U.S. patent application number 14/985412 was filed with the patent office on 2016-04-21 for group of alkaloids, the novel autophagic enhancers for treatment of cancers and neurodegenerative conditions thereof.
This patent application is currently assigned to Macau University of Science and Technology. The applicant listed for this patent is Macau University of Science and Technology. Invention is credited to Yuen Kwan LAW, Liang LIU, Jingrong WANG, Kam Wai WONG.
Application Number | 20160106732 14/985412 |
Document ID | / |
Family ID | 51794570 |
Filed Date | 2016-04-21 |
United States Patent
Application |
20160106732 |
Kind Code |
A1 |
WONG; Kam Wai ; et
al. |
April 21, 2016 |
Group of Alkaloids, the Novel Autophagic Enhancers for Treatment of
Cancers and Neurodegenerative Conditions Thereof
Abstract
The present invention discloses a method of treating cancer
comprising administering an effective amount of an alkaloid, in
which the alkaloid is liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine or thalidezine and isolated from the
traditional Chinese medicinal herbs. The use of the alkaloid in
treating neurodegenerative disorder is also disclosed.
Inventors: |
WONG; Kam Wai; (Macau,
CN) ; LAW; Yuen Kwan; (Macau, CN) ; LIU;
Liang; (Macau, CN) ; WANG; Jingrong; (Macau,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Macau University of Science and Technology |
Macau |
|
CN |
|
|
Assignee: |
Macau University of Science and
Technology
|
Family ID: |
51794570 |
Appl. No.: |
14/985412 |
Filed: |
December 31, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14562781 |
Dec 8, 2014 |
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14985412 |
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61923231 |
Jan 3, 2014 |
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Current U.S.
Class: |
514/308 ;
514/279; 546/140; 546/31; 546/35 |
Current CPC
Class: |
A61K 31/4745 20130101;
A61P 25/28 20180101; A61P 35/00 20180101; A61K 31/4748 20130101;
A61K 31/4725 20130101 |
International
Class: |
A61K 31/4748 20060101
A61K031/4748; A61K 31/4725 20060101 A61K031/4725 |
Claims
1. A method of treating cancer comprising administering an
effective amount of an alkaloid to a subject in need thereof,
wherein said alkaloid is biscoclaurine alkaloid.
2. The method of claim 1 wherein said biscoclaurine alkaloid is
cepharanthine.
3. The method of claim 1 wherein said cancer is selected from a
group consisting of cervical cancer, breast cancer, liver cancer,
lung cancer and prostate cancer.
4. The method of claim 1 wherein said alkaloid exhibits specific
cytotoxic effect towards a panel of human cancer cells.
5. The method of claim 1 wherein said cancer is treatable by
alkaloids-mediated autophagy.
6. The method of claim 5 wherein said alkaloids-mediated autophagy
is autophagy-related gene 7 dependent.
7. A pharmaceutical composition for treating cancer comprising an
alkaloid, wherein said alkaloid is biscoclaurine alkaloid.
8. The pharmaceutical composition of claim 7 wherein said
biscoclaurine alkaloid is cepharanthine.
9. The pharmaceutical composition of claim 7 wherein said cancer is
selected from a group consisting of cervical cancer, breast cancer,
liver cancer, lung cancer and prostate cancer.
10. The pharmaceutical composition of claim 7 wherein cancer is
treatable by alkaloids-mediated autophagy.
11. The pharmaceutical composition of claim 10 wherein said
alkaloids-mediated autophagy is autophagy-related gene 7 dependent.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of U.S. Ser.
No. 14/562,781 filed on 8 Dec. 2014, which claims benefit under 35
U.S.C. .sctn.119(e) of U.S. Provisional Application having Ser. No.
61/923,231 filed 3 Jan. 2014, which is hereby incorporated by
reference herein in its entirety.
FIELD OF INVENTION
[0002] This invention relates to a group of novel autophagy
enhancers, namely liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine, and their use thereof
in treating cancers and neurodegenerative conditions.
BACKGROUND OF INVENTION
[0003] Autophagy is a cellular degradation process that involves
the delivery of cytoplasmic cargo such as long-lived protein,
mis-folded protein or damaged organelles, sequestered inside
double-membrane vesicles (autophagosome) before entering lysosome
for degradation. Autophagy occurs at low basal levels in cells to
maintain normal homeostatic functions by turnover of proteins and
organelles. Upon cellular stressful conditions such as nutrient
deprivation, oxidative stress, infection or protein aggregate
accumulation, autophagy starts with membrane isolation and
expansion to form autophagosome that sequesters all unwanted
cytoplasmic materials. Followed by fusion of the autophagosome with
lysosome to form an autolysosome, all the engulfed materials are
degraded to recycle intracellular nutrients and energy [1]. Both
autophagy impairment and the age-related decline of autophagic
function lead to the pathogenesis of many age-related diseases such
as neurodegenerative disorders and cancers [2].
[0004] One of the key roles for autophagy is to degrade toxic
aggregate-prone cytoplasmic proteins that are inaccessible to the
proteasome when they form oligomers or aggregates [3];
aggregate-prone proteins with polyglutamine and polyalanine
expansions, in turn, are degraded by autophagy [4] Inhibition of
mTOR induces autophagy and reduces toxicity of polyglutamine
expansions or mutant proteins in fly and mouse models [4-7]. These
mutant proteins include mutant a-synuclein which causes Parkinson's
disease, and polyglutamine-expanded mutant huntingtin that causes
Huntington's disease [8,9]. In contrast, protein aggregates form in
the cytoplasm when autophagy is inhibited in normal mice [10].
Rapamycin, a United States Food and Drug Administration
(FDA)-approved immunosuppressant, is found effective in treating
fruit fly and mouse models of Huntington's disease through
increased autophagic clearance of mutant huntingtin [5]. Besides, a
small-molecule screen also revealed new chemicals that attenuate
the toxicity of mutant huntingtin through autophagy [9].
[0005] While autophagy may play a protective role in
neurodegenerative diseases [9], autophagic dysfunction is
associated with DNA damage, chromosome instability [11, 12], and
increased incidence of malignancies [12]. Modulators of autophagy
may play a protective role through promoting autophagic cell death
in tumors or augmenting the efficacy of chemotherapeutic agents
when used in combination. Several clinically approved or
experimental antitumor agents induced autophagy-related cell death
in various types of cancer cells [13-16].
[0006] Recently, natural compounds from alkaloids have been found
to induce autophagy with potential neuroprotective or anti-cancer
effects. For instance, alkaloids isolated from Chinese herbal
medicine are important source for drug discovery [17]. Alkaloids
such as berberine, matrine and tetrandrine, exhibit their
anti-cancer effects through cell cycle arrest, apoptosis,
autophagy, inhibition of metastasis or angiogenesis [18-20].
Camptothecin and vinblastine are chemotherapeutic drugs that have
been approved for clinical use [21,22]. In addition, alkaloids such
as isorhynchophylline [23] and berberine were also reported for
their neuroprotective effects in vitro.
SUMMARY OF INVENTION
[0007] In the light of the foregoing background, it is an object of
the present invention to provide the alternate alkaloids as novel
autophagy enhancers with their potential therapeutic application in
cancers and neurodegenerative diseases by induction of
autophagy-related cell death in a panel of cancer cells and
clearance of mutant huntingtin in neuronal cells. In one
embodiment, such alkaloids include liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine.
[0008] Accordingly, the present invention, in one aspect, is a
method of treating cancer including administering an effective
amount of an alkaloid to a subject in need thereof, wherein the
alkaloid is isoquinoline alkaloid, bisbenzylisoquinoline alkaloid,
biscoclaurine alkaloid or bisisoquinoline alkaloid.
[0009] In one exemplary embodiment, the isoquinoline alkaloid is
liensinine; the bisbenzylisoquinoline alkaloid is isoliensinine,
dauricine or hernandezine; the biscoclaurine alkaloid is
cepharanthine; and the bisisoquinoline alkaloid is thalidezine.
[0010] In an exemplary embodiment, the cancer is cervical cancer,
breast cancer, liver cancer, lung cancer or prostate cancer.
[0011] In another exemplary embodiment, the alkaloid exhibits
specific cytotoxic effect towards a panel of human cancer
cells.
[0012] In another exemplary embodiment, cancer is treatable by
alkaloids-mediated autophagy; in a further exemplary embodiment,
the alkaloids-mediated autophagy is autophagy-related gene 7
dependent.
[0013] In an exemplary embodiment, the cancer is caused by and/or
originated from cells containing wild-type autophagy-related gene
7, and is treated by administering liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and/or thalidezine to a
subject in need thereof.
[0014] In yet another exemplary embodiment, the cancer is caused by
and/or originated from apoptosis-resistant cells, and is treated by
administering isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine to a subject in need thereof.
[0015] According to another aspect of the present invention, a
pharmaceutical composition for treating cancer comprising an
alkaloid is provided, in which the alkaloid is isoquinoline
alkaloid, bisbenzylisoquinoline alkaloid, biscoclaurine alkaloid or
bisisoquinoline alkaloid.
[0016] In one exemplary embodiment, the isoquinoline alkaloid is
liensinine; the bisbenzylisoquinoline alkaloid is isoliensinine,
dauricine or hernandezine; the biscoclaurine alkaloid is
cepharanthine; and the bisisoquinoline alkaloid is thalidezine.
[0017] In an exemplary embodiment, the cancer is cervical cancer,
breast cancer, liver cancer, lung cancer or prostate cancer.
[0018] In another exemplary embodiment, cancer is treatable by
alkaloids-mediated autophagy; in a further exemplary embodiment,
the alkaloids-mediated autophagy is autophagy-related gene 7
dependent.
[0019] In a further aspect of the present invention, a method of
treating neurodegenerative disorder including administering an
effective amount of an alkaloid to a subject in need thereof is
provided, in which the alkaloid is isoquinoline alkaloid,
bisbenzylisoquinoline alkaloid, biscoclaurine alkaloid or
bisisoquinoline alkaloid.
[0020] In one exemplary embodiment, the isoquinoline alkaloid is
liensinine; the bisbenzylisoquinoline alkaloid is isoliensinine,
dauricine or hernandezine; the biscoclaurine alkaloid is
cepharanthine; and the bisisoquinoline alkaloid is thalidezine.
[0021] In an exemplary embodiment, the neurodegenerative disorder
is caused by cells containing mutant huntingtin HDQ55/74.
[0022] In another exemplary embodiment, the neurodegenerative
disorder is Huntington's disease.
[0023] In another aspect of the present invention, a pharmaceutical
composition for treating neurodegenerative disorder comprising an
alkaloid is provided, in which the alkaloid is isoquinoline
alkaloid, bisbenzylisoquinoline alkaloid, biscoclaurine alkaloid or
bisisoquinoline alkaloid.
[0024] In one exemplary embodiment, the isoquinoline alkaloid is
liensinine; the bisbenzylisoquinoline alkaloid is isoliensinine,
dauricine or hernandezine; the biscoclaurine alkaloid is
cepharanthine; and the bisisoquinoline alkaloid is thalidezine.
[0025] In an exemplary embodiment, the neurodegenerative disorder
is caused by cells containing mutant huntingtin HDQ55/74.
[0026] In another exemplary embodiment, the neurodegenerative
disorder is Huntington's disease.
BRIEF DESCRIPTION OF FIGURES
[0027] FIGS. 1a to 1f show the chemical structures of liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine.
[0028] FIG. 1g shows the results of cell cytotoxicity study of
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine towards a panel of cancer and normal cells.
[0029] FIGS. 2a to 2b show that liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine induce
autophagic GFP-LC3 puncta formation and autophagic protein LC3-II
conversion in HeLa cancer cells.
[0030] FIG. 2c shows that liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine induce autophagic
GFP-LC3 puncta formation in a panel of cancer cells.
[0031] FIG. 3 shows that liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine-induced autophagy are
abrogated by autophagic inhibitor, 3-methyl adenine (3-MA) in HeLa
cancer cells.
[0032] FIGS. 4a to 4c show that liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine-induced
autophagy are dependent on the presence of autophagy-related gene7
(Atg7).
[0033] FIGS. 5a to 5b show that liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine activate
autophagy through modulation of AMPK-mTOR signaling pathway.
[0034] FIGS. 6a to 6c show that liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine are able to
induce autophagic cell death in wild-type Atg7 cells, but not in
Atg7 deficient cells.
[0035] FIGS. 7a to 7e show that isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine are able to induce cell
death in apoptosis-resistant cells.
[0036] FIGS. 8a to 8c show the cell cytotoxicity and clearance of
HTT mutant HDQ55/74 of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] As used herein and in the claims, "comprising" means
including the following elements but not excluding others.
[0038] In this invention, a group of alkaloids including
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine are identified as novel inducers of autophagy. The
chemical structures of these six alkaloids are demonstrated in
FIGS. 1a to 1f respectively. Studies conducted by inventors
demonstrate that liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine can induce autophagy
and autophagic cell death in a panel of cancer and
apoptosis-resistant cells. On the other hand, these compounds are
capable of promoting the degradation of mutant huntingtin with
HDQ55 or 74 CAG repeats in PC12 cells. Taken together, works by the
inventors provide novel insights into the autophagic effect of
selected alkaloids and their potential uses in anti-tumor or
neuroprotective therapy in future.
[0039] Furthermore, in this invention, liensinine and isoliensinine
are derived and isolated from seed embryos of Nelumbo nucifera;
dauricine is derived and isolated from Asiatic Moonseed Rhizome;
cepharanthine is derived and isolated from Stephania cepharantha;
and hernandezine and thalidezine are derived and isolated from
Thalictrum podocarpum Humb.
[0040] The following preparations and examples are given to enable
those skilled in the art to more clearly understand and to practice
the present invention. They should not be considered as limiting
the scope of the invention, but merely as being illustrative and
representative thereof.
EXAMPLE 1
Study on Cell Cytotoxicity
[0041] This example describes in vitro cell cytotoxicity of
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine in a panel of human cancer and normal cells.
1.1 Cell Culture and Cytotoxicity Assay
[0042] The test compounds of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine were dissolved in DMSO
at a final concentration of 100 mmol/L and stored at -20 .degree.
C. Cytotoxicity was assessed using the
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay
as described previously [25]. 4000-8000 HeLa (human cervical
cancer), MCF-7 (human breast cancer), HepG2 (human liver cancer),
Hep3B (human liver cancer), H1299 (human lung cancer), A549 (human
lung cancer), PC3 (human prostate cancer) and LO2 (human normal
liver) cells were seeded on 96-well plates per well. After
overnight pre-incubation, the cells were exposed to different
concentrations of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine (0.039-100 .mu.mol/L)
for 3 days. Specifically, the following concentrations are used for
all of the above alkaloids: 100, 50, 25, 12.5, 6.25, 3.125, 1.5625,
0.78, 0.39, 0.195, 0.079, 0.039 .mu.mol/L. Subsequently, 10 .mu.L
of MTT reagents was added to each well and incubated at 37.degree.
C. for 4 hours followed by the addition of 100 .mu.L solubilization
buffer (10% SDS in 0.01 mol/L HCl) and overnight incubation.
Absorbance at 585 nm was determined from each well on the following
day. The percentage of cell viability was calculated using the
following formula: Cell viability (%)=Cells number treated/Cells
number DMSO control.times.100. Data was obtained from three
independent experiments.
1.2 Results
[0043] As shown in FIG. 1g, significant cell cytotoxicity was
observed with mean IC.sub.50 value ranging from 4.52-61.8 .mu.M
observed in a panel of human cancer cells treated with liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine for 72 hours as revealed by MTT assay. However, the
test compounds of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine indicated no or
insignificant cytotoxic effect toward human normal liver LO2
cells.
EXAMPLE 2
Study on Autophagic Effect
[0044] This example describes an in vitro study to demonstrate the
autophagic effect of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine.
2.1 Quantification of Autophagy GFP-LC3 Puncta
[0045] GFP-LC3 puncta formation was quantified as previously
described [15]. In brief, GFP-LC3 transfected cells grown on
coverslips in a 6-well plate were treated with or without 20 .mu.M
of liensinine, 10 .mu.M of isoliensinine, dauricine, cepharanthine,
hernandezine or thalidezine for 4 hours, the cells were then fixed
in 4% paraformaldehyde for 20 minutes at room temperature and then
rinsed with PBS. Slides were mounted with FluorSave.TM. mounting
media (Calbiochem, San Diego, Calif.) and examined by fluorescence
microscopy. The number of GFP-positive cells with GFP-LC3 puncta
formation was examined under the Nikon ECLIPSE 80i microscope.
Representative images were captured with CCD digital camera Spot
RT3.TM. (Diagnostic Instruments, Inc., Melville, N.Y.). To quantify
for autophagy, the percentage of cells with punctate GFP-LC3
fluorescence was calculated by counting the number of the cells
with punctate GFP-LC3 fluorescence in GFP-positive cells. A minimum
of 150 cells from 3 randomly selected fields was scored.
2.2 Detection of Autophagic Marker Protein LC3 Conversion
[0046] After treatments with liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine, cells were harvested
and lysed in RIPA buffer (Cell Signaling Technologies Inc.,
Beverly, Mass.). The cell lysates were then resolved by SDS-PAGE.
After electrophoresis, the proteins from SDS-PAGE were transferred
to nitrocellulose membrane which was then blocked with 5% non-fat
dried milk for 60 minutes. The membrane was then incubated with LC3
primary antibodies (1:1000) in TBST overnight at 4.degree. C. After
that, the membrane was further incubated with HRP-conjugated
secondary antibodies for 60 minutes. Finally, protein bands were
visualized by using the ECL Western Blotting Detection Reagents
(Invitrogen, Paisley, Scotland, UK).
2.3 Quantification of Liensinine, Isoliensinine, Dauricine,
Cepharanthine, Hernandezine and Thalidezine-Mediated Autophagy in
the Presence of Autophagic Inhibitor
[0047] GFP-LC3 puncta formation was quantified as previously
described [15]. In brief, HeLa cells expressing GFP-LC3 were
treated with 20 .mu.M of liensinine, or 10 .mu.M of isoliensinine,
dauricine, cepharanthine, hernandezine or thalidezine in the
presence of autophagic inhibitor, 3-methyl adenine (3-MA, 5 mM),
for 4 hours. The cells were then fixed in 4% paraformaldehyde for
20 minutes at room temperature and then rinsed with PBS. Slides
were mounted with FluorSave.TM. mounting media (Calbiochem) and
examined by fluorescence microscopy. To quantify for autophagy, the
percentage of cells with punctate GFP-LC3 fluorescence was
calculated by counting the number of the cells with punctate
GFP-LC3 fluorescence in GFP-positive cells. A minimum of 150 cells
from 3 randomly selected fields were scored.
2.4 Results
[0048] As compared to DMSO control treatment, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine significantly induced the GFP-LC3 puncta formation in
HeLa cancer cells as shown in FIG. 2a. Western blot analysis showed
that conversion of the autophagic marker LC3-II was also induced
upon treatments of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine as shown in FIG. 2b. In
addition, liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine also increased the formation of
GFP-LC3 puncta towards a panel of cancer and normal cells as
revealed by fluorescent microscopy as shown in FIG. 2c. However,
there was a significant reduction in the liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine-autophagy
induced by GFP-LC3 puncta formation in HeLa cells in the presence
of autophagic inhibitor (3-MA) as shown in FIG. 3, in which such
findings were consistent with the GFP-LC3 puncta formation and LC3
conversion from LC3-I to LC3-II as shown in FIGS. 2a to 2c.
2.5 Conclusion
[0049] The data of this study suggested that liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine are the novel autophagy enhancers. Although these
compounds could induce autophagy in LO2 human normal liver cells,
autophagy mediated by these compounds exhibits far less toxic in
human normal liver cells as shown in FIG. 1g, suggesting that the
cytotoxic effect mediated by liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine or thalidezine is tumor specific.
EXAMPLE 3
Study on Dependency of the Presence of Autophagy-related Gene 7
(Atg7) on Autophagic Effect
[0050] This example describes an in vitro study to demonstrate that
the autophagic effect of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine is dependent on the
presence of autophagy-related gene 7 (Atg7).
3.1 Quantification of Autophagy GFP-LC3 Puncta in Atg7 Wild Type
and Deficient MEFs
[0051] GFP-LC3 puncta formation was quantified as previously
described [15]. In brief, both Atg7 wild-type (Atg7-wt or Atg7+/+)
and deficient (Atg7-/-) mouse embryonic fibroblasts (MEFs) were
transfected with GFP-LC3 plasmid and then grown on coverslips in a
6-well plate. The cells were then treated with 20 .mu.M of
liensinine, 10 .mu.M of isoliensinine, 10 .mu.M of dauricine, 10
.mu.M of cepharanthine, hernandezine or 10 .mu.M of thalidezine.
for 24 h. The cells were then fixed in 4% paraformaldehyde for 20
minutes at room temperature and then rinsed with PBS. Slides were
mounted with FluorSavelM mounting media (Calbiochem, San Diego,
California) and examined by fluorescence microscopy. The number of
GFP-positive cells with GFP-LC3 puncta formation was examined under
the Nikon ECLIPSE 80i microscope. Representative images were
captured with CCD digital camera Spot RT3.TM. (Diagnostic
Instruments, Inc., Melville, N.Y.). To quantify for autophagy, the
percentage of cells with punctate GFP-LC3 fluorescence was
calculated by counting the number of the cells with punctate
GFP-LC3 fluorescence in GFP-positive cells. A minimum of 150 cells
from 3 randomly selected fields were scored.
3.2 Results
[0052] Liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine were found to induce GFP-LC3 puncta
formation in wild type Atg7 cells but not in Atg7-knockout (Atg7-ko
or Atg7-/-) mouse embryonic fibroblasts, as shown in FIGS. 4a to
4c.
3.3 Conclusion
[0053] Liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine work as the novel autophagy enhancers
which depend on autophagy related gene, Atg7, for the induction of
autophagy. In other words, the autophagy induced by the six
aforementioned compounds was Atg-7 dependent.
EXAMPLE 4
Study on Mechanism of Autophagy Induction
[0054] This example describes an in vitro study to demonstrate the
mechanism and action of liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine during autophagy
induction.
4.1 Detection of mTOR Signaling Marker Proteins
[0055] HeLa cells treated with 20 .mu.M of liensinine, 10 .mu.M of
isoliensinine, 10 .mu.M of dauricine, 10 .mu.M of cepharanthine, 10
.mu.M of hernandezine and 10 .mu.M of thalidezine were harvested
and lysed in RIPA buffer (Cell Signaling). The cell lysates were
then resolved by SDS-PAGE. After electrophoresis, the proteins from
SDS-PAGE were transferred to nitrocellulose membrane which was then
blocked with 5% non-fat dried milk for 60 minutes. The membrane was
then incubated with P-p70S6K, p70S6K, P-AMPK, AMPK and actin
primary antibodies (1:1000) in TBST overnight at 4.degree. C.
respectively. After that, the membrane was further incubated with
HRP-conjugated secondary antibodies for 60 minutes. Finally,
protein bands were visualized by using the ECL Western Blotting
Detection Reagents (Invitrogen).
[0056] cl 4.2 Quantification of Liensinine, Isoliensinine,
Dauricine, Cepharanthine, Hernandezine And Thalidezine-Mediated
Autophagy in the Presence of Specific Inhibitor
[0057] GFP-LC3 puncta formation was quantified as previously
described [15]. In brief, HeLa cells expressing GFP-LC3 were
treated with indicated concentrations of liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine in the
presence of AMPK inhibitor, compound C (CC, 5 .mu.M), for 24 hours.
The cells were then fixed in 4% paraformaldehyde for 20 minutes at
room temperature and then rinsed with PBS. Slides were mounted with
FluorSave.TM. mounting media (Calbiochem) and examined by
fluorescence microscopy. To quantify for autophagy, the percentage
of cells with punctate GFP-LC3 fluorescence was calculated by
counting the number of the cells with punctate GFP-LC3 fluorescence
in GFP-positive cells. A minimum of 150 cells from 3 randomly
selected fields were scored.
4.3 Results
[0058] Liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine were found to activate the
phosphorylation of AMPK as compared to DMSO control treatment as
shown in FIG. 5a and this activation was also accompanied by a
concomitant reduction in its downstream p70S6K phosphorylation. In
order to confirm whether the AMPK signaling is involved in
autophagy induced by liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine or thalidezine, specific AMPK
inhibitor, compound C, was used in the study. Results showed that
there was a significant reduction in the GFP-LC3 puncta formation
induced by liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine or thalidezine in HeLa cells treated with the presence
of AMPK inhibitor (Compound C), as shown in FIG. 5b, suggesting
that the AMPK signaling is required for autophagy induction by
these alkaloid compounds.
4.4 Conclusion
[0059] Liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine are shown to induce autophagy via
modulation of AMPK-mTOR signaling pathway.
EXAMPLE 5
Study of Induction of Autophagic Cell Death in Cells
[0060] This example describes an in vitro study to demonstrate that
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine induce autophagic cell death in cells.
5.1 Cell culture and flow cytometry analysis
[0061] Cell viability was measured using an annexin V staining kit
(BD Biosciences, San Jose, Calif., USA). Briefly, Atg7 wild-type
(Atg7 +/+ or Atg7-wt) and Atg7 deficient (Atg7 -/- or Atg7-ko)
mouse embryonic fibroblasts (MEFs) were treated with the selected
alkaloids for 24 h. Cells were then harvested and analysed by
multiparametric flow cytometry using FITC-Annexin V and Propidium
iodide staining (BD Biosciences, San Jose, Calif., USA) according
to the manufacturer's instructions. Flow cytometry was then carried
out using a FACSCalibur flow cytometer (BD Biosciences, San Jose,
Calif., USA). Data acquisition and analysis was performed with
CellQuest (BD Biosciences, San Jose, Calif., USA). Data were
obtained from three independent experiments.
5.2 Results
[0062] Among the six tested compounds, as shown in FIGS. 6a to 6c,
all alkaloids are found to exhibit less cytotoxic effect to
autophagy deficient cells (Atg7 -/- or Atg7-ko).
5.3 Conclusion
[0063] The results suggest that liensinine, isoliensinine,
dauricine, cepharanthine, hernandezine and thalidezine induce cell
death or cell cytotoxicity via autophagy induction.
EXAMPLE 6
Study on Study of Induction of Cell Cytotoxicity in
Apoptosis-Resistant Cells
[0064] This example describes an in vitro study to demonstrate that
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine potently induce cell cytotoxicity in
apoptosis-resistant cells.
6.1 Cell Culture and Cytotoxicity Assay
[0065] The test compounds of isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine were dissolved in DMSO
at a final concentration of 100 mmol/L and stored at -20 .degree.
C. Cytotoxicity was assessed using the
3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay
as previously described [25]. 2500 of caspase wild-type (caspase
WT), caspase-3 deficient (caspase 3KO), caspase-7 deficient
(caspase 7KO), caspase-3/-7 deficient (caspase 3/7 DKO), caspase-8
deficient (caspase 8KO), Bax-Bak wild-type (Bak-Bak WT) and Bax-Bak
double knock out (Bak-Bak DKO) mouse embryonic fibroblasts (MEFs)
were seeded on 96-well plates per well. After overnight
pre-incubation, the cells were exposed to different concentrations
of isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine (0.039-100 .mu.mol/L) for 3 days. Specifically, the
following concentrations are used for all of the above alkaloids:
100, 50, 25, 12.5, 6.25, 3.125, 1.5625, 0.78, 0.39, 0.195, 0.079,
0.039 pmol/L. Subsequently, 10 .mu.L of MTT reagents was added to
each well and incubated at 37.degree. C. for 4 hours, followed by
the addition of 100 .mu.L solubilization buffer (10% SDS in 0.01
mol/L HCl) and overnight incubation. Absorbance at 585 nm was
determined from each well on the following day. The percentage of
cell viability was calculated using the following formula: Cell
viability (%)=Cells number treated/Cells number DMSO
control.times.100. Data was obtained from three independent
experiments.
6.2 Results
[0066] Isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine are found to exhibit similar cytotoxic effect on both
wild-type and apoptosis-resistant cells, i.e. caspase-3/-7/-8 as
compared to the caspase wild-type MEFs as shown in FIGS. 7a to 7e).
In addition, from FIGS. 7a to 7e, similar cytotoxicity is also
shown in Bax-Bak DKO apoptosis-resistant cells as compared to
Bax-Bak wild-type MEFs, indicating that these alkaloid compounds
are able to induce cell death in apoptosis-resistant cells.
6.3 Conclusion
[0067] These findings suggest that isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine are capable to induce
cell cytotoxicity in apoptosis-resistant cancer cells.
EXAMPLE 7
Study on Clearance of Mutant Huntingtin HDQ55/74
[0068] This example describes an in vitro study to demonstrate the
clearance of mutant huntingtin HDQ55/74 by liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine.
7.1 Cell Culture and Cytotoxicity Assay
[0069] For cell viability assay measured by crystal violet
staining, PC-12 cells were incubated in 35 mm disc followed by the
addition of liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine at 5-10 .mu.M for 24 h. The cells were
then incubated with crystal violet for 10 minutes followed by a
ddH.sub.2O wash. Images of the stained cells were captured by CCD
digital camera Spot RT3.TM. under the Nikon ECLIPSE 80i microscope
with 4.times. magnification. Cell viability was quantified by
dissolving stained cells in 10% acetic acid (200 .mu.L/well). The
colorimetric reading of the solute mixture was then determined by
spectrophotometer at OD 560 nm The percentage of cell viability was
calculated using the following formula: Cell viability (%)=Cells
number.sub.treated/Cells number.sub.DMSO control.times.100. Data
was obtained from three independent experiments.
7.2 Removal of Mutant Huntingtin
[0070] PC 12 cells were transfected transiently with EGFP-HDQ55/74
plasmids for 24 h using Lipofectamine Plus LTX reagent (Invitrogen)
according to the manufacturer's protocol. The transfected cells
were then treated with liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine for 24 h. The removal
of mutant huntingtin, (HDQ55& HDQ74) was then quantitated by
immunoblotting with antibody against EGFP or by immunocytochemistry
under fluorescence microscopy.
7.3 Results
[0071] As shown in FIG. 8a, liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine exhibit no toxicity in
PC 12 at 5-10 .mu.M. In addition, 5-10 .mu.M of liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine enhanced the clearance of overexpressed EGFP-tagged
mutant huntingtin (HDQ55, HDQ74) with 55 and 74 CAG repeats as
measured by immunoblotting against EGFP antibody as shown in FIG.
8b. Concomitantly, fluorescence imaging as illustrated in FIG. 8c
further revealed that the six aforesaid compounds significantly
reduced the formed mutant huntingtin aggregate (HDQ55) in PC 12
cells.
7.4 Conclusion
[0072] Liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine and thalidezine may work as a novel neuroprotective
agent through accelerating the clearance of mutant huntingtin.
[0073] The present invention relates to the identification of a
group of novel autophagy enhancers, namely, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine, which are isolated from Chinese medicinal herbs,
Nelumbo nucifera (liensinine and isoliensinine), Asiatic Moonseed
Rhizome (dauricine), Stephania cepharantha (cepharanthine),
Thalictrum hernandezii (hernandezine) and Thalictrum podocarpum
Humb (thalidezine) respectively. The invention also covers the
anti-cancer effect of the above alkaloid compounds through
induction of autophagic cell death in a panel of cancer cells and
apoptosis-resistant cells. In addition, the invention further
covers the neuroprotective effect of the above compounds on
neuronal cells via enhancing the clearance of mutant
huntingtin.
[0074] In one embodiment of the present invention, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine exhibit significant cytotoxic effect towards a panel of
cancer cells, but not in human normal liver LO2 cells. In the
further embodiment of the present invention, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine exhibit specific cytotoxic effect toward human cancer
cells.
[0075] In one embodiment of the present invention, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine are the novel autophagy enhancers and never be reported
before. In the further embodiment of the present invention,
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine are capable to induce autophagy in a panel of
cancer and normal cells, and animals.
[0076] In one embodiment of the present invention, autophagy
induced liensinine, isoliensinine, dauricine, cepharanthine,
hernandezine or thalidezine is dependent on autophagy-related gene
7 (Atg7)). In the further embodiment of the present invention,
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine are capable to induce autophagy in Atg7 dependent
manner
[0077] In one embodiment of the present invention, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine induce autophagy via activation of AMP-activated
protein kinase (AMPK) and inhibition of mammalian target of
rapamycin (mTOR) signaling. In the further embodiment of the
present invention, liensinine, isoliensinine, dauricine,
cepharanthine, hernandezine and thalidezine are capable to induce
autophagy via modulation of AMPK-mTOR signaling pathway.
[0078] In one embodiment of the present invention, liensinine,
isoliensinine, dauricine and thalidezine are found to exhibit less
cytotoxicity in autophagy deficient cells (Atg7-/-), indicating
that liensinine, isoliensinine, dauricine and thalidezine are able
to induce autophagic cell death in wild-type Atg7 cells. In the
further embodiment of the present invention, liensinine,
isoliensinine, dauricine and thalidezine are capable to induce
autophagic cell death mechanism in Atg7 containing cancer
cells.
[0079] In another embodiment of the present invention,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine exhibit significant cytotoxic effect towards a panel of
apoptosis-resistant cells. In the further embodiment of the present
invention, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine exhibit potent cytotoxic effect towards
apoptosis-resistant cancer cells.
[0080] In another embodiment of the present invention, liensinine,
isoliensinine, dauricine, cepharanthine, hernandezine and
thalidezine enhance the clearance of mutant huntingtin HDQ55/74 in
PC12 cells. In the further embodiment of the present invention,
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine are capable to enhance the clearance of mutant
huntingtin.
[0081] The preferred embodiment of the present invention,
liensinine, isoliensinine, dauricine, cepharanthine, hernandezine
and thalidezine could be developed as novel anti-cancer and
neuroprotective agents for patients with cancers or
neurodegenerative diseases.
[0082] In another embodiment, the neurodegenerative diseases can be
selected from Alzheimer's disease, Parkinson's disease,
Huntington's disease, amyotrophic lateral sclerosis, ataxia
telangiectasia, spinocerebellar atrophy and multiple sclerosis.
[0083] The exemplary embodiments of the present invention are thus
fully described. Although the description referred to particular
embodiments, it will be clear to one skilled in the art that the
present invention may be practiced with variation of these specific
details. Hence this invention should not be construed as limited to
the embodiments set forth herein.
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