Abstract 4393: Electrochemotherapy with irreversible electroporation and FOLFIRINOX improves survival in murine pancreatic adenocarcinoma by increasing apoptosis and decreasing tumor cell proliferation

Abstract

Abstract Introduction: Combining gemcitabine (gem) with irreversible electroporation (IRE) has been shown to result in increased tumor cell apoptosis in a murine model of pancreatic adenocarcinoma (PDAC). However, it remains unclear whether this effect can be augmented locally and systemically by utilizing more active chemotherapies. The objective of this study was to evaluate the efficacy of IRE+FOLFIRINOX (FOL: 5-FU, leucovorin, irinotecan, and oxaliplatin). Methods: Athymic nude mice underwent intrapancreatic injection with S2-013 PDAC cells. After 7-10 days, tumors were confirmed with ultrasound and mice were treated with chemotherapy (gem or FOL), IRE, or chemotherapy+IRE. Four hours after last chemotherapy, pancreas was evaluated histologically. Levels of irinotecan and its active metabolite (SN-38) were evaluated in organs of mice treated with FOL and IRE+FOL. Experiments were repeated and survival analyses performed to evaluate long-term efficacy. Pancreas was harvested for histology and evaluation of apoptotic machinery, cell cycle proteins, and tumor cell proliferation. Results: IRE+FOL (ECT) resulted in increased tumor cells apoptosis compared to gem, gem+IRE, or FOL (apoptotic index (AI) 34.6% vs. 3.8%, 7.3%, 5.8%, respectively, p<0.001). High performance liquid chromatography (HPLC) demonstrated a 1.5-2-fold increase in irinotecan and SN-38 in the pancreas and a 4-fold increase of both compounds in the liver in mice treated with ECT vs. FOL. ECT significantly improved overall survival when compared to mice treated with IRE or FOL (median 7 days ECT vs. 4 days IRE vs. 3 days FOL, p=0.03). Histology demonstrated increased tumor cell apoptosis at time of death (AI = 34.2% ECT vs. 13.2% IRE vs. 4.4% FOL, p=0.026). Western blot demonstrated an increase in active caspase 3 (0.14 ECT vs. 0.00 IRE vs. 0.03 FOL fold change/GAPDH, p=0.02). ECT resulted in lower cell proliferation compared to IRE or FOL (0.2% vs. 0.3% vs. 0.9, p<0.001). Conclusions: ECT with IRE and FOL causes significant tumor cell apoptosis, decreases tumor cell proliferation, enhances systemic FOL exposure, and improves overall survival. Human Phase 1 trials have been initiated to evaluate safety and efficacy of this therapeutic modality. Citation Format: Neal Bhutiani, Harshul Pandit, Qianqian Zheng, Suping Li, Yan Li, Robert C. Martin. Electrochemotherapy with irreversible electroporation and FOLFIRINOX improves survival in murine pancreatic adenocarcinoma by increasing apoptosis and decreasing tumor cell proliferation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4393.