Yiqian Liang, Ting Wang, Dong Shang, Asmitananda Thakur, Tian Yang, Shuo Zhang, Feng Liu, Hua Guo, Feng Xu, Jing Feng, Johnson J. Liu, Mingwei Chen, Hui Ren, Lei Gao, Puyu Shi, and Tianjun Chen
// Hui Ren 1, 2, * , Hua Guo 3, * , Asmitananda Thakur 1, 4 , Shuo Zhang 1 , Ting Wang 1 , Yiqian Liang 1 , Puyu Shi 1 , Lei Gao 1 , Feng Liu 1 , Jing Feng 1 , Tianjun Chen 1 , Tian Yang 1 , Dong Shang 1 , Johnson J. Liu 5 , Feng Xu 2 , Mingwei Chen 1 1 Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China 2 Bioinspired Engineering and Biomechanics Center, Xi’an Jiaotong University, Xi’an, Shaanxi, China 3 Department of Respiratory Medicine, Xi’an Central Hospital, Xi’an, Shaanxi, China 4 Department of Internal Medicine, Life Guard Hospital, Biratnagar, Nepal 5 Department of Pharmacology, School of Medical Sciences, University of New South Wales, Sydney, Australia * These authors have contributed equally to this work Correspondence to: Mingwei Chen, email: chenmingwei@mail.xjtu.edu.cn Keywords: autophagy, apoptosis, BKM120, ERK, lung cancer Received: September 15, 2015 Accepted: August 13, 2016 Published: August 27, 2016 ABSTRACT NVP-BKM120 (BKM120) is a new pan-class I phosphatidylinositol-3 kinase (PI3K) inhibitor and has been tested in clinical trials as an anticancer agent. In this study, we determined whether BKM120 induces autophagy and the impact of autophagy induction on BKM120’s growth-inhibitory activity. BKM120 potently induced elevation of autophagosome-bound type II LC3 (LC3-II) protein, predominantly in cell lines insensitive to BKM120, thereby inducing autophagy. The presence of lysosomal protease inhibitor chloroquine further enhanced the levels of LC3-II. BKM120 combined with chloroquine, enhanced growth-inhibitory effects including induction of apoptosis, suggesting that autophagy is a protective mechanism counteracting BKM120’s growth-inhibitory activity. Interestingly, BKM120 increased p-ERK1/2 levels. When blocking the activation of this signaling with MEK inhibitors or with knockdown of ERK1/2, the ability of BKM120 to increase LC3-II was attenuated and the growth-inhibitory effects including induction of apoptosis were accordingly enhanced, suggesting that the MEK/ERK activation contributes to BKM120-induced authophagy. In mouse xenograft model, we also found that the combination of BKM120 and PD0325901 synergistically suppressed cell growth in human lung cancer cells. Thus, the current study not only reveals mechanisms accounting for BKM120-induced autophagy, but also suggests an alternative method to enhance BKM120’s therapeutic efficacy against non-small cell lung cancer(NSCLC) by blocking autophagy with either a lysosomal protease inhibitor or MEK inhibitor.