Abstract 2674: Synergistic combinations of lurbinectedin with irinotecan and ONC212 in pancreatic cancer

Abstract

Abstract Pancreatic cancer is a devastating disease with a five-year survival rate below 10% according to the American Cancer Society. Novel chemotherapeutics and targeted therapies in pancreatic cancer have shown limited success, illustrating the urgent need for new treatments. Lurbinectedin is a chemotherapeutic synthetic tetrahydroisoquinoline alkaloid that inhibits active transcription by binding to guanine rich sequences in the minor groove of DNA. Lurbinectedin has been shown to reduce oncogenic transcription by stalling and degrading RNA Polymerase II while also inducing single- and double-stranded breaks to DNA, causing subsequent apoptosis. Lurbinectedin received accelerated FDA approval in 2020 for metastatic small cell lung cancer on or after platinum-based chemotherapy and is currently undergoing clinical trials in a variety of tumor types. We recently described a synergistic interaction between lurbinectedin and ONC201/TIC10, a compound that induces the TRAIL pathway, in killing SCLC cell lines associated with activation of p-Chk1 and the integrated stress response. We now demonstrate lurbinectedin’s efficient killing of pancreatic tumor cells as a single agent in PANC-1, BxPC-3, and HPAF-II cell lines, with IC-50s corresponding to sub-nanomolar concentrations. We also demonstrate that a combination of lurbinectedin and irinotecan, a topoisomerase I inhibitor with FDA approval for advanced pancreatic cancer, results in synergistic killing of pancreatic tumor cells in vitro. We further demonstrate a combination of lurbinectedin and ONC212, an imipridone, the same class of compounds as ONC201, also results in synergistic killing of pancreatic tumor cells. Cell viability was measured using the CellTiterGlo assay at varying drug concentrations. We hypothesize a combination therapy of lurbinectedin and irinotecan or ONC212 can enhance immune cell killing of pancreatic tumor cells. This is being explored by co-culturing CD8+ T lymphoblast cells with pancreatic tumor cells treated with lurbinectedin, irinotecan, ONC212, and combination, along with molecular mechanisms of cell death and effects on cytokines in the tumor microenvironment. Our results are developing insights regarding molecular mechanisms underlying therapeutic efficacy of a novel combination drug treatment for pancreatic cancer. Citation Format: Tej Tummala, Arielle De La Cruz, Ash Uruchurtu, Nicholas R. Liguori, Abbas E. Abbas, Leiqing Zhang, Christopher G. Azzoli, Lanlan Zhou, Wafik S. El-Deiry. Synergistic combinations of lurbinectedin with irinotecan and ONC212 in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2674.