Open AccessR ad51 in regulating the radiosensitivity of non‐small cell lung cancer with different epidermal growth factor receptor mutation status
Author(s) -
Zhong Xing,
Luo Guomin,
Zhou Xiaojuan,
Luo Wen,
Wu Xia,
Zhong Renming,
Wang Yanping,
Xu Feng,
Wang Jin
Publication year - 2016
Publication title -
thoracic cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 28
eISSN - 1759-7714
pISSN - 1759-7706
DOI - 10.1111/1759-7714.12274
Subject(s) - radiosensitivity , epidermal growth factor receptor , radioresistance , rad51 , microbiology and biotechnology , cell cycle , a549 cell , biology , apoptosis , mutant , cancer research , cell culture , cell , dna repair , medicine , cancer , dna , genetics , gene , radiation therapy
Background Non‐small cell lung cancer ( NSCLC ) harboring kinase‐domain mutations in epidermal growth factor receptors ( EGFR ) has been observed to be sensitive to ionizing radiation ( IR ). We explore R ad51‐dependent homologous recombination ( HR ) DNA repair in regulating radiosensitivity in two NSCLC cell lines with different EGFR mutation status. Methods NSCLC cell lines, wild‐type EGFR A 549 and mutant EGFR H 820 with an in‐frame deletion in exon 19 of EGFR (Δ E 746– E 750), were cultured. Radiosensitivity was estimated by colony forming assay. R ad51 expression was evaluated by quantitative real time‐polymerase chain reaction and W estern‐blot. Lentiviral small hairpin ribonucleic acid‐ R ad51 and Δ E 746– E 750 deletion mutant EGFR were constructed and transfected into cells. Flowcytometry assay was used to analyze DNA double strand breaks, cell cycle alterations, and apoptosis. Results A 549 had a higher survival factor ( SF )2 (0.66 vs. 0.44) and lower α/β value (4.07 vs. 9.01). Compared with the A 549 cell, the H 820 cell exhibited defective arrest in the S ‐phase, a higher rate of G2/M accumulation, early apoptosis, and residual γ‐ H2AX . Downregulated Rad51 expression decreased SF 2 (0.42 vs. 0.31) and increased the α/β ratio (7.51 vs. 10.5), G2/M accumulation, early apoptosis, and γ‐ H2AX in two cell lines. H 820 had a low IR ‐induced R ad51 expression and nuclear translocation. Exogenous expression of the Δ E 746– E 750 deletion mutant EGFR caused the A 549 cell to become more radiosensitive. Conclusions An EGFR mutated NSCLC cell line is sensitive to IR , which is correlated with reduced IR ‐induced R ad51 expression and nuclear translocation. The signaling pathway of EGFR maintaining R ad51 protein levels maybe a novel lung cancer therapeutic target to overcome radioresistance.