title: Effects of RNAi-mediated TUSC3 silencing on radiation-induced autophagy and radiation sensitivity of human lung adenocarcinoma cell line A549 under hypoxic condition.
abstract: This study examined the effects of RNAi-mediated TUSC3 silencing on radiation-induced autophagy and radiation sensitivity of human lung adenocarcinoma cell line A549 under hypoxic condition. Different CoCl2concentrations were used to treat A549 cells and establish a CoCl2-induced hypoxic model of A549 cells. MTT and clone formation assays were used to determine the effects of different concentrations of CoCl2on the growth and proliferation of A549 cells treated by different doses of X-ray irradiation. The siRNA-expressing vector was transfected by liposomes and for silencing of TUSC3. Flow cytometry was used to measure cell cycle changes and apoptosis rate. Real-time quantitative polymerase chain reaction (qRT-PCR) assay was performed to detect the expression of TUSC3 mRNA. Western blotting was applied to detect the changes of TUSC3, LC3, and p62 proteins under different CoCl2concentrations and after siRNA silencing of TUSC3. The TUSC3 levels in A549 cells increased under hypoxic conditions in a dose-dependent manner (P < 0.05). Hypoxia inhibited the growth and proliferation of A549 cells and promoted apoptosis (P < 0.05). With an increasing dose of X-ray irradiation, A549 cells showed significantly increased growth and proliferation and decreased apoptosis (P < 0.05). After siRNA-TUSC3 was transfected by liposome, the TUSC3 level was substantially inhibited (P < 0.05). Silencing TUSC3 inhibited A549 cell growth and proliferation after radiotherapy under hypoxic condition, promoted apoptosis, increased G0/G1 phase cells, and reduced S phase cells (all P < 0.05). Hypoxia and radiation along with different CoCl2concentrations could induce cell autophagy, which increased with concentration and dose, while silencing the TUSC3 gene inhibited autophagy (all P < 0.05). RNAi silencing of TUSC3 inhibited growth and proliferation, while enhanced apoptosis and radiation sensitivity of hypoxic A549 lung adenocarcinoma cells.
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, People's Republic of China.
authors.forename: Ya-Guang
authors.initials: YG
authors.lastname: Li
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, People's Republic of China.
authors.forename: Nai-Xin
authors.initials: NX
authors.lastname: Liang
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, People's Republic of China.
authors.forename: Ying-Zhi
authors.initials: YZ
authors.lastname: Qin
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, People's Republic of China.
authors.forename: Dong-Jie
authors.initials: DJ
authors.lastname: Ma
authors.affiliation: Plastic Surgery Hospital, CAMS, PUMC, Beijing, 100144, People's Republic of China.
authors.forename: Chang-Jin
authors.initials: CJ
authors.lastname: Huang
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, People's Republic of China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Thoracic Surgery, Peking Union Medical College Hospital, No. 1 Shuaifuyuan, Wangfujing Street, Dongcheng District, Beijing, 100730, People's Republic of China. shanqing31@126.com.
authors.forename: Shan-Qing
authors.initials: SQ
authors.lastname: Li
keywords: Autophagy; Cell apoptosis; Cell cycle; Hypoxia; Lung adenocarcinoma A549; Radiation sensitivity; Tumor suppressor candidate 3; siRNA