Abstract 1667: In vitro and in vivo validation of CSE1L/hCAS as a potential molecular target in pancreatic cancer

Abstract

Abstract Background: The human cellular apoptosis susceptibility protein (hCAS) is a Ran- binding protein playing a role as mitotic spindle checkpoint regulator and as nuclear export factor. hCAS expression is frequently altered in metastatic cancers. To date the role of hCAS in pancreatic cancer is unknown. Therefore this study aimed to investigate the role of hCAS in human pancreatic cancer in vitro and in vivo. Methods: The hCAS protein expression was determined using Western immunoblotting in human pancreatic cancer cell lines (AsPc-1, BxPc-3, Capan-2, MiaPaCa-2, Panc-1, and SW1990) and immortalized normal human pancreatic ductal epithelial cell (HPNE) and HPNE-Kras. siRNA induced hCAS knockdown pancreatic cancer cells were compared to scrambled siRNA cells with regard to proliferative (MTT assay), cell death, cell cycle (Trypan blue and Flow cytometry), malignant transformation (colony formation assay) and protein expression (Western and confocal microscopy). hCAS KD MiaPaCa-2 cells were xenografted in SCID nude mice. Tumor growth, expression of hCAS, proliferation index (Ki-67), and caspase-3 were immunostained in tumor tissues and compared with scr siRNA MiaPaCa-2 cells. Expression of hCAS was determined in human pancreatic tumor tissues using immunohistochemical stain. Results: hCAS protein expression was low in HPNE cells compared to HPNE-Kras. Lowest expression of hCAS noted in BxPc-3 cells compared to other pancreatic cancer cells. When compared to Scr-MiaPaCa-2, KD-MiaPaCa-2 cells demonstrated lower proliferation, G2/M phase cell cycle arrest, increased apoptosis, as well as inhibition of malignant transformation. Pancreatic ductal carcinomas (PCA) were hCAS strongly positive. Normal pancreatic ducts (ND) were hCAS weakly positive. hCAS KD-MiaPaCa-2 tumor growth was retarded in mice compared to Scr-MiaPaCa-2 tumors. hCAS KD-MiaPaCa-2 tumors showed hCAS depletion, lower proliferative index, increased caspase-3 immunostaining and PARP1 cleavage. Conclusion: This is the first report of hCAS expression in human pancreatic cancer. Our data suggest that hCAS is a regulator of cell proliferation, cell cycle regulation and apoptosis. hCAS may represent a potential chemopreventive and therapeutic target for human pancreatic cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1667. doi:10.1158/1538-7445.AM2011-1667