Open AccessAtaxia‐telangiectasia mutated ( ATM ) participates in the regulation of ionizing radiation‐induced cell death via MAPK14 in lung cancer H1299 cells
Author(s) -
Liang Nan,
Zhong Rui,
Hou Xue,
Zhao Gang,
Ma Shumei,
Cheng Guanghui,
Liu Xiaodong
Publication year - 2015
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/cpr.12203
Subject(s) - autophagy , gene silencing , cancer research , ataxia telangiectasia , phosphorylation , microbiology and biotechnology , programmed cell death , pi3k/akt/mtor pathway , biology , kinase , chemistry , apoptosis , dna damage , signal transduction , genetics , dna , gene
Objectives The role of Ataxia‐telangiectasia mutated ( ATM ) in response to DNA damage has previously been studied, but its underlying mechanisms specific to ionizing radiation ( IR ) have remained to be elucidated. In this study, function of ATM on radiation‐induced cell death in lung cancer H1299 cells was analysed. Materials and methods Human lung cancer cells, H1299, were used, and cell models with ATM −/− and MAPK 14 −/− were established by genetic engineering. Radiosensitivity was analysed using colony formation assays. Western blotting and co‐immunoprecipitation were implemented to detect protein expression and interaction. MDC staining and GFP ‐ LC 3 relocalization were used to detect autophagy. Results Autophagy as well as phosphorylation of ATM was activated by ionizing radiation. Both the inhibitor of ATM , KU 55933 and ATM silencing reduced phosphorylation of ATM and MAPKAPK 2 expression. Both ATM −/− and MAPK 14 −/− cells displayed hypersensitivity. IR increased autophagy level by more than 129% in DMSO ‐treated cells, while only by 47% and 27% in KU 55933‐treated and ATM −/− cells respectively. MAPK 14 knock‐down alone gave rise to the basal autophagy level, but decreased notably after IR . KU 55933 and ATM knock‐down inhibited IR ‐induced autophagy by activating mTOR pathways. Both Beclin1– PI 3 KIII and Beclin1– MAPKAPK 2 interactions as were remarkably affected by silencing either ATM or MAPK 14. Conclusions ATM promoted IR ‐induced autophagy via the MAPK 14 pathway, mTOR pathway and Beclin1/ PI 3 KIII complexes. MAPK 14 contributed to radiosensitization of H1299 cells.