Abstract 249: Inhibition of nestin using siRNA as a novel therapeutic option for pancreatic cancer.

Abstract

Abstract Introduction: Nestin is a member of the class VI intermediate filaments and it was first described as a central nervous system (CNS) progenitor/stem cell marker. Nestin is highly expressed in various cancers and was recently reported as a tumor stem cell marker for glioblastoma and melanoma. Previously,we have reported that 30% of pancreatic cancer cases expressed nestin in cancer cells, and its expression correlated with nerve invasion and the presence of cancer cells in the tumor resection margins (Kawamoto, et al. Hum Pathol 2009). Knockdown of nestin exhibited a sheet-like appearance with tight cell-cell adhesion, increased expression of filamentous actin and E-cadherin, and attenuated migration and invasion (Matsuda, et al. Cancer Biol Ther 2011). These findings suggest that nestin is a novel therapeutic target for pancreatic cancer. In this study, we examined the effects of siRNA targeting nestin on pancreatic cancer cell growth migration, and invasion in vitro and in vivo. Methods: Two types of siRNA targeting nestin, which binds to different sites of nestin mRNA, were prepared and transfected to PANC-1 and PK-45H cells. Cell growth, migration, invasion and sphere formation abilities of these cells were analyzed in vitro. We also determined the synergistic effects of gemcitabine in pancreatic cancer cells under treatment with siRNA targeting nestin. For an in vivo study, we constructed luciferase-gene-transfected pancreatic cancer cells and orthotopically implanted the cells into the pancreas of NOD/Shi-scid/IL-2Rγnull (NOG) mice. We injected siRNA into the tail vein of NOG mice once per week with Invivofectamine. Every week, luciferin was injected into the peritoneal cavity of NOG mice and images of primary and metastases were taken using IVIS. After 6 weeks, animals were sacrificed, and the primary and metastatic tumors were macro and microscopically examined. Results: siRNA targeting nestin inhibited the growth, migration, invasion and sphere-forming ability of both PANC-1 and PK-45H cells. Treatment with gemcitabine, in addition to the treatment with siRNA targeting nestin in pancreatic cancer cells, decreased cell viability as compared with only gemcitabine, siRNA targeting nestin or control siRNA- treated pancreatic cancer cells. In the orthotopic implantation model, siRNA targeting nestin significantly decreased primary tumor formation in the pancreas, as compared with negative control siRNA groups. Furthermore, nestin siRNA markedly suppressed the formation of metastatic nodules in the liver and lungs. Conclusion: In pancreatic cancer cells, siRNA targeting nestin inhibited cell growth, migration, invasion and sphere formation in vitro, and primary tumor growth and metastatic tumor formation in vivo. Furthermore, siRNA targeting nestin had synergistic effects with gemcitabine. Inhibition of nestin using siRNA may be a novel therapeutic optiont for pancreatic cancer treatment. Citation Format: Toshiyuki Ishiwata, Hisashi Yoshimura, Taeko Suzuki, Yuji Yanagisawa, Yoko Kawamoto, Kiyoko Kawahara, Zenya Naito, Murray Korc, Yoko Matsuda. Inhibition of nestin using siRNA as a novel therapeutic option for pancreatic cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 249. doi:10.1158/1538-7445.AM2013-249