Regulator of G-protein signaling 5 (RGS5) inhibits cell proliferation and enhances radiosensitivity of human lung cancer cells

Abstract

Objective To investigate the effects of regulator and the underlying molecular mechanisms of G-protein signaling 5 (RGS5) on radiation response in human lung cancer cells.Methods The effects of RGS5 on viability were determined by MTT assay,and apoptosis rate was detected by flow cytometry,in human lung cancer cells.The combined effect of ionizing radiation and RGS5 on tumor cells was detected by colony formation assay.The protein expression was detected by Western blot.Results RGS5 overexpression remarkably inhibited the survival of human lung cancer cells,and the growth inhibition rate of RGS5 overexpression on A549 and Calu-3 cells were 44.4％ (F =29.18,P ＜ 0.05) and 39.27％ (F=23.04,P＜0.05) at 48 h,and 54.3％(F=103.45,P＜0.05),44.7％(F=108.02,P ＜ 0.05) at 72 h post-irradiation,respectively.RGS5 might exert its inhibitory effects on human lung cancer cells by inducing tumor cell apoptosis,while the apoptotic cells rate in A549 and Calu-3 cells in control group,pTRiEX group and pTRiEX-RGS5 group were (1.3 ± 0.2) ％,(3.4 ± 0.6) ％,(19.6 ± 2.3)％ (F=86.62,P＜0.05),and (3.2±0.8)％,(3.0±0.9)％,(12.8±1.8)％ (F=28.80,P ＜ 0.05) at 36 h post-irradiation,respectively.Furthermore,RGS5 could sensitize the lung cancer cells to radiation.Conclusions RGS5 might play an inhibitory role in human lung cancer cell proliferation,which may explain the pathoclinical observation thet high expression of RGSS is a favorable prognostic factor in NSCLC patients.In addition,RGS5 also enhance the anti-tumor effects of radiation in human lung cancer cells. Key words: Regulator of G-protein signaling 5; Lung cancer; Cell apoptosis; Radiation therapy