/ - \
Home
-Experience - Innovation - Persistence
SBH 17 Years!The World's Leading Provider of Cytokine Cell-Based Assays
-

Publications / Abstracts


American Society of Clinical Oncology (ASCO) Annual Meeting
Chicago, USA
June, 2012

Preclinical evaluation of selective inhibitors of nuclear export (SINE) in basal-like breast cancer (BLBC).

Dilara McCauley 1, Yosef Landesman1, William Senapedis1, Trinayan Kashyap1, Jean-Richard Saint-Martin1, Louis Plamondon1, Vincent Sandanayaka1, Sharon Shechter1, Doriana Froim1, Raphael Nir2, Jennifer Williams2, Lynda Chin, Cyril Benes, Mansoor Raza Mirza6, Michael Kauffman1, Sharon Shacham1;

  1. Karyopharm Therapeutics, Natick, MA;
  2. SBH Sciences, Natick, MA;
  3. Institute for Applied Cancer Science, University of Texas M. D. Anderson Cancer Center, Houston, TX;
  4. Massachusetts General Hospital Cancer Center, Boston, MA;
  5. NSGO-Nordic Society of Gynaecological Oncology, Copenhagen, Denmark

Abstract:

Background:Basal-like breast cancers (BLBC) compose up to 15% of breast cancer (BC) and are usually triple negative characterized by lack of ER, PR, and HER-2 amplification. In addition, most BRCA1-associated BCs are BLBC and TNBC, expressing basal cytokeratins and EGFR. BLBC is characterized by an aggressive phenotype, high histological grade, and poor clinical outcomes: high recurrence and metastasis rates. CRM1 (XPO1) is the exclusive nuclear exporter of multiple Tumor Suppressor Proteins (TSP) including p53, p21, BRCA1&2, pRB, FOXO. CRM1 inhibition forces nuclear accumulation of TSPs, inducing apoptosis in cancer cells. KPT-SINE are novel, small molecule, irreversible inhibitors of CRM1 with potent anti cancer activity.

Methods: The Cancer Genome Atlas (TCGA) and BC cell line databases were used for mRNA analyses. MTT assay was used to determine the cytotoxic effect of KPT-SINE (KPT-185 and KPT-330) on 44 breast cell lines including luminal A, luminal B, HER2 positive, BLBC and TNBC cells. The effect of KPT-330 treatment on tumor growth was tested in vivo in the TNBC model MDA-MB-468 xenograft.

Results: Analyses of nuclear pore complex (NPC)-related mRNA levels (including CRM1) showed clear separation of BCs into high and low NPC expression. BLBC subtype was enriched with high NPC transcripts while luminal BC was enriched in low NPC levels (p<1.53e-20). High NPC levels had higher mutation levels in BRCA2 (cor=0.33, p=1.83e-8) and ABL1. NPC expression was inversely correlated with ER mRNA expression (cor=-0.58, p=1.37e-7). KPT-SINE showed potent cytotoxicity on >75% of the cell lines (IC50 values <1 μM). Only three of 24 TNBC cell lines displayed IC50 values >1.5 μM upon KPT-SINE treatment. Genomic analyses on all BC lines indicated that p53, PI3K/AKT and BRCA1 or 2 status did not affect cytotoxicity. In MDA-MB-468 xenograft, KPT-330 displayed efficacy in a dose-dependent manner inhibiting nearly 100% of tumor growth compared with vehicle treated animals, and was well tolerated.

Conclusions: These data show that NPC/CRM1 mRNAs are overexpressed in BLBC/TNBC and that CRM-1 mediated nuclear export inhibition by SINE represents a potentially novel and well tolerated therapy for BLBC / TNBC.

 



^ Top


American Association for Cancer Research (AACR) Meeting- I
Chicago, USA
April 2, 2012

KPT-SINE (Selective Inhibitors of Nuclear Export) induce apoptosis in colon cancer cells in-vitro and in-vivo through nuclear localization of Tumor Suppressor Proteins (TSPs)

William Senapedis 1, Yossi Landesman 1, Jean St-Martin 1, Trinayan Kashyap 1, Louis Plamondon 1, Vincent Sandanayaka 1, Sharon Shechter 1, Doriana Froim 1, Dilara McCauley 1, Raphael Nir 2, Jennifer L. Williams 2, Michael Kauffman 1, Sharon Shacham 1

  1. Karyopharm Therapeutics,Inc., Natick, MA; 
  2. SBH Sciences, Natick, MA

Background: Chromosome Region Maintenance 1/Exportin-1 (CRM1) is a key nuclear export protein whose inhibition leads to the nuclear accumulation of TSPs and negative regulators of cell proliferation. Through CRM1 inhibition, nuclear localization of these proteins restores cell cycle checkpoints and genome surveying functions culminating in apoptosis of tumor cells. Conversely, CRM1 inhibition of normal cells induces reversible cell cycle arrest. We are developing novel small molecules, KPT-SINE, which irreversibly bind and inhibit CRM1 nuclear export killing a broad range of tumor cell lines and xenografts. We used human colon cancer cells HCT116 to track the molecular and cellular events that follow KPT-SINE treatment and ultimately lead to cancer cell death.

Methods: Using our proprietary in silico hierarchical structure-based discovery platform, we designed and tested novel SINE in a cell-based microscopy assay to confirm CRM1-mediated nuclear export inhibition. Cytotoxic IC50s of KPT-SINE were determined on a panel of cancer cell lines. KPT-SINE -- KPT-185, -251 and -276 were selected for additional testing based on their potency and pharmacokinetics. These include; 1. Nuclear localization of TSPs, 2. Effects on cell cycle and viability, 3. Effects on TSP mRNA and protein expression. Additionally, we transiently transfected mutant CRM1-C528S into cells and treated with KPT-SINE to show binding to Cysteine 528. We tested the effects of KPT-276 in an in vivo HCT116 xenograft model.

Results: KPT-276, a potent inhibitor in the cell-based microscopy assay (EC50 = 130 nM), was a robust inhibitor of HCT116 proliferation (IC50 = 400 nM). KPT-SINE inhibition of CRM1 started within 30 minutes and reached a maximum in 8 hrs. Additionally, KPT-SINE effects were blocked by transient transfection of CRM1-C528S, confirming KPT-SINE - Cysteine 528 interaction. Washout experiments demonstrated that 4 hrs of KPT-SINE incubation sustained 24 hrs of CRM1 inhibition. We also identified nuclear accumulation of p53, FOXO3a, pRb, APC, IκB, p27, PTEN, and p21, which was followed by cell cycle arrest and cell death. Although KPT-276 treatment had less effect on cell cycle and cytotoxicity assays of p53null HCT116 cells, the p53 wildtype and null HCT116 cells showed similar kill curves after 8 days of treatment. Mouse xenografts treated with 75 mg/kg QDX5 of KPT-276 each week for 4 weeks inhibited tumor growth by more than 70%. Further analysis of the tumor molecular markers from KPT-276 treated animals will be reported.

Conclusions: In this study we described the correlative effects of KPT-SINE from the accumulation of nuclear TSPs through to cancer cell death in mouse models. These results suggest that KPT-SINE display potent in vivo efficacy in the xenograft model of human colon cancer.



^ Top


American Association for Cancer Research (AACR) Meeting- II
Chicago, USA
April 2, 2012

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

Dilara McCauley 1, Tami Rashal2, Sharon Shacham1, Michael Kauffman1, Yossi Landesman1, Jean St-Martin1, Trinayan Kashyap1, William Senapedis1, Jennifer L. Williams3, Raphael Nir3, Maya Illuz2, Nir Peled2.

  1. Karyopharm Therapeutics, Natick, MA
  2. Sheba Medical Center, Tel Hashomer, Israel
  3. SBH Sciences, Natick, MA

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.



^ Top


American Society of Clinical Oncology (ASCO) Annual Meeting
Chicago, USA
June, 2011

Cytotoxicity of novel, small molecule, CRM1-selective inhibitors of nuclear export (SINE) in colorectal cancer (CRC) cells.

This abstract (e14091) was not presented at the 2011 ASCO Annual Meeting but has been published in conjunction with the meeting.

Citation: J Clin Oncol 29: 2011 (suppl; abstr e14091)

Author(s): 

G. F. Draetta, S. Shacham, M. Kauffman, V. Sandanayaka, S. Schechter, J. Williams, R. Nir;

Dana-Farber Cancer Institute, Boston, MA;

Karyopharm Therapeutics, Newton, MA;

Karyopharm Therapeutics, Natick, MA;

SBH Sciences, Natick, MA

Abstract: 

Background: In order to maintain their malignant phenotype, neoplastic cells must neutralize most of their tumor suppressor (TSP) and growth regulatory (GRP) proteins. CRM1, also called exportin 1, mediates the nuclear export of the majority of TSP/GRP, leading to their inactivation. Blockade of CRM1 with SINE induces cytotoxicity in neoplastic cells, but only reversible cell cycle arrest in normal cells. We report on the potential of SINE for the treatment of molecular subtypes of CRC.

Methods: KPT-127 is a moderate potency, small-molecule SINE with broad-spectrum, tumor-selective cytotoxicity in vitro and in vivo tolerability. Twenty human CRC cell lines with distinct genotypes were tested for KTP-127-induced cytotoxicity after 72 hours using MTT assay. Mouse embryo fibroblasts (MEF) were cycling, normal controls. Genetic profiles of cells were obtained from the literature. In vivo efficacy and tolerability of KPT-127 were evaluated in HCT-116 xenografts. 

Results: Cytotoxicity IC50s were determined for the 20 CRC lines, and they were grouped into most quartiles, and the genotypes of most sensitive (<300nM) and most resistant (>1200nM) determined. The status of p53 or APC, or the presence of p16 methylation, K-ras mutations, microsatellite instability (MSI), EGFR, or Pgp (mdr1) did not correlate with killing by KPT-127. Moreover, HCT-116 p53Ð/Ð variant CRC line cytotoxicity was similar to that of the parenteral (p53+) line. Consistent with its action as an irreversible CRM1 inhibitor, expression of the multidrug resistance pump Pgp1 also did not affect KPT-127 potency. In HCT-116 xenografts, KTP-127 150mg/kg induced >80% tumor growth inhibition similar to irinotecan 30mg/kg twice weekly but without causing myelosuppression or other toxicities. 

Conclusions: KTP-127, a SINE that irreversibly blocks CRM1, kills a variety of CRC cell lines regardless of commonly used molecular prognostic markers including p53, K-ras, and Pgp status. KPT-127 has minimal effects on normal cells and is well tolerated with significant antitumor activity in vivo. More potent SINEs with improved pharmacokinetic profiles are being developed for clinical use as single agents and in combination.



^ Top


American Association for Cancer Research (AACR) Meeting
Orlando, USA
April 6, 2011

Discovery of SINE: Selective inhibitors of Nuclear Export increase levels of regulatory proteins p53, p21, FOXO and IkB leading to apoptosis of malignant cells

S. Shacham, M. Kauffman, V. Sandanayaka, G. Draetta, S. Shechter, J. Williams, R. Nir

  • Karyopharm Therapeutics, Newton, MA
  • Dana-Farber Cancer Institute, Boston, MA
  • SBH Sciences, Natick, MA

Transport of macromolecules across nuclear membrane is fundamental to the proper functioning of living cells. Nuclear localization of intact tumor suppressor proteins (TSPs) and other growth regulatory proteins (GRPs) such as p53, FOXO, pRB, p21, p27 and IB are critical for their "policing" function and mislocalization of a nuclear protein into the cytoplasm can render it ineffective as a tumor suppressor protein. During disease progression or in response to the tumor environment, cancer cells appear to acquire intracellular mechanisms to export anti-cancer nuclear proteins, in many cases resulting in proteasome dependent degradation. Most known TSP utilize the nuclear export protein CRM1 (XPO1, chromosomal region maintenance 1), to exit the nucleus, and overexpression of CRM1 has been reported as a poor prognostic factor in a variety of neoplasms. Inhibition of CRM1 can force the nuclear localization of key TSPs, activate their pathways, resulting in induction of cell death of cancer cells (Table 1). SINEs are novel, potent, selective, drug-like, nuclear export inhibitors (EC50 ~40-100nM) that derive their activity through direct covalent modification and inhibition of CRM1. SINE compounds exerts a potent and prolonged inhibition of CRM1-mediated forkhead (FOXO), p53, p21 and IB nuclear export in a variety of normal and transformed cell lines. Cell cycle analysis following incubation with SINE compound, KPT-0127, revealed that it blocks at both the G1/S and G2/M phases, consistent with induction of multiple checkpoint controls. SINE-induced apoptosis is observed in many cancer cell lines (e.g. A375, Jurkat, BL-40, HCT-116), but not in other proliferating cells (e.g. 3T3, mouse embryo fibroblasts). In cytotoxicity assays, SINE compounds showed high potency in both hematologic and solid tumor cell lines (EC50 < 100nM) with limited effect on normal cells (PBMCs, HUVEC, 3T3 EC50 >2000nM).SINE compounds show no significant effect on 37 proteins including several cysteine proteases, minimal CYP inhibition (> 10 M for all major CYPs) and no hERG inhibition. In single dose mouse toxicology studies, KPT-0127 was generally well tolerated (p.o. or s.c.) up to 560 mg/kg, and no deaths were observed. The pharmacokinetics of KPT-0127 is adequate for s.c. and i.v. dosing in vivo. Tumor xenograft studies have been undertaken in colon cancer HCT-116 and myeloma MM.1S tumor bearing mice. SINE induce a potent, dose dependent anti cancer activity in both small (~140mm3) and large (~1400mm3) tumors. All together, these data demonstrate that SINE represents a novel mechanism of action with robust anti tumor activity both in-vitro and in-vivo and promising applications as single agent and for combination therapies.

^ Top


2011 Gastrointestinal Cancers
San Fransisco, USA
January 20-22, 2011

Preclinical development of small-molecule CRM1 inhibitors as novel therapy for the treatment of colorectal cancer (CRC).

S. Shacham, M. Kauffman, V. Sandanayaka, G. Draetta, S. Shechter, J. Williams, R. Nir

  • Karyopharm Therapeutics, Newton, MA
  • Dana-Farber Cancer Institute, Boston, MA
  • SBH Sciences, Natick, MA

Background: CRM1 (XPO1) is a key nuclear export protein which controls the location of multiple tumor suppressor (TSP) and growth regulatory (GRP) proteins including p53, PI3K/AKT, Wnt/ß-catenin and NF-kB. Forced nuclear expression of TSP and GRP by CRM1 inhibition can lead to apoptosis in cancer cells while sparing normal cells.

Methods: Novel small-molecule CRM1 inhibitors were synthesized and nuclear distribution studies were performed in cells transfected with HIV-rev GFP proteins. Cell proliferation studies were performed in 16 CRC cell lines: LS-123, SW-626, Colo-201, Colo-205, Colo-320DM, Colo-320HSR, Lovo, DLD-1, HCT-15, WiDi, LS-174T, LS-180, SW-620, C2BBe1, HCT-8, HCT-116, and in human peripheral leukocytes (PBMC). Cellular distribution and apoptosis assays were performed on HCT-116. Antitumor activity is assessed in human HCT-116 xenografts in scid-mice.

Results: The lead CRM1 inhibitor, KPT-0127, blocks CRM1 mediated nuclear export of HIV-Rev-GFP, FOXO, and p53 with an IC50 of ~300 nM. KPT-0127 is cytotoxic to various CRC cell lines with EC50s of 0.07-1.1 µM; in 9 CRC lines EC50s were < 0.3 mM. In contrast, normal cell lines and PBMCs had EC50 > 5-20 µM. In HCT- 116 cells, KPT-0127 induces cell cycle arrest at both G1/S and G2/M checkpoints and dose dependently increases nuclear p53, followed by an increase in caspase 3. KTP-0127 10µM shows no significant effect on 37 proteins including several cysteine proteases. In mice, KPT-0127 given by SC injection of 30-100 mg/kg leads to serum levels exceeding the effective CRM1 inhibitory concentration for at least 4 hours and is well tolerated. KPT-0127 given SC to mice bearing HCT-116 colon xenografts results in dose-dependent antitumor activity.

Conclusions: The novel small- molecule CRM1 inhibitor KTP-0127 kills CRC lines with multiple TSP, GRP, and oncogenic abnormalities, including p53 mutations/deletions and PTEN deficiency/AKT activation, while sparing normal cells. This likely reflects the ability of CRM1 inhibition to affect multiple critical and non-redundant regulatory pathways. These results support the development of CRM1 inhibitors for the treatment of CRC. IND-enabling CMC and toxicology work are in preparation.

^ Top


52nd ASH Annual Meeting and Exposition
Orlando, USA
December 4-7, 2010

Title: Preclinical Development of Small-Molecule CRM1 Inhibitors as Novel Therapy for the Treatment of Myeloma and Other Hematological Malignancies

Sharon Shacham1, Joel Turner2, Raphael Nir3, Giulio Draetta 4, Sharon Shechter1, Vincent Sandanayaka1, Michael Kauffman1 and Daniel Sullivan 2

  1. Karyopharm Therapeutics Inc., Newton, MA
  2. H. Lee Moffitt Cancer Center, Tampa, FL
  3. SBH Sciences Inc., Natick, MA
  4. Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA

Background: CRM1 (XPO1) is a key nuclear export protein which controls multiple tumor suppressor proteins (TSP) and cell proliferation pathways including p53, PI3K/AKT, Wnt/ß-catenin and NF-fB. Further, mislocalization of proteins can abrogate TSP functions and render chemotherapies ineffective. For example, multiple myeloma (MM) cells that are grown at high densities (to mimic the in vivo situation) become resistant to topoisomerase 2 (topo2) inhibitors (e.g., doxorubicin) simply because topo2a is exported from the nucleus. Forcing the nuclear expression of chemotherapy targets, TSP and growth regulatory proteins by CRM1 inhibition can restore drug sensitivity and restore checkpoint control / genome surveying functions. These events lead to apoptosis or autophagy in cancer cells while sparing normal cells. Methods: CRM1 inhibitors were synthesized and nuclear distribution studies were performed in U2OS cells transfected with HIV-rev GFP proteins. Cell proliferation studies were performed in multiple myeloma (MM), leukemia and lymphoma cell lines and in human peripheral blood mononuclear cells (PBMCs). Toxicology studies were performed in several mouse strains. Antitumor activity is assessed in a xenograft model of human MM.1 cells growing in scid-mice.

Results: The lead CRM1 inhibitor, KPT-0127, blocks CRM1 mediated nuclear export of HIV-Rev-GFP, FOXO, and p53 with an IC50 of ~300 nM. KPT-0127 is selectively cytotoxic to various hematological cell lines with EC50s in the 0.02-1.0 µM range, and shows limited cytotoxicity in similar studies in normal cell lines (NIH-3T3, MRC5, HUVECs) and PBMCs (EC50 >5-20 µM). KPT-0127 increases the nuclear localization of IB in HUT-78 leukemia cells and human PBMCs, and inhibits TNF-a secretion in LPS stimulated U937 macrophage derived cells, likely through inhibition of NFB signaling. In MM cells grown at high densities which actively export topo2 to the cytoplasm via CRM1, blocking CRM1-dependent transport strongly enhanced topo2 nuclear localization and augmented the apoptotic effects of doxorubicin in < 24 hours showing clear synergy between KPT-0127 and the anthracycline. Combination of sublethal concentrations of bortezomib plus KPT-0127 in MM1.S and MM.1R myeloma cells (as well as in Jurkat and HS-Sultan) induced synergistic cytotoxicities. In mice, KPT-0127 given by subcutaneous (SC) injection of 30-100 mg/kg leads to serum levels exceeding the effective CRM1 inhibitory concentration for at least 4 hours. In 5 day repeated dose toxicology studies, SC administration of 100 mg/kg KPT-0127 (QD x 5) was well tolerated in mice with no cutaneous or obvious systemic clinical findings. Modest neutrophilia and mild lymphopenia were seen and no neurologic signs resulted from treatment with KPT-0127. Administration of KPT-0127 SC to mice bearing HCT-116 colon cancer results in dose-dependent antitumor activity. Xenograft studies with MM.1 myeloma cells are underway and will be presented at the meeting.

Conclusions: The sensitivity of tumors with multiple TSP and oncogenic abnormalities, including p53 mutations/deletions and PTEN deficiency/AKT activation, to killing with KPT-0127 likely reflects the ability to affect multiple critical and non-redundant regulatory pathways. CRM1 inhibition also forces topo 2 to remain in the nucleus, and increases levels of nuclear IkB antagonizing NF-kB function, thereby reducing the likelihood of resistance development. These results support the development of small molecule, drug-like CRM1 inhibitors for the treatment of MM and other hematological cancers. IND-enabling CMC and toxicology work are expected to begin in early 2011.

^ Top


XXXIII World Congress of the International
Society of Hematology (ISH 2010)
Jerusalem, Israel
October 10-13, 2010

KPT0127, A novel, potent and selective inhibitor of CRM-1Mediated Nuclear export shows selective cytotoxicity for the treatment of hematological cancers

S. Shacham1, R. Nir2, D. Daelemans3, S. Shechter1, I. Vancurova4, A. Juvekar4, J. Turner5, W. Lau6, G. Higgins6, G. Draetta7, M. Kauffman1

  1. Karyopharm Therapeutics, Newton, MA, USA
  2. SBH Sciences, Natick, MA, USA
  3. Rega Institute for Medical Research, Leuven, Belgium
  4. St.John's University, New York, NY, USA
  5. Moffitt Cancer Center, Tampa, FL, USA
  6. Cancog Technologies, Toronto, ON, Canada
  7. DanaFarber Cancer Institute, Boston, MA, USA

CRM1 (Xpo1) is the major export factor for proteins from the nucleus to the cytoplasm, including tumor suppressors (TSPs) and other modulators of proliferative responses such as p53, FOXO, pRB, Topoisomerase IIA and IkB. Leptomycin B (LMB), a non-drug like natural product is a potent inhibitor of CRM1. LMB demonstrated potent anti-cancer activity in vitro with limited efficacy in vivo due to severe gastrointestinal toxicity. Our lead compound KPT-0127, is a novel, small molecule, water soluble, drug-like, selective, irreversible CRM1 antagonist. KPT-0127 exerts potent (IC50 300-400nM) inhibition of CRM1-mediated HIV-1 Rev, FOXO and p53 nuclear export. In cytotoxicity assays, KPT-0127 showed high potency in most hematologic cancer cell lines (EC50 20-500nM) with limited effect on normal cells (EC50 >5-10µM). Treatment of human myeloma cell lines with KPT-0127 and doxorubicin at high cell densities resulted in >5-fold increased sensitivity to topoisomerase II inhibitors as determined by an activated caspase assay. In normal peripheral blood mononuclear cells (PBMCs) and in Hut78 leukemia cells, KPT-0127 potently increased the nuclear levels of IkB. However, KPT-0127 induced cell death of Hut78 cells with no effect on normal PBMCs. In combination studies, KPT-0127 showed additive or synergistic cytotoxicity activity with either 5-FU, carboplatin, or doxorubicin. KPT-0127 was well tolerated in acute and 5 day, once daily repeated dose mouse toxicology studies. In vivo efficacy studies are currently being performed and will be presented. Together, these data demonstrate that KPT-0127 represents a novel, tumor selective and well-tolerated irreversible Crm1 as a novel therapy for hematological cancers.

^ Top


American Chemical Society Meeting
Boston, USA
August 22, 2010

Discovery of CRM1- Mediated Nuclear Transport Inhibitors as Novel Modulators of Epigenetic Enzymes.

Vincent Sandanayaka, Raphael Nir, Sharon Shechter, Michael Kauffman and Sharon Shacham

Karyopharm Therapeutics, 262 Arnold Rd, Newton, MA 02459, USA

Transport of macromolecules across nuclear membrane is fundamental to the proper functioning of living cells (Figure I). Molecular transport between the nucleus and the cytoplasm through the nuclear pore complex is mediated by transport receptors called karyopherins. One such well-recognized receptor is CRM1 (XPO1, chromosomal region maintenance 1), which is essential to the nuclear export of various "cargo" proteins (e.g., p53, c-Abl, IkB, FOXO) and epigenetic histone deacetylases (HDACs) including HDACs 1, 3, 4, 5, 6, 7 and SIRT proteins. Moreover, histone acetyl-transferase (HAT) and HDACs modulate p53, NFkB and AKT pathways. Therefore, inhibition of CRM1 may alter the epigenetic activity of HDAC and HAT. Abnormal CRM1 expression is well correlated with the prognosis of various human cancers, including pancreas, glioma, liver, ovarian, cervical and osteosarcoma. Moreover, CRM1 has been validated in animal models as a novel target for cancer. CRM1 inhibitors such as Leptomycin B (LMB) are efficacious in xenografts, but exhibit dose limiting toxicities that have prevented successful testing in human clinical trials (Figure II). Karyopharm Therapeutics is taking the lead in this field to discover small molecule CRM1 inhibitors that are devoid of toxicities seen with other compounds. Employing the power of in-silico screening and structural biology, we discovered a variety of chemotypes with potent CRM1 inhibition. We will describe the design of several chemotypes using our integrated computational and medicinal chemistry strategies, and their biological activities. Our compounds have shown CRM1-mediated HIV-rev (IC50 = 360 nM), FOXO, IkB and p53 nuclear export inhibition similar to LMB. In addition, our small molecule irreversible inhibitors were shown to act at the CRM1 Cys528 position, and exhibited potent cytotoxicity in hematologic and solid tumor cancer cell lines. We will describe the design of several chemotypes using our integrated computational and medicinal chemistry strategies and their biological activities. Our compounds showed CRM1-mediated HIV-rev nuclear export inhibition similar to LMB (IC50 = 360 nM), CRM1-mediated FOXO nuclear export inhibition in U2OS cells (IC50 = 276 nM), and exhibited potent cytotoxicity in hematologic and solid tumor cancer cell lines. Our data indicate that our irreversible compounds specifically modify CYS528 of CRM1, as a CYS528SER mutant CRM1, which retains full export activity, is not inhibited with our compounds. Pharmacokinetic and in-vivo efficacy studies are on-going and results will be presented at the meeting.
^ Top


AACR Translational Cancer Medicine 2010
San Francisco, USA
July 11 – 14, 2010.


KPT0127, A Novel, Potent and Selective Inhibitor of Crm1-Mediated Nuclear Export Shows Selective Cytotoxicity for Neoplastic over Normal Cells and is Well Tolerated in Animals

Sharon Shacham1, Raphael Nir2, Dirk Daelemans3, Sharon Shechter1, Ivana Vancurova4, Ashish Juvekar4, Winnie Lau5, Guy Higgins5, Giulio Draetta6 and Michael Kauffman1

  1. Karyopharm Therapeutics, 262 Arnold Rd, Newton, MA
  2. SBH Sciences, Natick, MA
  3. Rega Institute for Medical Research, Leuven, Belgium
  4. St. John's University 8000 Utopia Parkway New York 11439
  5. Cancog Technologies, Toronto, Canada
  6. Dana Farber Cancer Institute, Boston, MA

CRM1 (Xpo1) is the major export factor for proteins from the nucleus to the cytoplasm, including tumor suppressors (TSPs) and other modulators of proliferative responses such as p53, FOXO, c-Abl, pRB and IB. Leptomycin B (LMB), a non-drug like natural product is a potent inhibitor of CRM1-mediated nucleocytoplasmic transport. LMB and related analogs trap TSPs and other proteins in the nucleus, forcing neoplastic cells into apoptosis while normal cells undergo reversible cell cycle arrest. However, LMB has limited efficacy in vivo due to its severe gastrointestinal toxicity. Here, we describe our lead compound KPT-0127 a novel small molecule, water soluble, drug-like, selective, irreversible CRM1 antagonist. Like LMB, KPT-0127 forms a covalent bond with Cys-528 in the CRM1 cargo-binding pocket, abrogating most, but not all, export functions of CRM1. KPT-0127 exerts a potent (EC50 300-400nM) and prolonged inhibition of CRM1-mediated HIV-1 Rev, forkhead (FOXO), and p53 nuclear export in a variety of normal and transformed cell lines. In cytotoxicity assays, KPT-0127 showed high potency in most hematologic cancer cell lines (EC50 <500nM, with leukemia and lymphoma lines often <100nM) and variable activity in solid tumor cell lines (EC50 90-2000nM), with colon and melanoma cells being the most sensitive (EC50< 100 nM). By contrast, normal cells were largely unaffected by treatment with KPT-0127 (EC50 >5-10µM). Studies in the HCT-116 colon cancer cell line suggested that KPT-0127 dose dependently increases the nuclear levels of p53 followed by an increase in caspase 3 activity, and appears to induce cell cycle arrest at both the G1/S and G2/M checkpoints, prior to inducing apoptosis. In normal peripheral blood mononuclear cells (PBMCs) and in Hut78 leukemia cells, KPT-0127 potently increased the nuclear levels of IB. However, KPT-0127 induced cell death of Hut78 cells with no effect on normal PBMCs. In drug combination studies, KPT-0127 showed additive or synergistic cytotoxicity activity with either 5-FU, carboplatin, or doxorubicin. Mechanism of action studies demonstrated that the Cys-528 residue in the cargo-binding pocket of CRM1 is essential for the inhibitory effect of KPT-0127. Mutagenesis of Cys-528 to a Ser completely abrogated KPT-0127 inhibition. KPT-0128, the trans isomer of KPT-0127, shows little effect on both HIV-Rev nuclear export and in cytotoxicity assays (EC50s > 10 µM), supporting the specificity of KPT-0127 for CRM1. Moreover, the selectivity of KTP-0127 was demonstrated across a panel of 37 proteins including several cysteine proteases.

In single dose mouse toxicology studies, KPT-0127 was generally well tolerated (oral or SC) up to 560 mg/kg, and no deaths were observed. SC dosing daily for 5 days up to 100mg/kg (the highest dose tested) showed no behavioral, clinical chemistry, or hematogical effects in mice; Pharmacokinetics of KPT-0127 is adequate and in vivo efficacy studies are currently being performed; results will be presented. All together, these data demonstrate that KPT-0127 represents a novel, tumor selective and well-tolerated irreversible Crm1 inhibitor which may be suitable for clinical development both as a single agent and in combination with standard therapies.
^ Top

 


-
- - -


The World's Leading Provider of Cytokine Cell-Based Assays

/ - \
 

Cheap Canada Goose 2014,Canada Goose Outlet Store

Cheap Canada Goose for Men shops, poor range, very few other brands can match. Canada goose jackets outlet collection in different ranges of labels, such as tags: purple, black, cheap Canada goose jackets, denim, RLX, golf and tennis collection of different styles of jackets and is therefore suitable male, each conceivable, clothing and price range.Canada Goose outlet online

Cheap Canada Goose launched his menswear line initially before he launched the womens wear line. He was no fashion designer by profession but he stumbled upon his passion for clothes and accessories while working as a salesman. Today, the jackets cheap canada goose is an international fashion brand which has fashion clothing and accessories for men and women as well as children. Canada Goose Outlet Store

Canada Goose Cheap of the Purple Label collection When it comes to canada goose jacket outlets for men, each collection has a distinctly style to offer. Take for instance the Brookelands Cashmere Sports Coat of the Purple Label collection. It is made of cashmere and has a three buttoned formal jacket look, fit for the scholarly amongst men. The Morton Calf Aviator Jacket is a deviation from the previous style, made of calfskin leather and fit for the finest pilots to sport on fashionable outings or on the job as well. The Hamilton Calfskin Jacket and the Belton Cropped Trench coat are all distinct styles fitted for varied occasions, each exuding style and class.Canada Goose Outlet

Canada Goose Sale Online of the Black Label collection The canada goose jacket outlets amongst the Black Label collection mostly comprise of formal jackets and suits for office or formal evening wear. However, there are many outerwear range in this collection too, most in classic leather styles. The Leather Moto Jacket, the Patrol Leather Bomber Jacket, the Lambskin Belted Jacket all come in luxurious leather finishes with black or brown shades. Even the suede belted jackets in this range are a smart outer wear for men of style.Cheap Canada Goose

High-Quality Parajumpers Jacket,Cheap Parajumpers Outlet Store

Parajumpers Outlet a unique and extensive collection to choose between men and women. parajumpers selling brand has a simple, sophisticated brand essence to stabilize the emerging modern design. Parajumpers Outlet.

Cheap Parajumpers sell their never educated fashion. He went to business school, he even had a brief army. Then, while working as a salesman, he opened his own shop in the men's tie. He expanded his collection of men's polo began to emphasize the range of T-shirts and casual clothing, he strengthened his own brand purchased from Hilton Polo label and make it in the fashion of his signature line.. Cheap Parajumpers .

Parajumpers Cheap Therefore, casual jacket has been his expertise and his jacket simple elegant lines, formal and casual, is well known. Even for women's collection he launched his men's shirts and jackets designed for women's slim silhouette. Parajumpers

Parajumpers Sale Online export & ndash; Lauren Collection In the women's collection, Lauren and Lauren Jeans collection parajumpers export company is well known. Such as gene stretching hunting jacket. Cotton stretch twill fabric and in front of the wide belt, hunting jackets and stretch material is a fashion to wear high heels with long, bell-bottoms PJS

.

beats by dre pas cher,monster casque beats

Si vous êtes sérieux dans la musique, vous voulez absolument obtenir la meilleure qualité de son possible, vous pouvez avoir. En outre, vous pouvez également avoir l'air cool tout en écoutant votre musique en déplacement. Si cela décrit le genre de personne que vous êtes, vous devriez certainement envisager d'avoir une paire de hallucinante casque beats by dre pas cher Monster Beats Dr. Dre. Cet article va vous aider à regarder les capacités de ces écouteurs exclusifs et vous fournir des informations sur oU vous pouvez trouver ces Beats pas cher et exclusifs par casque Dre. Monster casque beats pas cher a combiné un style exclusif et fonctionnalité grace à son incroyable gamme d'écouteurs Dr Dre. Non seulement ces écouteurs sont livrés dans les regards charmants, mais aussi une qualité sonore incroyable. Les sons de ces écouteurs sont parfaitement équilibrés au principal le long d'un milieu de gamme profonde et basse frapper. Certains écouteurs de basse lourds donnent des sons nuageux et indistinctes, mais ce n'est certainement pas le cas avec Monster Beats casque exclusif. Certains des genres les plus compatibles comprennent le hard rock, électronique ainsi que mid tempo hip-hop, ainsi que divers autres genres qui sonnent vraiment bien. Si vous êtes en métaux lourds ou de la musique classique, la qualité sonore est brillante à faible volume et tr ès poussée à la hausse des volumes. En résumé, pratiquement n'importe quel genre de musique est agréable grace à ces écouteurs. Beats pas cher par Dre écouteurs exclusifs par Dre sont idéales pour les iPhones, iPods ainsi que les lecteurs audio à portée de main. Ces écouteurs offrent un son parfait qui enrichit votre expérience musicale. Bien que ces écouteurs effectuée, vous pouvez également bénéficier d'un meilleur volume.casque beats by dre pas cher Les oreillettes sont également bien rembourrés, offrant un niveau de confort supérieur pour les longues heures d'écoute. L'oreillette droite se compose d'un onglet muet alors que l'écouteur gauche comprend le bouton d'arrêt du son. Battements de monstre par des écouteurs Dre viennent dans une variété de couleurs, de styles et de prix. Si vous préférez, ces casques sont également avec des bourgeons au-oreille.

Suisse Replique Montre:Rolex Pas Cher,Montre Breitling Pas Cher

Rolex Cup Regarder précision pour eux comme chacun le sait, ils ont ces montres portent le nom célèbre Rolex largement reconnue. En raison des excellentes compétences, et même ressemblent comme deux gouttes d'eau montre Rolex Daytona vont-ils travailler pour une longue période, même si chaque partie de la réparation des fabricants recommandés après une période de temps ou même rarement le besoin de réparation et l'entretien.

Belle, grande classique d'une replique montre Rolex Pas Cher est appelé la nature et les caractéristiques de la célèbre montre. Beaucoup de gens utilisent ces concepteurs de montres de comprendre la signification d'une montre de luxe, d'une combinaison de ces designers ont un concepteur de montres. Si vous voulez être un concepteur peut devenir une sorte de mode, si la montre classique de Rolex. La conception des montres Rolex, Rolex de la classique créateur de montres de luxe, ce qui rend la combinaison de la beauté et de grand designer montres créativité et riche.

Cette replique montre rolex pas cher vous offre merveilleuse précision de mouvement de quartz japonais de travail Chronographe qualité. D'autre part, la vertu précis est renforcée par Entièrement fonctionnelle travail chronographe (chronomètre). En outre, le cas habille PVD de haute qualité. De plus, cette montre réplique solennelle vient avec une très haute qualité sangle en nylon. Et le temps est clairement lisible à travers le verre de cristal minéral qui est durable. Avec une grande résistance à l'eau, ces gardiens du temps ont la couronne vissée dans laquelle se verrouille dans le bo?tier de la montre.

Lorsque vous achetez une copie de la Daytona regarder boutique en ligne, vous devez tout d'abord, la taille de votre poignet, afin d'obtenir un adapté à votre poignet, même avec réglable. Vous devez également tenir compte de la taille de. La qualité de ces montres sont garanties. En plus de la technologie de pointe, il est de votre copie Rolex Daytona un choix parfait pour un investissement, parce que ces temps montre communiquer que vous êtes un avoir de bonnes chances de gain de la personne. Un homme ou une femme, est une personne tout habillé vivant dans de grandes maisons et de conduire des voitures de luxe, une telle réplique particulière Rolex Daytona montre sera les meilleurs accessoires et ajouter plus de charme, sa personnalité.

Up To 70% Off Cheap Chanel Replica Handbags Outlet Free Shipping

chanel replica handbags have two main forms, one is Kelly and other one is Birkin. Although both of them are quite different in shape and style from each other, both have got the same amount of fans running after them to buy one. chanel outlet are bags that are in the wish list of every woman that have ever dreamed to enhance their fashionable outlooks.

If you are a fashion fanatic and you don't have a chanel outlet online in your wardrobe, that's not an uncommon scenario. chanel replica handbags are sold with precise details and you have to wait in a long line in order to get your desired cheap chanel bag. Celebrities try to make a fashion statement of their own.

That's why they use customized handbag that is only made for the celebrities made by chanel. This customized piece of handbags can be very pricey. If you have a huge amount of cash and have got enough inspiration to design and produce your own handbag then chanel replica handbags are the best choice for you. They will provide you with great customer support and make an exquisite bag only for you. Although it might cost a lot of money, you will seriously make a bold fashion statement everywhere you go.

Chanel replica handbags production is the best handbag. They have professional craftsmen who make quality handbag every day. They take a lot of quality in a handbag handbag greatly improved, compared to the time they are quite durable with others. Chanel replica handbags in the fashion accessories to keep you is a dream, attracting all the women. It & amp; my stuff; you can resist, after all, you have to recognize this fact, Chanel replica handbags is the world & amp; my best handbag. If you are in your pocket, if you really want to look like a street full of stars have enough money, in Chanel handbags customer lists, etc.

Replica Watches Uk:swiss rolex replica watches,fake rolex watches

  • Swiss Replica Watches - this is one of the most famous brand of designer accessories, we have today.
  • This popular watch brands have been many famous stars and movie stars from around the world.
  • Needless to say, these high-quality watches with amazing design and mechanical detail is very expensive and is not suitable for many of our budget.
  • He really can not afford to buy, the existence of those Rolex replica watches a good choice.
  • Secrets of these exclusive Swiss replica Rolex watches is their perfect high demand similar appearance, functionality and quality.
  • These versions are true copies of counterfeit brand models.
  • Taking into account that they are in their budget, everyone wants to follow the latest fashion trends, not just because they look impressive, but also because they look pretty standard and prestige.
  • Fake Rolex watch passion for fashion lovers who can not play to a copy of the version seems to be their favorite model accurately reflected. However, the most important factor to remember is that some of these replica watches versions of Rolex watches come really cheap, poor quality. However, Swiss watches Rolex replica watches copy without using a low-quality material. Every detail is true version, completely resolved in these versions.
  • 100% High Quality Handbags For Kate Spade Outlet Online

    • Well, Kate Spade outlet on procurement best part is replica handbags at reasonable prices decline, LED want to seize any customers.
    • You can be yourself with as many copies of Kate Spade replica handbags can export from $ 100 to about $ 1,000 places.
    • This stock can make every customer to wear these amazing projects.
    • You can get the best design and the best quality of leather.
    • Therefore, we strongly recommend the purchase of these items
    • if you consider yourself a fashion admirers.

    Kate Spade sale outlet is a recognized brand in the fashion dazzling customers through decades of excellence in our world.

    This is the only brand to live up to the dream of all customers, it belongs to France. We must tell you the truth, now you can for your project from home. This means that it is not needed to go to the store, carefully check the quality of the product, you may want to find an outlet imitation cheap Kate Spade handbags & amp; my store and jump; seeing some of the year's most stunning design.

    2014 USA Cheap Burberry Handbags Outlet Online Store

    • Handbag is usually the best supporting every woman longing development.
    • Since they began in the presence of humans. Similarly, designers and fashion handbags fashion market exists in about 150 years ago.
    • At this time, a variety of styles have been developed, making it all the more bewildering variety of practical differences to identify a few people.
    • Help alleviate confusion, the proposed purchase of a famous designer handbags discount Burberry handbags, which will at a later time when you're looking for yourself in fashion dilemma definitely help you.
    • British exports of Volkswagen brand Burberry outlet online. In addition, Burberry brand is wealthy elite celebrity favorites and the entire world population.
    • Burberry handbag or carry through symbolic discount burberry outlet store and fashion taste statements status.
    • You are looking for the most favorable interest rates or discount Burberry handbag is Burberry products?
    • Although you might also think that these designer burberry replica spend the whole heaven and earth, you should know the most appropriate expression and you'll get the best price.
    • Now, if you've decided that you just want to have a fashion designer Burberry handbag Favorite your fashion and designer wardrobe. Burberry handbags discount online hunting is undoubtedly a clever and wise. There are some discounts apply to these burberry outlet store. Similarly, you do not want to have any style the most updated.burberry outlet

    Mulberry UK Sale:Mulberry Outlet Online,Mulberry Handbags Sale

  • mulberry outlet online - You think you can buy your budget no tampering mulberry handbags? This is probably the only one small program.
  • in case you love your annual mulberry sale and tilt to get it at all the low-budget cost targets since you can not to do so, then you do not have to panic.
  • You only need a small Research in order to achieve your heart's desire to buy your designer handbag mulberry choice.
  • Do not let the curious, mulberry outlet you only need to be updated you see The offer of the company and then the advantage of the dirty season maximized.
  • In addition, this, that it occurs There are many times that the celebrities and other rich personality with mulberry handbags sale ounce then have them in order to Buy some other things.
  • This type of handbag is Mulberry main New and made available at cheaper spleen.
  • Therefore, by choosing this type of used car cheap mulberry bags creativity is another way of the enjoying the elegant and high-quality apparel ideas produced by Sang company without your spending huge cash on the amount of purchase.
  • mulberry uk You can choose some mulberry handbags from in order to make fashion statements include Mulberry Alexa shellfish, mulberry outlet online, mulberry Roxanne, Anthony, Kayla, Matt Aberdeen, Somerset and Tyler Mulberry.
  • canada goose
  • mulberry
  • rolex
  • mulberry pung
  • canada goose jakke
  • rolex ure