Propranolol induced G0/G1/S phase arrest and apoptosis in melanoma cells via AKT/MAPK pathway

Abstract

// Chengfang Zhou 1 , Xiang Chen 3 , Weiqi Zeng 3 , Cong Peng 3 , Gang Huang 4 , Xian’an Li 4 , Zhengxiao Ouyang 4 , Yi Luo 4 , Xuezheng Xu 4 , Biaobo Xu 1 , Weili Wang 1 , Ruohui He 1 , Xu Zhang 3 , Liyang Zhang 5 , Jie Liu 1 , Todd C. Knepper 2 , Yijing He 1, 2, 3 , Howard L. McLeod 1, 2 1 Department of Clinical Pharmacology, XiangYa Hospital, Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, China 2 Moffitt Cancer Center, DeBartolo Family Personalized Medicine Institute, Tampa, FL, USA 3 Department of Dermatology, XiangYa Hospital, Central South University, Changsha, China 4 Department of Orthopedics, Hunan Tumor Hospital, Changsha, China 5 Department of Neurosurgery, Xiang-Ya Hospital, Central South University, Changsha, China Correspondence to: Howard L. McLeod, email: Howard.McLeod@moffitt.org Yijing He, email: yijing.he@moffitt.org Keywords: melanoma, propranolol, apoptosis, AKT pathway, MAPK pathway Received: February 15, 2016     Accepted: August 12, 2016     Published: August 25, 2016 ABSTRACT Both preclinical and epidemiology studies associate β-adrenoceptors-blockers (β-blockers) with activity against melanoma. However, the underlying mechanism is still unclear, especially in acral melanoma. In this study, we explored the effect of propranolol, a non-selective β-blocker, on the A375 melanoma cell line, two primary acral melanoma cell lines (P-3, P-6) and mice xenografts. Cell viability assay demonstrated that 50μM-400μM of propranolol inhibited viability in a concentration and time dependent manner with an IC50 ranging from 65.33μM to 148.60μM for 24h -72h treatment, but propranolol (less than 200μM) had no effect on HaCaT cell line. Western blots showed 100μM propranolol significantly reduced the expression of Bcl-2 while increasing the expressions of Bax, cytochrome c, cleaved capase-9 and cleaved caspase-3, and down-regulated the levels of p-AKT, p-BRAF, p-MEK1/2 and p-ERK1/2 in melanoma cells, after a 24h incubation. The in vivo data confirmed the isolation results. Mice received daily ip. administration of propranolol at the dose of 2 mg/kg for 3 weeks and the control group was treated with the same volume of saline. The mean tumor volume at day 21 in A375 xenografts was 82.33 ± 3.75mm 3 vs. 2044.67 ± 54.57mm 3 for the propranolol-treated mice and the control group, respectively, and 31.66 ± 4.67 mm 3 vs. 1074.67 ± 32.17 mm 3 for the P-3 xenografts. Propranolol also reduced Ki67, inhibited phosphorylation of AKT, BRAF, MEK1/2 and ERK1/2 in xenografts. These are the first data to demonstrate that propranolol might inhibit melanoma by activating the intrinsic apoptosis pathway and inactivating the MAPK and AKT pathways.