Although combination chemotherapy treatments such as FOLFIRINOX (5-fluorouracil, oxaliplatin, iri... more Although combination chemotherapy treatments such as FOLFIRINOX (5-fluorouracil, oxaliplatin, irinotecan), gem-abraxane (gemcitabine and nab-paclitaxel) and GTX (gemcitabine, docetaxel and capecitabine) have improved survival of pancreatic cancer patients incrementally, 5-year-survival for this disease remains dismal. New and more effective treatments are needed. Pancreatic stellate cells (PSCs), a form of fibroblasts that comprise much of the pancreatic tumor microenvironment, interact with the cancer cells via the cytokine leukemia inhibitory factor (LIF) and its receptor, LIF-R. This interaction contributes to tumor progression, survival, and resistance to various therapies, and is an important target for novel therapy. A small molecule inhibitor of LIF-R, EC359, inhibits growth of breast cancer cell line tumor explants in mice (Mol Cancer Ther 18: 1341-1354, 2019) and potentially modulates the activity of gemcitabine against such explants (Genes Cancer 10: 1-10, 2019). Given the...
Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast ... more Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast cancer include the lack of highly-specific PR modulators, a poor understanding of the pro- or anti-tumorigenic networks for PR isoforms and ligands, and an incomplete understanding of the cross talk between PR and estrogen receptor (ER) signaling. Through genomic analyses of xenografts treated with various clinically-relevant ER and PR-targeting drugs, we describe how the activation or inhibition of PR differentially reprograms estrogen signaling, resulting in the segregation of transcriptomes into separate PR agonist and antagonist-mediated groups. These findings address an ongoing controversy regarding the clinical utility of PR agonists and antagonists, alone or in combination with tamoxifen, for breast cancer management. Additionally, the two PR isoforms PRA and PRB, bind distinct but overlapping genomic sites and interact with different sets of co-regulators to differentially modula...
A series of estradiol-17-β esters of N-(p-sulfomylbenzamide)-amino acids were prepared and evalua... more A series of estradiol-17-β esters of N-(p-sulfomylbenzamide)-amino acids were prepared and evaluated for systemic and hepatic estrogenic activity after oral administration in ovariectomized rats. The alkyl substitution at nitrogen of amino acids such as proline or N-methyl-alanine produced compounds that exhibit potent oral activity. The proline analog (EC508) was further evaluated along with 17β-estradiol (E2) and ethinyl-estradiol (EE) and compared their effects on the uterus, angiotensin and HDL-cholesterol after oral administration to ovariectomized female rats. Orally administered EC508 produced systemic estrogenic activity 10 times greater than EE and a 100 times higher activity than E2 with no influence on levels of angiotensin and HDL-cholesterol, whereas EE and E2 reduced the HDL-cholesterol and increased the angiotensine plasma levels. EC508 might offer significant advantages in indications like fertility control and HRT based on its high oral bioavailability and lack of h...
Exposure to endocrine disrupting compounds (EDC's) is an important determinant of mammary gla... more Exposure to endocrine disrupting compounds (EDC's) is an important determinant of mammary gland development and mammary tumor pathogenesis. The risk of breast cancer in adulthood is known to be influenced by environmental factors experienced as a fetus. Fetal exposure to dietary factors or certain pharmaceuticals and environmental chemicals that affect or mimic steroid hormones increase predisposition to breast cancer. The mechanisms by which EDC's alter epigenetic programming, differentiation and deregulation of ductal branching of mammary glands are poorly understood. A high ratio of estrogen receptor a (ERα) to ERβ has been recently found to be associated with poor prognosis and aggressive disease in breast cancer patients. Preliminary studies from our laboratory revealed that bis(2-ethylhexyl) phthalate (DEHP) is a possible EDC which induces cell proliferation in T47D, MCF7, MCF7/Aro breast cancer cells in vitro and confers insensitivity to letrozole, a third generation ...
Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a critical role in cancer prog... more Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a critical role in cancer progression, metastasis, stem cell maintenance, and therapy resistance. Here, we describe a rationally designed first-in-class inhibitor of LIFR, EC359, which directly interacts with LIFR to effectively block LIF/LIFR interactions. EC359 treatment exhibits antiproliferative effects, reduces invasiveness and stemness, and promotes apoptosis in triple-negative breast cancer (TNBC) cell lines. The activity of EC359 is dependent on LIF and LIFR expression, and treatment with EC359 attenuated the activation of LIF/LIFR-driven pathways, including STAT3, mTOR, and AKT. Concomitantly, EC359 was also effective in blocking signaling by other LIFR ligands (CTF1, CNTF, and OSM) that interact at LIF/LIFR interface. EC359 significantly reduced tumor progression in TNBC xenografts and patient-derived xenografts (PDX), and reduced proliferation in patient-derived primary TNBC explants. EC359 exhibits distin...
Although systemic hormone therapies that either block local estrogen production by aromatase inhi... more Although systemic hormone therapies that either block local estrogen production by aromatase inhibitors (AI) such as letrozole or block actions of estrogen/ER actions by anti-estrogens like tamoxifen are well tolerated, the development of resistance to these agents is still a major concern. We have investigated whether treatment of letrozole resistant breast cancer cells with selective ER beta agonists (synthetic and of natural origin) in combination with letrozole restored sensitivity to this AI. We performed similar combination treatment of tamoxifen resistant cells with ER beta agonists and tamoxifen. To test whether combination therapy restores sensitivity to letrozole, we have treated letrozole resistant breast cancer cells LTLTca, derived from MCF-7-aromatase tumors resistant to letrozole] with either letrozole alone or with a combination of letrozole and DPN. Compared to single agents, combination treatment not only restored sensitivity to letrozole but also resulted in decre...
Endometriosis is a chronic estrogen-dependent disease that occurs in approximately 10% of reprodu... more Endometriosis is a chronic estrogen-dependent disease that occurs in approximately 10% of reproductive age women. Baboons offer a clear benefit for studying the initiation and progression of endometriosis since baboon is very close to humans phylogenetically. Progestins are used in the treatment of endometriosis. The therapeutic window of progestins depend on the ratio of its affinity towards progesterone receptor agonism verses antagonism. The present study is to determine the role of pure antiprogestin in baboon endometriosis. We hypothesize that pure antiprogestin will induce unopposed estrogenicity and spontaneous endometriosis in baboons. The rate of endometrial invasion and attachment through modeled peritoneum in the presence and absence of progesterone and antiprogestin was evaluated in this study. A baboon model of endometriosis induced by unopposed estrogenicity using progesterone receptor antagonist (EC304) was used in this study. We observed EC304 has induced unopposed e...
Breast Cancer (BC) is the second leading cause of cancer deaths in the U.S. women. Hormone ablati... more Breast Cancer (BC) is the second leading cause of cancer deaths in the U.S. women. Hormone ablation therapy reduces the risk of cancer recurrence and improves the survival rate of most BC patients. Although BC initially responds to estrogen ablation therapy, as the cancer progresses, the cancer cells become hormone-independent and prone to metastasis, a major cause of mortality in BC patients. The few currently available drugs that restore hormone dependence are only partially effective and prohibitively costly. Hence there is an urgent need for novel therapeutic modalities. We have recently shown that aldose reductase (AR)-catalyzed GSH-lipid aldehyde conjugates such as GS-DHN induces growth factors-, cytokines- and chemokines-mediated signals that activate PKC, PLC and PI3K, which regulate transcription of NF-κB- and AP1-dependent inflammatory markers. Further, AR has been shown to be overexpressed in human breast cancers. We have investigated the efficacy of AR inhibition in preventing BC cells growth and reversing hormone dependency of BC cells. Our results indicate that pharmacological inhibition of AR or siRNA ablation of AR prevents growth factor -induced proliferation of BC cells (MCF-7) in culture. Similar results were observed when MDA-MB-231 and MDA-MB-468 BC cells were used. To further investigate how AR inhibitor prevents BC cell growth, we have examined the role of AR in resensitization of BC cells to letrozole. We found that combination of fidarestat with letrozole was very effective in inducing maximum cell death in LTLT-Ca cells when compared to fidarestat alone. The combination treatment not only restored estrogen receptor-α (ER-α) levels but also down-regulated HER2/MAPK-signaling proteins. Further, AR-siRNA - transfected MCF-7/Aro and MCF-7 cells upregulated ER-α in western blot and ER-functionality assays whereas in LTLT-Ca cells, ER-α levels were down-regulated as in fidarestat treated cells. Targeting the LTLT-Ca cells with PLG-based fidarestat nanoparticles having polyethylene glycol (PEG)-5000 as stabilizer and conjugated with FITC significantly prevented the aromatase activity in BC cells. Thus we have identified a novel role of AR in BC cell growth and estrogen-dependence of hormone insensitive BC cells and suggest the use of AR inhibitors either alone or in combination with letrozole to prevent as well as treat BC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1484.
Abstract #3120 The macrophage colony-stimulating factor (CSF-1) is a cytokine produced by macroph... more Abstract #3120 The macrophage colony-stimulating factor (CSF-1) is a cytokine produced by macrophages as well as epithelial cancer cells. By signaling via its receptor c-fms, CSF-1 induces growth/survival pathways in breast cancer cells. Defects in mammary gland development were observed in mice deficient in CSF-1/c-fms signaling, implicating this pathway in normal mammary development as well. In breast cancer, elevated levels of both CSF-1 and c- fms have been detected, with 80% of invasive breast carcinomas abnormally expressing c-fms. To study the role of CSF-1 signaling in breast cancer, we have previously generated mammary specific transgenic mouse models that over-express these factors (termed MMTV-CSF-1 and MMTV-c-fms). Both these transgenic mouse strains developed ductal hyperplasia and dysplasia as well as tumor formation. Our previous evidence also showed increase in cellular proliferation factors such as Cyclin D1 and PCNA in these mice. To examine which signaling pathways are altered in these mice, we have compared in this study the expression profile of target genes of signaling pathways in MMTV-CSF-1 mice and wild type mice using the Signal Transduction Pathway Finder RT-PCR array (Superarrray). Wnt signaling pathway was induced in the mammary gland of the MMTV-CSF-1 mouse strain compared to wild type, suggesting that this pathway may mediate CSF-1 signaling. In a proof-of-principle experiment, an MMTV-CSF-1 mouse was injected subcutanuously with neutralizing anti-c-fms antibody (Santacruz Biotech, 2-4A5) at a dose of 5 μg daily for 7 days. The treated mouse exhibited a decrease in the elevated ductal branching and hyperplasia that are characteristics of untreated MMTV-CSF-1 mice. This treatment also resulted in reversing many of expression alterations in MMTV-CSF-1 mice. For example, expression of the CSF-1 responsive gene Cyclin D1 was reduced by over 3-fold due to antibody treatment. Fas, the receptor for the pro-apoptotic factor Fas ligand, decreased by 5-folds in the MMTV-CSF-1 strain relative to wild type but increased 14-folds due to c-fms antibody treatment. The expression of the proapoptotic factor Bax increased about 4-fold, whereas the angiogenic factor Angiopoietin 1 was reduced by 60% due to anti-cfms antibody treatment. The treatment also reversed alterations in the expression of the wnt transcription factors Lef-1/TCF7. Because small molecule tyrosine kinase inhibitors that target c-fms, Gleevecâ (Imatinib, obtained from Novartis) and GW2580 (Calbiochem), are emerging, we examined their effects on the growth of SKBR3 breast cancer cells that express both CSF-1 and c-fms. Our data showed both these drugs inhibited the growth of SKBR3 cells, providing the rationale to test their effects on tumor formation and underlying biochemical effects in our transgenic preclinical models. The current studies warrant further investigation of treating breast cancer using antibody and small molecule drugs targeting CSF-1/c-fms signaling. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3120.
Abstract #3080 Cyclin-dependent kinases (CDKs) play essential roles in the intracellular control ... more Abstract #3080 Cyclin-dependent kinases (CDKs) play essential roles in the intracellular control of the cell cycle. The encapsulated therapeutic drug molecules as nanoparticles will offer a sustained delivery of chemotherapeutics in to the target tissue. Nanoparticles enhance the therapeutic efficacy of an encapsulated drug by increased and sustained delivery of the drug inside the cell. Most anticancer drugs are taken up non-specifically by all types of cells, resulting in serious side-effects. Therefore, an ideal delivery carrier for an anticancer drug should be able to transport the drug specifically to cancer cells and release the drug molecules inside the cells to the site of their pharmacological activities. Most of the activity proven natural products were not entered in to the clinical practice due to lack of active formulation and/ or effective targeted delivery systems. In our study we found that gossypin (3,5,7,39,49-Pentahydroxy-8-O-glucosylflavone) is inhibiting cell cycle progression by inhibiting cyclin dependent kinase-2 (cdk2) when compared with roscovitine, a known cdk2 inhibitor. Gossypin has been shown to induce the accumulation of the tumor suppressor p53, cell cycle arrest in G1 and G2/M phases of the cell cycle, and to induce apoptosis in MCF-7, SKBR-3, and MDA-MB-231 cells with a mean IC 50 of 40uM. Gossypin also found to inhibit vascular endothelial growth factor (VEGF) in vitro. Nanoparticle formulation of gossypin effectively inhibited the growth and colony formation in vitro when compared to parent compound. Gossypin might exert inhibition of tumor cell growth and invasion by cell cycle arrest as well as VEGF induced vascular permeability and tumor neovascularization. The dual mode of action of gossypin may results in highly efficacious inhibition of tumor growth and management of breast cancer. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3080.
Endometrial cancer (EC) is the fourth most common cancer in women. Advanced-stage EC has limited ... more Endometrial cancer (EC) is the fourth most common cancer in women. Advanced-stage EC has limited treatment options with a poor prognosis. There is an unmet need for the identification of actionable drivers for the development of targeted therapies in EC. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a major role in cancer progression, metastasis, stemness, and therapy resistance. However, little is known about the functional significance of the LIF/LIFR axis in EC progression. In this study using endometrial tumor tissue arrays, we identified that expression of LIF, LIFR is upregulated in EC. Knockout of LIFR using CRISPR/Cas9 in two different EC cells resulted in a significant reduction of their cell viability and cell survival. In vivo studies demonstrated that LIFR-KO significantly reduced EC xenograft tumor growth. Treatment of established and primary patient-derived EC cells with a novel LIFR inhibitor, EC359 resulted in the reduction of cell viability with...
Histone deacetylase inhibitors (HDACi) are identified as novel therapeutic agents, however, recen... more Histone deacetylase inhibitors (HDACi) are identified as novel therapeutic agents, however, recent clinical studies suggested that they are marginally effective in treating triple negative breast cancer (TNBC). Here, we show that first-in-class Leukemia Inhibitory Factor Receptor (LIFRα) inhibitor EC359 could enhance the therapeutic efficacy of HDACi against TNBC. We observed that both targeted knockdown of LIFR with CRISPR or treatment with EC359 enhanced the potency of four different HDACi in reducing cell viability, cell survival, and enhanced apoptosis compared to monotherapy in TNBC cells. RNA-seq studies demonstrated oncogenic/survival signaling pathways activated by HDACi were attenuated by the EC359 + HDACi therapy. Importantly, combination therapy potently inhibited the growth of TNBC patient derived explants, cell derived xenografts and patient-derived xenografts in vivo. Collectively, our results suggest that targeted inhibition of LIFR can enhance the therapeutic efficac...
Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain o... more Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p
Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain o... more Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p < 0.01). Estradiol (E2) induced proliferation was blocked significantly in EC313-treated xenograft fibroids (p < 0.0001). Uterine weight was reduced by EC313 treatment compared to UPA treatment. ER and PR were reduced in EC313-treated groups compared to controls (p < 0.001) and UPA treatments (p < 0.01). UF specific desmin and collagen were markedly reduced with EC313 treatment. The partial PR agonism and no signs of unopposed estrogenicity makes EC313 a candidate for the long-term treatment for UFs. Docking studies have provided a structure based explanation for the SPRM activity of EC313.
Although combination chemotherapy treatments such as FOLFIRINOX (5-fluorouracil, oxaliplatin, iri... more Although combination chemotherapy treatments such as FOLFIRINOX (5-fluorouracil, oxaliplatin, irinotecan), gem-abraxane (gemcitabine and nab-paclitaxel) and GTX (gemcitabine, docetaxel and capecitabine) have improved survival of pancreatic cancer patients incrementally, 5-year-survival for this disease remains dismal. New and more effective treatments are needed. Pancreatic stellate cells (PSCs), a form of fibroblasts that comprise much of the pancreatic tumor microenvironment, interact with the cancer cells via the cytokine leukemia inhibitory factor (LIF) and its receptor, LIF-R. This interaction contributes to tumor progression, survival, and resistance to various therapies, and is an important target for novel therapy. A small molecule inhibitor of LIF-R, EC359, inhibits growth of breast cancer cell line tumor explants in mice (Mol Cancer Ther 18: 1341-1354, 2019) and potentially modulates the activity of gemcitabine against such explants (Genes Cancer 10: 1-10, 2019). Given the...
Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast ... more Major roadblocks to developing effective progesterone receptor (PR)-targeted therapies in breast cancer include the lack of highly-specific PR modulators, a poor understanding of the pro- or anti-tumorigenic networks for PR isoforms and ligands, and an incomplete understanding of the cross talk between PR and estrogen receptor (ER) signaling. Through genomic analyses of xenografts treated with various clinically-relevant ER and PR-targeting drugs, we describe how the activation or inhibition of PR differentially reprograms estrogen signaling, resulting in the segregation of transcriptomes into separate PR agonist and antagonist-mediated groups. These findings address an ongoing controversy regarding the clinical utility of PR agonists and antagonists, alone or in combination with tamoxifen, for breast cancer management. Additionally, the two PR isoforms PRA and PRB, bind distinct but overlapping genomic sites and interact with different sets of co-regulators to differentially modula...
A series of estradiol-17-β esters of N-(p-sulfomylbenzamide)-amino acids were prepared and evalua... more A series of estradiol-17-β esters of N-(p-sulfomylbenzamide)-amino acids were prepared and evaluated for systemic and hepatic estrogenic activity after oral administration in ovariectomized rats. The alkyl substitution at nitrogen of amino acids such as proline or N-methyl-alanine produced compounds that exhibit potent oral activity. The proline analog (EC508) was further evaluated along with 17β-estradiol (E2) and ethinyl-estradiol (EE) and compared their effects on the uterus, angiotensin and HDL-cholesterol after oral administration to ovariectomized female rats. Orally administered EC508 produced systemic estrogenic activity 10 times greater than EE and a 100 times higher activity than E2 with no influence on levels of angiotensin and HDL-cholesterol, whereas EE and E2 reduced the HDL-cholesterol and increased the angiotensine plasma levels. EC508 might offer significant advantages in indications like fertility control and HRT based on its high oral bioavailability and lack of h...
Exposure to endocrine disrupting compounds (EDC's) is an important determinant of mammary gla... more Exposure to endocrine disrupting compounds (EDC's) is an important determinant of mammary gland development and mammary tumor pathogenesis. The risk of breast cancer in adulthood is known to be influenced by environmental factors experienced as a fetus. Fetal exposure to dietary factors or certain pharmaceuticals and environmental chemicals that affect or mimic steroid hormones increase predisposition to breast cancer. The mechanisms by which EDC's alter epigenetic programming, differentiation and deregulation of ductal branching of mammary glands are poorly understood. A high ratio of estrogen receptor a (ERα) to ERβ has been recently found to be associated with poor prognosis and aggressive disease in breast cancer patients. Preliminary studies from our laboratory revealed that bis(2-ethylhexyl) phthalate (DEHP) is a possible EDC which induces cell proliferation in T47D, MCF7, MCF7/Aro breast cancer cells in vitro and confers insensitivity to letrozole, a third generation ...
Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a critical role in cancer prog... more Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a critical role in cancer progression, metastasis, stem cell maintenance, and therapy resistance. Here, we describe a rationally designed first-in-class inhibitor of LIFR, EC359, which directly interacts with LIFR to effectively block LIF/LIFR interactions. EC359 treatment exhibits antiproliferative effects, reduces invasiveness and stemness, and promotes apoptosis in triple-negative breast cancer (TNBC) cell lines. The activity of EC359 is dependent on LIF and LIFR expression, and treatment with EC359 attenuated the activation of LIF/LIFR-driven pathways, including STAT3, mTOR, and AKT. Concomitantly, EC359 was also effective in blocking signaling by other LIFR ligands (CTF1, CNTF, and OSM) that interact at LIF/LIFR interface. EC359 significantly reduced tumor progression in TNBC xenografts and patient-derived xenografts (PDX), and reduced proliferation in patient-derived primary TNBC explants. EC359 exhibits distin...
Although systemic hormone therapies that either block local estrogen production by aromatase inhi... more Although systemic hormone therapies that either block local estrogen production by aromatase inhibitors (AI) such as letrozole or block actions of estrogen/ER actions by anti-estrogens like tamoxifen are well tolerated, the development of resistance to these agents is still a major concern. We have investigated whether treatment of letrozole resistant breast cancer cells with selective ER beta agonists (synthetic and of natural origin) in combination with letrozole restored sensitivity to this AI. We performed similar combination treatment of tamoxifen resistant cells with ER beta agonists and tamoxifen. To test whether combination therapy restores sensitivity to letrozole, we have treated letrozole resistant breast cancer cells LTLTca, derived from MCF-7-aromatase tumors resistant to letrozole] with either letrozole alone or with a combination of letrozole and DPN. Compared to single agents, combination treatment not only restored sensitivity to letrozole but also resulted in decre...
Endometriosis is a chronic estrogen-dependent disease that occurs in approximately 10% of reprodu... more Endometriosis is a chronic estrogen-dependent disease that occurs in approximately 10% of reproductive age women. Baboons offer a clear benefit for studying the initiation and progression of endometriosis since baboon is very close to humans phylogenetically. Progestins are used in the treatment of endometriosis. The therapeutic window of progestins depend on the ratio of its affinity towards progesterone receptor agonism verses antagonism. The present study is to determine the role of pure antiprogestin in baboon endometriosis. We hypothesize that pure antiprogestin will induce unopposed estrogenicity and spontaneous endometriosis in baboons. The rate of endometrial invasion and attachment through modeled peritoneum in the presence and absence of progesterone and antiprogestin was evaluated in this study. A baboon model of endometriosis induced by unopposed estrogenicity using progesterone receptor antagonist (EC304) was used in this study. We observed EC304 has induced unopposed e...
Breast Cancer (BC) is the second leading cause of cancer deaths in the U.S. women. Hormone ablati... more Breast Cancer (BC) is the second leading cause of cancer deaths in the U.S. women. Hormone ablation therapy reduces the risk of cancer recurrence and improves the survival rate of most BC patients. Although BC initially responds to estrogen ablation therapy, as the cancer progresses, the cancer cells become hormone-independent and prone to metastasis, a major cause of mortality in BC patients. The few currently available drugs that restore hormone dependence are only partially effective and prohibitively costly. Hence there is an urgent need for novel therapeutic modalities. We have recently shown that aldose reductase (AR)-catalyzed GSH-lipid aldehyde conjugates such as GS-DHN induces growth factors-, cytokines- and chemokines-mediated signals that activate PKC, PLC and PI3K, which regulate transcription of NF-κB- and AP1-dependent inflammatory markers. Further, AR has been shown to be overexpressed in human breast cancers. We have investigated the efficacy of AR inhibition in preventing BC cells growth and reversing hormone dependency of BC cells. Our results indicate that pharmacological inhibition of AR or siRNA ablation of AR prevents growth factor -induced proliferation of BC cells (MCF-7) in culture. Similar results were observed when MDA-MB-231 and MDA-MB-468 BC cells were used. To further investigate how AR inhibitor prevents BC cell growth, we have examined the role of AR in resensitization of BC cells to letrozole. We found that combination of fidarestat with letrozole was very effective in inducing maximum cell death in LTLT-Ca cells when compared to fidarestat alone. The combination treatment not only restored estrogen receptor-α (ER-α) levels but also down-regulated HER2/MAPK-signaling proteins. Further, AR-siRNA - transfected MCF-7/Aro and MCF-7 cells upregulated ER-α in western blot and ER-functionality assays whereas in LTLT-Ca cells, ER-α levels were down-regulated as in fidarestat treated cells. Targeting the LTLT-Ca cells with PLG-based fidarestat nanoparticles having polyethylene glycol (PEG)-5000 as stabilizer and conjugated with FITC significantly prevented the aromatase activity in BC cells. Thus we have identified a novel role of AR in BC cell growth and estrogen-dependence of hormone insensitive BC cells and suggest the use of AR inhibitors either alone or in combination with letrozole to prevent as well as treat BC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1484.
Abstract #3120 The macrophage colony-stimulating factor (CSF-1) is a cytokine produced by macroph... more Abstract #3120 The macrophage colony-stimulating factor (CSF-1) is a cytokine produced by macrophages as well as epithelial cancer cells. By signaling via its receptor c-fms, CSF-1 induces growth/survival pathways in breast cancer cells. Defects in mammary gland development were observed in mice deficient in CSF-1/c-fms signaling, implicating this pathway in normal mammary development as well. In breast cancer, elevated levels of both CSF-1 and c- fms have been detected, with 80% of invasive breast carcinomas abnormally expressing c-fms. To study the role of CSF-1 signaling in breast cancer, we have previously generated mammary specific transgenic mouse models that over-express these factors (termed MMTV-CSF-1 and MMTV-c-fms). Both these transgenic mouse strains developed ductal hyperplasia and dysplasia as well as tumor formation. Our previous evidence also showed increase in cellular proliferation factors such as Cyclin D1 and PCNA in these mice. To examine which signaling pathways are altered in these mice, we have compared in this study the expression profile of target genes of signaling pathways in MMTV-CSF-1 mice and wild type mice using the Signal Transduction Pathway Finder RT-PCR array (Superarrray). Wnt signaling pathway was induced in the mammary gland of the MMTV-CSF-1 mouse strain compared to wild type, suggesting that this pathway may mediate CSF-1 signaling. In a proof-of-principle experiment, an MMTV-CSF-1 mouse was injected subcutanuously with neutralizing anti-c-fms antibody (Santacruz Biotech, 2-4A5) at a dose of 5 μg daily for 7 days. The treated mouse exhibited a decrease in the elevated ductal branching and hyperplasia that are characteristics of untreated MMTV-CSF-1 mice. This treatment also resulted in reversing many of expression alterations in MMTV-CSF-1 mice. For example, expression of the CSF-1 responsive gene Cyclin D1 was reduced by over 3-fold due to antibody treatment. Fas, the receptor for the pro-apoptotic factor Fas ligand, decreased by 5-folds in the MMTV-CSF-1 strain relative to wild type but increased 14-folds due to c-fms antibody treatment. The expression of the proapoptotic factor Bax increased about 4-fold, whereas the angiogenic factor Angiopoietin 1 was reduced by 60% due to anti-cfms antibody treatment. The treatment also reversed alterations in the expression of the wnt transcription factors Lef-1/TCF7. Because small molecule tyrosine kinase inhibitors that target c-fms, Gleevecâ (Imatinib, obtained from Novartis) and GW2580 (Calbiochem), are emerging, we examined their effects on the growth of SKBR3 breast cancer cells that express both CSF-1 and c-fms. Our data showed both these drugs inhibited the growth of SKBR3 cells, providing the rationale to test their effects on tumor formation and underlying biochemical effects in our transgenic preclinical models. The current studies warrant further investigation of treating breast cancer using antibody and small molecule drugs targeting CSF-1/c-fms signaling. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3120.
Abstract #3080 Cyclin-dependent kinases (CDKs) play essential roles in the intracellular control ... more Abstract #3080 Cyclin-dependent kinases (CDKs) play essential roles in the intracellular control of the cell cycle. The encapsulated therapeutic drug molecules as nanoparticles will offer a sustained delivery of chemotherapeutics in to the target tissue. Nanoparticles enhance the therapeutic efficacy of an encapsulated drug by increased and sustained delivery of the drug inside the cell. Most anticancer drugs are taken up non-specifically by all types of cells, resulting in serious side-effects. Therefore, an ideal delivery carrier for an anticancer drug should be able to transport the drug specifically to cancer cells and release the drug molecules inside the cells to the site of their pharmacological activities. Most of the activity proven natural products were not entered in to the clinical practice due to lack of active formulation and/ or effective targeted delivery systems. In our study we found that gossypin (3,5,7,39,49-Pentahydroxy-8-O-glucosylflavone) is inhibiting cell cycle progression by inhibiting cyclin dependent kinase-2 (cdk2) when compared with roscovitine, a known cdk2 inhibitor. Gossypin has been shown to induce the accumulation of the tumor suppressor p53, cell cycle arrest in G1 and G2/M phases of the cell cycle, and to induce apoptosis in MCF-7, SKBR-3, and MDA-MB-231 cells with a mean IC 50 of 40uM. Gossypin also found to inhibit vascular endothelial growth factor (VEGF) in vitro. Nanoparticle formulation of gossypin effectively inhibited the growth and colony formation in vitro when compared to parent compound. Gossypin might exert inhibition of tumor cell growth and invasion by cell cycle arrest as well as VEGF induced vascular permeability and tumor neovascularization. The dual mode of action of gossypin may results in highly efficacious inhibition of tumor growth and management of breast cancer. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 3080.
Endometrial cancer (EC) is the fourth most common cancer in women. Advanced-stage EC has limited ... more Endometrial cancer (EC) is the fourth most common cancer in women. Advanced-stage EC has limited treatment options with a poor prognosis. There is an unmet need for the identification of actionable drivers for the development of targeted therapies in EC. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a major role in cancer progression, metastasis, stemness, and therapy resistance. However, little is known about the functional significance of the LIF/LIFR axis in EC progression. In this study using endometrial tumor tissue arrays, we identified that expression of LIF, LIFR is upregulated in EC. Knockout of LIFR using CRISPR/Cas9 in two different EC cells resulted in a significant reduction of their cell viability and cell survival. In vivo studies demonstrated that LIFR-KO significantly reduced EC xenograft tumor growth. Treatment of established and primary patient-derived EC cells with a novel LIFR inhibitor, EC359 resulted in the reduction of cell viability with...
Histone deacetylase inhibitors (HDACi) are identified as novel therapeutic agents, however, recen... more Histone deacetylase inhibitors (HDACi) are identified as novel therapeutic agents, however, recent clinical studies suggested that they are marginally effective in treating triple negative breast cancer (TNBC). Here, we show that first-in-class Leukemia Inhibitory Factor Receptor (LIFRα) inhibitor EC359 could enhance the therapeutic efficacy of HDACi against TNBC. We observed that both targeted knockdown of LIFR with CRISPR or treatment with EC359 enhanced the potency of four different HDACi in reducing cell viability, cell survival, and enhanced apoptosis compared to monotherapy in TNBC cells. RNA-seq studies demonstrated oncogenic/survival signaling pathways activated by HDACi were attenuated by the EC359 + HDACi therapy. Importantly, combination therapy potently inhibited the growth of TNBC patient derived explants, cell derived xenografts and patient-derived xenografts in vivo. Collectively, our results suggest that targeted inhibition of LIFR can enhance the therapeutic efficac...
Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain o... more Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p
Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain o... more Uterine fibroids (UFs) are associated with irregular or excessive uterine bleeding, pelvic pain or pressure, or infertility. Ovarian steroid hormones support the growth and maintenance of UFs. Ulipristal acetate (UPA) a selective progesterone receptor (PR) modulator (SPRM) reduce the size of UFs, inhibit ovulation and lead to amenorrhea. Recent liver toxicity concerns with UPA, diminished enthusiasm for its use and reinstate the critical need for a safe, efficacious SPRM to treat UFs. In the current study, we evaluated the efficacy of new SPRM, EC313, for the treatment for UFs using a NOD-SCID mouse model. EC313 treatment resulted in a dose-dependent reduction in the fibroid xenograft weight (p < 0.01). Estradiol (E2) induced proliferation was blocked significantly in EC313-treated xenograft fibroids (p < 0.0001). Uterine weight was reduced by EC313 treatment compared to UPA treatment. ER and PR were reduced in EC313-treated groups compared to controls (p < 0.001) and UPA treatments (p < 0.01). UF specific desmin and collagen were markedly reduced with EC313 treatment. The partial PR agonism and no signs of unopposed estrogenicity makes EC313 a candidate for the long-term treatment for UFs. Docking studies have provided a structure based explanation for the SPRM activity of EC313.
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Papers by Hareesh Nair