The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
V K Moudgil - One of the best experts on this subject based on the ideXlab platform.
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effects of ly117018 a serm analog of raloxifene on Tumor Suppressor Proteins and proliferation of breast cancer cells
Hormone Molecular Biology and Clinical Investigation, 2010Co-Authors: Sumi Dinda, Amelita Sanchez, V K MoudgilAbstract:We have previously shown that presence of estradiol (E2) in the growth medium causes (i) proliferation of T47D breast cancer cells, (ii) elevation of p53 levels, and (iii) hyperphos-phorylation of retinoblastoma protein (pRb). In the present study, we examined the expression of p53, phosphorylation state of pRb and proliferation of T47D cells in the presence of LY117018 (Courtesy of Lilly Research Laboratories), an analog of raloxifene, which is a known selective estrogen receptor modulator (SERM). The cells grown in charcoal-treated serum were treated with 1 nM E2 or different concentrations of LY117018 for 24 h. E2 or LY117018 treatments caused a 2- to 3-fold increase in the level of p53 and hyperphosphorylation of pRb. E2 treatment increased cell proliferation, whereas LY117018 treatment had no such effect but inhibited the E2-dependent cell proliferation. E2 and LY117018 treatments of T47D cells also caused differential effects on intracellular structures. Thus, LY117018 treatment induces changes in the level/activity of p53 and pRb and ultrastructure of T47D cells. Importantly, LY11708 inhibits estrogen-induced cell proliferation while mimicking E2 actions on p53 induction and pRb phosphorylation. The SERM also induced structural alterations in the T47D cells.
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estrogen like effects of thyroid hormone on the regulation of Tumor Suppressor Proteins p53 and retinoblastoma in breast cancer cells
Oncogene, 2002Co-Authors: Sumi Dinda, Amelita Sanchez, V K MoudgilAbstract:T47D cells represent an estrogen-responsive human ductal carcinoma cell line which expresses detectable levels of estrogen receptor (ER). We have previously shown that estradiol (E(2)) treatment of T47D cells causes an increase in the level of p53 and a concomitant phosphorylation of retinoblastoma protein (pRb). In the present study, we have analysed the expression of p53 and phosphorylation state of pRb and compared the effects of E(2) and triiodothyronine (T(3)) on these phenomena. Cells were grown in a medium containing charcoal-treated serum to deplete the levels of endogenous steroids. Upon confluency, the cells were treated with T(3) (10(-12) to 10(-7) M) for 24 h and the presence of p53 and pRb was detected by Western analysis. E(2) treatment of cells caused a 2-3-fold increase in the level of p53. Presence of T(3) in the medium caused a gradual increase in the level of p53 in a concentration-dependent manner. Under the above conditions, pRb was phosphorylated (detected as an upshift during SDS-PAGE) in the presence of E(2) and T(3). Supplementation of growth medium with T(3) (1 microM) caused an increase in the rate of proliferation of T47D cells and induced hyperphosphorylation of pRb within 4 h; this effect was maintained for up to 12 h. When ICI 164 384 (ICI) (1 microM), an ER antagonist, was combined with E(2) (1 nM) or T(3) (1 microM), effects of hormones on cell proliferation and hyperphosphorylation of pRb were blocked. Western analysis of p53 was supplemented with its cytolocalization by immuno-labeling using laser scanning confocal fluorescence microscopy, which revealed an ICI-sensitive increase in the abundance of p53 in hormone-treated cells. Steroid binding analysis revealed lack of competition by T(3) for the [(3)H]E(2) binding. These results indicate that T(3) regulates T47D cell cycle progression and proliferation raising the p53 level and causing hyperphosphorylation of pRb by a common mechanism involving ER and T(3) receptor (T(3)R)-mediated pathways.
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hormonal regulation of Tumor Suppressor Proteins in breast cancer cells
The Journal of Steroid Biochemistry and Molecular Biology, 2001Co-Authors: V K Moudgil, Sumi Dinda, Nidhi Khattree, Suresh C Jhanwar, Paul Alban, Cliff HurdAbstract:Abstract This laboratory is studying hormonal regulation of Tumor Suppressor Proteins, p53 and retinoblastoma (pRB). Estrogen receptor and progesterone receptor positive human breast cancer cell lines, T47D and MCF-7, were utilized for determining influence of hormonal and antihormonal agents on the level of expression of p53, state of phosphorylation of pRB, and rate of cell proliferation. The expression of p53 in T47D cells grown for 4–5 days in culture medium containing charcoal-treated (stripped) fetal bovine serum declined gradually to 10% of the level seen in control (whole serum, non charcoal-treated) groups. Supplementation of culture medium containing stripped serum with 0.1–1 nM estradiol (E 2 ) restored p53 to its level seen in the control within 6–24 h. Under above conditions, treatment of cells with R5020 or RU486 reduced (15–30%) the level of p53. Incubation of cells in E 2 -containing growth medium caused cell proliferation and hyperphosphorylation of pRB; the latter effect was seen maximally between 24–72 h. The E 2 -induced hyperphosphorylation of pRB and increase in the level of p53 were sensitive to the presence of ICI and 4-hydroxy tamoxifen (OHT). T47D and MCF-7 cells were also transiently transfected with a P1CAT reporter plasmid containing c-Myc responsive element and the levels of chloramphenicol acetyltransferase (CAT) activity were observed in response to various treatments. E 2 and OHT caused P1CAT induction as seen by increased CAT activity: E 2 caused an endogenous increase in the expression of an ICI-sensitive c-Myc form. These data suggest that estrogen upregulates p53 expression while progesterone downregulates this process. Further, E 2 regulates p53 level and pRB activity in a coordinated manner.
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regulation of Tumor Suppressor Proteins p53 and retinoblastoma by estrogen and antiestrogens in breast cancer cells
Oncogene, 1997Co-Authors: Cliff Hurd, Nidhi Khattree, Sumi Dinda, Paul Alban, V K MoudgilAbstract:We have utilized the estrogen receptor (ER)-positive human breast carcinoma cell line, T47D, to determine the role of ER in regulating cell proliferation, the level of expression of p53 and the state of phosphorylation of retinoblastoma protein (pRB) by 17 beta-estradiol (E2) and antiestrogens. T47D cells cultured for 7 days proliferated rapidly expressing maximal levels of p53 in medium containing 5% fetal bovine (whole) serum. Exogenously added E2 had no effect on either of the above parameters. The antiestrogen, ICI 164,384 (ICI, 1 microM), decreased cell number and p53 level to nearly 20% of the control. Comparatively, a treatment of the cells with 100 nM 4OH-tamoxifen (OHT) decreased cell number to 40% of the control without a concomitant decrease in the p53 levels suggesting a differential ability of these antiestrogens to regulate p53 levels in cells cultured in whole serum. When cells were cultured in medium containing serum depleted of endogenous steroids (charcoal stripped serum), cell number and p53 levels declined. Treatment with exogenous E2 (1 nM) increased cell proliferation, p53 expression and phosphorylation of pRB. The antiestrogens ICI and OHT blocked these E2 effects, demonstrating a direct antagonism of ER by ICI and OHT. These results indicate an ER-mediated mechanism for coordinate expression of p53 and hyperphosphorylation of pRB during E2-induced proliferation of T47D cells.
Dilara Mccauley - One of the best experts on this subject based on the ideXlab platform.
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xpo1 crm1 selective inhibitors of nuclear export sine reduce Tumor spreading and improve overall survival in preclinical models of prostate cancer pca
Journal of Hematology & Oncology, 2014Co-Authors: Giovanni Luca Gravina, Dilara Mccauley, Andrea Mancini, Yosef Landesman, Monica Tortoreto, Alessandro Addis, Ernesto Di Cesare, Andrea Lenzi, Michael KauffmanAbstract:Background Exportin 1 (XPO1), also called chromosome region maintenance 1 (CRM1), is the sole exportin mediating transport of many multiple Tumor Suppressor Proteins out of the nucleus.
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888ppreclinical and early clinical activity of the oral selective inhibitor of nuclear export sine exportin 1 xpo1 antagonist selinexor kpt 330 in patients pts with platinum resistant refractory ovarian cancer ovca
Annals of Oncology, 2014Co-Authors: John A Martignetti, Albiruni R A Razak, Ying Chen, Nashat Y Gabrail, Catalina Camacho, Elena Pereira, Peter Dottino, J F Gericitano, Brad R Evans, Dilara MccauleyAbstract:ABSTRACT Aim: Increased XPO1 expression has been linked to progression of OvCa. Nearly all Tumor Suppressor Proteins (TSPs) are transported out of the nucleus exclusively by XPO1 and thereby inactivated. The XPO1 inhibitor, Selinexor, forces the nuclear retention and activation of >10 TSPs resulting in OvCa cell death. Methods: SINE induced TSP nuclear localization and induction of apoptosis were tested in OvCa cell lines and patient-derived cells. Combination with cisplatin was assessed in vitro & in patient-derived xenograft models (30 mg/m2 po, 3 times/week). An on-going Phase 1 (KCP-330-002, NCT01607905) in pts with solid Tumors, oral selinexor (8 -10 doses/4-week cycle) was administered to pts with heavily pretreated OvCa that were progressing on study entry. Response was evaluated every 2 cycles (RECIST 1.1). Results: SINE potently induced cell death in platinum-sensitive and -resistant OvCa cell lines (IC50s Conclusions: Selinexor treatment provides synergistic activity with cisplatin in preclinical models. In pts, selinexor shows preliminary single agent antiTumor activity against heavily pretreated platinum resistant/refractory OvCa. A single agent phase 2 study is ongoing (NCT02025985) & combination studies are planned. Disclosure: All authors have declared no conflicts of interest.
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preclinical and early clinical activity of the oral selective inhibitor of nuclear export sine exportin 1 xpo1 antagonist kpt 330 selinexor in patients pts with platinum resistant refractory ovarian cancer ovca
Journal of Clinical Oncology, 2014Co-Authors: John A Martignetti, Sharon Shacham, Albiruni R A Razak, Ying Chen, Nashat Y Gabrail, John F Gerecitano, Catalina Camacho, Elena Pereira, Peter Dottino, Dilara MccauleyAbstract:5522 Background: Increased XPO1 expression has been linked to progression of OvCa and is an independent poor prognostic for survival. Most Tumor Suppressor Proteins (TSP) are transported out of the...
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abstract 1831 selective inhibitors of nuclear export sine induce multiple Tumor Suppressor Proteins tsp activity and show single agent antiTumor effect and synergy with bcl 2 antagonist in non small cell lung cancer
Cancer Research, 2012Co-Authors: Dilara Mccauley, William Senapedis, Sharon Shacham, Yosef Landesman, Michael Kauffman, Tami Rashal, Jean Stmartin, Trinayan Kashyap, Jennifer Williams, Raphael NirAbstract:Neoplastic cells must inactivate their Tumor Suppressor Proteins (TSP) in order to perpetuate their growth. Oncogene and growth factor driven nuclear export of TSPs is an increasingly recognized mechanism for TSP inactivation. We have developed orally active, small molecule SINE that irreversibly block the major nuclear export protein CRM1 (exportin 1, XPO1) and selectively induce the death of cancer cells. Forced nuclear accumulation of TSPs is believed to initiate a “genome survey” leading to the death of cancer cells, whereas normal cells undergo transient, reversible cell cycle arrest. We show that the small molecule SINE CRM1 inhibitor KPT-185 potently kills many types of Tumor cells in vitro (IC50 20-500nM, IC80 ≤ 1µM at 72 hours) including ∼75% of NSCLC lines with diverse genetic signatures (EGFR wt & mut, p53 wt & mut, K-ras wt & mut). In contrast, ∼25% of NSCLC lines with similar genotypes show cytotoxicity IC50s ≤ 1.5µM and IC80 is not reached. Treatment of the SINE-resistant A549 NSCLC (adenocarcinoma, EGFR wt, p53 wt, K-ras mut, KPT-185 IC50 = 1.75µM) leads to nuclear localization of p53, p21, FOXO, E2F4, IkB, underphosphorylated pRb and other CRM1 cargoes at concentrations similar to that of sensitive NSCLC cell lines, but apoptosis is not readily induced. To test whether the resistance to CRM1 inhibition-mediated cytotoxicity is due to activation of anti-apoptotic (or inactivation of pro-apoptotic) BCL-2 family Proteins, we combined SINE with ABT-737, a small-molecule BCL-2 inhibitor currently in Phase 2 clinical trials, and examined the molecular mechanisms leading to Tumor cell death. We show that combination of low doses (500nM, the IC20) of KPT-185 with non-cytotoxic doses of the Bcl-2 inhibitor (≥ 100µM) induces synergistic cytotoxicity. Moreover, the antiTumor effects of the combination therapy are manifested within 48 hours, whereas significant cytotoxicity by higher doses of SINE alone requires at least 72 hours. Similar results have been obtained with another SINE resistant cell line, HCC-2935 (EGFR mut, p53 mut, K-ras mut). We noted that in the resistant A549 line, levels of the pro-apoptotic BCL2 member, Bax, were reduced by ∼50% with SINE treatment, but that addition of the BCL2 inhibitor reversed this effect and induced significant synergistic cytotoxicity. The sensitive NSCLC cell line H-226 (EGFR wt, p53wt, K-ras wt; IC50 12nM) showed nuclear localization of CRM1 cargoes when treated with KPT-185 (100nM), but only modest additional killing by the addition of the Bcl-2 inhibitor. We conclude that mechanism of resistance to SINE mediated cytotoxicity can be overcome by antagonism of Bcl-2. In vivo studies using A-549 xenografts comparing the effects of KPT-SINE and ABT-737 alone or in combination are ongoing and will be reported at the meeting. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1831. doi:1538-7445.AM2012-1831
Patrick Sung - One of the best experts on this subject based on the ideXlab platform.
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the brca Tumor Suppressor network in chromosome damage repair by homologous recombination
Annual Review of Biochemistry, 2019Co-Authors: Weixing Zhao, Youngho Kwon, Claudia Wiese, Robert Hromas, Patrick SungAbstract:Mutations in the BRCA1 and BRCA2 genes predispose afflicted individuals to breast, ovarian, and other cancers. The BRCA-encoded products form complexes with other Tumor Suppressor Proteins and with...
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the brca Tumor Suppressor network in chromosome damage repair by homologous recombination
Annual Review of Biochemistry, 2019Co-Authors: Weixing Zhao, Youngho Kwon, Claudia Wiese, Robert Hromas, Patrick SungAbstract:Mutations in the BRCA1 and BRCA2 genes predispose afflicted individuals to breast, ovarian, and other cancers. The BRCA-encoded products form complexes with other Tumor Suppressor Proteins and with the recombinase enzyme RAD51 to mediate chromosome damage repair by homologous recombination and also to protect stressed DNA replication forks against spurious nucleolytic attrition. Understanding how the BRCA Tumor Suppressor network executes its biological functions would provide the foundation for developing targeted cancer therapeutics, but progress in this area has been greatly hampered by the challenge of obtaining purified BRCA complexes for mechanistic studies. In this article, we review how recent effort begins to overcome this technical challenge, leading to functional and structural insights into the biochemical attributes of these complexes and the multifaceted roles that they fulfill in genome maintenance. We also highlight the major mechanistic questions that remain.
Michael Kauffman - One of the best experts on this subject based on the ideXlab platform.
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A phase 3 randomized, controlled, open-label study of selinexor, bortezomib, and dexamethasone (SVd) versus bortezomib and dexamethasone (Vd) in patients with relapsed or refractory multiple myeloma (RRMM).
Journal of Clinical Oncology, 2018Co-Authors: Sosana Delimpasi, Sharon Shacham, Michael Kauffman, Ludek Pour, Holger W. Auner, Meletios A. Dimopoulos, Alon Rappaport, Lisa Fortin, Jatin J. Shah, Nizar J. BahlisAbstract:TPS8056Background: Selinexor is an oral, selective inhibitor of nuclear export that specifically blocks exportin 1, leading to the nuclear accumulation & reactivation of Tumor Suppressor Proteins. ...
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xpo1 crm1 selective inhibitors of nuclear export sine reduce Tumor spreading and improve overall survival in preclinical models of prostate cancer pca
Journal of Hematology & Oncology, 2014Co-Authors: Giovanni Luca Gravina, Dilara Mccauley, Andrea Mancini, Yosef Landesman, Monica Tortoreto, Alessandro Addis, Ernesto Di Cesare, Andrea Lenzi, Michael KauffmanAbstract:Background Exportin 1 (XPO1), also called chromosome region maintenance 1 (CRM1), is the sole exportin mediating transport of many multiple Tumor Suppressor Proteins out of the nucleus.
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selective inhibitors of nuclear export block pancreatic cancer cell proliferation and reduce Tumor growth in mice
Gastroenterology, 2013Co-Authors: Asfar S Azmi, Sharon Shacham, Michael Kauffman, Amro Aboukameel, Bin Bao, Fazlul H Sarkar, Philip A Philip, Ramzi M MohammadAbstract:Background & Aims Tumor-Suppressor Proteins are inactivated by many different mechanisms, including nuclear exclusion by chromosome region maintenance (CRM)-1. Increased Tumor levels of CRM-1 have been correlated with poor prognosis of patients with pancreatic cancer, making it a therapeutic target. Selective inhibitors of nuclear export (SINEs) bind to CRM-1 to irreversibly inhibit its ability to export Proteins; we investigated a new class of SINEs in pancreatic cancer cells. Methods We studied the effects of SINE analogs in a panel of pancreatic cancer cell lines and nontransformed human pancreatic ductal epithelial cells using proliferation, apoptosis, immunoblot, co-immunoprecipitation, small inhibitor RNA, and fluorescence microscopy analyses. The effects of the SINEs also were investigated in mice with subcutaneous and orthotopic Tumors. Results SINEs (KPT-185, KPT-127, KPT-205, and KPT-227) inhibited proliferation and promoted apoptosis of pancreatic cancer cells, but did not affect human pancreatic ductal epithelial cells. The nuclei of cells incubated with KPT-185 accumulated Tumor-Suppressor Proteins (p27, FOXO, p73, and prostate apoptosis response-4 [PAR-4]) and inhibited interactions between CRM-1 and these Proteins. Mutations in the region of CRM-1 that bind to SINEs (Cys-528), or small inhibitor RNA knockdown of PAR-4, prevented the ability of KPT-185 to block proliferation and induce apoptosis of pancreatic cancer cells. Oral administration of KPT-330 to mice reduced growth of subcutaneous and orthotopic xenograft Tumors without major toxicity. Analysis of Tumor remnants showed that KPT-330 disrupted the interaction between CRM-1 and PAR-4, activated PAR-4 signaling, and reduced proliferation of Tumor cells. Conclusions We identified SINEs that inhibit CRM-1 and promote nuclear accumulation of Tumor-Suppressor Proteins in pancreatic cancer cells. Oral administration of the drug to mice reduces growth of xenograft Tumors.
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abstract 1831 selective inhibitors of nuclear export sine induce multiple Tumor Suppressor Proteins tsp activity and show single agent antiTumor effect and synergy with bcl 2 antagonist in non small cell lung cancer
Cancer Research, 2012Co-Authors: Dilara Mccauley, William Senapedis, Sharon Shacham, Yosef Landesman, Michael Kauffman, Tami Rashal, Jean Stmartin, Trinayan Kashyap, Jennifer Williams, Raphael NirAbstract:Neoplastic cells must inactivate their Tumor Suppressor Proteins (TSP) in order to perpetuate their growth. Oncogene and growth factor driven nuclear export of TSPs is an increasingly recognized mechanism for TSP inactivation. We have developed orally active, small molecule SINE that irreversibly block the major nuclear export protein CRM1 (exportin 1, XPO1) and selectively induce the death of cancer cells. Forced nuclear accumulation of TSPs is believed to initiate a “genome survey” leading to the death of cancer cells, whereas normal cells undergo transient, reversible cell cycle arrest. We show that the small molecule SINE CRM1 inhibitor KPT-185 potently kills many types of Tumor cells in vitro (IC50 20-500nM, IC80 ≤ 1µM at 72 hours) including ∼75% of NSCLC lines with diverse genetic signatures (EGFR wt & mut, p53 wt & mut, K-ras wt & mut). In contrast, ∼25% of NSCLC lines with similar genotypes show cytotoxicity IC50s ≤ 1.5µM and IC80 is not reached. Treatment of the SINE-resistant A549 NSCLC (adenocarcinoma, EGFR wt, p53 wt, K-ras mut, KPT-185 IC50 = 1.75µM) leads to nuclear localization of p53, p21, FOXO, E2F4, IkB, underphosphorylated pRb and other CRM1 cargoes at concentrations similar to that of sensitive NSCLC cell lines, but apoptosis is not readily induced. To test whether the resistance to CRM1 inhibition-mediated cytotoxicity is due to activation of anti-apoptotic (or inactivation of pro-apoptotic) BCL-2 family Proteins, we combined SINE with ABT-737, a small-molecule BCL-2 inhibitor currently in Phase 2 clinical trials, and examined the molecular mechanisms leading to Tumor cell death. We show that combination of low doses (500nM, the IC20) of KPT-185 with non-cytotoxic doses of the Bcl-2 inhibitor (≥ 100µM) induces synergistic cytotoxicity. Moreover, the antiTumor effects of the combination therapy are manifested within 48 hours, whereas significant cytotoxicity by higher doses of SINE alone requires at least 72 hours. Similar results have been obtained with another SINE resistant cell line, HCC-2935 (EGFR mut, p53 mut, K-ras mut). We noted that in the resistant A549 line, levels of the pro-apoptotic BCL2 member, Bax, were reduced by ∼50% with SINE treatment, but that addition of the BCL2 inhibitor reversed this effect and induced significant synergistic cytotoxicity. The sensitive NSCLC cell line H-226 (EGFR wt, p53wt, K-ras wt; IC50 12nM) showed nuclear localization of CRM1 cargoes when treated with KPT-185 (100nM), but only modest additional killing by the addition of the Bcl-2 inhibitor. We conclude that mechanism of resistance to SINE mediated cytotoxicity can be overcome by antagonism of Bcl-2. In vivo studies using A-549 xenografts comparing the effects of KPT-SINE and ABT-737 alone or in combination are ongoing and will be reported at the meeting. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1831. doi:1538-7445.AM2012-1831
Sharon Shacham - One of the best experts on this subject based on the ideXlab platform.
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A phase 3 randomized, controlled, open-label study of selinexor, bortezomib, and dexamethasone (SVd) versus bortezomib and dexamethasone (Vd) in patients with relapsed or refractory multiple myeloma (RRMM).
Journal of Clinical Oncology, 2018Co-Authors: Sosana Delimpasi, Sharon Shacham, Michael Kauffman, Ludek Pour, Holger W. Auner, Meletios A. Dimopoulos, Alon Rappaport, Lisa Fortin, Jatin J. Shah, Nizar J. BahlisAbstract:TPS8056Background: Selinexor is an oral, selective inhibitor of nuclear export that specifically blocks exportin 1, leading to the nuclear accumulation & reactivation of Tumor Suppressor Proteins. ...
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preclinical and early clinical activity of the oral selective inhibitor of nuclear export sine exportin 1 xpo1 antagonist kpt 330 selinexor in patients pts with platinum resistant refractory ovarian cancer ovca
Journal of Clinical Oncology, 2014Co-Authors: John A Martignetti, Sharon Shacham, Albiruni R A Razak, Ying Chen, Nashat Y Gabrail, John F Gerecitano, Catalina Camacho, Elena Pereira, Peter Dottino, Dilara MccauleyAbstract:5522 Background: Increased XPO1 expression has been linked to progression of OvCa and is an independent poor prognostic for survival. Most Tumor Suppressor Proteins (TSP) are transported out of the...
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selective inhibitors of nuclear export block pancreatic cancer cell proliferation and reduce Tumor growth in mice
Gastroenterology, 2013Co-Authors: Asfar S Azmi, Sharon Shacham, Michael Kauffman, Amro Aboukameel, Bin Bao, Fazlul H Sarkar, Philip A Philip, Ramzi M MohammadAbstract:Background & Aims Tumor-Suppressor Proteins are inactivated by many different mechanisms, including nuclear exclusion by chromosome region maintenance (CRM)-1. Increased Tumor levels of CRM-1 have been correlated with poor prognosis of patients with pancreatic cancer, making it a therapeutic target. Selective inhibitors of nuclear export (SINEs) bind to CRM-1 to irreversibly inhibit its ability to export Proteins; we investigated a new class of SINEs in pancreatic cancer cells. Methods We studied the effects of SINE analogs in a panel of pancreatic cancer cell lines and nontransformed human pancreatic ductal epithelial cells using proliferation, apoptosis, immunoblot, co-immunoprecipitation, small inhibitor RNA, and fluorescence microscopy analyses. The effects of the SINEs also were investigated in mice with subcutaneous and orthotopic Tumors. Results SINEs (KPT-185, KPT-127, KPT-205, and KPT-227) inhibited proliferation and promoted apoptosis of pancreatic cancer cells, but did not affect human pancreatic ductal epithelial cells. The nuclei of cells incubated with KPT-185 accumulated Tumor-Suppressor Proteins (p27, FOXO, p73, and prostate apoptosis response-4 [PAR-4]) and inhibited interactions between CRM-1 and these Proteins. Mutations in the region of CRM-1 that bind to SINEs (Cys-528), or small inhibitor RNA knockdown of PAR-4, prevented the ability of KPT-185 to block proliferation and induce apoptosis of pancreatic cancer cells. Oral administration of KPT-330 to mice reduced growth of subcutaneous and orthotopic xenograft Tumors without major toxicity. Analysis of Tumor remnants showed that KPT-330 disrupted the interaction between CRM-1 and PAR-4, activated PAR-4 signaling, and reduced proliferation of Tumor cells. Conclusions We identified SINEs that inhibit CRM-1 and promote nuclear accumulation of Tumor-Suppressor Proteins in pancreatic cancer cells. Oral administration of the drug to mice reduces growth of xenograft Tumors.
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abstract 1831 selective inhibitors of nuclear export sine induce multiple Tumor Suppressor Proteins tsp activity and show single agent antiTumor effect and synergy with bcl 2 antagonist in non small cell lung cancer
Cancer Research, 2012Co-Authors: Dilara Mccauley, William Senapedis, Sharon Shacham, Yosef Landesman, Michael Kauffman, Tami Rashal, Jean Stmartin, Trinayan Kashyap, Jennifer Williams, Raphael NirAbstract:Neoplastic cells must inactivate their Tumor Suppressor Proteins (TSP) in order to perpetuate their growth. Oncogene and growth factor driven nuclear export of TSPs is an increasingly recognized mechanism for TSP inactivation. We have developed orally active, small molecule SINE that irreversibly block the major nuclear export protein CRM1 (exportin 1, XPO1) and selectively induce the death of cancer cells. Forced nuclear accumulation of TSPs is believed to initiate a “genome survey” leading to the death of cancer cells, whereas normal cells undergo transient, reversible cell cycle arrest. We show that the small molecule SINE CRM1 inhibitor KPT-185 potently kills many types of Tumor cells in vitro (IC50 20-500nM, IC80 ≤ 1µM at 72 hours) including ∼75% of NSCLC lines with diverse genetic signatures (EGFR wt & mut, p53 wt & mut, K-ras wt & mut). In contrast, ∼25% of NSCLC lines with similar genotypes show cytotoxicity IC50s ≤ 1.5µM and IC80 is not reached. Treatment of the SINE-resistant A549 NSCLC (adenocarcinoma, EGFR wt, p53 wt, K-ras mut, KPT-185 IC50 = 1.75µM) leads to nuclear localization of p53, p21, FOXO, E2F4, IkB, underphosphorylated pRb and other CRM1 cargoes at concentrations similar to that of sensitive NSCLC cell lines, but apoptosis is not readily induced. To test whether the resistance to CRM1 inhibition-mediated cytotoxicity is due to activation of anti-apoptotic (or inactivation of pro-apoptotic) BCL-2 family Proteins, we combined SINE with ABT-737, a small-molecule BCL-2 inhibitor currently in Phase 2 clinical trials, and examined the molecular mechanisms leading to Tumor cell death. We show that combination of low doses (500nM, the IC20) of KPT-185 with non-cytotoxic doses of the Bcl-2 inhibitor (≥ 100µM) induces synergistic cytotoxicity. Moreover, the antiTumor effects of the combination therapy are manifested within 48 hours, whereas significant cytotoxicity by higher doses of SINE alone requires at least 72 hours. Similar results have been obtained with another SINE resistant cell line, HCC-2935 (EGFR mut, p53 mut, K-ras mut). We noted that in the resistant A549 line, levels of the pro-apoptotic BCL2 member, Bax, were reduced by ∼50% with SINE treatment, but that addition of the BCL2 inhibitor reversed this effect and induced significant synergistic cytotoxicity. The sensitive NSCLC cell line H-226 (EGFR wt, p53wt, K-ras wt; IC50 12nM) showed nuclear localization of CRM1 cargoes when treated with KPT-185 (100nM), but only modest additional killing by the addition of the Bcl-2 inhibitor. We conclude that mechanism of resistance to SINE mediated cytotoxicity can be overcome by antagonism of Bcl-2. In vivo studies using A-549 xenografts comparing the effects of KPT-SINE and ABT-737 alone or in combination are ongoing and will be reported at the meeting. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1831. doi:1538-7445.AM2012-1831
