The role of ROS and subsequent DNA-damage response in PUMA-induced apoptosis of ovarian cancer cells

// Jun Yang 1, * , Xinyu Zhao 1, * , Mei Tang 1 , Lei Li 1 , Yi Lei 1 , Ping Cheng 1 , Wenhao Guo 2 , Yu Zheng 1 , Wei Wang 1 , Na Luo 3 , Yong Peng 1 , Aiping Tong 1 , Yuquan Wei 1 , Chunlai Nie 1 , Zhu Yuan 1 1 State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University/Collaborative Innovation Center of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China 2 Department of Abdominal Oncology, Cancer Center and State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu 610041, Sichuan Province, China 3 Nankai University, School of Medicine/Collaborative Innovation Center of Biotherapy, Tianjin 300071, China * These authors contributed equally to this work Correspondence to: Zhu Yuan, email: yuanzhu@scu.edu.cn Keywords: PUMA, ROS, apoptosis, DNA damage response, ovarian cancer Received: January 04, 2017 Accepted: February 14, 2017 Published: February 22, 2017 ABSTRACT PUMA is a member of the “BH3-only” branch of the BCL-2 family. Our previous study suggests a therapeutic potential of PUMA in treating ovarian cancer, however, the action mechanism of PUMA remains elusive. In this work, we found that in PUMA adenovirus-infected A2780s ovarian cancer cells, exogenous PUMA was partially accumulated in the cytosol and mainly located to the mitochondria. We further showed that PUMA induces mitochondrial dysfunction-mediated apoptosis and ROS generation through functional BAX in a ROS generating enzyme- and caspase-independent manner irrespective of their p53 status, and results in activation of Nrf2/HO-1 pathway. Furthermore, PUMA induces DNA breaks in γ-H2AX staining, and causes activation of DNA damage-related kinases including ATM, ATR, DNA-PKcs, Chk1 and Chk2, which are correlated with the apoptosis. PUMA also results in ROS-triggered JNK activation. Intriguingly, JNK plays a dual role in both DNA damage response and apoptosis, and has an additional contribution to apoptosis. Taken together, we have provided new insight into the action mechanism by which elevated PUMA first induces ROS generation then results in DNA damage response and JNK activation, ultimately contributing to apoptosis in ovarian cancer cells.