Abstract 1696: Selective nuclear export inhibitor kpt330 enhances the antitumor activity of gemcitabine in human pancreatic cancer
Authors: Kazim Sabiha , Malafa Mokenge P. , Husain Kazim , Kauffman Michael , Sharon Shacham , Mahipal Amit 
Published: May 2015

Background: Pancreatic cancer is the fourth leading cause of cancer-related deaths in the United States. Gemcitabine is currently the standard chemotherapeutic agent for advanced pancreatic cancer, but has limited efficacy due to chemoresistance and dose escalation toxicity. Therefore an effective and safer therapy is warranted against this deadly malignancy. Selective nuclear export inhibitor KPT-330 inhibits the exportin 1 (CRM1) leading to nuclear localization of tumor suppressor proteins. The aim of this study was to evaluate the combination of KPT-330 and gemcitabine on anchorage-dependent and indepencent metastatic tumor cell growth, pro and antiapoptotic protein expression in vitro and in vivo orthotopic mouse model of metastatic human pancreatic cancer.

Methods: Human pancreatic cancer cell MiaPaCa-2 and human metastatic pancreatic cancer cell L3.6pl were treated with different concentrations of KPT-330 (0.1-10 μM), and gemcitabine (0.1-10 μM) alone and in combination and anchorage-dependent growth recorded using MTT assay for 72 h. The effect of KPT330 and gemcitabine alone and in combination on anchorage independent growth were performed using soft agar colony formation assay. Human metastatic pancreatic cancer cells L3.6pl with luciferase were injected orthotopically into pancreas of female athymic nude mice and were treated with 1) Vehicle (PBS 1 ml/kg, ip, 2/week and PVP/PF68 1ml/kg, po, 3/week), 2) KPT330 (20 mg/kg, po, 3/week), 3) gemcitabine (100 mg/kg, ip, 2/week) and 4) KPT330 (10 mg/kg, po, 3/week + gemcitabine (50 mg/kg, ip, 2/week) for 4 weeks. The tumor volume and tumor weights were recorded after 4 weeks of treatment. The CRM1, p53, proapoptotic Bax and antiapoptotic survivin protein expressions in cells and tumor tissues were determined by Western blotting.

Results: KPT-330 and gemcitabine alone significantly inhibited the anchorage-dependent growth in a concentration dependent manner. The combination of the two drugs inhibited the growth synergistically and almost completely inhibited the malignant transformation of anchorage independent cell growth. KPT-330 and gemcitabine alone decreased tumor volume and tumor weight compared to vehicle (p&lt;0.05) but when combined together significantly decreased tumor size and weight (P&lt;0.001). KPT-330 and gemcitabine alone and in combination induced apoptosis (Bax expression). KPT-330 but not gemcitabine depleted CRM1 expression whereas no significant change was observed in mutant p53 expression with any treatment. KPT330 and gemcitabine alone moderately depleted survivin expression compared to vehicle but when combined together, they markedly depleted survivin expression.

Conclusion: KPT-330 potentiates antitumor activity of gemcitabine through inhibition of metastatic pancreatic tumor growth, depletion of the antiapoptotic protein and induction of apoptosis in human metastatic pancreatic cancer.

Citation Format: Sabiha Kazim, Mokenge P. Malafa, Kazim Husain, Michael Kauffman, Shacham Sharon, Amit Mahipal. Selective nuclear export inhibitor kpt330 enhances the antitumor activity of gemcitabine in human pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1696. doi:10.1158/1538-7445.AM2014-1696