciximab; antimigratory agents; antisecretory agents (breveldin);
immunosuppressives (cyclosporine, tacrolimus (FK-506), sirolimus
(rapamycin), azathioprine, mycophenolate mofetil); anti-angiogenic
compounds (TNP-470, genistein) and growth factor inhibitors
(vascular endothelial growth factor (VEGF) inhibitors, fibroblast
growth factor (FGF) inhibitors); angiotensin receptor blocker;
nitric oxide donors; anti-sense oligonucleotides; antibodies
(trastuzumab, rituximab); cell cycle inhibitors and differentiation
inducers (tretinoin); mTOR inhibitors, topoisomerase inhibitors
(doxorubicin (adriamycin), amsacrine, camptothecin, daunorubicin,
dactinomycin, eniposide, epirubicin, etoposide, idarubicin,
irinotecan (CPT-11) and mitoxantrone, topotecan), corticosteroids
(cortisone, dexamethasone, hydrocortisone, methylprednisolone,
prednisone, and prednisolone); growth factor signal transduction
kinase inhibitors; mitochondrial dysfunction inducers; caspase
activators; and chromatin disruptors, especially those which can be
conjugated to nanoparticles
[0076] The detectable components of the system (usually a
complement or substrate) may be labeled with any of a variety of
detectable labels, examples of which are described above. In
addition, especially useful detectable labels are those which are
highly sensitive and can be detected non-invasively, such as the
isotopes .sup.124I, .sup.123I, .sup.99mTC, .sup.18F, .sup.80Y,
.sup.11C, .sup.125I, .sup.64Cu, .sup.67Ga, .sup.68Ga, .sup.201Tl,
.sup.76Br, .sup.75Br, .sup.111In, .sup.82Rb, .sup.13N, and
others.
[0077] Those of skill in the art will recognize that many different
detection techniques exist which may be employed in the practice of
the present invention, and that the selection of one particular
technique over another generally depends on the type of signal that
is produced and also the medium in which the signal is being
detected, e.g. in the human body, in a laboratory animal, in cell
or tissue culture, ex vivo, etc. For example, bioluminescence
imaging (BLI); fluorescence imaging; magnetic resonance imaging
[MRI, e.g. using lysine rich protein (LRp) as described by Gilad et
al., Nature Biotechnology, 25, 2 (2007); or creatine kinase,
tyrosinase, .beta.-galactosidase, iron-based reporter genes such as
transferring, ferritin, and MagA; low-density lipoprotein
receptor-related protein (LRP; polypeptides such as poly-L-lysine,
poly-L-arginine and poly-L-threonine; and others as described,
e.g., by Gilad et al., J. Nucl. Med. 2008; 49(12):1905-1908);
computed tomography (CT); positron emission tomography (PET);
single-photon emission computed tomography (SPECT); boron 1.5
neutron capture; for metals: synchrotron X-ray fluorescence (SXRF)
microscopy, secondary ion mass spectrometry (SIMS), and laser
ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)
for imaging metals; photothermal imaging (using for example,
magneto-plasmonic nanoparticles, etc.
[0078] For aspects of the invention, which encompass both treatment
and imaging, the administration protocols may be any which serve
the best interest of the patient. For example, initially, an
imaging vector alone may be administered in order to determine
whether or not the subject does indeed have cancer, or to identify
the locations of cancer cells in a patient that has already been
diagnosed with cancer. If cancer is indeed indicated, then
compositions with therapeutic vectors are then administered as
needed to treat the disease. Usually a plurality of administrations
is required as discussed above, and one or more, and sometimes all
of these, include at least one imaging vector together with a least
one therapeutic vector; or optionally, a single vector with both
capabilities. The ability to alternate between therapy and imaging,
or to concomitantly carry out both, is a distinct boon for the
field of cancer treatment. This methodology allows a medical
professional to monitor the progress of treatment in a tightly
controlled manner, and to adjust and/or modify the therapy as
necessary for the benefit of the patient. For example,
administration of a therapeutic and an imaging vector may be
alternated; or, during early stages of treatment, initially an
imaging vector may be administered, followed by therapy and imaging
vectors together until the tumors are no longer visible, followed
by imaging vector alone for a period of time deemed necessary to
rule out or detect recurrence or latent disease.
[0079] Alternatively, if the protein form of M4 is utilized, the
other components of the "therapy-imaging" protocol may be
administered by a suitable method, e.g., as part of the
composition, or as part of a separate composition, or encoded by a
vector that is co-administered with the protein composition,
etc.
Compositions
[0080] The present invention provides compositions, which comprise
one or more vectors or to constructs as described herein (e.g.
encoding at least one or more recombinant M4 therakines) and a
pharmacologically suitable (physiologically acceptable) carrier; or
which comprise an isolated M4 therakine protein as described
herein. The compositions are usually for systemic administration,
although local administration (e.g. directly to a tumor) is also
encompassed. The preparation of such compositions is known to those
of skill in the art. Typically, they are prepared either as liquid
solutions or suspensions, or as solid forms suitable for solution
in, or suspension in, liquids prior to administration. The
preparation may also be emulsified. The active ingredients may be
mixed with excipients, which are pharmaceutically acceptable and
compatible with the active ingredients. Suitable excipients are,
for example, water, saline, dextrose, glycerol, ethanol and the
like, or combinations thereof. In addition, the composition may
contain minor amounts of auxiliary substances such as wetting or
emulsifying agents, pH buffering agents, and the like. If it is
desired to administer an oral form of the composition, various
thickeners, flavorings, diluents, emulsifiers, dispersing aids or
binders and the like may be added. The composition of the present
invention may contain any of one or more ingredients known in the
art to provide the composition in a form suitable for
administration. The final amount of vector or protein in the
formulations may vary. However, in general, the amount in the
formulations will be from about 1-99%.
Types of Cancer that can be Treated
[0081] The methods of treatment and/or of prevention of cancer
described herein are not specific for any one type of cancer.
However, the cancer cells that are attacked by the recombinant M4
therakine are those which have MDA-7/IL-24 receptors (which occur
as dimeric pairs), including but not limited to: IL-20R1/IL-20R2,
IL-20R1/IL-22R or IL-22R/IL-20R2, etc. Any type of cancer cell that
has such receptors may be targeted and killed or damaged by a
recombinant M4 therakine as described herein.
[0082] By "cancer" we mean malignant neoplasms in which cells
divide and grow uncontrollably, forming malignant tumors, and
invade nearby parts of the body. Cancer may also spread or
metastasize to more distant parts of the body through the lymphatic
system or bloodstream, metastatic cancer may also be prevented or
treated. The constructs and methods of the invention may be
employed to image, diagnose, treat, monitor, etc. any type of
cancer, tumor, neoplastic or tumor cells including but not limited
to: osteosarcoma, ovarian carcinoma, breast carcinoma, melanoma,
hepatocarcinoma, lung cancer, brain cancer, colorectal cancer,
hematopoietic cell cancer, prostate cancer, cervical carcinoma,
retinoblastoma, esophageal carcinoma, bladder cancer,
neuroblastoma, renal cancer, gastric cancer, pancreatic cancer, and
others.
[0083] In addition, the invention may also be applied to imaging
and therapy of benign tumors, which are generally recognized as not
invading nearby tissue or metastasizing, for example, moles,
uterine fibroids, etc.
EXAMPLES
Example 1. Construction of a Recombinant M4 Therakine
[0084] A secretory signal was added to the M4 fragment of
MDA-7/IL-24 using the Flt3 ligand. The procedure involved: A 309-bp
cDNA fragment of human MDA-7 (M4) was amplified by PCR using
synthetic primers and sub-cloned into a mammalian expression vector
in sense orientation. A 66 bp nucleotide fragment was (Flt3) also
added before M4 sequence in sense orientation in the same vector
following standard cloning procedures. The resulting constructs are
illustrated schematically in FIG. 1.
Example 2. Testing of Recombinant M4 Therakine
Materials and Methods
[0085] 1. Secretion. IM-PHFA (2.times.10.sup.6) cells were infected
with adenovirus expressing either null, Flt3-MDA-7 or Flt3-M4 (5000
vp) in 10-cm plates. Forty-eight hours after infection, the medium
was removed, cells were washed with serum free media (SFM) and 4 ml
of SFM was added and incubated for further 24 hours. This media was
collected and termed as conditioned medium (CM). 2. Western blot
analysis. IM-PHFA (2.times.10.sup.6) cells were infected with
adenovirus expressing either null (empty vector), Flt3-MDA-7 or
Flt3-M4 (5000 vp) in 10-cm plates for 48 hours. Conditioned medium
(CM) was collected as described above. DU145 or A549 cells
(2.times.10.sup.6) were plated overnight and the medium was
replaced with 5 ml of either CM collected from IM-PHFA cells or CM
collected from Ad-Null, or Ad-Flt3-M4, or Ad-Flt3-MDA-7 infected
cells and cultured for 72 hours. This media was replaced with fresh
CM after 48 hours. Cells were then collected and used for Western
blotting analysis for PARP cleavage. 3. TUNEL assay. DU145 or A549
cells (10.sup.4) were plated overnight in a 4-well chamber slide
and the medium was replaced with 1 nil of either CM collected from
IM-PHFA cells or CM collected from Ad-Null, Ad-Flt3-M4, or
Ad-Flt3-MDA-7 infected cells and cultured for 72 hours. TUNEL assay
was performed as per manufacturer's protocols and photomicrographs
were taken using fluorescent microscope and representative images
are shown. 4. DNA content. DU145 or A549 cells were treated as
above, stained with propidium iodide and FACS analysis was
performed for DNA content. 5. Analysis of pre- and anti-apoptotic
molecules in DU145 and A549 cells after exposure to CM. IM-PHFA
(2.times.10.sup.6) cells were infected with adenovirus expressing
either Flt3-MDA-7 or Flt3-M4 (5000 vp) in 10-cm plates for 48
hours. Conditioned medium (CM) was collected as described above.
DU145 or A549 cells (2.times.10.sup.6) were plated overnight and
the medium was replaced with 5 ml of either CM collected from PHFA
cells or CM collected from Ad-Flt3-M4, or Ad-Flt3-MDA-7 infected
cells and cultured for 72 hours. This media was replaced with fresh
conditioned medium after 48 hours. The cells were then collected
and used for Western blotting analysis. 6. Tumor volume reduction
in viva by Flt3-MDA-7 and Flt3-M4 in subcutaneous tumor cell
implants. 2.times.10.sup.6 DU145 cells were subcutaneously
implanted on both sides office. Once the tumors reached measurable
size (at least 5-mm), left flank tumors were infected with
2.times.10.sup.8 viral particles of either Flt3-MDA-7 or Flt3-M4
3.times. every alternate day and observed for tumor regression.
2.times.10.sup.6 DU-145 cells were subcutaneously implanted on the
left side and 5.times.10.sup.6 A549 cells were implanted on the
right side (5 days prior to DU145 cell implantation to maintain
equal tumor sizes). Once the tumors reached measurable sizes, left
flank tumors were treated with 2.times.10.sup.8 viral particles of
either Flt3-MDA-7 or Flt3-M4 3.times. every alternate day and
observed for tumor regression.
Results
[0086] The results showed that the recombinant therakine is
secreted (FIG. 2) and displays "bystander" activity equivalent to
that of native MDA-7/IL-24 (FIG. 3). In addition, like MDA-7/IL-24,
the recombinant M4 therakine induced production of SARI (Suppressor
of AP-1, regulated by Interferon), which is required for cell
killing by mda-7/IL-24 (FIG. 4). In addition, when tested in an
animal model, both direct and distant cancer cell killing was
exhibited (see FIGS. 5A and B).
[0087] These results show that Flt3-M4, an exemplary truncated,
modified version of mda-7/IL-24, exhibits both direct and distant
killing of cancer cells at levels similar to those of the
full-length gene product, and that these activities are exhibited
both in vitro and in vivo. The novel recombinant M4 therakines
described herein thus represent new therapeutic to molecules for
the treatment of diverse cancers.
Example 3. Further Testing of M4
[0088] The ability of MDA-7/IL-24 and M4 to promote "bystander"
activity was assessed. Subcutaneously implanted tumors in the left
side were treated with 2.times.10.sup.8 viral particles of either
Flt3-M4 or Flt3-MDA-7 3.times. every alternate day and observed for
tumor regression.
[0089] To evaluate the apoptotic (cell death) response of
Flt3-MDA-7 or Flt3-M4, TUNEL assays were done according to the
manufacturer's protocol in paraffin-embedded tumor tissue sections.
The slides were observed for TUNEL positive staining (green
florescence) under a florescence microscope and photographed. TUNEL
results are presented in FIG. 6. As can be seen, secreted
MDA-7/IL-24 and M4 promote profound "bystander" activity (evidenced
by TUNEL staining) in untreated distant right side receptor
positive DU145 tumors, but not in receptor negative A549
tumors.
[0090] A549 cells express IL20R1 endogenously, but do not express a
second member of the dimeric receptor pair that is required for
MDA-7/IL-24 activity. Hence, to test bystander activity, IL20R2 and
IL22R (labeled IL22RA and IL20RB in FIG. 7, respectively) were
overexpressed in A549 cells to reconstitute a dimeric receptor and
the ability of Flt3-MDA-7 or Flt3-M4 to exert "bystander" activity
on untreated right side tumors generated by implanting these and
receptor positive DU145 cells. The results are presented in FIG. 7.
As can be seen, tumor volume was reduced in DU145 tumors and in
A549 tumors with reconstituted dimeric receptors, but not in A549
receptor negative cells.
[0091] The ability of secreted MDA-7/IL-24 and M4 to induce
apoptosis in IL-20/IL-22 receptor positive cells was tested.
IM-PHFA (2.times.10.sup.6) cells were infected with adenovirus
expressing either null, Flt3-MDA-7 or Flt3-M4 (5000 vp) in 10-cm
plates for 48 hours. Conditioned media (CM) was collected as
described above. A549 cells (2.times.10.sup.6) (receptor negative)
or A549 IL-20R2/A549 IL-22R (receptor reconstituted cells) were
plated overnight and the medium was replaced with 5 ml of either CM
collected from Ad-Null, or Ad-Flt3-M4, or Ad-Flt3-MDA-7 infected
cells and cultured for 72 hours. This media was replaced with fresh
conditioned medium after 48 hours. Cells were then collected and
used for Western blotting analysis for PARP cleavage. All the
experiments were repeated at least three times and representative
images are shown.
[0092] The results are presented in FIG. 8. As can be seen,
secreted MDA-7/IL-24 and M4 induce apoptosis in IL-20/IL-22
receptor positive cells.
Example 4. Purified M4 Protein
[0093] Purified His-M4 was generated as follows: IM-PHFA cells
(hTERT-immortalized primary human fetal astrocytes) were infected
with either Ad.His-Fl3-MDA-7 or Ad.His-Flt-3-M4 and cultured for 72
hours in medium. Once cell detachment from the culture vessel was
noted the medium containing secreted His-MDA-7 or His-M4,
respectively, was collected. The collected medium was centrifuged
and cell debris were removed. The collected medium was mixed with
binding buffer (50 mM NaH.sub.2PO4 (pH 8.0), 150 mM NaCl, 5 mM
Imidazole, 5% glycerol, 0.05% Tween-20) and with Ni-NTA slurry and
incubated over night to allow His-MDA-7 or His-M4 to bind to the Ni
slurry. The slurry with the medium was then passed through the
column and allowed to drain completely. The slurry in the column
was washed 3 times with wash buffer (50 mM NaH.sub.2PO4 (pH 8.0),
300 mM NaCl, 10 mM. Imidazole, 5% glycerol, 0.05% Tween-20). After
washing the slurry was incubated with 5 nil of elution buffer (50
mM NaH.sub.2PO.sub.4 (pH 8.0), 300 mM NaCl, 400 mM Imidazole, 5%
glycerol, 0.05% Tween-20) for 2-3 hours. The eluent was collected
and concentrated using 3 KDa cut-off membrane.
[0094] His-M4 exerts significant growth inhibitory effects on
receptor positive cancer cells (such as DU145), but not in receptor
complex negative cells (such as A549), in a similar manner as
His-MDA-7 (FIG. 9). Treatment with these pure proteins was
associated with induction of PARP cleavage, and ER stress markers,
but only in the receptor positive DU145 cells (FIG. 10).
Example 5
[0095] Comparative testing of the two cytokines M4 and MDA-7/IL-24
is carried out for different properties in serum relative to
half-life, bioactivity based on concentration, bioavailability,
tissue distribution, etc. The growth inhibitory properties and
signaling effects of His-M4 are found to be comparable to those of
His-MDA-7.
[0096] The invention can be practiced with modification within the
spirit and scope of the appended claims. Accordingly, the present
invention should not be limited to the embodiments as described
above, but should further include all modifications and equivalents
thereof within the spirit and scope of the description provided
herein.
[0097] The complete contents of all patents, patent applications
and publications cited herein are hereby incorporated by reference
in entirety.
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Sequence CWU 1
1
61103PRTArtificial SequenceSynthetic cytokine 1Glu Ser Cys Tyr Leu
Val His Thr Leu Leu Glu Phe Tyr Leu Lys Thr 1 5 10 15 Val Phe Lys
Asn Tyr His Asn Arg Thr Val Glu Val Arg Thr Leu Lys 20 25 30 Ser
Phe Ser Thr Leu Ala Asn Asn Phe Val Leu Ile Val Ser Gln Leu 35 40
45 Gln Pro Ser Gln Glu Asn Glu Met Phe Ser Ile Arg Asp Ser Ala His
50 55 60 Arg Arg Phe Leu Leu Phe Arg Arg Ala Phe Lys Gln Leu Asp
Val Glu 65 70 75 80 Ala Ala Leu Thr Lys Ala Leu Gly Glu Val Asp Ile
Leu Leu Thr Trp 85 90 95 Met Gln Lys Phe Tyr Lys Leu 100
2312DNAArtificial SequenceSnythetic nucleic acid sequence encoding
truncated cytokine 2gagagctgtt accttgtcca caccctgctg gagttctact
tgaaaactgt tttcaaaaac 60taccacaata gaacagttga agtcaggact ctgaagtcat
tctctactct ggccaacaac 120tttgttctca tcgtgtcaca actgcaaccc
agtcaagaaa atgagatgtt ttccatcaga 180gacagtgcac acaggcggtt
tctgctattc cggagagcat tcaaacagtt ggacgtagaa 240gcagctctga
ccaaagccct tggggaagtg gacattcttc tgacctggat gcagaaattc
300tacaagctct ga 312323PRTArtificial SequenceSynthetic secretory
signal sequence 3Met Thr Val Leu Ala Pro Ala Trp Ser Pro Thr Thr
Tyr Leu Leu Leu 1 5 10 15 Leu Leu Leu Leu Ser Gly Ser 20
469DNAArtificial SequenceSnythetic nucleic acid sequence encoding
secretory signal sequence 4atgacagtgc tggcgccagc ctggagccca
acaacctatc tcctcctgct gctgctgctg 60agcggatcc 695126PRTArtificial
SequenceSnythetic cytokine with secretory signal sequence 5Met Thr
Val Leu Ala Pro Ala Trp Ser Pro Thr Thr Tyr Leu Leu Leu 1 5 10 15
Leu Leu Leu Leu Ser Gly Ser Glu Ser Cys Tyr Leu Val His Thr Leu 20
25 30 Leu Glu Phe Tyr Leu Lys Thr Val Phe Lys Asn Tyr His Asn Arg
Thr 35 40 45 Val Glu Val Arg Thr Leu Lys Ser Phe Ser Thr Leu Ala
Asn Asn Phe 50 55 60 Val Leu Ile Val Ser Gln Leu Gln Pro Ser Gln
Glu Asn Glu Met Phe 65 70 75 80 Ser Ile Arg Asp Ser Ala His Arg Arg
Phe Leu Leu Phe Arg Arg Ala 85 90 95 Phe Lys Gln Leu Asp Val Glu
Ala Ala Leu Thr Lys Ala Leu Gly Glu 100 105 110 Val Asp Ile Leu Leu
Thr Trp Met Gln Lys Phe Tyr Lys Leu 115 120 125 6381DNAArtificial
SequenceSynthetic nucleic acid sequence encoding recombinant
cytokine wtih secretory signal sequence 6atgacagtgc tggcgccagc
ctggagccca acaacctatc tcctcctgct gctgctgctg 60agcggatccg agagctgtta
ccttgtccac accctgctgg agttctactt gaaaactgtt 120ttcaaaaact
accacaatag aacagttgaa gtcaggactc tgaagtcatt ctctactctg
180gccaacaact ttgttctcat cgtgtcacaa ctgcaaccca gtcaagaaaa
tgagatgttt 240tccatcagag acagtgcaca caggcggttt ctgctattcc
ggagagcatt caaacagttg 300gacgtagaag cagctctgac caaagccctt
ggggaagtgg acattcttct gacctggatg 360cagaaattct acaagctctg a 381
* * * * *