Exogenous agents and endogenous processes, such as reactive oxygen species (ROS) can induce base oxidation and DNA lesions. One of the most severe DNA lesions is the double-strand break (DSB). There are several repair systems to fix the resulting DNA lesions to prevent error copies of genetic information to be carried to daughter cells. Oxidative stress is an important factor to induce DNA damage during normal cellular metabolism. In this study, we wanted to use lung cancer cells, CL1-0 and CL1-5 cells, which have differential invasiveness ability to characterize DNA repair function. Hydrogen peroxide (H2O2) was treated in lung adenocarcinoma cells to induced DNA DSB. By using immunoflurecence microscope, we found that CL1-5 had more gamma-H2AX foci (DNA DSB marker) and ROS accumulation than CL1-0 post both 1 mM and 5 mM H2O2 treatment. Moreover, CL1-0 had a tight G2/M checkpoint and has a longer G2 arrest after H2O2 treatment, but not found in CL1-5. In addition, increasing sub-G1 population (apoptotic cells) was found in H2O2-treated CL1-5 but less in CL1-0. Furthermore, phosphorylated-Akt (S473) was decreased in CL1-5, In contrast, phosphorylated-ATM (S1981) and Chk2 were increased after 5 mM H2O2 treatment for 90 min. In addition, the level of GSH was persistently lower at the steady state and post H2O2 treatment in CL1-5 by LC-MS/MS analysis. Besides, the apoptotic cells were decreased but no differences in CL1-0 while supplement reduced-GSH before H2O2 treatment. We therefore hypothesize that there are different processes on dealing with ROS scavenging post oxidative stress between CL1-0 and CL1-5. Taken together, using hydrogen peroxide for treating two lung cancer cell lines seem to have different DNA repair function to regulate cellular function. In the following experiments, the activities of antioxidant enzymes, superoxide dismutase (SOD), catalase as well as glutathione peroxidase (GPx) post oxidative stress in CL1-0 and CL1-5 will be determined. Moreover, we will examine the level of GSH in different tumor cell lines to investigate whether GSH involved in tumor invasion ability.

Citation Format: Feng- Chang Wu, Yu-Fen Lin, Liang-Chuan Lai, Eric Y Chuang, Mong-Hsun Tsai. To study DNA repair function of two closely related human lung adenocarcinoma cell lines, CL1-0 and CL1-5. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2914. doi:10.1158/1538-7445.AM2013-2914

Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.