Abstract A45: Quinacrine induces necrosis of ovarian high-grade serous carcinoma cells by breaking the mitochondria ROS balance

Abstract

Abstract Ovarian high-grade serous ovarian carcinoma (HGSC) was found to be initiated and promoted by repeated exposure of fimbrial epithelium to ovulatory ROS with resultant intolerable stress of oxidative damages and DNA repair load. Consequential cell apoptosis is overcome on the one hand by quenching excessive ROS by hemoglobin contributed by retrograde menstruation and on the other by upregulation of antioxidant machinery. A dangerous balance is achieved between the oxidative stress and antioxidation and between DNA damage stress and repair. Breaking of this balance on the stress side such as by DNA chelating agent such as cisplatin or inhibitors targeting on DNA repair enzyme such as PARP leads to therapeutic cell killing. In this report, we show ROS enhancing drug such as quinacrine effectively kill HGSC cells and its tubal precursor cells with p53 and Rb defect. Quinacrine is a traditional antimalarial drug with wide antitumor effect in either a single agent or combined with chemotherapy drugs. We show here that quinacrine has a cytotoxic effect in two HGSC cell lines (KURAMOCHI, OVSAHO) and in an HPV E6/E7-immortalized human fimbrial epithelial cells, which are readily fully transformed by ovulatory follicular fluid. Cytotoxicity was observed dose-dependently at concentrations ranging from 2.5μM to 25μM. Flow cytometry analysis indicated a cell necrosis (PI +, annexin V-) 48hr post-treatment. We further found a significant induction of the mitochondrial ROS upon quinacrine treatment, and ROS inhibitor N-acetyl-l-cysteine considerably reversed this cytotoxic effect. The study proves the concept of breaking the balance of mitochondria-ROS is a feasible strategy for the development of a new drug for ovarian HGSC. Note: This abstract was not presented at the conference. Citation Format: Ching-I Huang, Tang-Yuan Chu, Hsuan-Shun Huang. Quinacrine induces necrosis of ovarian high-grade serous carcinoma cells by breaking the mitochondria ROS balance [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr A45.