Abstract 5842: Oxidative stress and protein carbonylation towards multi-drug resistance in cancer

Abstract

Abstract Reactive oxygen species (ROS) are constantly produced under normal as well as stress conditions and play important roles in cell signaling and homeostasis. An elevated level of ROS has been reported in most cancers which may play a critical role in both cancer progression or cancer suppression. One proposed therapeutic strategy is to alter the oxidative stress from ROS-induced tumor promoting event to a ROS-induced apoptotic signaling. Most ROS inducing therapeutic agents initially induce ROS to kill cancer cells by apoptosis; however, prolonged exposure of drugs may result in reduced ROS level and an adaptive microenvironment that makes cancer cells resistant to the same ROS-inducing therapeutic drugs. Chronic exposure of ROS may also upregulate the multidrug resistance protein expression in cancer cells. We hypothesize that differences in oxidative stress and the antioxidant response between drug sensitive and drug resistance cells may play a key role in drug resistance to redox-active drugs. We used two pairs of cell lines, a mitoxantrone sensitive and resistance MCF7 human breast adenocarcinoma (MCF7/MCF7MX) and H460 non-small lung cancer cell lines (H460/H460MX) for our experiments. We employed western blot and ELISA assays to determine the total and specific protein oxidation by carbonylation. Both MCF7MX and H460MX showed slightly lower level of total protein carbonylation compared to their mitoxantrone sensitive counterparts. In western blot analysis, we observed two specific proteins that were differentially carbonylated in MCF7MX compared to and MCF7. Both cytoskeletal and multifunctional proteins were identified by mass spectrometry and confirmed by two-color western blot analysis. Investigation of the potential roles of these specific protein carbonylation in drug resistance will be presented. Citation Format: Baikuntha P. Aryal, Jean-Pierre Gillet, V Ashutosh Rao. Oxidative stress and protein carbonylation towards multi-drug resistance in cancer [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 5842.