Abstract 3535: A novel tumor-specific oncolytic biological therapy against invasive pancreatic cancer

Abstract

Abstract Pancreatic cancer is one of the worst prognosis disease all over the world and has an overall 5-year survival rate of less than 5%. At the time of diagnosis, more than 80% of patients are not eligible for curative surgical resection due to extensive local tumor invasion and early systemic metastasis. Moreover, even after curative surgery, pancreatic cancers still show poor prognosis due to local recurrence and systemic metastasis. Gemcitabine is the standard chemotherapeutic agent to treat advanced pancreatic cancers, but median overall survival ranged from 5.0 to 7.2 months, suggesting that standard chemotherapy is less effective to most of pancreatic cancer patients. Therefore, the development of novel therapeutic strategy is needed for the treatment of pancreatic cancers. We developed a novel oncolytic adenovirus, OBP-702, in which a human telomerase reverse transcriptase gene promoter drives viral E1 gene for virus replication, and armed with the wild-type tumor suppressor p53 gene. Precise antitumor effects of OBP-702 have been evaluated in human pancreatic cancer cells. We used four pancreatic cancer cell lines with different invasion ability, including non-invasive type (MIA PaCa-2, Panc-1) and invasive type (BxPC-3, Capan-1). The antitumor effect of OBP-702 for each cell line was assessed using XTT assay. OBP-702 induced profound anti-tumor effect in all human pancreatic cancer cells, whereas OBP-301 lacking the p53 tumor suppressor gene showed differential effects among the cell types. OBP-301 induced moderate anti-tumor effect in MIA Paca-2, BxPC-3 and Capan-1 cells and strong anti-tumor effect in Panc-1 cells in a dose-dependent manner, suggesting the broad spectrum of OBP-702's efficacy. The molecular mechanism of anti-tumor effect was assessed by Western blot analysis. OBP-301 induced autophagy-related cell death, whereas OBP-702 induced autophagy- and apoptosis-related cell deaths. These results suggest that an oncolytic adenovirus, OBP-702, is a promising antitumor agent to induce profound cell death in invasive human pancreatic cancer cells. The clinical trial of intratumoral administration of OBP-702 in patients with invasive pancreatic cancer is warranted. Citation Format: Takeshi Koujima, Hiroshi Tazawa, Naoto Hori, Shuta Tamura, Shinji Kuroda, Hiroyuki Kishimoto, Masahiko Nishizaki, Yasuo Urata, Shunsuke Kagawa, Toshiyoshi Fujiwara. A novel tumor-specific oncolytic biological therapy against invasive pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3535. doi:10.1158/1538-7445.AM2015-3535