ABSTRACT
Objective To investigate the biological functions of IncRNA-BG on the radiosensitivity of normal human bronchial epithelial cell line Beas-2B.Methods Three IncRNA-BG siRNAs were designed,synthesized and traasfected into Beas-2B cells via lipofectamine.The RNA transcription level of BG was detected by quantitative real time-PCR to confirm the siRNA transfection efficiency.The experiment was divided into control group,control siRNA transfected group,and BG transfected group.Cell survival was detected by clonogenic assay,and the cell cycle distribution was determined by flow cytometry assay.The γ-H2AX foci formation after irradiation was visualized via immunofluorescence.Western blot assay was performed to detect the protein expressions of RAD50,p-P53,KU70,KU80,MDM2,CDK2 and RB.Results BG-siRNA transfection significantly reduced the BG transcription level (t =8.32-15.29,P ＜0.05) and increased cell survival after irradiation at 0.5,1,2,4 and 6 Gy.Analyzed with the multi-target model,the SERD0 of Beas-2B cells and control siRNA transfected cells were calculated to be 0.80 and 0.82,respectively.In addition,BG-siRNA transfection enhanced radiation-induced cell cycle arrest at G2 phase so that,after 4 Gy irradiation,the cells in G2 phase was increased from (37.37 ±0.63) ％ of control siRNA cells to (64.19 ± 1.01) ％ (t =30.65,P ＜ 0.05).Meanwhile,the γ-H2AX foci of BG-siRNA transfected cells was decreased from 76 ± 1.78 per 100 cells to 59-± 3.49 per 100 cells (t =13.72,P ＜0.05).The expressions of DNA damage related proteins including KU70,KUS0,CDK2 and RB were increased,but the expressions of p-P53 and RAD50 were decreased.Conclusions LncRNA-BG could regulate the radiosensitivity of the normal human bronchial epithelial cells,probably through inducing cell cycle G2 phase arrest and promoting DNA damage repair after irradiation.