U.S. patent application number 11/612414 was filed with the patent office on 2007-05-17 for indole compounds useful for the treatment of cancer.
Invention is credited to Dennis A. Carson, Howard B. Cottam, Lorenzo M. Leoni.
Application Number | 20070111950 11/612414 |
Document ID | / |
Family ID | 37526560 |
Filed Date | 2007-05-17 |
United States Patent
Application |
20070111950 |
Kind Code |
A1 |
Carson; Dennis A. ; et
al. |
May 17, 2007 |
INDOLE COMPOUNDS USEFUL FOR THE TREATMENT OF CANCER
Abstract
The present invention provides novel indole derivatives useful
to inhibit cancer or sensitize cancer cells to chemotherapeutic
agents, radiation or other anti-cancer treatments.
Inventors: |
Carson; Dennis A.; (Del Mar,
CA) ; Leoni; Lorenzo M.; (San Diego, CA) ;
Cottam; Howard B.; (Escondido, CA) |
Correspondence
Address: |
SCHWEGMAN, LUNDBERG, WOESSNER & KLUTH, P.A.
P.O. BOX 2938
MINNEAPOLIS
MN
55402
US
|
Family ID: |
37526560 |
Appl. No.: |
11/612414 |
Filed: |
December 18, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09634207 |
Aug 9, 2000 |
7151100 |
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11612414 |
Dec 18, 2006 |
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09360020 |
Jul 23, 1999 |
6545034 |
|
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09634207 |
Aug 9, 2000 |
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60189976 |
Mar 16, 2000 |
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Current U.S.
Class: |
514/23 ;
514/232.8; 514/337; 514/411; 514/81; 536/17.4; 544/142; 546/276.7;
548/413; 548/430 |
Current CPC
Class: |
A61K 31/535 20130101;
A61K 45/06 20130101; A61P 35/02 20180101; A61K 31/535 20130101;
A61K 2300/00 20130101 |
Class at
Publication: |
514/023 ;
514/232.8; 514/411; 514/337; 514/081; 536/017.4; 544/142; 548/413;
548/430; 546/276.7 |
International
Class: |
A61K 31/7056 20060101
A61K031/7056; A61K 31/5377 20060101 A61K031/5377; A61K 31/4439
20060101 A61K031/4439; A61K 31/407 20060101 A61K031/407; C07D
491/04 20060101 C07D491/04; C07D 498/04 20060101 C07D498/04 |
Claims
1. A compound of formula (I): ##STR4## wherein R.sup.1 is lower
alkyl, lower alkenyl, (hydroxy)lower alkyl, lower alkynyl, phenyl,
benzyl or 2-thienyl, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are the
same or different and are each hydrogen or lower alkyl; each
R.sup.6 is individually hydrogen, lower alkyl, hydroxy,
(hydroxy)lower alkyl, lower alkoxy, benzyloxy, lower alkanoyloxy,
nitro or halo, n is 1-3, R.sup.7 is hydrogen, lower alkyl or lower
alkenyl, X is oxy and thio, Y is carbonyl, (CH.sub.2).sub.1-3,
(CH.sub.2).sub.1-3,SO.sub.2 or (CH.sub.2).sub.1-3C(O), and Z is
(.omega.-(4-pyridyl)(C.sub.2-C.sub.4 alkoxy),
(.omega.-((R.sup.8)(R.sup.9) amino)(C.sub.2-C.sub.4 alkoxy),
wherein R.sup.8 and R.sup.9 are each H, (C.sub.1-C.sub.3)alkyl or
together with N are a 5- or 6-membered heterocyclic ring comprising
1-3 N(R.sup.8), S or nonperoxide O; an amino acid ester of
(.omega.-(HO)(C.sub.2-C.sub.4))alkoxy,
N(R.sup.8)CH(R.sup.8)CO.sub.2H, 1'-D-glucuronyloxy; or Y-Z is
(CH.sub.2).sub.1-3R8; wherein R.sup.8 is OH,
(C.sub.2-C.sub.4)acyloxy, SO.sub.3H, PO.sub.4H.sub.2, N(NO)(OH),
SO.sub.2NH.sub.2, PO(OH)(NH.sub.2), or tetrazolyl; or a
pharmaceutically acceptable salt thereof.
2. The compound of claim 1 wherein Z is the L-valine or L-glycine
ester of 2-hydroxyethoxy.
3. The compound of claim 1 wherein Z is N-morpholinoethoxy.
4. The compound of claim 1 wherein each R.sup.8 is H, CH.sub.3 or
i-Pr.
5. The compound of claim 1 wherein Z is
OCH.sub.2CH.sub.2N(CH.sub.3).sub.3.sup.+.
6. A composition comprising the compound of claim 1 in combination
with a pharmaceutically acceptable carrier.
7. The composition of claim 6 which is a tablet, granule or
capsule.
8. The composition of claim 6 wherein the carrier is an aqueous
vehicle.
9. The composition of claim 8 which is an aqueous solution.
10-48. (canceled)
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 09/360,020 filed Jul. 23, 1999, and claims
priority of U.S. provisional patent application Ser. No.
60/189,976, filed Mar. 16, 2000, both of which are incorporated by
reference herein.
BACKGROUND OF THE INVENTION
[0002] The invention was made with Government support under Grant
No. 5ROI GM23200-24 awarded by the National Institute of Health.
The Government has certain rights in the invention.
[0003] Prostate cancer is the second leading cause of cancer death
among males in the United States in 1998, an estimated 185,000 men
were diagnosed with prostate cancer, and more than 39,000 men died
of the disease. See, S. H. Landis et al., Cancer Statistics, CA
Cancer J. Clin., 48, 6 (1998). Although survival rates are good for
prostate cancer that is diagnosed early, the treatments for
advanced disease are limited to hormone ablation techniques and
palliative care. Hormone ablation techniques (orchiectomy and
anti-androgen treatments) generally allow only temporary remission
of the disease. It usually recurs within 1-3 years of treatment,
with the recurrent tumors no longer requiring androgens for growth
and survival. D. G. Tang et al., Prostate, 32, 284 (1997). Therapy
with conventional chemotherapeutic agents, such as progesterone,
estramustine and vinblastine, has also not been demonstrated to be
effective to halt progression of the disease.
[0004] The number of nonsteroidal anti-inflammatory drugs (NSAIDs)
has increased to the point where they warrant separate
classification. In addition to aspirin, the NSAIDs available in the
U.S. include meclofenamate sodium, oxyphenbutazone, phenylbutazone,
indomethacin, piroxicam, sulindac and tolmetin for the treatment of
arthritis; mefenamic acid and zomepirac for analgesia; and
ibuprofen, fenoprofen and naproxen for both analgesia and
arthritis. Ibuprofen, mefenamic acid and naproxen are used also for
the management of dysmenorrhea.
[0005] The clinical usefulness of NSAIDs is restricted by a number
of adverse effects. Phenylbutazone has been implicated in hepatic
necrosis and granulomatous hepatitis; and sulindac, indomethacin,
ibuprofen and naproxen with hepatitis and cholestatic hepatitis.
Transient increases in serum aminotransferases, especially alanine
aminotransferase, have been reported. All of these drugs, including
aspirin, inhibit cyclooxygenase, that in turn inhibits synthesis of
prostaglandins, which help regulate glomerular filtration and renal
sodium and water excretion. Thus, the NSAIDs can cause fluid
retention and decrease sodium excretion, followed by hyperkalemia,
oliguria and anuria. Moreover, all of these drugs can cause peptic
ulceration. See, Remington's Pharmaceutical Sciences, Mack Pub.
Co., Easton, Pa. (18th ed., 1990) at pages 1115-1122.
[0006] There is a large amount of literature on the effect of
NSAIDs on cancer, particularly colon cancer. For example, see H. A.
Weiss et al., Scand J. Gastroent., 31, 137 (1996) (suppl. 220) and
Shiff et al., Exp. Cell Res., 222, 179 (1996). More recently, B.
Bellosillo et al., Blood, 92, 1406 (1998) reported that aspirin and
salicylate reduced the viability of B-cell CLL cells in vitro, but
that indomethacin, ketoralac and NS-398, did not.
[0007] C. P. Duffy et al., Eur. J. Cancer, 34, 1250 (1998),
reported that the cytotoxicity of certain chemotherapeutic drugs
was enhanced when they were combined with certain non-steroidal
anti-inflammatory agents. The effects observed against human lung
cancer cells and human leukemia cells were highly specific and not
predictable; i.e., some combinations of NSAID and agent were
effective and some were not. The only conclusion drawn was that the
effect was not due to the cyclooxygenase inhibitory activity of the
NSAID.
[0008] The Duffy group filed a PCT application (WO98/18490) on Oct.
24, 1997, directed to a combination of a "substrate for MRP", which
can be an anti-cancer drug, and a NSAID that increases the potency
of the anti-cancer drug. NSAIDs recited by the claims are
acemetacin, indomethacin, sulindac, sulindac sulfide, sulindac
sulfone, tolmetin and zomepirac. Naproxen and piroxicam were
reported to be inactive.
[0009] Recently, W. J. Wechter et al., Cancer Res. 60, 2203 (2000)
reported that the NSAID, R-flurbiprofen, inhibited progression of
prostate cancer in the TRAMP mouse, a prostate cancer model. The
Wechter group filed a PCT application (W098/09603) on Sep. 8, 1997,
disclosing that prostate cancer can be treated with R-NSAIDs,
including R(-)-etodolac and R-flurbiprofen. In contrast to
R(-)-etodolac, the R-enantiomer of flurbiprofen and other
(R)-2-aryl propionate NSAIDs are converted in the body to the
anti-inflammatory S-enantiomers, and hence are pro-drugs of the
NSAIDs, while R(-) etodolac is not per se an NSAID. Therefore, a
continuing need exists for effective methods to employ these
preliminary findings to develop new compounds to treat neoplastic
disease, including prostate cancer and other cancers.
SUMMARY OF THE INVENTION
[0010] The present invention provides indole compounds of formula
(I): ##STR1## wherein R.sup.1 is lower alkyl, lower alkenyl,
(hydroxy)lower alkyl, lower alkynyl, phenyl, benzyl or 2-thienyl,
R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are the same or different and
are each hydrogen or lower alkyl; each R.sup.6 is individually
hydrogen, lower alkyl, hydroxy, (hydroxy)lower alkyl, lower alkoxy,
benzyloxy, lower alkanoyloxy, nitro or halo, n is 1-3, R.sup.7 is
hydrogen, lower alkyl or lower alkenyl, X is oxy and thio, Y is
carbonyl, (CH.sub.2).sub.1-3, (CH.sub.2).sub.1-3C(O), or
(CH.sub.2).sub.1-3SO.sub.2 and Z is
(.omega.-(4-pyridyl)(C.sub.2-C.sup.4alkoxy),
(.omega.((R.sup.8)(R.sup.9) amino)(C.sub.2-C.sub.4 alkoxy), wherein
R.sup.8 and R.sup.9 are each H, (C.sub.1-C .sub.3)alkyl or together
with N are a 5- or 6-membered heterocyclic ring comprising 1-3
N(R.sup.8), S or nonperoxide O; an amino acid ester of
(.omega.-(HO)(C.sub.2-C.sub.4))alkoxy,
N(R.sup.8)CH(R.sup.8)CO.sub.2H, 1'-D-glucuronyloxy; Y-Z is
(CH.sub.2).sub.1-3R.sup.8 wherein R.sup.8 is OH, (C.sub.2-C
.sub.4)acyloxy, SO.sub.3H, PO.sub.4H.sub.2, N(NO)(OH),
SO.sub.2NH.sub.2, PO(OH)NH.sub.2, or tetrazolyl; or a
pharmaceutically acceptable salt thereof.
[0011] The present invention also provides a therapeutic method to
inhibit the growth of cancer cells and/or to sensitize cancer cells
to inhibition by a chemotherapeutic agent. The method comprises
contacting cancer cells with an effective amount of the compound of
formula (I), preferably in combination with a pharmaceutically
acceptable carrier. The present compounds can be used to treat a
mammal afflicted with cancer, such as a human cancer patient, and
are preferably administered in conjunction with a chemotherapeutic
agent, such as an alkylating agent or an anti-androgen, radiation
and/or other anti-cancer therapy.
[0012] The present compounds are effective against hematopoietic
cancers, such as leukemias and cancers of the bone marrow,
including chronic lymphocytic leukemia (CLL) and multiple myeloma
(MM). The present compounds were unexpectedly found to be effective
against cancer cells that express high levels of the nuclear
hormone receptor, peroxisome proliferator activated
receptor-.gamma., (PPAR-.gamma.), and/or high levels of the
anti-apoptotic proteins, Mcl-1 and/or Bag-1. Such cancer cells
include at least some types of prostate cancer cells.
[0013] Activated PPAR-.gamma. binds co-activator protein (CBP), a
co-activator of the androgen receptor known to be overexpressed in
hormone-resistant prostate cancer. Thus, compounds of formula (I)
that activate PPAR-.gamma. production can reduce the level of
expression of the androgen receptor known to be over-expressed in
hormone-resistant prostate cancer. Therefore, the present compounds
can enhance the efficacy of conventional anti-androgen therapy, and
can act to inhibit the spread of prostate cancer.
[0014] The present invention is based on the discovery by the
inventors that racemic etodolac inhibits the viability of purified
CLL or MM cells at concentrations that do not inhibit the viability
of normal peripheral blood lymphocytes (PBLs). It was then
unexpectedly found that the R(-) enantiomer of etodolac is as toxic
to CLL cells as is the S(+) enantiomer. It was then found that
etodolac synergistically interacted with fludarabine and
2-chloroadenosine to kill CLL cells at concentration at which the
chemotherapeutic agents alone were inactive. Finally, it was found
that both R(-)- and S(+)-etodolac inhibited a number of prostate
cancer cell lines. Again the R(-) enantiomer was at least as
effective as the S(+)-"anti-inflammatory" enantiomer. This was
unexpected since the R(-) enantiomer of etodolac does not possess
significant anti-inflammatory activity and is not converted to the
S(+) enantiomer to a significant extent in vivo. As noted above,
the R-enantiomers of other R-2-arylpropionate NSAIDs are converted
to the "active" anti-inflammatory S-enantiomers in vivo, and so
function as pro-drugs for the NSAD.
[0015] The extent of inhibition was markedly related to the level
of expression of PPAR-.gamma. by the cell line. Cell lines with an
elevated level of PPAR-.gamma. expression were inhibited much more
effectively than cell lines expressing relatively low levels of
PPAR-.gamma., as disclosed in the working examples.
[0016] A compound of formula (I) is preferred for practice of the
present therapeutic method that does not exhibit undesirable
bioactivities due to inhibition of cyclooxygenase (COX) that are
exhibited by some NSAIDs. However, the preferred compounds of
formula (I) would not be considered NSAIDs by the art, as they
would not exhibit significant anti-inflammatory activity.
[0017] Thus, the present invention also provides a method for
determining whether or not a particular cancer patient, such as a
prostate cancer patient, is amenable to treatment by a compound of
formula (I), comprising isolating cancer cells and evaluating in
vitro the relative level of PPAR-.gamma. and/or Mcl-1 and/or Bag-1
relative to the level in a cancer cell line, such as prostate
cancer cell line, known to be susceptible to treatment by a
compound of formula (I).
[0018] The present invention also provides a method to determine
the ability of a test agent to inhibit cancer cells, such as
prostate cancer cells, comprising contacting a population of cancer
cells, as from a prostate cancer cell line, with said agent and
determining whether the agent increases expression of PPAR-.gamma.,
or decreases the expression of Mcl-1 and/or Bag-1 (or does both).
The present invention also provides a general multilevel screening
method to evaluate etodolac analogs, other NSAIDs or other agents
for their ability to inhibit cancer, preferably etodolac-sensitive
cancers, such as prostate cancer, CLL and MM. Agents that exhibit a
positive activity, preferably at least equal to that of
R(-)-etodolac, or do not exhibit a negative activity, e.g., are no
more active than R(-)-etodolac, are passed to the next screen.
[0019] Test agents are first evaluated for their ability to
competitively inhibit the binding of etodolac, e.g., radiolabeled
R(-) etodolac to its receptor(s) on etodolac-sensitive cancer cells
such as CLL cells. Agents that can compete effectively with R(-)
etodolac for etodolac binding site(s) on the cells are then
evaluated in an assay to determine if they can increase Ca+.sup.2
uptake in cancer cells, such as CLL cells, preferably as
effectively as R(-) etodolac. Agents that can induce intracellular
Ca+.sup.2 uptake are screened to determine if they can induce
chemokinetic activity (chemokinesis or chemotaxis) in a population
of lymphocytes, such as B-CLL lymphocytes, preferably as
effectively as R(-) etodolac. Agents that are positive in this
screen are then evaluated to determine if they can induce apoptosis
or pro-apototic factors, such as increased caspase activity in
cancer cells, such as CLL cells and other cancer cells known to be
etodolac sensitive, at least as effectively as R(-) etodolac.
[0020] Agents that test positive in this screen are evaluated for
their ability to deplete lymphocytes in mice, and those that are no
more active than R(-) etodolac are then evaluated in animal models
of cancer to see if they can inhibit the induction of, or spread of
cancer.
[0021] As used herein with respect to cancer or cancer cells, the
term "inhibition" or "inhibit" includes both the reduction in
cellular proliferation, blockage of cellular proliferation, or
killing some or all of said cells. Thus, the term can be used in
both the context of a prophylactic treatment to prevent development
of cancer or as a treatment that will block, or slow the spread of
established cancer. Whether or not the level of expression of a
marker of susceptibility to etodolac treatment is sufficiently
elevated to continue treatment with etodolac or an analog thereof
is determined by comparison between the relative levels of
expression of said marker in resistant and susceptible cancer cell
lines, as disclosed hereinbelow.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 is a graph depicting the sensitivity of normal
peripheral blood lymphocytes (PBL) to racemic etodolac.
[0023] FIG. 2 is a graph depicting the sensitivity of CLL cells to
racemic etodolac.
[0024] FIG. 3 is a graph depicting the synergistic effect of a
combination of racemic etodolac and fludarabine against CLL
cells.
[0025] FIG. 4 is a graph depicting the synergistic effect of a
combination of 50 .mu.M etodolac with 10 .mu.M 2CdA or 10 .mu.M
Fludara against CLL cells.
[0026] FIG. 5 is a graph depicting the sensitivity of CLL cells to
S- and R-etodolac.
[0027] FIGS. 6 and 7 depict the viability of CLL cells from two
patients before and after etodolac administration.
[0028] FIG. 8 depicts a flow cytometric analysis of CLL cells
before and after etodolac treatment.
[0029] FIGS. 9 and 10 depict the selective action of R(-)-etodolac
against MM cells from two patients.
[0030] FIG. 11 is a photocopy of a SDS-PAGE gels demonstrating that
etodolac induces a rapid downregulation in Mcl-1 (Panel A) and
Bag-1 (Panel B), that is blocked by MG-132.
[0031] FIG. 12 is a photocopy of an SDS-PAGE gel depicting
expression of PPAR-.gamma. by seven cancer cell lines.
[0032] FIG. 13 is a graph depicting induction of PPAR-.gamma.
expression by etodolac and indomethacin.
[0033] FIG. 14 is a graph depicting expression of CD36 induced by
etodolac and TGZ, in the presence and absence of TPA in human
monocytes.
[0034] FIG. 15 is a photocopy of sections of prostate cancer
tissue, untreated (A) or treated (B, C, D) with etodolac.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Indole compounds of the present inventions include compounds
of formula (I): ##STR2## wherein R.sup.1 is selected from the group
consisting of lower alkyl, lower alkenyl, (hydroxy)lower alkyl,
lower alkynyl, phenyl, benzyl and 2-thienyl, R.sup.2, R.sup.3,
R.sup.4 and R.sup.5 are the same or different and are each selected
from the group consisting of hydrogen and lower alkyl, each R.sup.6
is individually selected from the group consisting of hydrogen,
lower alkyl, hydroxy, (hydroxy)lower alkyl, lower alkoxy,
benzyloxy, lower alkanoyloxy, nitro and halo, n is 1-3, R.sup.7 is
selected from the group consisting of hydrogen, lower alkyl and
lower alkenyl, X is selected from the group consisting of oxy and
thio, Y is selected from the group consisting of carbonyl
(CH.sub.2).sub.1-3, (CH.sub.2).sub.1-3SO.sub.2 or
(CH.sub.2).sub.1-3C(O), and Z is selected from the group consisting
of hydroxy, lower alkoxy optionally substituted with OH, 4-pyridyl,
amino, lower , di(lower alkyl)amino, or N-morpholino; amino, lower
alkylamino, [(carboxy)(lower alkyl)]amino, di(lower)alkylamino and
phenylamino, or Y-Z is (CH.sub.2).sub.1-3R.sup.8 wherein R.sup.8 is
OH, (C.sub.2-C.sub.4)acyloxy, SO.sub.3H, PO.sub.4H.sub.2,
N(NO)(OH), SO.sub.2NH.sub.2, PO(OH)NH.sub.2, or tetrazolyl or a
pharmaceutically acceptable salt thereof. Lower alkyl, alkenyl,
alkanoyl, etc. indicates a branched, cyclic or straight chain
C.sub.1-C.sub.6 group, preferably a C.sub.1-C.sub.4 group,
including cycloalkyl and (cycloalkyl)alkyl. (Hydroxy)lower alkyl or
alkoxy is preferably 1- or 2-hydroxyethyl.
[0036] As discussed above, the relatively low water solubility of
the R(-) enantiomer of etodolac can reduce its usefulness against
cancer when administered orally, or in an aqueous vehicle.
Therefore, the present invention also provides novel indole
compounds that exhibit enhanced water solubility and/or
bioavailability over the free acid or the simple alkyl esters of
etodolac. Such analogs include (pyridinyl) lower alkyl esters,
(amino)lower alkyl esters, (hydroxy)lower alkyl esters and
1'-D-glucuronate esters of etodolac, e.g., compounds of formula
(II) wherein (a) Y is carbonyl and (b) Z is
(.omega.-(4-pyridyl)(C.sub.2-C .sub.4 alkoxy),
(.omega.-((R.sup.8)(R.sup.9) amino)(C.sub.2-C.sub.4 alkoxy),
wherein R.sup.8 and R.sup.9 are each H, (C.sub.1-C .sub.3)alkyl or
together with N are a 5- or 6-membered heterocyclic ring comprising
1-3 N(R.sup.8), S or nonperoxide O; an amino acid ester of
(.omega.-(HO)(C.sub.2-C.sub.4)alkoxy, e.g., the L-valine or
L-glycine ester of 2-hydroxyethoxy, 1'-D-glucuronyloxy; and the
pharmaceutically acceptable salts thereof, e.g., with organic or
inorganic acids. Other analogs of increased water solubility
include amino acid amides, where Y is carbonyl and Z is
N(R.sup.8)CH(R.sup.8)CO.sub.2H, and the pharmaceutically acceptable
salts thereof.
[0037] Such compounds can be prepared as disclosed in U.S. Pat. No.
3,843,681, U.S. patent application Ser. No. 09/313,048, Ger. Pat.
No. 2,226,340 (Amer. Home Products), R. R. Martel et al., Can. J.
Pharmacol., 54, 245 (1976); Demerson et al., J. Med. Chem., 19, 391
(1976); PCT application Ser. No. US/00/13410 and Rubin (U.S. Pat.
No. 4,337,760).
[0038] The resolution of racemic compounds of formula (I) can be
accomplished using conventional means, such as the formation of a
diastereomeric salt with a optically active resolving amine; see,
for example, "Stereochemistry of Carbon Compounds," by E. L. Eliel
(McGraw Hill, 1962); C. H. Lochmuller et al., J Chromatog., 113,
283 (1975); "Enantiomers, Racemates and Resolutions," by J.
Jacques, A. Collet, and S. H. Wilen, (Wiley-Interscience, New York,
1981); and S. H. Wilen, A. Collet, and J. Jacques, Tetrahedron, 33,
2725 (1977). For example, the racemate has been resolved by
fractional crystallization of RS-etodolac using optically active
1-phenylethylamine and HPLC has been used to determine racemic
etodolac and enantiomeric ratios of etodolac and two hydroxylated
metabolites in urine (U. Becker-Scharfenkamp et al., J. Chromatog.,
621, 199 (1993)). B. M. Adger et al. (U.S. Pat. No. 5,811,558),
disclosed the resolution of etodolac using glutamine and
N(C.sub.1-C.sub.4 alkyl)-glutamine salts.
[0039] Etodolac itself
(1,8-diethyl-1,3,4,9-tetrahydro[3,4-6]indole-1-acetic acid) is a
NSAID of the pyranocarboxylic acid class, that was developed in the
early 1970s. Its structure is depicted as formula (II), below,
wherein (*) denotes the chiral center. See also, The Merck Index,
(11th ed.), at page 608. ##STR3##
[0040] The pharmacokinetics of etodolac have been extensively
reviewed by D. R. Brocks et al., Clin. Pharmacokinet., 26, 259
(1994). Etodolac is marketed as the racemate. The absolute
configurations of the enantiomers were found to be S-(+) and R-(-),
which is similar to that for most other NSAIDs. However, Demerson
et al., J. Med. Chem., 26, 1778 (1983) found that the
S(+)-enantiomer of etodolac possessed almost all of the
anti-inflammatory activity of the racemate, as measured by
reduction in paw volume of rats with adjuvant polyarthritis, and
prostaglandin synthetase inhibitory activity of the drug. No
anti-inflammatory activity was discernible with the (-)-enantiomer,
and it is not converted significantly to the S(+) enantiomer in
vivo. Hence, R(-) etodolac is not a NSAID. However, as disclosed
below, R(-) etodolac paradoxically was found to have potent
activity against cancer cells that is at least equivalent to that
of the S(+) enantiomer.
[0041] Etodolac possesses several unique disposition features due
to their stereoselective pharmacokinetics. In plasma, after the
administration of RS-etodolac, the concentrations of the "inactive"
R-enantiomer of etodolac are about 10-fold higher than those of the
active S-enantiomer, an observation that is novel among the chiral
NSAIDs. See, D. R. Brocks et al., Clin. Pharmacokinet., 26, 259
(1994). After a 200 mg dose in six elderly patients, the maximum
plasma concentration of the R-enantiomer was about 33 .mu.M. In
contrast, the maximum concentration of the S-enantiomer was 5-fold
lower. The typical dosage of the racemic mixture of etodolac is 400
mg BID, and the drug has an elimination half-life between 6-8
hours. Moreover, it is likely that the administration of the
purified R-enantiomer will not display the side effects associated
with cyclooxygenase (COX) inhibitors, such as ulcers and renal
insufficiency, and thus can be given at considerably higher
dosages. Nonetheless, the relatively low solubility of
R(-)-etodolac in water can impede attaining plasma levels in humans
that can inhibit cancer cells, particularly prostate cancer cells.
However, the compounds of formula (I) can be dissolved in water and
other aqueous carriers at substantially higher concentrations than
R(-) etodolac.
[0042] The compounds of formula (I) can also be prepared in the
form of their pharmaceutically acceptable salts or their
non-pharmaceutically acceptable salts. The non-pharmaceutically
acceptable salts are useful as intermediates for the preparation of
pharmaceutically acceptable salts. Pharmaceutically acceptable
salts are salts that retain the desired biological activity of the
parent compound and do not impart undesired toxicological effects.
Examples of such salts are (a) acid addition salts formed with
inorganic acids, for example hydrochloric acid, hydrobromic acid,
sulfuric acid, phosphoric acid, nitric acid and the like; and salts
formed with organic acids such as, for example, acetic acid, oxalic
acid, tartaric acid, succinic acid, maleic acid, fumaric acid,
gluconic acid, citric acid, malic acid, ascorbic acid, benzoic
acid, tannic acid, palnitic acid, alginic acid, polyglutamic acid,
naphthalenesulfonic acid, methanesulfonic acid, p-toluenesulfonic
acid, naphthalenedisulfonic acid, polygalacturonic acid, and the
like; and (b) salts formed from elemental anions such as chlorine,
bromine, and iodine. Preferred carboxylic acid salts are those of
hydrophilic amines, such as glucamine or N-(C.sub.1-C
.sub.4)alkylglucamine (see, Adger et al. (U.S. Pat. No.
5,811,558)).
[0043] The magnitude of a prophylactic or therapeutic dose of a
compound or compounds of formula (I) in the acute or chronic
management of cancer, i.e., prostate cancer, will vary with the
type and/or stage of the cancer, the adjunct chemotherapeutic
agent(s) or other anti-cancer therapy used, and the route of
administration. The dose, and perhaps the dose frequency, will also
vary according to the age, body weight, condition, and response of
the individual patient. In general, the total daily dose range for
a compound or compounds of formula (I), for the conditions
described herein, is from about 50 mg to about 5000 mg, in single
or divided doses. Preferably, a daily dose range should be about
100 mg to about 4000 mg, most preferably about 1000-3000 mg, in
single or divided doses, e.g., 750 mg every 6 hr of orally
administered compound. This can achieve plasma levels of about
500-750 .mu.M, which can be effective to kill cancer cells. In
managing the patient, the therapy should be initiated at a lower
dose and increased depending on the patient's global response. It
is further recommended that infants, children, patients over 65
years, and those with impaired renal or hepatic function initially
receive lower doses, particularly of analogs which retain COX
inhibitory activity, and that they be titrated based on global
response and blood level. It may be necessary to use dosages
outside these ranges in some cases. Further, it is noted that the
clinician or treating physician will know how and when to
interrupt, adjust or terminate therapy in conjunction with
individual patient response. The terms "an effective inhibitory or
amount" or "an effective sensitizing amount" are encompassed by the
above-described dosage amounts and dose frequency schedule.
[0044] Any suitable route of administration may be employed for
providing the patient with an effective dosage of a compound of
formula (I). For example, oral, rectal, parenteral (subcutaneous,
intravenous, intramuscular), intrathecal, transdermal, and like
forms of administration may be employed. Dosage forms include
tablets, troches, dispersions, suspensions, solutions, capsules,
patches, and the like. The compound may be administered prior to,
concurrently with, or after administration of chemotherapy, or
continuously, i.e., in daily doses, during all or part of, a
chemotherapy regimen. The compound, in some cases, may be combined
with the same carrier or vehicle used to deliver the anti-cancer
chemotherapeutic agent.
[0045] Thus, the present compounds may be systemically
administered, e.g., orally, in combination with a pharmaceutically
acceptable vehicle such as an inert diluent or an assimilable
edible carrier. They may be enclosed in hard or soft shell gelatin
capsules, may be compressed into tablets, or may be incorporated
directly with the food of the patient's diet. For oral therapeutic
administration, the active compound may be combined with one or
more excipients and used in the form of ingestible tablets, buccal
tablets, troches, capsules, elixirs, suspensions, syrups, wafers,
and the like. Such compositions and preparations should contain at
least 0.1% of active compound. The percentage of the compositions
and preparations may, of course, be varied and may conveniently be
between about 2 to about 60% of the weight of a given unit dosage
form. The amount of active compound in such therapeutically useful
compositions is such that an effective dosage level will be
obtained.
[0046] The tablets, troches, pills, capsules, and the like may also
contain the following: binders such as gum tragacanth, acacia, corn
starch or gelatin; excipients such as dicalcium phosphate; a
disintegrated agent such as corn starch, potato starch, alginic
acid and the like; a lubricant such as magnesium stearate; and a
sweetening agent such as sucrose, fructose, lactose or aspartame or
a flavoring agent such as peppermint, oil of wintergreen, or cherry
flavoring may be added. When the unit dosage form is a capsule, it
may contain, in addition to materials of the above type, a liquid
carrier, such as a vegetable oil or a polyethylene glycol. Various
other materials may be present as coatings or to otherwise modify
the physical form of the solid unit dosage form. For instance,
tablets, pills, or capsules may be coated with gelatin, wax,
shellac or sugar and the like. Tablets, capsules, pills, granules,
microparticles and the like can also comprise an enteric coating,
such as a coating of one of the Eudragit.RTM. polymers, that will
permit release of the active compound(s) in the intestines, not in
the acidic environment of the stomach. This can be advantageous in
the case of elderly or frail cancer patients treated with any
compound that retains a significant COX-inhibitory activity, and
concomitant ulceration.
[0047] A syrup or elixir may contain the active compound, sucrose
or fructose as a sweetening agent, methyl and propylparabens as
preservatives, a dye and flavoring such as cherry or orange flavor.
Of course, any material used in preparing any unit dosage form
should be pharmaceutically acceptable and substantially non-toxic
in the amounts employed. In addition, the active compound may be
incorporated into sustained-release preparations and devices.
[0048] The active compound may also be administered intravenously
or intraperitoneally by infusion or injection. Solutions of the
active compound or its salts can be prepared in water, optionally
mixed with a non-toxic surfactant. Dispersions can also be prepared
in glycerol, liquid polyethylene glycols, triacetin, and mixtures
thereof and in oils. Under ordinary conditions of storage and use,
these preparations contain a preservative to prevent the growth of
microorganisms.
[0049] The pharmaceutical dosage forms suitable for injection or
infusion can include sterile aqueous solutions or dispersions or
sterile powders comprising the active ingredient which are adapted
for the extemporaneous preparation of sterile injectable or
infusible solutions or dispersions, optionally encapsulated in
liposomes. In all cases, the ultimate dosage form must be sterile,
fluid and stable under the conditions of manufacture and storage.
The liquid carrier or vehicle can be a solvent or liquid dispersion
medium comprising, for example, water, ethanol, a polyol (for
example, glycerol, propylene glycol, liquid polyethylene glycols,
and the like), vegetable oils, non-toxic glyceryl esters, and
suitable mixtures thereof. The proper fluidity can be maintained,
for example, by the formation of liposomes, by the maintenance of
the required particle size in the case of dispersions or by the use
of surfactants. The prevention of the action of microorganisms can
be brought about by various antibacterial and antifungal agents,
for example, parabens, chlorobutanol, phenol, sorbic acid,
thimerosal, and the like. In many cases, it will be preferable to
include isotonic agents, for example, sugars, buffers or sodium
chloride. Prolonged absorption of the injectable compositions can
be brought about by the use in the compositions of agents delaying
absorption, for example, aluminum monostearate and gelatin.
[0050] Sterile injectable solutions are prepared by incorporating
the active compound in the required amount in the appropriate
solvent with various of the other ingredients enumerated above, as
required, followed by filter sterilization. In the case of sterile
powders for the preparation of sterile injectable solutions, the
preferred methods of preparation are vacuum drying and the freeze
drying techniques, which yield a powder of the active ingredient
plus any additional desired ingredient present in the previously
sterile-filtered solutions.
[0051] Useful dosages of the compounds of formula I can be
determined by comparing their in vitro activity, and in vivo
activity in animal models. Methods for the extrapolation of
effective dosages in mice, and other animals, to humans are known
to the art; for example, see U.S. Pat. No. 4,938,949.
[0052] Due to the ability of compounds of formula (I) that elevate
PPAR-.gamma. levels, to lower the expression of the androgen
receptor known to be overexpressed in hormone-refractory prostate
cancer, compounds that upregulate PPAR-.gamma. are advantageously
used in combination with steroidal and non-steroidal anti-androgens
used in the treatment of prostate cancer. These compounds include
leuprolide or goserelin acetate, bicalutamide and flutamide,
nilutamide, cycloproterone acetate, among others.
[0053] Due to the ability of compounds of formula (I) that reduce
PPAR-.gamma. levels to sensitize prostate cancer cells to killing
by conventional chemotherapeutic agents, such compounds can be
employed with chemotherapeutic agents used to treat cancers such as
prostate cancer, including estramustine, vinblastine,
mitoxanthrone, prednisone and the like, or melphalan to treat MM.
Other chemotherapeutic agents, irradiation or other anti-cancer
agents such as anti-tumor antibodies, or cytokines can be used with
the present compounds. See, e.g., Remington's Pharmaceutical
Sciences (18th ed. 1990) at pages 1138-1162.
[0054] The invention will be further described by reference to the
following detailed examples.
EXAMPLE 1
Sensitivity of Normal Peripheral Blood Lymphocytes and CLL Cells to
Etodolac
[0055] Mononuclear cells were isolated from the peripheral blood of
B-CLL patients and normal donors using density gradient
centrifugation (Ficoll-Paque). Cells were cultured at
2.times.10.sup.6 cells per mL in RPMI with 20% autologous plasma in
96-well plates with or without the indicated .mu.M concentrations
of etodolac (racemic, S-etodolac, R-etodolac) and in combination
with 2-chloro-2'-deoxyadenosine (2CdA) or fludarabine. At indicated
times (12, 24, 36, 48, 60, 72 hours), viability assays were
performed using the erythrocin B exclusion assay, as described by
D. Carson et al., PNAS USA, 89, 2970 (1992).
[0056] As shown in FIG. 1, significant death of normal PBLs
occurred only at 800 .mu.M racemic etodolac, a concentration which
cannot be obtained in vivo.
[0057] Peripheral blood lymphocytes from a normal donor were
cultured with 1.0 mM etodolac for 24 hours. Then B lymphocytes were
identified by staining with anti-CD19 antibody, and viability was
assessed by DiOC.sub.6 fluorescence. Etodolac under these
conditions did not reduce the viability of the normal B cells,
compared to control cultures. When the same viability assay was run
with purified CLL cells from the peripheral blood of a CLL patient,
the results were different. As shown in FIG. 2, 50% of the CLL
cells were killed by a 48 hour exposure to 200 .mu.M racemic
etodolac. More than 95% of the treated cells were malignant B
lymphocytes.
EXAMPLE 2
Synergistic Combinations of Etodolac and Chemotherapeutic
Agents
[0058] Fludarabine is a nucleoside analog commonly used for the
treatment of CLL. In this experiment the in vitro survival of CLL
cells at the indicated time points was compared in cultures
containing medium alone ("Con", squares), fludarabine 10 nM
(diamonds), etodolac 10 .mu.M (closed circles), and fludarabine 10
nM plus etodolac 10 .mu.M (open circles). The two drugs together
exhibited a synergistic cytotoxic effect. FIG. 3 shows that the
combination killed 50% of CLL cells during 48 hours of culture,
while either drug alone was ineffective. FIG. 4 demonstrates
synergy between 50 .mu.M etodolac and 10 nM 2-chlorodeoxyadenosine
and fludarabine, under the same test conditions.
EXAMPLE 3
Effect of R(-) and S(+) Etodolac Against CLL Cells
[0059] Etodolac tablets were ground in a mortar and extracted from
the formulation using ethyl acetate. The resulting racemic mixture
of enantiomers was separated into R and S isomers on a preparative
scale by fractional crystallization by the procedure of
Becker-Scharfenkamp and Blaschke, J. Chromatog., 621, 199 (1993).
Thus, the racemic mixture solid was dissolved in absolute
2-propanol and S-1-phenylethylamine was added to the solution. The
resulting salt solution was stored in the refrigerator for 4 days.
The crystalline white salt product was filtered and washed with
cold 2-propanol and recrystallized two more times from 2-propanol.
The same procedure was repeated for the R isomer only using
R-1-phenylethlamine as the resolving agent. Finally, the R and S
salts were decomposed using 10% sulfuric acid (v/v) and extracted
with ethyl acetate. The chiral purity of each isomer was verified
by HPLC using a Chiral-AGP column from ChromTech.
[0060] The toxicities of the two enantiomers to CLL cells cultured
in RPMI 1640 medium with 10% autologous plasma were compared at the
indicated concentrations and time points, as shown in FIG. 5. The
R- and S-enantiomers are equivalently cytotoxic to the CLL
cells.
EXAMPLE 4
Viability of CLL Cells Before and After Etodolac Treatment
[0061] Heparinized blood was taken from two patients (JK and NA)
with CLL. Then each patient immediately took a 400 mg etodolac
tablet, and a second tablet 12 hours later. After another 12 hours,
a second blood specimen was obtained. The CLL cells were isolated
and their survival in vitro were compared in RPMI 1640 medium
containing 10% autologous plasma, as described in Example 1. The
circles show CLL cells before etodolac treatment. In FIGS. 6-7, the
upward pointing triangles represent CLL cell viability after
etodolac treatment, wherein the cells are dispersed in medium
containing the pretreatment plasma. The downward pointing triangles
are CLL cells after treatment maintained in medium with the
post-treatment plasma.
[0062] FIG. 6 shows the different survivals of the two cell
populations from patient JK. Note that the cells after treatment
had a shortened survival compared to the cells before treatment.
FIG. 7 shows a less dramatic but similar effect with patient NA.
FIG. 8 is a flow cytometric analysis of CLL cells from patient JK
before and after etodolac treatment. DiOC.sub.6 is a dye that is
captured by mitochondria. When cells die by apoptosis, the
intensity of staining decreases. The X axis on the four panels in
FIG. 8 shows the DiOC.sub.6 staining. An increased number of dots
in the left lower box indicates cell death by apoptosis. If one
compares the cells taken from the patient before etodolac
treatment, and after etodolac treatment, one can see that the
number of dots in the left lower box is much higher after the drug.
This effect is detectable at 12 hours, and increases further after
24 hours.
[0063] To conduct the flow cytometric analysis, the mitochondrial
transmembrane potential was analyzed by 3,3'
dihexyloxacarboncyanide iodide (DiOC.sub.6), cell membrane
permeability by propidium iodide (PI).sup.3' and mitochondrial
respiration by dihydrorhodamine 123 (DHR) (See J. A. Royall et al.,
Arch. Biochem. Biophys., 302, 348 (1993)). After CLL cells were
cultured for 12 or 24 hours with the indicated amount of etodolac,
the cells were incubated for 10 minutes at 37.degree. C. in culture
medium containing 40 nM of DiOC.sub.6 and 5 .mu.g/ml PI. Cells were
also cultured for 3 hours with the indicated amount of etodolac,
spun down at 200.times.g for 10 minutes and resuspended in fresh
respiration buffer (250 mM sucrose, 1 g/L bovine serum albumin, 10
mM MgCl.sub.2, 10 mM K/Hepes, 5 mM KH.sub.2PO.sub.4 (pH 7.4)) and
cultured for 10 minutes at 37.degree. C. with 0.04% digitonin. Then
cells were loaded for 5 minutes with 0.1 .mu.M dihydrorhodamine
(DHR). Cells were analyzed within 30 minutes in a Becton Dickinson
FAC-Scalibur cytofluorometer. After suitable comprehension,
fluorescence was recorded at different wavelength: DiOC.sub.6 and
DHR at 525 nm (Fl-1) and PI at 600 nm (FL-3).
[0064] As a general matter a reduction of 10% in the survival of
the post-treatment malignant cells, compared to the pretreatment
malignant cells, at 16 hours after culture in vitro is considered a
"positive" in this test, and indicates the use of etodolac, i.e.,
R(-) etodolac in CLL or other cancer therapy.
EXAMPLE 5
Ability of R(-)-Etodolac to Selectively Kill MM Cells
[0065] Bone marrow was obtained from two patients with multiple
myeloma. The marrow contained a mixture of malignant cells, as
enumerated by high level expression of the CD38 membrane antigen,
and normal cells. The suspended marrow cells were incubated for 72
hours in RPMI 1640 medium with 10% fetal bovine serum, and various
concentrations of the purified R-enantiomer of etodolac. Then the
dead cells were stained with propidium iodide, and the multiple
myeloma cells were stained with fluorescent monoclonal anti-CD38
antibodies. The data were analyzed by fluorescent activated cell
sorting. FIGS. 9-10 show that R-etodolac did not kill the normal
bone marrow cells (light bars), but dose-dependently killed the
multiple myeloma cells (dark shaded areas), in the marrow cells
from both patients.
EXAMPLE 6
Etodolac Cytotoxicity to Cancer Cell Lines
[0066] Table 1 summarizes the cytotoxic effects of R(-)-etodolac
toward prostate cancer cell lines and one colon cancer cell line
are indeed within clinically achievable concentrations, given that
a 1 gram dosage of R(-)-etodolac should yield a maximal plasma
concentration in a human subject of about 400 .mu.M. The fact that
the R(-)- and S(+)-enantiomers are both cytotoxic indicates that
the anti-prostate cancer activity is COX independent. Note that
R(-)-etodolac, which is devoid of anti-inflammatory activity,
nonetheless is more toxic to prostate cancer cells than is S(+)
etodolac. TABLE-US-00001 TABLE 1 Cell line Origin Etodolac R/S
Etodolac R Etodolac S Phenoty PC-3 Prostate 340 .+-. 20* 150 .+-.
15* 800 + Sensitive 30* LNCaP- Prostate 400 .+-. 35 270 .+-. 50 220
.+-. 20 Sensitive FGC Alva-31 Prostate >1000 >1000 >1000
Resistant OVCAR- Ovarian >1000 >1000 >1000 Resistant 3
MDA- Breast >1000 >1000 >1000 Resistant MB-231 HCT- Colon
450 .+-. 15 280 .+-. 20 420 .+-. 50 Sensitive 116 SW260 Colon 1000
.+-. 120 ND ND Resistant A549 Lung >1000 >1000 >1000
Resistant *IC.sub.50 (.mu.M) of Etodolac R/S, R or S. Cytotoxicity
was assessed by MTT assay after three days continuous exposure to
decreasing concentrations of the agent. The results were confirmed
by FACS using propidium iodide uptake.
EXAMPLE 7
Etodolac Downregulation of Mcl-1 and Bag-1
[0067] As planar hydrophobic compounds, etodolac and other NSAIDS
can readily insert into cell and organ membranes, and can disrupt
their structure and function (S. B. Abramson et al., Arthritis and
Rheumatism, 32, 1(1989)). The proteins Mcl-1 and Bag-1 are
anti-apoptotic members of the bcl-2 family that are found in
mitochondria (X. Wang et al., Exp. Cell Res., 235, 210 (1997)). As
early as two hours after incubation with 100 .mu.M etodolac, Mcl-1
and Bag-1 levels fell in an etodolac sensitive prostate cancer cell
line (LNCaP). The fallin Mcl-1 and Bag-1 levels was prevented by
co-incubation of the prostate cells with 5.0 .mu.M MG-132, a
recently described inhibitor of the proteasome (FIG. 11, Panels A
and B, respectively) (D. H. Lee at al., Trends Cell Biol., 8, 397
(1998)). Detergent lysates (20 .mu.g per lane) were subjected to
SDS-PAGE and immunoblotted with anti-Mcl-1 and anti-Bag-1
antibodies. Pre-incubation of the cells with Z-VAD, a
broad-spectrum caspase inhibitor, did not prevent the Mcl-1 and
Bag-1 downregulation. Etodolac incubation did not alter Bcl-2 and
Bax levels (data not shown). Thus, etodolac did not interfere with
Mcl-1 synthesis, but probably accelerated its turnover. Both R- and
S-etodolac induced Mcl-1 degradation at equivalent
concentrations.
EXAMPLE 8
Expression of PPAR-.gamma. in Cancer Cell Lines
[0068] Although etodolac has not been previously studied, high
concentrations of other NSAIDs have been reported to activate the
nuclear hormone receptor PPAR-.gamma. (J. M. Lehmann et al., J.
Biol. Chem., 272, 3406 (1997). Moreover, maximal activation of
PPAR-.gamma. induces apoptosis in human macrophages (G. Chinetti et
al., J. Biol. Chem., 273, 25579 (1998). Therefore, it was of
interest to determine if prostate cells express PPAR-.gamma., and
to compare the expression level with other cancer types. Detergent
lysates (20 .mu.g per lane) obtained from subconfluent cell lines
were subjected to SDS-PAGE and immunoblotted with anti-PPAR-.gamma.
antibodies. To normalize the PPAR-.gamma. content, the membrane was
reblotted with an anti-actin monoclonal antibody. Lane 1: PC-3,
Lane 2: SW260, Lane 3: A549, Lane 4: MDA-MB-231, Lane 5: Alva-31,
Lane 6: LNCaP, Lane 7: HCT-116 (see Table 1). It was observed that
some etodolac-susceptible prostate cells (PC3 especially) expressed
remarkably high levels of immunoreactive PPAR-.gamma. (FIG.
12).
EXAMPLE 9
Activation of PPAR-.gamma. by Etodolac
[0069] RAW264.7 cells were transfected at a density of
3.times.10.sup.5 cells/ml in six well plates using lipofectamine
with the PPAR-.gamma. expression vector pCMX-PPAR-.gamma. (0.1
.mu.g), and the PPAR-.gamma. reporter construct (AOx).sub.3-TK-Luc
(1 .mu.g) as previously described by M. Ricote et al., Nature, 391,
79 (1998). Cells were treated for 24 hours with the compounds
indicated on FIG. 13, harvested and assayed for luciferase
activity. Results are expressed as the mean .+-. SD. As shown in
FIG. 13, both the R- and S-enantiomers of etodolac activated a
PPAR-.gamma. reporter gene construct at concentrations readily
achieved in human plasma after in vivo administration. THP-1 human
monocytic cells (ATCC) were incubated in the presence or absence of
phorbol ester (40 ng TPA) and 200 .mu.M racemic etodolac or 20
.mu.M troglitazone. After three days of culture, the surface
expression of the scavenger receptor CD36 was measured by flow
cytometry. As shown in FIG. 14, both R- and S-etodolac caused the
expression of CD36, a marker of PPAR-.gamma. activation, in the
human cell line THP-1 during macrophage differentiation.
EXAMPLE 10
Etodolac Treatment of Prostate Cancer Tissue Samples
[0070] Freshly obtained prostatectomy samples were cut into 3
mm.sup.3 pieces, and incubated for 72 hours in RPMI-1640
supplemented with 10% FBS and antibiotics in the absence (A, 400X)
or presence of racemic etodolac (B, 400X) or the purified R
enantiomer (C, 400X; and D, 630X). The tissues were next fixed in
4% paraformaldehyde in PBS, embedded in paraffin, sectioned and
stained with hematoxylin and eosin. FIG. 15A shows the infiltrating
tumor cells (large nuclei) and some residual normal epithelium.
FIGS. 15B to 15D show the effect of etodolac: note the abundant
presence of pyknotic apoptotic nuclei (dark arrows, B and D), and
the disintegration of the neoplastic glandular architecture (B+C).
Etodolac was found to be selectively toxic to the tumor cells, but
did not affect normal basal cells. The racemic mixture (R/S) and
the purified R and S analogs were found both active.
EXAMPLE 11
Prospective Protocol for Screening to Identify Etodolac Analogs
A. Screening of Analogs by Competition Against Radiolabeled
R-etodolac
[0071] Etodolac-sensitive chronic lymphocytic leukemia [CLL] cells,
or other cancer cells, will be utilized for drug screening in
radioreceptor binding assay. In brief, frozen CLL cells will be
washed three times in Hanks' Balanced Salt Solution (HBSS) and
resuspended in HBSS-HEPES. The assay will be done in a total volume
of 200 .mu.l containing approximately 2 million cells,
[3H]-R-Etodolac [sp.act.20-25 Ci/mmol, prepared by Sibtech] and
potential competitors or buffer are incubated in at varying
temperatures [4 and 37.degree. C.] and times [0-60 minutes]. For
each sample, triplicate 50 .mu.l aliquots will be layered over 300
.mu.l 20% sucrose in HBSS-HEPES in 1.5 ml polypropylene snap top
tubes and pelleted for 2.5 minutes at 15000 rpm in a Beckman
microfuge. This procedure rapidly separates the cell-bound and
cell-free etodolac. The tube tips will be cut off and the cell
pellets will be solubilized and counted in a scintillation counter.
Some of the incubation mixtures will contain excess unlabeled
etodolac as a control. Specific binding is the difference in the
bound cpm in tubes containing the radiolabeled etodolac minus the
cpm in the tubes containing the radiolabeled etodolac and the
excess cold competitor etodolac. Test agents are compared to the
unlabeled cold competitor etodolac for their abilities to inhibit
radiolabeled etodolac binding. Compounds that can inhibit the
binding of radiolabeled etodolac to its receptor(s) are advanced to
the next screen.
B. Intracellular Ca.sup.2+Mobilization in CLL
[0072] Increase of intracellular calcium levels in CLL cells by
test compounds such as etodolac analogs will be measured by a flow
cytometric assay (FACS) and by using a fluorometric imaging plate
reader system (FLIPR, Molecular Devices Corp., Sunnyvale, Calif.)
using the Fluo-4 dye (Molecular Probes). Briefly, CLL cells
(5.times.10.sup.6/ml) will be loaded for 30 min with 4 .mu.M of
Fluo-4 at 37.degree. C. in serum-free medium, washed twice, and
resuspended for an additional 30 min in normal cell culture medium.
The loaded cells will be then mixed in FACS tubes with medium
containing a test agent, and immediately thereafter the
fluorescence will be followed by FACS analysis over a period of 3
minutes. For high-throughput screening (HTS) assays, the
FLIPR-based assay will allow screening in a 96-well plate format,
using the same fluorometric dye (Fluo-4). Positive controls will be
performed using the calcium ionophore ionomycin at 50 ng/ml final
concentration, with chemokines such as SDF-1 and IP-10, and with
anti-IgM cross-linking antibodies. Compounds that increase the
Ca.sup.+2 uptake by CLL cells, preferably to at least the level
induced by R(-)-etodolac are advanced to the next screen.
C. Chemotaxis and Chemokinesis Assays
[0073] Cell migration will be measured in a 24-well modified Boyden
chamber (Transwell, Corning-Costar, N.Y.). The recombinant human
IP-10 chemokine (R&D Systems, McKinley Place, Nebr.) will be
diluted in RPMI-1640 medium at 200 ng/ml, and used to evaluate the
chemotactic properties of lymphocytes from B-CLL patients.
Polycarbonate membranes with pore size of 3 mm will be used. A
total of 600 mL of chemokines or control medium will be added to
the bottom wells, and 100 mL of 2 to 5.0.times.106 cells/ml cells
resuspended in RPMI-1640 will be added to the top wells. The
chamber will be incubated at 37.degree. C. with 5% CO.sub.2 for 2
hours. The membranes will then be removed, and the cells present on
the bottom well will be quantified by flow cytometry. For cell
quantification, a fixed acquisition time of 30 seconds will be used
per sample, and beads will be run during each experiment to ensure
a reproducible acquisition. Test agents that induce a chemokinetic
response in the lymphocytes, such a chemotactic response,
preferably at least as effectively as R(-) etodolac, will be
advanced to the next screen.
D. Induction of Apoptosis in Cancer Cells
[0074] The pro-apoptotic activity of the test agents, e.g., the
R-etodolac analogs, will be tested in primary CLL cells, as well as
in other tumor cells, by using the MTT assay and by measuring the
catalytic activation of caspase-3 using a fluorometric assay. In
brief, cells will be incubated for up to 3 days in presence of
serial dilutions of the selected test agents. Cells viability will
be quantified in 96-well plates by adding the MTT reagent (at 1
mg/ml final) for 2-4 hours followed by SDS cell lysis and
spectrophotometric analysis at 570 nm. Caspase catalytic activity
will be measured in a 96-well plate assay using a specific
fluorometric substrate (DEVD-AMC), after lysing the treated cells
with a CHAPS/NP-40 lysing buffer followed by fluorometric analysis.
Test agents that exhibit pro-apoptotic activity, e.g., that
increase caspase activity, preferably at least as effectively as
R(-)-etodolac, will be advanced to the next screen.
E. Lymphocyte Depletion in Mouse
[0075] The selected test agent will be orally delivered to mice of
various backgrounds in a single dose of 25 and 100 mg/kg. The
number of white blood cells will be counted using a neubauer
chamber after 4, 24 hrs, 7 and 14 days post treatment. Test agents
that do not lower white cell levels substantially, preferably no
more than does R(-) etodolac, will be advanced to the next
screen.
F. Tumor Animal Model
[0076] The anti-cancer and preventive activity of the R-etodolac
analogs will be tested using the pristane-induced mouse myeloma
model, and the transgenic adenocarcinoma mouse prostate (TRAMP)
model. The mice will receive a diet supplemented with 0.05% to 0.5%
of the selected test agent or control. The experimental diets will
be in the form of sterile pellets containing the test agent
(provided by Dyets Inc., Pa.). For prevention of cancer experiments
in the mouse myeloma model, the diet will be initiated at the same
time as the first pristane injection. For the transgenic prostate
cancer model, the diet will begin at birth. For therapeutic
experiments, the diet will begin in the TRAMP mice at week 10, when
the first histological pathologic markers are usually observed.
Analogs will advance to clinical trials or further development
based on their activity to inhibit cancer in at least one of these
screens.
[0077] All of the publications and patent documents cited
hereinabove are incorporated by reference herein. The invention has
been described with reference to various specific and preferred
embodiments and techniques. However, it should be understood that
many variations and modifications may be made while remaining
within the spirit and scope of the invention.
* * * * *