U.S. patent application number 17/069300 was filed with the patent office on 2021-06-03 for uses of hypoxia-inducible factor inhibitors.
This patent application is currently assigned to OncoImmune, Inc.. The applicant listed for this patent is OncoImmune, Inc.. Invention is credited to Yan LIU, Yang LIU, Sami N. MALEK, Yin WANG, Pan ZHENG.
Application Number | 20210161991 17/069300 |
Document ID | / |
Family ID | 1000005399285 |
Filed Date | 2021-06-03 |
United States Patent
Application |
20210161991 |
Kind Code |
A1 |
LIU; Yang ; et al. |
June 3, 2021 |
USES OF HYPOXIA-INDUCIBLE FACTOR INHIBITORS
Abstract
The present invention relates to treating a hematologic cancer
using a Hypoxia-Inducible Factor (HIF inhibitor). The invention
also relates to inducing acute myeloid leukemia remission using the
HIF inhibitor. The invention further relates to inhibiting a
maintenance or survival function of a cancer stem cell (CSC) using
the HIF inhibitor.
Inventors: |
LIU; Yang; (Baltimore,
MD) ; WANG; Yin; (Washington, DC) ; LIU;
Yan; (Washington, DC) ; MALEK; Sami N.; (Ann
Arbor, MI) ; ZHENG; Pan; (Baltimore, MD) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
OncoImmune, Inc. |
Rockville |
MD |
US |
|
|
Assignee: |
OncoImmune, Inc.
Rockville
MD
|
Family ID: |
1000005399285 |
Appl. No.: |
17/069300 |
Filed: |
October 13, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16748455 |
Jan 21, 2020 |
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17069300 |
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16294615 |
Mar 6, 2019 |
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16748455 |
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15839643 |
Dec 12, 2017 |
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16294615 |
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15448737 |
Mar 3, 2017 |
9877998 |
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15839643 |
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15234195 |
Aug 11, 2016 |
9623070 |
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15448737 |
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13513659 |
Jul 2, 2012 |
9427413 |
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PCT/US2010/039910 |
Jun 25, 2010 |
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15234195 |
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61266856 |
Dec 4, 2009 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61K 31/565 20130101;
A61K 31/395 20130101; A61K 38/07 20130101; A61K 45/06 20130101;
A61K 31/00 20130101; A61K 31/498 20130101; A61K 31/4355
20130101 |
International
Class: |
A61K 38/07 20060101
A61K038/07; A61K 31/395 20060101 A61K031/395; A61K 31/498 20060101
A61K031/498; A61K 31/565 20060101 A61K031/565; A61K 45/06 20060101
A61K045/06; A61K 31/00 20060101 A61K031/00; A61K 31/4355 20060101
A61K031/4355 |
Claims
1. A method of treating a leukemia or lymphoma in a human subject
in need thereof, comprising administering echinomycin to the
subject.
2.-3. (canceled)
4. The method of claim 1, wherein the echinomycin is administered
at a dose and interval to maintain a serum concentration of
echinomycin of less than or equal to 5 nM.
5. (canceled)
6. The method of claim 1, wherein the echinomycin is coadministered
with a Hedgehog pathway inhibitor.
7. The method of claim 6, wherein the Hedgehog pathway inhibitor is
cyclopamine.
8. The method of claim 1, wherein the echinomycin is coadministered
with a second cancer therapy.
9. (canceled)
10. The method of claim 1, wherein the treatment is for the
leukemia, and wherein the leukemia is acute myeloid leukemia.
11. The method of claim 10, wherein the subject carries a
cytogenetic alteration.
12. The method of claim 11, wherein the cytogenetic alteration is
selected from the group consisting of: 47,XY, +21; 46,XY; 45,XX,
-7; 46,XY,t(8; 21)(q22; q22); 49,XX, +8, +8,inv(16)(p13.1q22), +21;
46,XX,inv(16)(p13q22)/46,XX; 46,XY,inv(16)(p13q22); 46,XX,t(2;
13)(p23; q12)/46,XX; 45,XY,inv(3)(q21q26.2), -7/46,XY; 47,XY,
+4,inv(5)(p15q13)/47,sl, -4, +22; 46,XX,t(11; 19)(q23; p13.1);
46,XX,t(6; 11)(q27; q23)/46,XX; and 46,XX,t(1; 17)(p13; q25),t(9;
11)(p22; q23).
13. The method of claim 9, wherein the subject carries leukemia
cells of the phenotype CD38-CD34+.
14. The method of claim 10, wherein the subject carries cancer stem
cells.
15. The method of claim 14, wherein the cancer stem cells are
multiple drug resistant.
16. The method of claim 14, wherein the cancer stem cells are
chemoresistant or radioresistant.
17. A method of inducing acute myeloid leukemia remission in a
human patient in need thereof, comprising administering echinomycin
to the patient.
18. The method of claim 17, wherein the echinomycin is administered
at a dose and interval to maintain a serum concentration of
echinomycin of less than or equal to 5 nM.
19.-20. (canceled)
21. A method of preventing future relapse of acute myeloid leukemia
in a human patient in need thereof, comprising administering
echinomycin to the patient during remission from acute myeloid
leukemia.
22. The method of claim 21, wherein the echinomycin is administered
at a dose and interval to maintain a serum concentration of
echinomycin of less than or equal to 5 nM.
23. The method of claim 4, wherein the maintained serum
concentration is 0.01 to 5 nM.
24. The method of claim 18, wherein the maintained serum
concentration is 0.01 to 5 nM.
25. The method of claim 22, wherein the maintained serum
concentration is 0.01 to 5 nM.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to treating hematologic
cancers.
REFERENCE TO THE SEQUENCE LISTING
[0002] Applicant hereby makes reference to the Sequence Listing
that is contained in the file
"060275-0300-05USCN-Sequence-Listing.txt" (6 kB; created on Mar. 5,
2019), the contents of which are incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0003] It is estimated that 12,800 new cases acute myeloid leukemia
(AML) will be reported in 2009, with 9000 deaths. Although complete
remission can be achieved in most cases through chemotherapy,
prolonged remission or cure is rare. Accordingly there is a need in
the art to treat AML postremission. Postremission leukemia,
however, tends to be more resistant to chemotherapy in general.
Underlying reasons for this include expression of the multi-drug
resistance protein Pgp1, and possible residence in a bone marrow
area that is beyond the reach of drugs.
[0004] AML has been hypothesized to be associated with cancer stem
cells (CSC). This idea is supported by phenotypically identifiable
CSC subsets in AML cells, and the efficacy in testing CSC in an AML
model of both in vitro colony-forming units (CFU) and xenogeneic
transplantation models.
[0005] Many human cancers besides AML contain CSC that are
considered to be responsible for driving and maintaining tumor
growth and resistance to therapy. Understanding the mechanism of
self-renewal of CSC is therefore not only crucial for understanding
the fundamental mechanism of cancer development, but also provides
new approaches for long-lasting cancer therapy. Much like normal
stem cells, self-renewal of CSC involves two related processes.
First, the stem cells must undergo proliferation to produce
undifferentiated cells. The known pathways for self-renewal of
normal and cancer stem cells, including Wnt and Hedgehog, regulate
the proliferation, at least in part by controlling the expression
of Bmi-1, a critical regulator for proliferation of normal and
cancer stem cell proliferation. Second, the CSC must survive in an
undifferentiated state throughout tumorigenesis. Survival of CSC
may underlie difficulties in treating hematologic cancers, such as
AML. Such cancers are particularly more intransigent to therapy
postremission. Accordingly, there is a need in the art for
additional hematologic cancer therapies that target CSC, including
to treat AML. The present invention addresses this need by
disclosing a method of treating hematologic cancer using a HIF
inhibitor.
SUMMARY OF THE INVENTION
[0006] Provided herein is a method for treating a hematologic
cancer, which may comprise administering a HIF inhibitor to a
mammal in need thereof. The HIF inhibitor may be echinomycin,
2-methoxyestradiol, or geldanamycin. The echinomycin may be
administered at a non-toxic dose, which may be 1-100 mcg/m.sup.2.
The echinomycin may be coadministered with a Hedgehog pathway
inhibitor, which may be cyclopamine. The HIF inhibitor may also be
coadministered with a second cancer therapy.
[0007] The hematologic cancer may be a lymphoma or a leukemia,
which may be acute myeloid leukemia. The mammal may carry a
cytogenetic alteration, which may be 47,XY, +21; 46,XY; 45,XX, -7;
46,XY,t(8; 21)(q22; q22); 49,XX, +8, +8,inv(16)(p13.1q22), +21;
46,XX,inv(16)(p13q22)/46,XX; 46,XY,inv(16)(p13q22); 46,XX,t(2;
13)(p23; q12)/46,XX; 45,XY,inv(3)(q21q26.2), -7/46,XY; 47,XY,
+4,inv(5)(p15q13)/47,sl, -4, +22; 46,XX,t(11; 19)(q23; p13.1);
46,XX,t(6; 11)(q27; q23)/46,XX; or 46,XX,t(1; 17)(p13; q25),t(9;
11)(p22; q23). The mammal may carry leukemia cells of the phenotype
CD38.sup.-CD34.sup.+. The patient may carry cancer stem cells,
which may be multiple drug resistant, chemoresistant, or
radioresistant.
[0008] Also provided herein is a method for inducing acute myeloid
leukemia remission, which may comprise administering echinomycin to
a patient in need thereof. The echinomycin may be administered at a
non-toxic dose, which may be 1-100 mcg/m.sup.2. Further provided
herein is a method for inhibiting a maintenance or survival
function of a cancer stem cell (CSC), which may comprise contacting
the CSC with a HIF inhibitor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1. Isolation of CSC from a spontaneous mouse lymphoma.
a. Lymphoma cells, isolated from an enlarged spleen TGB transgenic
mice, were sorted by BD FACSAria into c-Kit.sup.+Sca-1.sup.+ or
c-Kit.sup.-Sca-1.sup.- fractions. The left panel shows tumor
phenotype while the right panels show post-sort purities. b.
Colony-forming activity of the tumor cells resides within the
c-Kit.sup.+Sca-1.sup.+ subset. The c-Kit.sup.+Sca-1.sup.+ or
c-Kit.sup.-Sca-1.sup.- fractions (10.sup.3/well) were plated in 1%
methylcellulose medium, the colony numbers were counted under a
microscope after 7 days of culture. Data shown are means and SD of
colony numbers in triplicate plates and are representative of three
independent experiments. The insert shows the morphology of a
typical colony. c. Photograph of spleens from mice that received
either c-Kit.sup.+Sca-1.sup.+ or c-Kit.sup.-Sca-1.sup.- tumor
cells. d. Phenotypic conservation and evolution of lymphoma arising
from c-Kit.sup.+Sca-1.sup.+ cells. Lymphoma cells were stained with
antibodies against CD8 and V.beta.8. The left panel shows cultured
lymphoma cells with predominantly high V.beta.8.sup.+ transgenic
CD8.sup.+ cells; while the right panel shows lymphoma cells from
the spleen of Rag-2.sup.-/- mice that received
c-Kit.sup.+Sca-1.sup.+ cells purified from cultured lymphoma cells.
Note the increase in Vb8-population. The enlarged double negative
populations in the right panel are resident spleen cells.
[0010] FIG. 2. HIF addiction of CSC. a. Selective ablation of
lymphoma CFU by echinomycin. The cultured lymphoma cells were
treated with given doses of pharmacologically effective drugs in
medium for 24 hours. After washing away the drugs, the cells were
cultured in 1% methylcellulose-containing medium, and the colony
number was counted after 6 to 7 days. Data shown are means and SD
of triplicates and have been confirmed by 3 independent
experiments. b. A reporter system for HIF activity in the TGB
lymphoma. Diagram of lentiviral construct for HIF activity is shown
on the top. Pause, a sequence fragment to eliminate the effect of
lentiviral promoter; HRE, Hypoxia response element (SEQ ID NO: 20);
TATA, TATA sequence (TATATAAT) (top). Lower left, validation of the
reporter. HEK293 cells were transiently transfected with cDNA
encoding mutant HIF1.alpha. (P402A/P577A) or vector control in
conjunction with either HRE-driven EGFP reporter, HRE mutant
reporter (SEQ ID NO: 21). The cells were analyzed by flow cytometry
to detect EGFP expression 36 hours after transduction. Lower right,
HIF activity in the lymphoma CSCs as revealed by co-expression of
GFP expressing cells and c-Kit in WT HRE, but not mutant HRE
lentiviral reporters (lower middle panel). c. IC50 of echinomycin
in the inhibition of HIF1.alpha. activity in lymphoma CSC. The
lymphoma cells transfected with the HRE reporter system were
cultured in the presence of different concentration of echinomycin
for 12 hours, the % of c-Kit.sup.+GFP.sup.+ cells was normalized
against the untreated group (1.13%, which was defined as 100%). The
dose that resulted in 50% reduction of the c-Kit.sup.+GFP.sup.+
cells is defined as IC50. d. Selectivity of HIF inhibitor for CFU
of lymphoma CSC over the CFU from hematopoietic progenitor cells.
c-Kit.sup.+Sca-1.sup.+ cells from either TGB or normal bone marrow
were treated with given concentration of echinomycin overnight
prior to plating in the medium containing 1% methylcellulose for
CFU assay. The data shown were % of untreated controls, and were
means+/-S.D. of triplicates. e. Therapeutic effect of a low dose of
echinomycin. Cultured lymphoma cells (1.times.10.sup.6/mouse) were
injected i.p. into immune competent B10.BR mice. Fourteen days
later, 10 .mu.g/Kg/Injection of echimomycin was injected at a
two-day interval for a total of 5 times. Control mice received
vehicle only. The mice were observed daily for survival.
[0011] FIG. 3. Increased HIF activity in the lymphoma CSCs under
normoxia. a &b. Gene expression. The cultured lymphoma cells
were sorted by BD FACSAria sorting system into
c-Kit.sup.+Sca-1.sup.+ or c-Kit.sup.-Sca-1.sup.- fractions. The
transcripts of HIF1.alpha., HIF-2.alpha., HIF-3.alpha., VHL and
Glut1 were determined by RT-PCR. a. Photograph of RT-PCR products.
b. Relative expression as measured by real-time PCR: comparison
with HPC. Relative expression of HIF1.alpha. and VHL transcripts in
FACS sorted c-Kit.sup.+Sca-1.sup.+ cells from either TGB tumor
(Spl-tumor) or bone marrow (BM). The expression levels were
expressed as fractions of house-keeping gene, b-actin. c.
Echinomycin selectively induces apoptosis of CSC. The cultured
lymphoma cells were treated with 20 pM echinomycin or vehicle in
medium for 16 hours. The treated cells were stained with c-Kit and
Sca-1, followed by staining with Annexin V. The stained cells were
analyzed by FACS analysis. Data shown are representative of 3
independent experiments. d. Isolation of 4 subsets of tumor cells
in AML samples. Bone marrow cells from AML patient MI-AML-36 were
stained for CD34 and CD38 and sorted into 4 subsets for RNA
isolation. The presort samples and the gates used for sorting are
shown in the left panel and the post sorted populations were shown
in the middle and right panels. The percentages of cells in each
gates are provided in the panels. e. Expression of HIF1.alpha.
(top) and GLUT1 in the subsets. Data shown are means+/-S.D. of
transcript levels of the genes, presented as % of b-actin from the
same samples. Enhanced expression in the CD34.sup.+CD38.sup.-
samples have been observed in all 6 AML samples tested. f. AML-CFU
in all 6 AML samples are highly sensitive to echinomycin. AML
samples (2.5.times.10.sup.5/ml) from either peripheral blood (PB)
or bone marrow (BM) were pretreated with given concentrations of
echinomycin in 2 ml medium for 24 hours. Viable treated cells were
then plated at 105/well for CFU assay in triplicates. The colony
numbers were counted 7-10 days later. The data shown were %
means+/-S.D. of untreated controls.
[0012] FIG. 4. ShRNA silencing revealed a critical role for
HIF1.alpha. in CSC maintenance. a. Silencing HIF1.alpha. abrogates
the c-Kit.sup.+Sca-1.sup.+CSC. TGB tumor cells were infected with
either lentiviral vector control with scrambled ShRNA (core
sequence 5'-tct cgt cat aac aag ttg a-3), or lentiviral vector
expressing two independent ShRNA (sh-1 or sh-2). Three days after
infection, the bulk tumor cells were analyzed by flow cytometry.
The GFPhi and GFPlo cells were gated and analyzed for expression of
c-Kit and Sca-1. b. HIF1.alpha. shRNA reduces CFU. The cultured
lymphoma cells were infected with either lentiviral HIF1.alpha.
shRNA or vector with scrambled ShRNA by spinoculation, and the
infected cells were selected with 5 .mu.g/ml of blasticidin for one
week. The infected cells were seeded into 1% of methylcellulose
culture medium at the density of 2.times.10.sup.5/well. The colony
numbers were counted under a microscope. Data shown are means and
SD of colony numbers in triplicates and are representative of three
independent experiments. c. HIF1.alpha. shRNAs abrogate
tumor-initiating activity. TGB tumor cells were infected 3 times
with lentiviral expressing scrambled ShRNA or HIF1.alpha. ShRNA and
then injected into B10.BR mice (9.times.10.sup.5/mouse, i.p.). The
survival of the recipient mice (n=5) was compared by Kaplan-Meier
analysis. All mice that succumbed have developed lymphoma as
revealed by necropsy. All data in this figure have been repeated at
least twice.
[0013] FIG. 5. Down-regulation of the Vhl gene is essential for
maintenance of CSC. a. Down-regulation of Vhl transcript in
c-Kit.sup.+Sca-1.sup.+ cells. TGB thymoma cells were sorted into
c-Kit.sup.+Sca-1.sup.+ and c-Kit.sup.-Sca-1.sup.- subsets, as
described in FIG. 1, the levels of Vhl transcripts were determined
by real-time PCR. b. Ectopic expression of Vhl ablated CSC. TGB
tumor cells were infected with either lentiviral vector control, or
lentiviral vector expressing two Vhl cDNA. Three days after
infection, the bulk tumor cells were analyzed by flow cytometry.
The GFPhi and GFPlo cells were gated and analyzed for expression of
c-Kit and Sca-1. c. Vhl expression reduces tumor CFU. The cultured
lymphoma cells were infected with either lentiviral Vhl cDNA or
vector by spinoculation, and the infected cells were selected with
5 .mu.g/ml of blasticidin for one week. The transduced cells were
seeded into 1% of methylcellulose culture medium at a density of
2.times.10.sup.5/well. The colony numbers were counted under a
microscope. Data shown are means and SD of colony numbers in
triplicates and are representative of three independent
experiments. d. Ectopic expression of Vhl cDNA inhibits
tumor-initiating activity. TGB tumor cells were infected 3 times
with lentiviral expressing vector alone or HIF1.alpha. ShRNA and
then injected into B10.BR mice (9.times.10.sup.5/mouse, i.p.). The
survival of the recipient mice (n=5) was compared by Kaplan-Meier
analysis. The development of lymphoma was confirmed by necropsy of
the succumbed mice. This experiment has been repeated twice.
[0014] FIG. 6. HIF works in concert with Notch pathway to maintain
CSC. a. Inhibition of colony-forming activity of CSC. The cultured
lymphoma cells were treated with given doses of L685, 458 for 24
hours. After that, the cells were cultured in 1%
methylcellulose-containing medium, and the colony number was
counted after 6 to 7 days. Data shown are means+/-SD of triplicate
samples and are representative of those of at least 3 independent
experiments. b. Enhanced Notch activity in CSC, as indicated by the
levels of Hes1 transcripts. The lymphoma cells from spleen with
tumor in TGB transgenic mouse were sorted into
c-kit.sup.+Sca-1.sup.+ or c-kit-Sca-1.sup.- fractions. The
expressions of Hes1.alpha.nd mRNA in these two fractions were
measured by real time PCR. c. Inhibition of Notch activity by 3
distinct HIF inhibitors. Cultured TGB lymphoma cells were stained
with APC conjugated anti-c-Kit- antibody and enriched twice using
anti-APC coated MACS beads according to manufacturer's protocol
(Militenyi Biotec). The c-kit positive cells-enriched samples
(60.4% c-Kit.sup.+ cells) were treated with inhibitors of HIF for
16 hours. The mRNA from the treated cells were extracted for
quantitation by real-time PCR. Data shown are means+/-SD of
triplicates and represent those from at least 3 independent
experiments. 2ME2, 2-methoxyestradiol; GA, geldamycin. d-g. A
critical role for Notch in maintenance of CSC, as revealed by
ectopic expression of Notch I-C dRdA.sub.1-42dOP. d. A truncated
Notch gene with potent dominant negative activity in inhibiting the
expression of Notch target gene Hes. The upper left panel shows the
diagram of the intracellular portion of Notch protein, with the
position of RAM, 7 ankyrin repeats (ANK1-7), transcriptional
activation domain (TAD), C-terminal OPA (O) and PEST (P) sequence
are marked. The lower left panel showed the composition of the
dRdA.sub.1-4dOP mutant lacking RAM, ANK1-4 and C-terminal O and P
sequence, but with insertion of nuclear localization sequence
(NLS). The right panel show dominant inhibition of Hes expression.
After three consecutive transductions by either vector control or
the dRdA.sub.1-4dOP mutant, the RNA were isolated and the
transcripts of Hes measured by quantitative PCR. Data shown are
means of triplicates and have been reproduced by two independent
experiments. e. Notch I-C deltaRAM abrogates the
c-Kit.sup.+Sca-1.sup.+ subset. TGB tumor cells were infected with
either lentiviral vector control, or lentiviral vector expressing
dRdA.sub.1-4dOP. Three days after infection, the bulk tumor cells
were analyzed by flow cytometry. The GFPhi and GFPlo cells were
gated and analyzed for expression of c-Kit and Sca-1. f. Notch IC--
dRdA.sub.1-42dOP reduces in vitro self-renewal activity of CSC. The
cultured lymphoma cells were infected with either lentiviral vector
encoding dRdA.sub.1-4dOP or vector control by spinoculation. The
same numbers of infected cells were seeded into 1% of
methylcellulose culture medium for 3 days and the numbers of colony
with GFP were counted under microscope. The same procedure was
performed for second round colony formation assay. Data shown are
the means and SD of the colony numbers in triplicate plates, and
are representative of those from at least three independent
experiments. g. dRdA.sub.1-4dOP abrogates tumor-initiating
activity. TGB tumor cells were infected 3 times with lentiviral
expressing vector alone or HIF1.alpha. ShRNA and then injected into
B10.BR mice (1.times.10.sup.6/mouse, i.p.). The survival of the
recipient mice was compared by Kaplan-Meier analysis with
statistical significance determined by log-rank tests. All
succumbed mice have developed lymphoma as revealed by necropsy.
This experiment has been repeated twice. h-l. HIF1.alpha. inhibits
negative feedback regulation of Hes1 by preventing Hes1 binding to
the N-boxes in the Hes1 promoter. h. Diagram of Hes1 promoter.
Detail sequence is provided in FIG. 16. i. HIF1.alpha. did not
co-operate with Notch directly in activating Hes1 promoter. The
Hes1 promoter sequence (-225 to +65, TSS as +1) were linked to GFP
and transfected into 293 cells in conjunction with vector controls,
or vector containing cDNA encoding HIF1.alpha. (P402, 577>A,
called HIF1.alpha.-PA), Notch-IC cDNA or Notch-IC+HIF1.alpha.PA.
The promoter activity is measured by the green fluorescence
intensity of transfected cells. Data shown were relative
intensities. The intensity of Hes1-GFP reporter is defined as 1.0.
Transfection efficiency is normalized by co-transfected Renilla
lucifease. j. HIF1.alpha. partially inhibited Hes1-mediated
repression of the Hes1 promoter. As in i, except that the Hes1 or
mutant HIF1.alpha. cDNA are used. k. HIF1.alpha. diminishes the
negative auto-regulation of Hes1 expression in Notch signaling. As
in i, except different combination of cDNAs were used. Activity of
Hes1 reporter in the absence of transfected Hes, HIF1.alpha.-PA and
Notch is defined as 1.0. l. Competitive inhibition between
HIF1.alpha.-PA and Hes1 to Hes promoter, as revealed by chIP. cDNAs
encoding Flag or Myc-tagged Hes1 and HIF-1.alpha.PA were
transfected into 293 cells. Thirty-six hours after transfection,
the transfectants were subject or ChIP. Equal fractions of cells in
each group were used for Western blot to confirm essentially
identical levels of protein expression when Hes1 and HIF1.alpha.-PA
were transfected alone or in combination (data not shown). The data
present are means+/-S.D. (n=3) of % of input DNA, as measured by
real-time PCR using primers marked in FIG. 16. Data shown in i-l
are means+/-S.D. of triplicates. The experiments have been repeated
at least 3 times.
[0015] FIG. 7. The progenies of c-Kit.sup.+Sca-1.sup.+ subset are
heterogenous with a small fraction retaining the
c-Kit.sup.+Sca-1.sup.+ phenotype. Ex vivo tumor cells were sorted
as described in FIG. 1a and plated in FIG. 1b. Five days later, the
cells from the colonies were re-analyzed for expression of c-Kit
and Sca-1.
[0016] FIG. 8. Cells with HIF activity express both c-Kit and
Sca-1. TGB tumor cells were infected with lentiviral vector
containing the WT HRE sequence as depicted in FIG. 2d. Three days
after infection, the tumor cells were stained with anti-c-Kit and
anti-Sca-1 mAbs. The GFP+ and GFP.sup.- cells were analyzed for the
expression of c-Kit and Sca-1.
[0017] FIG. 9. Inhibition of colony formation of
c-Kit.sup.+Sca-1.sup.+ tumor cells by HIF-1.alpha. inhibitors. Data
shown were means and S.D. of triplicate culture and have been
repeated at least 3 times. a. Continuous inhibition by echinomycin.
c-Kit.sup.+Sca-1.sup.+ cells sorted from TGB tumor cells were
cultured and resorted for c-Kit.sup.+Sca-1.sup.+ cells. The first
and second rounds of sorted cells (1000/well) were cultured in the
presence or absence of different doses of echinomycin for 24 hours.
The drugs were washed away and the cells plated. The colonies were
counted 5 days after culture. b. Inhibition by other classes of
HIF1.alpha. inhibitors, 2-Methoxyestradiol (2ME2) and Geldanamycin
(GA), but not by a P38 inhibitor, SB203580. As described in a,
except additional drugs were used as control. c. At low
concentrations (5-20 pM), echinomycin inhibits self-renewal of
colony-initiating cells without affecting colony formation. Equal
aliquots of TGB tumor cells were cultured in
methylcellulose-containing medium in the presence of given
concentrations of echinomycin for 5 days when the first round
colonies were counted. After washing away the drugs, Equal aliquots
of cells from the first round were replated. The newly formed
colonies were counted. The numbers of colonies were normalized
against the untreated group. The numbers of colonies in untreated
cultures: first round, 362; second round 202.
[0018] FIG. 10. Continuous resistance of HPC activity to high doses
of echinomycin. For the first round, total bone marrow cells (106)
were treated with given concentration of echinomycin for 24 hours.
After washing away the drugs, aliquots corresponding to
0.25.times.10.sup.6 seeded cells/well were plated into
methylcellulose containing medium for CFU assay. The colonies were
counted on day 5. For the second round analysis, 0.5.times.10.sup.6
viable cells isolated from the untreated group in the first round
were incubated with given concentration of echinomycin. Aliquots
corresponding to 5.times.10.sup.4 cells/well were replated and the
colonies were counted on day 5. The data shown are means and SD of
triplicates.
[0019] FIG. 11. Therapeutic effect of echinomycin administrated 4
days after tumor transplantation. Cultured lymphoma cells
(1.times.10.sup.6/mouse) were transplanted into immune competent
B10.BR mice i.p. Four days later, 10 .mu.g/Kg/Injection of
echimomycin was injected with a two day interval for a total of 3
times. Control mice received vehicle only.
[0020] FIG. 12. Multiple HIF-1.alpha. inhibitors repress
self-renewal and tumor initiating activity of the TGB tumor cells.
a. Dose-dependent inhibition of colony formation by
2-methoxyestradiol (2ME2) and Geldanamycin. b. Inhibition of tumor
formation by HIF inhibitors 2ME2 and Geldanamycin. Cultured
lymphoma cells (9.times.10.sup.5/mouse) were injected into immune
competent B10.BR mice i.p. Eight days later, given doses of 2ME2
and Geldanamycin were injected with a two day interval for a total
of 5 times. Control mice received vehicle only. The mice were
observed daily for survival. The P values given were obtained by
log-rank tests in comparison to treated and control groups.
[0021] FIG. 13. At ranges used in the study, Echinomycin inhibits
HIF1.alpha. but not cMyc activity. HEK293 cells were co-transfected
with the Ebox or HRE reporters (see FIG. 2b) with the vector
encoding c-Myc or HIF1.alpha.-PA. After 16 hours, the cells were
treated with different concentrations of Echinomycin for additional
24 hrs. The transcriptional activities of c-Myc and HIF1.alpha.
were quantified by flow cytometry. The untreated group is defined
as 100%. Data shown are means+/-S.D. of triplicates. The experiment
was repeated three times.
[0022] FIG. 14. Verification of the efficacy of HIF-1.alpha. shRNA.
The 293T cells were transfected with a cDNA encoding the
HIF-1.alpha. mutant (P402A/P577A) that is stable under normoxia
condition in conjunction with either control vectors V (Core
scrambled sequence: 5'-cgcgtagcgaagctca taa-3') or HIF-1.alpha.
shRNA-1 and -2. The cell lysates were probed with anti-Flag mAb 24
hours after transfection.
[0023] FIG. 15. TGB tumor cells express both Notch 1 and Notch 2.
The TGB tumor cells were sorted into c-Kit.sup.+Sca-1.sup.+ and
c-Kit.sup.-Sca-1.sup.- subsets. The expression of Notch family
members were detected by RT-PCR.
[0024] FIG. 16. Sequence of mouse (SEQ ID NO: 22) and human (SEQ ID
NO: 23) Hes1 promoter sequence. The N-box, CBF1, TSS, and HRE are
labeled. The primers used for reporter construction and real-time
PCR in ChIP assays are also marked.
[0025] FIG. 17. Echinomycin abrogated AML in NOD-SCID mice. A.
Elimination of AML-derived human cells in the blood of recipient
mice. Data shown are means and S.D. (n=3). B. Lack of human cells
in echinomycin-treated mice. Data shown are representative profile
of human CD45 expression among bone marrow cells. Essentially
identical profiles were obtained with two other mice. C. Human AML
cells in the bone marrow of untreated mice. The left panel shows
human CD45 staining of bone marrow cells, while the right panels
show phenotypes of the gated human CD45.sup.+ cells. Data shown are
representative of three mice per group.
[0026] FIG. 18. HIF1.alpha. is a target for therapeutic elimination
of human AML in a xenogenic mouse model. a. Isolation of 4 subsets
of tumor cells in AML samples. Bone marrow cells from AML patient
MI-AML-71 were stained for CD34 and CD38 and sorted into 4 subsets
for RNA isolation. The presort samples and the gates used for
sorting are shown in the left panel and the post-sorted populations
are shown in the middle and right panels. The percentages of cells
in each gate are provided in the panels. b. Expression of
HIF1.alpha. (top) and GLUT1 in the subsets. Data shown are
means+/-S.D. of transcript levels of the genes, presented as % of
.beta.-actin from the same samples. Enhanced expression in the
CD34.sup.+CD38.sup.- samples was observed in all 6 AML samples
tested. c. AML-CFU in all 6 AML samples were highly sensitive to
echinomycin. AML samples (2.5.times.10.sup.5/ml) from either
peripheral blood (PB) or bone marrow (BM) were pretreated with
given concentrations of echinomycin in 2 ml medium for 24 hours.
Treated viable cells were then plated at 10.sup.5/well for CFU
assay in triplicates. The colony numbers were counted 7-10 days
later. The data shown are % means+/-S.D. of untreated controls. d.
Echinomycin selectively eliminates the CD34.sup.+CD38.sup.- subset
of AML cells. Primary AML samples were cultured with given doses of
echinomycin or vehicle control for 30 hours in RPMI 1640 containing
10% fetal calf serum and human cytokine cocktail consisting of CSF,
GM-CSF and IL-3 at a density of 5.times.10.sup.5/ml. The cells were
stained with antibodies against CD34, CD38 in conjunction with
Annexin V and DAPI. Data shown are the % of Annexin
V.sup.+DAPI.sup.-/+ cells. The Annexin V.sup.+ cells % in vehicle
treated group was subtracted. The filled symbols show the data for
the CD34.sup.+CD38.sup.- subsets, while the open symbols show data
for the bulk leukemia cells (CD34.sup.+CD38.sup.+ for AML9, AML32,
AML60 and AML71 and CD34.sup.-CD38.sup.+ for AML15 and AML36).
These data were repeated twice. e-h. Therapeutic effect of
echinomycin. e. Therapeutic effect of human AML in NOD-SCID mice,
data shown are % of human CD45 (hCD45).sup.+ cells in the bone
marrow of the recipient mice at 40 days after last treatment. The
therapeutic effect has been repeated twice. f. Echinomycin does not
induce differentiation of AML cells in vivo, as revealed by lack of
mature myeloid markers on the bulk of human cells in treated and
untreated group. Data shown are profiles of CD14 and CD15 among
human CD45.sup.+ cells. g. Selective depletion of the
CD34.sup.+CD38.sup.- subset by echinomycin. Data shown in the top
panels are the abundance of CD34.sup.+CD38.sup.- subsets in mouse
bone marrow, while the lower panel shows that within human leukemia
cells. h. Despite presence of leukemia cells, bone marrow from
echinomycin-treated mice failed to reinitiate leukemia in the new
NOD-SCID mice. Representative profiles are presented in the top
panel, while the summary data from 5 mice per group are presented
in the lower panel.
DETAILED DESCRIPTION
[0027] The inventors have made the surprising discovery that the
HIF inhibitor echinomycin is capable of treating a hematologic
cancer at a non-toxic dose. This indicates a unique susceptibility
of lymphoma CSC to echinomycin, and that as little as 30
mcg/m.sup.2 of echinomycin is sufficient to abrogate lymphoma in
100% of the recipients. For example, in vitro, AML-CFUs of all 6
cases of human AML samples tested were highly susceptible to
echinomycin.
[0028] Echinomycin was brought into clinical trials about 20 years
ago based on its antitumor activity against two i.p. implanted
murine tumors, the B16 melanoma and the P388 leukemia. However,
testing of the efficacy of echinomycin phase II clinical trials for
a number of solid tumors revealed that echinomycin exhibits
significant toxicity, and had minimal or no efficacy. The efficacy
of echinomycin for treating hematological cancer had not been
tested. Additionally, the body-surface adjusted dose used in
previous human clinical trials was about 100-fold higher than the
dose the inventors have discovered to be effective for treating
hematologic cancer. The toxicity observed in previous human trials
was likely due to excess dose used, while the lack of effect may
have been due to clinical endpoints that do not reflect the unique
requirement for HIF in lymphoma CSC. Thus, echinomycin may be used
to treat hematologic cancer associated with CSC, including
lymphoma, and in particular, at a non-toxic dose.
1. Definitions
[0029] The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting. As
used in the specification and the appended claims, the singular
forms "a," "an" and "the" include plural referents unless the
context clearly dictates otherwise.
[0030] For recitation of numeric ranges herein, each intervening
number there between with the same degree of precision is
explicitly contemplated. For example, for the range of 6-9, the
numbers 7 and 8 are contemplated in addition to 6 and 9, and for
the range 6.0-7.0, the numbers 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6,
6.7, 6.8, 6.9, and 7.0 are explicitly contemplated.
[0031] A "peptide" or "polypeptide" is a linked sequence of amino
acids and may be natural, synthetic, or a modification or
combination of natural and synthetic.
[0032] "Treatment" or "treating," when referring to protection of
an animal from a disease, means preventing, suppressing,
repressing, or completely eliminating the disease. Preventing the
disease involves administering a composition of the present
invention to an animal prior to onset of the disease. Suppressing
the disease involves administering a composition of the present
invention to an animal after induction of the disease but before
its clinical appearance. Repressing the disease involves
administering a composition of the present invention to an animal
after clinical appearance of the disease.
2. Hypoxia-Inducible Factor Inhibitor
[0033] Provided herein is an inhibitor of Hypoxia-Inducible Factor
protein (HIF). The HIF inhibitor may be echinomycin,
2-methoxyestradiol, or geldanamycin.
[0034] a. Echinomycin
[0035] The echinomycin may be a peptide antibiotic such as
N,N'-(2,4,12,15,17,25-hexamethyl-11,24-bis(1-methylethyl)-27-(methylthio)-
-3,6,10,13,16,19,23,26-octaoxo-9,22-dioxa-28-thia-2,5,12,15,18,25-hexaazab-
icyclo(12.12.3)nonacosane-7,20-diyl)bis(2-quinoxalinecarboxamide).
The echinomycin may be a microbially-derived quinoxaline
antibiotic, which may be produced by Streptomyces echinatus. The
echinomycin may have the following structure.
##STR00001##
[0036] The echinomycin may have a structure as disclosed in U.S.
Pat. No. 5,643,871, the contents of which are incorporated herein
by reference. The echinomycin may also be an echinomycin
derivative, which may comprise a modification as described in
Gauvreau et al., Can J Microbiol, 1984; 30(6):730-8; Baily et al.,
Anticancer Drug Des 1999; 14(3):291-303; or Park and Kim,
Bioorganic & Medicinal Chemistry Letters, 1998; 8(7):731-4, the
contents of which are incorporated by reference. The echinomycin
may also be a bis-quinoxaline analog of echinomycin
[0037] b. HIF
[0038] The HIF may be a functional hypoxia-inducible factor, which
may comprise a constitutive b subset and an oxygen-regulated a
subunit. The HIF may be over-expressed in a broad range of human
cancer types, which may be a breast, prostate, lung, bladder,
pancreatic or ovarian cancer. While not being bound by theory, the
increased HIF expression may be a direct consequence of hypoxia
within a tumor mass. Both genetic and environmental factors may
lead to the increased HIF expression even under the normoxia
condition. Germline mutation of the von Hippel-Lindau gene (VHL),
which may be the tumor suppressor for renal cancer, may prevent
degradation HIF under normoxia. It may be possible to maintain
constitutively HIF activity under normoxia by either upregulation
of HIF and/or down regulation of VHL. The HIF may be HIF1.alpha. or
HIF2.alpha..
[0039] c. Pharmaceutical Composition
[0040] Also provided is a pharmaceutical composition comprising the
HIF inhibitor. The pharmaceutical composition may be in the form of
tablets or lozenges formulated in a conventional manner. For
example, tablets and capsules for oral administration may contain
conventional excipients may be binding agents, fillers, lubricants,
disintegrants and wetting agents. Binding agents include, but are
not limited to, syrup, accacia, gelatin, sorbitol, tragacanth,
mucilage of starch and polyvinylpyrrolidone. Fillers may be
lactose, sugar, microcrystalline cellulose, maizestarch, calcium
phosphate, and sorbitol. Lubricants include, but are not limited
to, magnesium stearate, stearic acid, talc, polyethylene glycol,
and silica. Disintegrants may be potato starch and sodium starch
glycollate. Wetting agents may be sodium lauryl sulfate. Tablets
may be coated according to methods well known in the art.
[0041] The pharmaceutical composition may also be liquid
formulations such as aqueous or oily suspensions, solutions,
emulsions, syrups, and elixirs. The pharmaceutical composition may
also be formulated as a dry product for constitution with water or
other suitable vehicle before use. Such liquid preparations may
contain additives such as suspending agents, emulsifying agents,
nonaqueous vehicles and preservatives. Suspending agents may be
sorbitol syrup, methyl cellulose, glucose/sugar syrup, gelatin,
hydroxyethylcellulose, carboxymethyl cellulose, aluminum stearate
gel, and hydrogenated edible fats. Emulsifying agents may be
lecithin, sorbitan monooleate, and acacia. Nonaqueous vehicles may
be edible oils, almond oil, fractionated coconut oil, oily esters,
propylene glycol, and ethyl alcohol. Preservatives may be methyl or
propyl p-hydroxybenzoate and sorbic acid.
[0042] The pharmaceutical composition may also be formulated as
suppositories, which may contain suppository bases such as cocoa
butter or glycerides. The pharmaceutical composition may also be
formulated for inhalation, which may be in a form such as a
solution, suspension, or emulsion that may be administered as a dry
powder or in the form of an aerosol using a propellant, such as
dichlorodifluoromethane or trichlorofluoromethane. Agents provided
herein may also be formulated as transdermal formulations
comprising aqueous or nonaqueous vehicles such as creams,
ointments, lotions, pastes, medicated plaster, patch, or
membrane.
[0043] The pharmaceutical composition may also be formulated for
parenteral administration such as by injection, intratumor
injection or continuous infusion. Formulations for injection may be
in the form of suspensions, solutions, or emulsions in oily or
aqueous vehicles, and may contain formulation agents including, but
not limited to, suspending, stabilizing, and dispersing agents. The
pharmaceutical composition may also be provided in a powder form
for reconstitution with a suitable vehicle including, but not
limited to, sterile, pyrogen-free water.
[0044] The pharmaceutical composition may also be formulated as a
depot preparation, which may be administered by implantation or by
intramuscular injection. The pharmaceutical composition may be
formulated with suitable polymeric or hydrophobic materials (as an
emulsion in an acceptable oil, for example), ion exchange resins,
or as sparingly soluble derivatives (as a sparingly soluble salt,
for example).
[0045] (1) Administration
[0046] Administration of the pharmaceutical composition may be
orally, parenterally, sublingually, transdermally, rectally,
transmucosally, topically, via inhalation, via buccal
administration, or combinations thereof. Parenteral administration
includes, but is not limited to, intravenous, intraarterial,
intraperitoneal, subcutaneous, intramuscular, intrathecal, and
intraarticular. For veterinary use, the agent may be administered
as a suitably acceptable formulation in accordance with normal
veterinary practice. The veterinarian can readily determine the
dosing regimen and route of administration that is most appropriate
for a particular animal. The pharmaceutical composition may be
administered to a human patient, cat, dog, large animal, or an
avian.
[0047] The pharmaceutical composition may be administered
simultaneously or metronomically with other treatments. The term
"simultaneous" or "simultaneously" as used herein, means that the
pharmaceutical composition and other treatment be administered
within 48 hours, preferably 24 hours, more preferably 12 hours, yet
more preferably 6 hours, and most preferably 3 hours or less, of
each other. The term "metronomically" as used herein means the
administration of the agent at times different from the other
treatment and at a certain frequency relative to repeat
administration.
[0048] The pharmaceutical composition may be administered at any
point prior to another treatment including about 120 hr, 118 hr,
116 hr, 114 hr, 112 hr, 110 hr, 108 hr, 106 hr, 104 hr, 102 hr, 100
hr, 98 hr, 96 hr, 94 hr, 92 hr, 90 hr, 88 hr, 86 hr, 84 hr, 82 hr,
80 hr, 78 hr, 76 hr, 74 hr, 72 hr, 70 hr, 68 hr, 66 hr, 64 hr, 62
hr, 60 hr, 58 hr, 56 hr, 54 hr, 52 hr, 50 hr, 48 hr, 46 hr, 44 hr,
42 hr, 40 hr, 38 hr, 36 hr, 34 hr, 32 hr, 30 hr, 28 hr, 26 hr, 24
hr, 22 hr, 20 hr, 18 hr, 16 hr, 14 hr, 12 hr, 10 hr, 8 hr, 6 hr, 4
hr, 3 hr, 2 hr, 1 hr, 55 mins., 50 mins., 45 mins., 40 mins., 35
mins., 30 mins., 25 mins., 20 mins., 15 mins, 10 mins, 9 mins, 8
mins, 7 mins., 6 mins., 5 mins., 4 mins., 3 mins, 2 mins, and 1
mins. The pharmaceutical composition may be administered at any
point prior to a second treatment of the pharmaceutical composition
including about 120 hr, 118 hr, 116 hr, 114 hr, 112 hr, 110 hr, 108
hr, 106 hr, 104 hr, 102 hr, 100 hr, 98 hr, 96 hr, 94 hr, 92 hr, 90
hr, 88 hr, 86 hr, 84 hr, 82 hr, 80 hr, 78 hr, 76 hr, 74 hr, 72 hr,
70 hr, 68 hr, 66 hr, 64 hr, 62 hr, 60 hr, 58 hr, 56 hr, 54 hr, 52
hr, 50 hr, 48 hr, 46 hr, 44 hr, 42 hr, 40 hr, 38 hr, 36 hr, 34 hr,
32 hr, 30 hr, 28 hr, 26 hr, 24 hr, 22 hr, 20 hr, 18 hr, 16 hr, 14
hr, 12 hr, 10 hr, 8 hr, 6 hr, 4 hr, 3 hr, 2 hr, 1 hr, 55 mins., 50
mins., 45 mins., 40 mins., 35 mins., 30 mins., 25 mins., 20 mins.,
15 mins., 10 mins., 9 mins., 8 mins., 7 mins., 6 mins., 5 mins., 4
mins., 3 mins, 2 mins, and 1 mins.
[0049] The pharmaceutical composition may be administered at any
point after another treatment including about 1 min, 2 mins., 3
mins., 4 mins., 5 mins., 6 mins., 7 mins., 8 mins., 9 mins., 10
mins., 15 mins., 20 mins., 25 mins., 30 mins., 35 mins., 40 mins.,
45 mins., 50 mins., 55 mins., 1 hr, 2 hr, 3 hr, 4 hr, 6 hr, 8 hr,
10 hr, 12 hr, 14 hr, 16 hr, 18 hr, 20 hr, 22 hr, 24 hr, 26 hr, 28
hr, 30 hr, 32 hr, 34 hr, 36 hr, 38 hr, 40 hr, 42 hr, 44 hr, 46 hr,
48 hr, 50 hr, 52 hr, 54 hr, 56 hr, 58 hr, 60 hr, 62 hr, 64 hr, 66
hr, 68 hr, 70 hr, 72 hr, 74 hr, 76 hr, 78 hr, 80 hr, 82 hr, 84 hr,
86 hr, 88 hr, 90 hr, 92 hr, 94 hr, 96 hr, 98 hr, 100 hr, 102 hr,
104 hr, 106 hr, 108 hr, 110 hr, 112 hr, 114 hr, 116 hr, 118 hr, and
120 hr. The pharmaceutical composition may be administered at any
point prior after a pharmaceutical composition treatment of the
agent including about 120 hr, 118 hr, 116 hr, 114 hr, 112 hr, 110
hr, 108 hr, 106 hr, 104 hr, 102 hr, 100 hr, 98 hr, 96 hr, 94 hr, 92
hr, 90 hr, 88 hr, 86 hr, 84 hr, 82 hr, 80 hr, 78 hr, 76 hr, 74 hr,
72 hr, 70 hr, 68 hr, 66 hr, 64 hr, 62 hr, 60 hr, 58 hr, 56 hr, 54
hr, 52 hr, 50 hr, 48 hr, 46 hr, 44 hr, 42 hr, 40 hr, 38 hr, 36 hr,
34 hr, 32 hr, 30 hr, 28 hr, 26 hr, 24 hr, 22 hr, 20 hr, 18 hr, 16
hr, 14 hr, 12 hr, 10 hr, 8 hr, 6 hr, 4 hr, 3 hr, 2 hr, 1 hr, 55
mins., 50 mins., 45 mins., 40 mins., 35 mins., 30 mins., 25 mins.,
20 mins., 15 mins., 10 mins., 9 mins., 8 mins., 7 mins., 6 mins., 5
mins., 4 mins., 3 mins, 2 mins, and 1 mins.
[0050] d. Dosage
[0051] The pharmaceutical composition may be administered in a
therapeutically effective amount of the HIF inhibitor to a mammal
in need thereof. The therapeutically effective amount required for
use in therapy varies with the nature of the condition being
treated, the length of time desired to inhibit HIF activity, and
the age/condition of the patient.
[0052] The dose may be a non-toxic dose. The dose may also be one
at which HIF activity is inhibited, but at which c-Myc activity is
unaffected. In general, however, doses employed for adult human
treatment typically may be in the range of 1-100 mcg/m.sup.2 per
day, or at a threshold amount of 1-100 mcg/m.sup.2 per day or less,
as measured by a body-surface adjusted dose. The desired dose may
be conveniently administered in a single dose, or as multiple doses
administered at appropriate intervals, for example as two, three,
four or more sub-doses per day. Multiple doses may be desired, or
required.
[0053] The dosage may be a dosage such as about 1 mcg/m.sup.2, 2
mcg/m.sup.2, 3 mcg/m.sup.2, 4 mcg/m.sup.2, 5 mcg/m.sup.2, 6
mcg/m.sup.2, 7 mcg/m.sup.2, 8 mcg/m.sup.2, 9 mcg/m.sup.2, 10
mcg/m.sup.2, 15 mcg/m.sup.2, 20 mcg/m.sup.2, 25 mcg/m.sup.2, 30
mcg/m.sup.2, 35 mcg/m.sup.2, 40 mcg/m.sup.2, 45 mcg/m.sup.2, 50
mcg/m.sup.2, 55 mcg/m.sup.2, 60 mcg/m.sup.2, 70 mcg/m.sup.2, 80
mcg/m.sup.2, 90 mcg/m.sup.2, 100 mcg/m.sup.2, 200 mcg/m.sup.2, 300
mcg/m.sup.2, 400 mcg/m.sup.2, 500 mcg/m.sup.2, 600 mcg/m.sup.2, 700
mcg/m.sup.2, 800 mcg/m.sup.2, 900 mcg/m.sup.2, 1000 mcg/m.sup.2,
1100 mcg/m.sup.2, or 1200 mcg/m.sup.2, and ranges thereof.
[0054] The dosage may also be a dosage less than or equal to about
1 mcg/m.sup.2, 2 mcg/m.sup.2, 3 mcg/m.sup.2, 4 mcg/m.sup.2, 5
mcg/m.sup.2, 6 mcg/m.sup.2, 7 mcg/m.sup.2, 8 mcg/m.sup.2, 9
mcg/m.sup.2, 10 mcg/m.sup.2, 15 mcg/m.sup.2, 20 mcg/m.sup.2, 25
mcg/m.sup.2, 30 mcg/m.sup.2, 35 mcg/m.sup.2, 40 mcg/m.sup.2, 45
mcg/m.sup.2, 50 mcg/m.sup.2, 55 mcg/m.sup.2, 60 mcg/m.sup.2, 70
mcg/m.sup.2, 80 mcg/m.sup.2, 90 mcg/m.sup.2, 100 mcg/m.sup.2, 200
mcg/m.sup.2, 300 mcg/m.sup.2, 400 mcg/m.sup.2, 500 mcg/m.sup.2, 600
mcg/m.sup.2, 700 mcg/m.sup.2, 800 mcg/m.sup.2, 900 mcg/m.sup.2,
1000 mcg/m.sup.2, 1100 mcg/m.sup.2, or 1200 mcg/m.sup.2, and ranges
thereof.
[0055] e. Coadministration
[0056] The HIF inhibitor may be coadministered with another
pharmacological agent. The agent may be an inhibitor of the
Hedgehog pathway, which may be cyclopamine. The agent may also be a
second cancer therapy. The cancer therapy may be a cytotoxic agent
or cytostatic agent. The cytotoxic agent may be selected from the
group consisting of: alkylating agents (including, without
limitation, nitrogen mustards, ethylenimine derivatives, alkyl
sulfonates, nitrosoureas and triazenes): uracil mustard,
chlormethine, cyclophosphamide (Cytoxan.RTM.), ifosfamide,
melphalan, chlorambucil, pipobroman, triethylene-melamine,
triethylenethiophosphoramine, busulfan, carmustine, lomustine,
streptozocin, dacarbazine, and temozolomide; antimetabolites
(including, without limitation, folic acid antagonists, pyrimidine
analogs, purine analogs and adenosine deaminase inhibitors):
methotrexate, 5-fluorouracil, floxuridine, cytarabine,
6-mercaptopurine, 6-thioguanine, fludarabine phosphate,
pentostatine, and gemcitabine; natural products and their
derivatives (for example, vinca alkaloids, antitumor antibiotics,
enzymes, lymphokines and epipodophyllotoxins): vinblastine,
vincristine, vindesine, bleomycin, dactinomycin, daunorubicin,
doxorubicin, epirubicin, idarubicin, ara-c, paclitaxel (paclitaxel
is commercially available as Taxol.RTM.), mithramycin,
deoxyco-formycin, mitomycin-c, 1-asparaginase, interferons
(preferably IFN-{umlaut over (.gamma.)}), etoposide, and
teniposide. Other proliferative cytotoxic agents are navelbene,
CPT-11, anastrazole, letrazole, capecitabine, reloxafine,
cyclophosphamide, ifosamide, and droloxafine.
[0057] The cytotoxic agent may be a microtubule affecting agent,
which may interfere with cellular mitosis. The microtubule
affecting agent may be selected from the group consisting of:
allocolchicine (NSC 406042), halichondrin B (NSC 609395),
colchicine (NSC 757), colchicine derivatives (e.g., NSC 33410),
dolastatin 10 (NSC 376128), maytansine (NSC 153858), rhizoxin (NSC
332598), paclitaxel (Taxol.RTM., NSC 125973), Taxol.RTM.
derivatives (e.g., derivatives (e.g., NSC 608832), thiocolchicine
(NSC 361792), trityl cysteine (NSC 83265), vinblastine sulfate (NSC
49842), vincristine sulfate (NSC 67574), natural and synthetic
epothilones including but not limited to epothilone A, epothilone
B, and discodermolide (see Service, (1996) Science, 274:2009)
estramustine, nocodazole, and MAP4. The microtubule affecting agent
may also be as described in Bulinski (1997) J. Cell Sci. 110:3055
3064; Panda (1997) Proc. Natl. Acad. Sci. USA 94:10560-10564;
Muhlradt (1997) Cancer Res. 57:3344-3346; Nicolaou (1997) Nature
387:268-272; Vasquez (1997) Mol. Biol. Cell. 8:973-985; and Panda
(1996) J. Biol. Chem 271:29807-29812, the contents of which are
incorporated herein by reference.
[0058] The cytotoxic agent may also be selected from the group
consisting of: epidophyllotoxin; an antineoplastic enzyme; a
topoisomerase inhibitor; procarbazine; mitoxantrone; platinum
coordination complexes such as cis-platin and carboplatin;
biological response modifiers; growth inhibitors; antihormonal
therapeutic agents; leucovorin; tegafur; and haematopoietic growth
factors.
[0059] The cytostatic agent may be selected from the group
consisting of: hormones and steroids (including synthetic analogs):
17.alpha.-ethinylestradiol, diethylstilbestrol, testosterone,
prednisone, fluoxymesterone, dromostanolone propionate,
testolactone, megestrolacetate, methylprednisolone,
methyl-testosterone, prednisolone, triamcinolone, hlorotrianisene,
hydroxyprogesterone, aminoglutethimide, estramustine,
medroxyprogesteroneacetate, leuprolide, flutamide, toremifene, and
zoladex. The cytostatic agent may also be an antiangiogenic such as
a matrix metalloproteinase inhibitor or a VEGF inhibitor, which may
be an anti-VEGF antibody or small molecule such as ZD6474 or
SU6668. The agent may also be an Anti-Her2 antibody from Genentech,
an EGFR inhibitor such as EKB-569 (an irreversible inhibitor), or
an Imclone antibody C225 immunospecific for the EGFR, or a src
inhibitor.
[0060] The cytostatic agent may also be selected from the group
consisting of: Casodex.RTM. (bicalutamide, Astra Zeneca) which
renders androgen-dependent carcinomas non-proliferative; the
antiestrogen Tamoxifen.RTM. which inhibits the proliferation or
growth of estrogen dependent breast cancer; and an inhibitor of the
transduction of cellular proliferative signals. The inhibitor of
the transduction of cellular proliferative signals may be selected
from the group consisting of epidermal growth factor inhibitors,
Her-2 inhibitors, MEK-1 kinase inhibitors, MAPK kinase inhibitors,
PI3 inhibitors, Src kinase inhibitors, and PDGF inhibitors.
3. Method
[0061] a. Treating a Hematologic Cancer
[0062] Provided herein is a method of treating a hematologic
cancer. The method may comprise administering a HIF inhibitor to a
mammal in need thereof. The mammal may be a human patient. The
hematologic cancer may be lymphoma or leukemia. The hematologic
cancer may be treated by inhibiting a maintenance or survival
function of a CSC. Without being bound by theory inhibiting HIF may
target both the cancer stem cell and cancer resistance.
[0063] Further without being bound by theory, the CSC in the
hematologic cancer may require self-renewal, which may be similar
to the requirement in tissue cells. The CSC may require a hypoxic
environment, and exposure to a high level of oxygen may reduce CSC
function. Self-renewal of CSC function may be strongly inhibited by
drugs targeting the HIF pathway. CSC may be addicted to the HIF,
which may be associated with over-expression of HIF and
down-regulation of VHL. HIF over-expression and VHL down-regulation
may be critical in the maintenance of CSC. HIF may work in concert
with the Notch pathway to mediate self-renewal of the lymphoma
CSC.
[0064] (1) Cancer Stem Cell
[0065] The cancer stem cell may be chemoresistant or
radioresistant. The CSC may also be multiple drug resistant.
[0066] (2) Acute Myeloid Leukemia
[0067] The leukemia may be acute myeloid leukemia (AML). The AML
may be associated with a CSC characterized by the genotype
CD38-CD34.sup.+. The AML may also be associated with a patient who
carries a cytogenetic alteration. The cytogenetic alteration may be
selected from the group consisting of: 47,XY, +21; 46,XY; 45,XX,
-7; 46,XY,t(8; 21)(q22; q22); 49,XX, +8, +8,inv(16)(p13.1q22), +21;
46,XX,inv(16)(p13q22)/46,XX; 46,XY,inv(16)(p13q22); 46,XX,t(2;
13)(p23; q12)/46,XX; 45,XY,inv(3)(q21q26.2), -7/46,XY; 47,XY,
+4,inv(5)(p15q13)/47,sl, -4, +22; 46,XX,t(11; 19)(q23; p13.1);
46,XX,t(6; 11)(q27; q23)/46,XX; and 46,XX,t(1; 17)(p13; q25),t(9;
11)(p22; q23).
[0068] The CSC of the AML may be extremely sensitive to the HIF
inhibitor. The CFU of AML may be highly susceptible to the HIF
inhibitor, with an IC50 between 50-120 pM. The HIF inhibitor may be
used to eliminate CSC of AML as part of postremission therapy.
[0069] b. Inducing Acute Myeloid Leukemia Remission
[0070] Also provided herein is a method for inducing remission of
acute myeloid leukemia, which may comprise administering the HIF
inhibitor to a mammal in need thereof. The HIF inhibitor may be
administered to the mammal during remission of acute myeloid
leukemia to prevent future relapse. The HIF inhibitor may be
administered as elsewhere disclosed herein.
[0071] c. Inhibiting a Maintenance or Survival Function of a
CSC
[0072] Further provided herein is a method for inhibiting a
maintenance or survival function of a CSC. Contacting the CSC with
the HIF inhibitor may inhibit the maintenance or survival function.
The contacting may comprise administering the HIF inhibitor to a
mammal in need of inhibiting the maintenance or survival function
of the CSC. The HIF inhibitor may be administered as elsewhere
disclosed herein.
[0073] The present invention has multiple aspects, illustrated by
the following non-limiting examples.
Example 1
Identification of Self-Renewing Lymphoma Initiating Cells in
Syngeneic Immune Competent Host
[0074] Hundred percent of the transgenic mice (TGB) with
insertional mutation of the Epm2a gene succumb to lymphoma. In
search for the expression of potential stem cell markers in the TGB
lymphoma cells, it was found that a small subset of cells expressed
both c-Kit and Sca-1, which partly constitute markers for HSC (FIG.
1a). To test if these cells may have CSC activity, lymphoma cells
from the spleen of TGB transgenic mice with tumors were sorted
based on expression of both c-Kit and Sca-1 (FIG. 1a right panels).
As shown in FIG. 1b, no colony formed from 10.sup.3 of
c-Kit.sup.-Sca-1.sup.- cells. In striking contrast, 10.sup.3 of
cells with c-Kit.sup.+Sca-1.sup.+ yielded about 800 colonies, which
suggests that every cells in the subset was CFU. Most colonies are
tightly packed (FIG. 1b insert), in contrast to the diverse
colonies obtained from bone marrow HSC. The progenies of the
c-Kit.sup.+Sca-1.sup.+ cells consist of both c-Kit.sup.+Sca-1.sup.+
and c-Kit.sup.-Sca-1.sup.- subsets (FIG. 7). Therefore, the
c-Kit.sup.+Sca-1.sup.+ cells are the self-renewing population among
the single cells isolated from the TGB lymphoma. To determine if
the c-Kit.sup.+Sca-1.sup.+ cells are also the lymphoma-initiating
cells in vivo, we injected either c-Kit.sup.+Sca-1.sup.+ cells or
c-Kit.sup.-Sca-1.sup.- cells intraperitoneally (i.p.) into the
syngeneic B10BR mice. As shown in Table 1, expt 1, three out of
three mice receiving 100 c-Kit.sup.+Sca-1.sup.+ cells developed
lymphomas usually within 10 weeks after injection, yet none of the
recipients of 10.sup.4 of c-Kit.sup.-Sca-1.sup.- cells did even
after 40 weeks of observation. Similar results were obtained when
the experiments were repeated by intravenous injection (Table 1,
Expt 2). The lymphomas are characterized by enlarged spleens (FIG.
1c), lymph nodes, and metastasis to the liver and lung but not
thymus (data not shown), unlike the spontaneously developed
lymphoma that first appeared as thymoma and then metastasized into
other organ. Furthermore, no constitution of other cell lineages
was achieved from the c-Kit.sup.+Sca-1.sup.+ subset isolated from
tumors, which indicates that the c-Kit.sup.+Sca-1.sup.+ cells are
not the tumor-infiltrating HSC. In three rounds of serial
transplantation (Table 1, expt 5), the c-Kit.sup.+Sca-1.sup.+
cells, but not the c-Kit.sup.-Sca-1.sup.- cells, gave rise to
lymphoma at a comparable potency. The tumors maintained expression
of T-cell marker CD8, but gradually lost cell surface expression of
the transgenic TCR (FIG. 1d and Table S1). More importantly, the
frequency of the c-Kit.sup.+Sca-1.sup.+ cells remained around 1%
(Table S1). Thus, the self-renewing tumor-initiating cells are
among the c-Kit.sup.+Sca-1.sup.+ tumor cells.
TABLE-US-00001 TABLE 1 Identification of CSC using c-Kit and Sca-1
markers Recip- Number of cells injected Expt Donor ient 10,000
1,000 500 100 1. c-Kit.sup.+Sca-1.sup.+ B10.BR -- -- 3/3 3/3
c-Kit.sup.-Sca-1.sup.- B10.BR 0/3 -- -- -- 2.
c-Kit.sup.+Sca-1.sup.+ B10.BR -- -- 4/4 3/3 c-Kit.sup.-Sca-1.sup.-
B10.BR 0/3 -- 0/3 -- 3. c-Kit.sup.+Sca-1.sup.+ B10.BR -- -- 5/5 5/5
c-Kit.sup.-Sca-1.sup.- B10.BR 1/5 0/5 -- -- 4.
c-Kit.sup.+Sca-1.sup.+ RAG2.sup.-/- -- -- 5/5 5/5
c-Kit.sup.-Sca-1.sup.- RAG2.sup.-/- 1/5 0/5 -- -- 5. Serial
transplantation Round 1 c-Kit.sup.+Sca-1.sup.+ B10.BR -- -- 3/3 3/3
c-Kit.sup.-Sca-1.sup.- B10.BR 1/3 0/3 -- -- Round 2
c-Kit.sup.+Sca-1.sup.+ B10.BR -- -- -- 5/5 c-Kit.sup.-Sca-1.sup.-
B10.BR 2/5 -- -- -- Round 3 c-Kit.sup.+Sca-1.sup.+ B10.BR -- -- --
3/3 c-Kit.sup.-Sca-1.sup.- B10.BR 0/3 (5000/mouse) -- --
[0075] The donor cells were isolated from either ex vivo lymphoma
(expt 1 and 2) or those that have been cultured for more than 30
passages in vitro. The routes of injection were intraperitoneal
(i.p.) for experiments 1, 3, and 4, and intravenous for experiment
2. There was no tumor growth (0/3) when 10 c-Kit.sup.+Sca-1.sup.+
cells were transplanted into B10.BR mice. In experiment 5, donor
cells were isolated from ex vivo lymphoma and injected i.p. The
lymphoma cells obtained in round 1 were sorted and injected for the
second around, then repeated for the third round. The tumor-free
mice were observed for 22-40 weeks to confirm the lack of tumor
growth.
TABLE-US-00002 TABLE S1 % marker.sup.+ cells Markers Primary Round
1 Round 2 Round 3 c-Kit.sup.+Sca-1.sup.- 3.80 3.92 4.81 1.32
c-Kit.sup.-Sca-1.sup.+ 1.52 15.38 19.5 5.14 c-Kit.sup.+Sca1.sup.+
0.87 0.81 0.97 0.83 CD8.sup.+V.beta.8.sup.- 3.48 ND 47.39 54.27
CD8.sup.+V.beta.8.sup.+ 92.36 ND 19.30 9.20
[0076] Table S1. Conservation and dynamic changes of tumor cell
phenotypes. The c-Kit.sup.+Sca-1.sup.+ cells from spontaneous
tumors were isolated by FACS sorting and serially transplanted into
syngeneic B10.BR mice. Single-cell suspensions of tumors that arose
in each round were analyzed by flow cytometry using antibodies
specific for CD8, Vb8, c-Kit and Sca-1. The % of cells among spleen
cells are presented. N.D., not determined.
[0077] Using the medium for assaying the colony-forming units (CFU)
of hematopoeitic progenitor cells, it was possible to establish
long term cultures of the TGB lymphoma cells. In over 30 passages,
the c-Kit.sup.+Sca-1.sup.+ cells remained at about 0.5-1.5% of
total lymphoma cell population and maintained the CFU in vitro
(data not shown) and tumor initiation in vivo (Table 1, expts 3 and
4), with an undiminished efficiency. The fact that the
c-Kit.sup.+Sca-1.sup.+ cells remained at low % indicates that these
markers must have been lost during differentiation that occurred
after the initiation of the colony formation. The
c-Kit.sup.+Sca-1.sup.- population usually disappeared during in
vitro culture. The loss of the Kit.sup.+Sca-1.sup.- cells during
culture does not accompany the loss of tumor-initiation and CFU
(data not shown).
Example 2
Essential Role for Up-Regulation of HIF1.alpha. Expression in the
Maintenance of CSC
[0078] Having established that the c-Kit.sup.+Sca-1.sup.+ cells are
CSCs in the lymphoma model, the molecular program responsible for
the self-renewal of CSC activity was identified, using CFU as a
surrogate assay. As shown in FIG. 2a, treatment with
pharmacologically effective doses of Ly294002 (inhibitor of PI-3
kinase-AKT signal pathway), Rapamycin (mTor-S6K protein synthesis
pathway), SB216763 (GSK3-beta-catenin pathway), G66983 (PKC
inhibitor), 2-DG (hexokinase inhibitor), H89 (PKA-CREB), PDTC
(NF-1B signal pathway), PD98059, SB203580, and SP600126 (MAPK
family ERK, p38, and JNK respectively) had no effect on CFU. In
contrast, low doses of echinomycin abrogated the CFU.
[0079] In order to monitor the HIF1.alpha. activity of the CSC, a
lentiviral reporter was generated, consisting of triple HIF
responsive elements (HRE) in the upstream of a minimum TATA box
sequence and an EGFP sequence, as shown in FIG. 2b. A pause
sequence was introduced to eliminate effect of LTR promoter on the
reporter. To validate the reporter, the HEK293 cells were
transiently transfected with either control vector or a mutant
HIF1.alpha. (P402A/P577A) cDNA in conjunction with either WT or
mutant HRE-driven EGFP reporters. The mutation made HIF1.alpha.
functional under normoxia condition by resisting prolyl
hydroxylation-mediated degradation. As expected, the HER-EGFP
reporter was specifically induced by HIF1.alpha. but not by the
control vector. In contrast, the mutant HRE EGFP reporter did not
respond to HIF1.alpha. (FIG. 2b, lower left panel). Using this
lentiviral vector, the effect of echinomycin on the % of cells with
active HIF activity was determined. As shown in FIG. 2b lower right
panel, a distinct GFP+ population of cells that expressed both
c-Kit and Sca-1 markers was found (FIG. 2b and FIG. 8). The
expression of GFP reflected HIF activity as it can be abrogated by
mutation of the HRE (FIG. 2b, lower middle panel). The sensitivity
of this subset to echinomycin was further tested. As shown in FIG.
2c, echinomycin abrogated the CSC with an IC50 of 29.4 pM, which is
considerably more sensitive than other cell types, with IC50 in the
nM range (Kong et al., 2005).
[0080] To substantiate the role of HIF activity in CSC function,
the effect of HIF inhibitors for both CFU in vitro and
tumor-initiating activity in vivo was tested. Since the CFU from
the lymphoma CSC and normal hematopoeitic progenitor cells (HPC)
can be assayed under similar conditions, the selectivity of
echinomycin for HPC vs lymphoma CSC was tested. As shown in FIG.
2d, lymphoma CSC was approximately 100-fold more sensitive to
echinomycin than HPC. In serial plating experiments, the effect of
echinomycin in both first and second round of CSC was tested. As
shown in FIG. 9a, the CSC in both rounds were equally susceptible
to echinomycin. The specificity was confirmed by the effect of 3
different classes of HIF1.alpha. inhibitors but not by the P38
inhibitor (FIG. 9b). It is worth noting that, at doses (5-20 pM)
that had little effect on CFUs in the first round, the CFU in the
second-round of colony formation was significantly reduced (FIG.
9c). These data suggest that the in vitro self-renewal of CSC is
more addicted to HIF1.alpha. than colony initiation. In contrast,
neither the first nor the second round of HPC-CFU is affected by
considerably higher doses of echinomycin (FIG. 10).
[0081] Based on these observations, we explored the therapeutic
potential of HIF inhibitors. 1.times.10.sup.6 of cultured lymphoma
cells were injected i.p. into immune competent B10BR mice. Four or
14 days later, the mice that received lymphoma cells were either
treated with vehicle only or 3 (FIG. 11) or 5 (FIG. 2e) injections
of 200 ng/mouse of echinomycine at 2 day intervals. As shown in
FIG. 2e and FIG. 11, the untreated mice survived only 6-10 weeks,
while all treated mice lived until euthanasia at 134 (FIG. 2e) or
252 days (FIG. 11) after tumor cell injection. Two other known HIF
inhibitors, 2-methoxyestradiol (Mabjeesh et al., 2003) and
Geldanamycin (Minet et al., 1999), also reduced both CFU and tumor
initiation of CSC, albeit at less efficacy (FIG. 12). The
difference in efficacy may be due to different mechanisms of action
and bio-availability. The therapeutic efficacy of these HIF
inhibitors demonstrated that HIF may serve as an effective
therapeutic target.
[0082] To determine the molecular mechanism for the high
HIF1.alpha. activity in the CSC, the lymphoma cells were sorted
into c-Kit.sup.+Sca-1.sup.+ or c-Kit.sup.-Sca-1.sup.- subsets and
analyzed HIF1.alpha., HIF-2.alpha. and HIF-3.alpha. expression by
RT-PCR. As illustrated in FIG. 3a and quantified in FIG. 3b,
c-Kit.sup.+Sca-1.sup.+ cells expressed HIF1.alpha. at a level that
is 4-fold higher than the c-Kit.sup.-Sca-1.sup.- cells. No
expression of HIF2.alpha. or HIF3.alpha. was detected in the
c-Kit.sup.+Sca-1.sup.+ cells. Consistent with higher levels of
HIF1.alpha., expression of glucose transporter Glut1, a known
target gene of HIF1.alpha., is also highly elevated in the
c-Kit.sup.+Sca-1.sup.+ cells. In contrast, no up-regulation of
HIF1.alpha. and Glut1 was observed in the c-Kit.sup.+Sca-1.sup.+
bone marrow cells. To test if HIF activity is selectively required
for survival of the c-Kit.sup.+Sca-1.sup.+CSC, the tumor cell
culture were treated with low doses of echinomycin (20 pM) for 16
hours and analyzed the % of apoptotic c-Kit.sup.+Sca-1.sup.+ and
c-Kit.sup.-Sca-1.sup.- tumor cells. In the vehicle treated group,
approximately 1.8% of c-Kit.sup.+Sca-1.sup.+ and
c-Kit.sup.-Sca-1.sup.- tumor cells bound to Annexin V. Echinomycin
increased Annexin V+ cells in the c-Kit.sup.+Sca-1.sup.+tumor cells
by 6-fold, or to about 10%. No effect was observed in the
c-Kit.sup.-Sca-1.sup.- tumor cells (FIG. 3c, lower panel). In three
separate experiments involving 10 pM of echinomycin, apoptosis of
c-Kit.sup.+Sca-1.sup.+ tumor cells was on average 3.8+0.8-fold of
what was observed in vehicle control. In the same culture,
apoptosis of the c-Kit.sup.-Sca-1.sup.- tumor cells in the
echinomycin-treated group is roughly the same (1.2+/-0.3 fold) as
the vehicle group. The difference between the two groups is highly
significant (P=0.01).
[0083] To test the general significance of HIF1.alpha., we analyzed
expression and function of the HIF1.alpha. in human acute myeloid
leukemia (AML)-initiating cells. Leukemia-initiating cells of AML
have a phenotype of CD38.sup.-CD34.sup.+. To determine whether the
HIF1.alpha. gene is over-expressed in this subset, the
CD38.sup.-CD34.sup.+, CD38.sup.+CD34.sup.+, CD38.sup.-CD34.sup.-
and the CD38.sup.+CD34.sup.- subsets were sorted by FACS (FIG. 3d)
and the expression of HIF1.alpha. and its target GLUT1 were
analyzed. As shown in FIG. 3e, the CD38.sup.-CD34.sup.+ subset had
the highest levels of HIF1.alpha. transcript. Correspondingly,
GLUT1 transcript was also elevated in the CD38.sup.-CD34.sup.+
cells. All 6 cases of AML tested showed increased expressions of
HIF1.alpha. and GLUT1 in the CD38.sup.-CD34.sup.+ subset (data not
shown), which indicate that increased HIF1.alpha. expression is a
general feature of those bearing markers of AML-initiating
cells,
[0084] The CD38.sup.-CD34.sup.+ are also known to form AML-colonies
in vitro, which provides us with a simple assay to test the
significance of HIF1.alpha.. As shown in FIG. 6f, for all cases
tested, echinomycin inhibitions colony formation with IC50 between
50-120 pM. Although the echinomycin is also known to inhibit c-Myc
activity, its IC50 is in the nM range. As shown in FIG. 13, in the
ranges used in this study, echinomycin strongly inhibited
HIF1.alpha. but had no effect on c-Myc function. Given the fact
that the AML cases used have diverse genetic alterations (Table
S2), the broad inhibition by echinomycin is consistent with an
important function of HIF1.alpha. in AML-CFU, which include the
CD38.sup.-CD34.sup.+ AML-initiating cells.
TABLE-US-00003 TABLE S2 Rx status Flts status Cytogenetics at
Sample FAB type Age at enrollment exons13-15 and 20 diagnosis
MI-AML-9 M4 64 untreated WT 46, XY[20].sup.b MI-AML-15 M4 58
pre-treated heterozygous point 46, XY[20] mutation: Y572YC in exon
14 MI-AML-32 M0 55 untreated WT 47, XY, +21[4]; 46, XY[16]
MI-AML-36 M4 55 untreated WT 46, XY, t(11; 19)(q23; p13.1)[20]
MI-AML-60 M1 52 untreated Internal tandem 46, XY[20] duplication
MI-AML-71 AML-NOS 73 pre-treated WT 45, XX, -7[20] .sup.aGenetic
analysis of the following genes were carried out and found to be of
wild-type (WT): Trp53, NPM1, K-RAS and N-RAS. .sup.bNumbers in
bracket are the number of cells found of the same karyotypes among
a total of 20 cells analyzed.
[0085] Methods
[0086] To obtain the data shown in Table S2, primers to amplify
exons 5-9 of p53, exons 13-15 and exon 20 of Flt3, exon 12 of NPM1
and exons 2-3 of N-ras and K-ras were designed using the primer3
program (Steve Rozen and Helen J. Skaletsky (2000) Primer3 on the
WWW for general users and for biologist programmers. In: Krawetz S,
Misener S (eds) Bioinformatics Methods and Protocols: Methods in
Molecular Biology. Humana Press, Totowa, N.J., pp 365-386). PCR was
used to amplify exons of interest using genomic DNA from
FACS-sorted blasts as template. DNA was prepared for direct
sequencing using nested sequencing primers and Exo-SAP. Mutations
were identified using the Mutation Surveyor program and visual
inspection of sequence tracings.
[0087] To establish the significance of HIF1.alpha. up-regulation
in the c-Kit.sup.+Sca-1.sup.+ cells, lentiviruses expressing
HIF1.alpha. shRNA (see FIG. 14 for validation of shRNA) were first
used to transduce the lymphoma cells. GFP was used to track cells
expressing the lentiviral vector. As shown in FIG. 4a, in the
vector control group with scrambled ShRNA, equal numbers of
c-Kit.sup.+Sca-1.sup.+ cells were found in GFP.sup.hi and
GFP.sup.low subsets. In contrast, in two shRNA-transduced tumors,
the GFP.sup.hi population were essentially devoid of the
c-Kit.sup.+Sca-1.sup.+ cells, which indicated that the silencing of
HIF1.alpha. abrogates the c-Kit.sup.+Sca-1.sup.+ subset. Since more
than 50-fold reduction of CSC was observed on day 3 after
transduction, HIF activity is required for the maintenance of the
c-Kit.sup.+Sca-1.sup.+CSC.
[0088] Consistent with this notion, after drug selection to enrich
the transduced cells, the colony formation assay revealed 70-80%
reduction in the HIF1.alpha. ShRNA-transduced cells (FIG. 4b). To
test the role for HIF1.alpha. in tumor-initiating activity, control
vector (with scrambled shRNA) or HIF1.alpha. shRNA-transduced tumor
cells were transplanted into B10.BR mice after three rounds of
transduction. As shown in FIG. 4c, transduction with either shRNA
significantly reduced tumor-initiating activity as judged by the
significant delay of tumor-related death.
Example 3
Down-Regulation of Vhl in CSC is Essential for Maintenance of
CSC
[0089] Since HIF1.alpha. is normally degraded under normoxia by a
VHL-dependent mechanism, the expression of Vhl in the CSC was also
tested. The data demonstrate an approximate 4-fold reduction in the
Vhl transcripts of c-Kit.sup.+Sca-1.sup.+ cells (FIG. 5a). To
determine the significant of Vhl down-regulation, the tumor cells
were infected with Vhl-expressing lentivirus that also expresses
GFP. The GFP.sup.hi and GFP.sup.low subsets were compared for the
abundance of the c-Kit.sup.+Sca-1.sup.+ subset. The GFP.sup.hi
subset contained no c-Kit.sup.+Sca-1.sup.+ cells (FIG. 5b). Thus,
high Vhl expression ablated the c-Kit.sup.+Sca-1.sup.+ cells.
Consistent with this, the ectopic expression of Vhl significantly
reduced the colony forming activity of the tumor cells (FIG. 5c).
To test the role for reduced Vhl in tumor-initiating activity,
vector and VHL cDNA transduced tumor cells were transplanted into
B10.BR mice. As shown in FIG. 5d, transduction with lentivirus
expressing Vhl cDNA significantly reduced tumor-initiating activity
as judged by the onset of tumor-related death of the recipients.
Taken together, the data presented in FIGS. 4 and 5 demonstrate
that both over-expression of HIF1.alpha. and reduction in VHL are
essential for CSC activity.
Example 4
HIF Acts in Concert with the Notch Pathway in Self-Renewal of
CSC
[0090] In order to determine the underlying molecular mechanisms by
which HIF1.alpha. activation promotes self-renewal of CSC, the
potential involvement of Wnt and Notch pathways was examined.
Despite activation of the Wnt signaling in the TGB tumor, the data
demonstrate that the dominant negative TCF-1, which was shown to
inhibit tumor growth associated with Epm2a down regulation, did not
affect the CFU of the TGB CSC (data not shown). In contrast,
g-secretase inhibitor, L-685, 458, an inhibitor for Notch, potently
blocked the colony forming activity (FIG. 6a). To determine whether
the Notch signaling is over-activated in the CSC, the
c-Kit.sup.+Sca-1 cells were sorted and compared with the bulk
c-Kit.sup.-Sca-1.sup.- cells for expression of the Notch target
gene Hes1. As shown in FIG. 6b, sorted CSC had approximately 3.5
fold increase in expression of Hes1. In order to test whether the
increased Notch activity depended on HIF activity, three different
HIF inhibitors were used to block the up-regulation of Notch
targets in total TGB lymphoma cells and CSC enriched for
c-Kit.sup.+ cells. The data in FIG. 6c demonstrated that all HIF
inhibitors blocked expression of Hes1 among the c-Kit+ CSC.
[0091] Expression of Notch1-4 was analyzed in
c-Kit.sup.+Sca-1.sup.+ and the c-Kit.sup.-Sca-1.sup.- tumor cells.
As shown in FIG. 15, Notch1 and 2, but not Notch 3 and 4 are
expressed in the TGB tumor cells. Since two Notch genes are
expressed, a search for an effective dominant negative mutant to
suppress Notch signaling was performed. By trial and error, a
potent dominant negative mutant of Notch (AA1955-2370) was
identified, comprising intracellular domains of Notch1 with
truncation in both N and C-termini. A nuclear localization sequence
(NLS) from SV40 virus was inserted in the N-terminus to facilitate
its translocation into the nuclei. Based on the structure of Notch
I-C/CSL/Mastermind/DNA complex, the deletion removed both the DNA
binding RAM domain and the 4 ankyrin repeats responsible for
binding N-terminus of mastermind, while returning the bulk of
CSL-interacting residues. As such, it is predicted to act as a
dominant negative regulator of Notch signaling by preventing the
formation of mastermind-CSL-Notch IC-DNA complex. The mutant was
called dRdA.sub.1-4dOP (FIG. 6d, left panel). As shown in FIG. 6d
right panel, transduction of the dominant mutant resulted in about
30-fold reduction of the Hes transcripts. To substantiate the role
for Notch signaling, the TGB lymphoma was transduced with either
control lentiviral vector or that expressing dRdA.sub.1-4dOP. The
transduced cells were marked with GFP. As shown in FIG. 6e, in the
vector control group, the % of c-Kit.sup.+Sca-1.sup.+ cells were
comparable among the GFP.sup.hi and GFP.sup.low cells. In contrast,
dRdA.sub.1-4dOP-transduced group, more than 5-fold reduction in the
% c-Kit.sup.+Sca-1.sup.+ cells was observed in the GFP.sup.hi
subset. These data demonstrate that inactivation of the Notch
pathway prevents the survival of the c-Kit.sup.+Sca-1.sup.- cells.
In serial plating experiments, transduction of dRdA.sub.1-4dOP
reduced self-renewal activity as revealed by colony formation assay
(FIG. 6f). Moreover, when the dRdA.sub.1-4dOP- or control
vector-transduced cells were transplanted into syngeneic mice, it
was clear that dRdA.sub.1-4dOP--transduction prevented the
development of lymphoma, as demonstrated by the survival analysis
(FIG. 6g).
[0092] Previous studies demonstrated that HIF1.alpha. may interact
with Notch directly to activate its target gene, Hey2, under
hypoxia conditions. Using the reporter for Hes1 promote activity,
however, no significant enhancement of Notch signaling by the
oxygen-resistant HIF1.alpha. mutant was observed (FIG. 6h, i).
Alternative explanations for the function of HIF1.alpha. in Hes1
expression was therefore explored. It is well established that, in
response to Notch signaling, Hes1 expression is self-limiting, and
that the negative feedback is mediated by Hes1 binding to the
N-boxes in the Hes1 promoter region. Interestingly, immediately
after each of the two critical N-boxes, a bona fide HRE was
identified (FIG. 6h and FIG. 16). Given their proximity, it was
hypothesized that HIF1.alpha. may directly inhibit autoregulation
of Hes1. Indeed, transfection of Hes1 cDNA reduced the Hes1
promoter activity by about 10-fold. This inhibition was partially
reversed by the oxygen-resistant HIF1.alpha. (FIG. 6j). Likewise,
in the presence of Notch IC cDNA, Hes1 also repressed its own
promoter. HIF1.alpha. reversed the repression in a dose dependent
manner (FIG. 6k). Using chromatin immunoprecipitation (FIG. 6l),
significant binding of HIF1.alpha. to the region bound by Hes1 was
observed. Interestingly, the binding HIF1.alpha. and Hes1 appear to
compete with each other in binding to the region. The data suggest
that HIF1.alpha. may enhance Notch-induced Hes1 expression by
antagonizing the autoregulation of the Hes1.
Example 5
A Role for HIF in CSC Maintenance
[0093] The re-emergence of CSC concept relied on transplantation
studies to identify a subset of self-renewing tumor initiating
cells. Since most studies involved xenogeneic and allogeneic
transplantation into immune-deficient host, some have suggested
that the CSC concept requires reappraisal. An important feature of
the current study is to use syngeneic immune competent mice as
recipients. The self-renewing capacity of the CSC identified in
this study has been demonstrated by three rounds of serial
transplantation, in which as few as 100 c-Kit.sup.+Sca-1.sup.+
cells can give rise to lymphoma in nearly 100% of the recipients.
During the process, the number of c-Kit.sup.+Sca-1.sup.+ cells
remains around 1%. While maintaining the expression of the CD8
co-receptor, the bulk lymphoma cells appear to gradually lose the
expression of the T cell receptor. In addition to giving rise to
lymphoma, almost all c-Kit.sup.+Sca-1.sup.+ cells exhibit CFU
activity. The data substantiate an increasing list of genetic
studies in supporting the notion of CSC, although the potential
variation in tumor models with regard to existence of CSC cannot be
ruled out.
[0094] Both in vitro self-renewal and in vivo tumor initiating
properties were used to characterize the molecular mechanism of
self-renewal of CSC. In both assays, the role for HIF1.alpha. was
demonstrated by drug inhibition, shRNA silencing and
over-expression of oxygen-dependent HIF inhibitor VHL. Since the
expression of transduced vectors leads to almost immediate
disappearance of the CSC population, and since the short-term
treatment (12 hours) of echinomycin resulted in a specific
reduction of the c-Kit.sup.+Sca-1.sup.+ cells by increased
apoptosis, the HIF1.alpha. is likely necessary for survival of
CSC.
[0095] The increased HIF activity in the murine lymphoma is caused
by both over-expression of HIF1.alpha. and down-regulation of Vhl.
Since Vhl is responsible for the oxygen-mediated degradation of
HIFa, the increased HIFa activity no longer requires hypoxic
environment. In addition, it should be noted that in the 6 cases
AML samples tested, we have not observed increased expression of
VHL (data not shown). Yet the HIF are active based on expression of
its target and sensitivity to echinomycin. Therefore, additional
mechanisms likely exist to allow oxygen-resistant function of HIF
in AML-CFU. The effect of low doses of echinomycin on all AML
samples tested suggest that the mechanism described herein may be
generally applicable for tumors grown in area with high levels of
blood supplies, including leukemia and lymphoma. For areas of solid
tumors with poor blood supplies, the mechanism can be operative
even without HIF over-expression or VHL down-regulation.
Example 6
A Molecular Pathway for Maintenance of CSC
[0096] In investigating the molecular pathway responsible for the
maintenance of CSC, enhanced activity of Notch pathway was
observed, as revealed by increased expression of Notch target
genes, in the CSC in comparison to the bulk tumor cells. The data
demonstrate that all three HIF inhibitors tested block Notch
activation in the c-Kit.sup.+ subset. Interestingly, the inhibition
appear specific for the c-Kit.sup.+ subset of TGB lymphoma, which
is enriched for CSC, as the drugs had no effect on the Notch target
expression if the total TGB lymphoma cells were used. The
significance of Notch in CSC maintenance and tumor development is
demonstrated by effective ablation of the CSC and tumorigenesis by
an ectopic expression of a dominant inhibitor of Notch signaling,
dRdA.sub.1-4dOP in the TGB tumor cells. Again, the selective
ablation demonstrates that Notch signaling is specifically required
for the maintenance of CSC, while the survival of the bulk tumor
cells is independent of Notch signaling. Taken together, these data
demonstrate that HIF maintains CSC by regulating Notch
signaling.
[0097] Hes1 is an important Notch target known to be critical for
stem/progenitor cell functions. The data described herein indicate
that HIF1.alpha. potentiated the induction of Hes1 by Notch. In
contrast with the previous studies using Hey2 promoter as readout,
no direct co-operation between HIF1.alpha. and Notch IC in the
induction of the Hes1 gene was observed. Rather, it was shown that
HIF1.alpha. prevents the negative-feedback auto-regulation of the
Hes1 gene by inhibiting its binding to the N-boxes in the Hes1
promoter. Given the general, although not necessarily universal,
role of Notch in maintenance of a variety of tissue stem cells, the
data indicate an important functional conservation between CSC and
tissue stem cells.
Example 7
The HIF Pathway Plays a Role in CSC Function
[0098] An important way to validate the role for HIF pathway in the
CSC function was to test whether HIF inhibitor echinomycin can be
used to treat AML in a xenogeneic model. Studies using two AML
samples have been performed. 6.times.10.sup.6 AML cells (either
AML71-PB, which had poor prognosis based on cytogenetics data, or
AML-15-PB which had moderate prognosis based on cytogenetics; see
Table S2 above) from blood were transplanted into sublethally
irradiated NOD-SCID mice. Starting at 2 weeks after transfer, half
of the recipient mice received three injections of 200
ng/mouse/injection of echinomycin, once every other day. After two
weeks of pause, these mice received 3 more injections. The other
half of the mice were left untreated as control. At 7 weeks after
transplantation, all untreated mice in both groups (3 mice per
group) became moribund, while all echinomycin treated mice were
healthy. Analysis of the peripheral blood and bone marrow of
AML-71PB recipients is shown provided in FIG. 17.
[0099] As shown in FIG. 17A, the untreated group had an average of
12% human CD45.sup.+ cells in the blood. Echinomycin treatment
completely wiped out human CD45.sup.+ cells. A clearly definable
human cell population was observed in the bone marrow of untreated
bone marrow, but not with the echinomycin treatment (FIGS. 17B and
C). Further analysis of the human CD45.sup.+ cells indicated that
they were immature, as judged by their lack of CD14 and CD15 marker
(FIG. 17C lower right panel). Moreover, a high proportion of the
human CD45.sup.+ cells exhibited marker of AML stem cells
(CD34.sup.+CD38.sup.-), as indicated in FIG. 17C (upper right
panel). These data demonstrated the feasibility of the xenogeneic
model and critical support for treating hematologic cancer such as
AML using echinomycin. These data help demonstrate that HIF1.alpha.
activity is required for the maintenance of stem cells for
hematological malignancies and that HIF serves as a valuable
therapeutic target for cancer therapy. More importantly, the data
establish that the same principle applies to human AML.
Example 8
Therapeutic Elimination of Leukemia Stem Cells for AML
[0100] This example demonstrates the therapeutic potential of HIF
inhibitors for human hematological malignancies. AML was used as a
model because the phenotype of AML leukemia stem cells (AML-LSC)
was well-characterized, and because AML-LSC function in vivo can be
assayed using an established xenogeneic model. AML-LSC have the
phenotype of CD34.sup.+CD38.sup.-. To determine whether the
HIF1.alpha. gene is over-expressed in this subset of cells,
CD34.sup.+CD38.sup.-, CD34.sup.+CD38.sup.+, CD34.sup.-CD38.sup.-
and CD34.sup.-CD38.sup.+ subsets were sorted by FACS (FIG. 18a),
and the expression of HIF1.alpha. and its target GLUT1 were
analyzed. As shown in FIG. 18b, the CD34.sup.+CD38.sup.- subset had
the highest levels of HIF1.alpha. transcript. Correspondingly,
GLUT1 transcript was also elevated in the CD38.sup.-CD34.sup.-
cells. All 6 cases of AML tested showed increased expressions of
HIF1.alpha. and GLUT1 in the CD38.sup.-CD34.sup.- subset (data not
shown), which indicate that increased HIF1.alpha. expression is a
general feature of those cells bearing markers of AML-LSC
cells.
[0101] CD34.sup.-CD38.sup.- cells are also known to form
AML-colonies in vitro, thereby providing a simple assay to test the
significance of HIF1.alpha.. As shown in FIG. 18c, for all cases
tested, echinomycin inhibited colony formation with an IC50 between
50-120 pM. Although the echinomycin is also known to inhibit c-Myc
activity, its IC50 for c-Myc is in the nM range. The broad
inhibition by echinomycin is consistent with an important function
of HIF1.alpha. in AML-CFU, which include the CD34.sup.+CD38.sup.-
AML-LSC.
[0102] Conventional cancer therapy appears to enrich cancer stem
cells. An NFkB inhibitor, dimethylamino analog of parthenolide,
showed some selectivity for AML-LSC. Since the HIF1.alpha. activity
appears to be selectively activated in AML, AML-LSC might be
selectively targeted by echinomycin. As shown in FIG. 18d, low
doses of echinomycin selectively induced apoptosis of the
CD34.sup.+CD38.sup.- population, in comparison to the dominant AML
cells (CD34.sup.+CD38.sup.+ for most but CD34.sup.-CD38.sup.+ for
two AML cases).
[0103] A xenogeneic AML model using human AML samples was
established to test whether echinomycin can be used as a potential
therapeutic agent for AML. Primary clinical samples from AML
patients reconstituted irradiated NOD.SCID mice with immature human
myeloid cells were characterized by the expression of human CD45,
CD11b, but not mature myeloid markers CD14 and CD15. Remarkably, a
short term treatment with echinomycin starting at 15 days after
transplantation completely eliminated human cells from sample AML
150 and dramatically reduced the burden of human leukemia of AML 71
(FIG. 18e). The residual cells in echinomycin treated mice were not
differentiated as judged by the lack of mature myeloid markers
CD14, and CD15 (FIG. 18f).
[0104] The incomplete remission of AML71 enabled a determination of
whether echinomycin selectively reduces the AML-LSC, using the
CD34.sup.+CD38.sup.- markers. Echinomycin reduced the percentage of
CD34.sup.+CD38.sup.- cells in bone marrow by more than 10-fold
(FIG. 18g, top panel). Even among the human CD45.sup.+ compartment,
the relative abundance of AML-LSC was also reduced (FIG. 18g, lower
panel). To substantiate the impact of echinomycin on the leukemia
initiating cells, serial transplantation studies were carried to
determine whether echinomycin reduced self-renewal of AML-LSC. As
shown in FIG. 18h, while bone marrow from untreated mice induced
leukemia in all new recipients, bone marrow from echinomycin
treated mice failed to do so in any recipients. Therefore, the
residual cells in the echinomycin-treated bone marrow were devoid
of AML-LSC.
Example 9
Experimental Procedures
[0105] Materials and Methods for Examples 1-7 are disclosed
below.
[0106] AML Samples
[0107] AML patients diagnosed at the University of Michigan
Comprehensive Cancer Center between 2005 and 2009 were enrolled
into this study. The study was approved by the University of
Michigan Institutional Review Board. Written informed consent was
obtained from all patients prior to enrollment. The same AML
diagnostic criteria (>=20% myeloblasts in the bone marrow or
peripheral blood) were used and determined FAB subclassification
through review of both laboratory and pathology reports dated at
the time of diagnosis and interpreted by hematopathologists.
Cytogenetic risk stratification was determined according to
SWOG/ECOG criteria.
[0108] Antibodies, Flow Cytometry, and Immunofluorescence
[0109] Fluorochrome-conjugated antibodies specific for CD117
(c-kit) and Ly-6A/E (Sca-1) were purchased from either e-Bioscience
(Ja Jolla, Calif.), while those specific for CD8 and V.beta.8 were
purchased from Becton Dickinson-Pharmingen (Ja Jalla, Calif.). The
cell surface markers were analyzed by flow cytometry using LSRII
(Becton Dickinson, Mountain View, Calif.). The specific subsets
were sorted by FACSAria.
[0110] RT-PCR and Real-Time PCR
[0111] Expression of HIF1.alpha., HIF-2.alpha., HIF-3.alpha., VHL,
and Glut1 was determined by RT-PCR and real-time PCR. The primers
used were HIF1.alpha., forward, 5'-agtctagagatgcagcaagatctc-3' (SEQ
ID NO: 1); reverse, 5'-tcatatcgaggctgtgtcgactga-3' (PCR)(SEQ ID NO:
2), 5'-ttcctcatggtcacatggatgagt-3' (real-time PCR)(SEQ ID NO: 3);
hif-2a, forward, 5'-cgacaatgacagctgacaaggag-3' (SEQ ID NO: 4);
reverse, 5'-ttggtgaccgtgcacttcatcctc-3' (SEQ ID NO: 5); hif-3a,
forward, 5'-atggactgggaccaagacaggtc-3' (SEQ ID NO: 6); reverse,
5'-agcttcttctttgacaggttcggc-3' (SEQ ID NO: 7); vhl, forward,
5'-tctcaggtcatcttctgcaac-3' (SEQ ID NO: 8); reverse,
5'-aggctccgcacaacctgaag-3' (SEQ ID NO: 9); Glut1, forward
5'-tgtgctgtgctcatgaccatc-3' (SEQ ID NO: 10) and reverse
5'-acgaggagcaccgtgaagat-3' (SEQ ID NO: 11); mHes1F: gccagtgtc
aacacgacaccgg (SEQ ID NO: 12), mHes1R: tcacctcgttcatgcactcg (SEQ ID
NO: 13); HIF1.alpha.F, 5'-ccatgtgaccatgaggaaatgagag-3' (SEQ ID NO:
14); HIF1.alpha.R, 5'-tcatatccaggctgtgtcgactgag-3' (SEQ ID NO: 15);
GLUT1F, 5'-tcaatgctgatgatgaacctgct-3' (SEQ ID NO: 16); GLUTIR,
5'-ggtgacacttcacccacataca-3' (SEQ ID NO: 17).
[0112] ShRNA-mediated knockdown of HIF1.alpha. and ectopic
expression of VHL and dRdA1, 2dOP
[0113] Lentiviral vectors carrying siRNAs are known in the art. The
core sequence of HIF1.alpha.-ShRNA-1 is 5'-ctagagatgcagcaagatc-3'
(SEQ ID NO: 18), while that of HIF1.alpha.-ShRNA-2 is
5'-gagagaaatgcttacacac-3' (SEQ ID NO: 19). The same vector was used
to express full length VHL cDNA, and dominant negative Notch mutant
dRdA.sub.1-42dOP (AA1995-2370). The tumor cell cultures were
infected with either control lentivirus or lentivirus encoding
HIF1.alpha. shRNA, dRdA.sub.1-42dOP or VHL cDNA by spinoculation.
The cultures were selected with 5 .mu.g/ml of blasticidin for 5
days to remove uninfected cells.
[0114] In vitro colony formation assay for tumor cells and bone
marrow cells is known in the art.
[0115] In Vivo Tumorigenicity Assay
[0116] Given numbers of total tumor cells or sorted subsets were
injected into either immune competent B10.BR mice or RAG-2.sup.-/-
BALB/c mice. Moribund mice were considered to have reached
experimental endpoint and were euthanized. The therapeutic effects
were analyzed by Kaplan Meier survival analysis.
Sequence CWU 1
1
23124DNAArtificial Sequencehif1a forward primer 1agtctagaga
tgcagcaaga tctc 24224DNAArtificial Sequencehif1a reverse primer
2tcatatcgag gctgtgtcga ctga 24324DNAArtificial Sequencehif1a real
time pcr primer 3ttcctcatgg tcacatggat gagt 24423DNAArtificial
Sequencehif2a forward primer 4cgacaatgac agctgacaag gag
23524DNAArtificial Sequencehif2a reverse primer 5ttggtgaccg
tgcacttcat cctc 24623DNAArtificial Sequencehif3a forward primer
6atggactggg accaagacag gtc 23724DNAArtificial Sequencehif3a reverse
primer 7agcttcttct ttgacaggtt cggc 24821DNAArtificial Sequencevhl
forward primer 8tctcaggtca tcttctgcaa c 21920DNAArtificial
Sequencevhl reverse primer 9aggctccgca caacctgaag
201021DNAArtificial Sequenceglut1 forward primer 10tgtgctgtgc
tcatgaccat c 211120DNAArtificial Sequenceglut1 reverse primer
11acgaggagca ccgtgaagat 201222DNAArtificial SequencemHes1F primer
12gccagtgtca acacgacacc gg 221320DNAArtificial SequencemHes1R
primer 13tcacctcgtt catgcactcg 201425DNAArtificial Sequencehif1aF
primer 14ccatgtgacc atgaggaaat gagag 251525DNAArtificial
Sequencehif1aR primer 15tcatatccag gctgtgtcga ctgag
251623DNAArtificial Sequenceglut1f primer 16tcaatgctga tgatgaacct
gct 231722DNAArtificial Sequenceglut1R primer 17ggtgacactt
cacccacata ca 221819DNAArtificial SequenceHIF1a shRNA core sequence
18ctagagatgc agcaagatc 191919DNAArtificial SequenceHIF1a shRNA core
sequence 19gagagaaatg cttacacac 192024DNAArtificial SequenceHRE
20tctgtacgtg accacactca cctc 242124DNAArtificial SequenceHRE mutant
21tctgtaaaag accacactca cctc 2422359DNAMus musculus 22caaagcccag
aggaaagagt tagcaaaggg ttaaaatcct tttgattgac gttgtagcct 60ccggtgcccc
gggctcaggc gcgcgccatt ggccgccaga ccttgtgcct agcggccaat
120gggggggcgc agtccacgag cggtgccgcg tgtctcttcc tcccattggc
tgaaagttac 180tgtgggaaag aaagtttggg aagtttcaca cgagccgttc
gcgtgcagtc ccagatatat 240atagaggccg ccagggcctg cggatcacac
aggatctgga gctggtgctg ataacagcgg 300aatcccctgt ctacctctct
ccttggtcct ggaatagtgc taccgatcac taagtagcc 35923357DNAHomo sapiens
23caaagcccag agggagagta gcaaagggtt aaaatccttt tgattgacgt tgtagcctcc
60ggtgccctgg gctcaggcgc gcgccattgg ccgccagacc ttgtgcctgg cggccaatgg
120gggggcgcgg tccacgagcg gtgccgcgtg tctcctcctc ccattggctg
aaagttactg 180tgggaaagaa agtttgggaa gtttcacacg agccgttcgc
gtgcagtccc agatatatat 240agaggccgcc agggcctagg gatcacacag
gatccggagc tggtgctgat aacagcggaa 300tcccccgtct acctctctcc
ttggtcctgg aacagcgcta ctgatcacca agtagcc 357
* * * * *