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Rad51 in regulating the radiosensitivity of non-small cell lung cancer with different epidermal growth factor receptor mutation status.
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ABSTRACT: 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 Rad51-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 A549 and mutant EGFR H820 with an in-frame deletion in exon 19 of EGFR (ΔE746-E750), were cultured. Radiosensitivity was estimated by colony forming assay. Rad51 expression was evaluated by quantitative real time-polymerase chain reaction and Western-blot. Lentiviral small hairpin ribonucleic acid-Rad51 and ΔE746-E750 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
A549 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 A549 cell, the H820 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 SF2 (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. H820 had a low IR-induced Rad51 expression and nuclear translocation. Exogenous expression of the ΔE746-E750 deletion mutant EGFR caused the A549 cell to become more radiosensitive.Conclusions
An EGFR mutated NSCLC cell line is sensitive to IR , which is correlated with reduced IR-induced Rad51 expression and nuclear translocation. The signaling pathway of EGFR maintaining Rad51 protein levels maybe a novel lung cancer therapeutic target to overcome radioresistance.
SUBMITTER: Zhong X
PROVIDER: S-EPMC4718133 | biostudies-literature | 2016 Jan
REPOSITORIES: biostudies-literature
Publications
Rad51 in regulating the radiosensitivity of non-small cell lung cancer with different epidermal growth factor receptor mutation status.
Thoracic cancer 20150519 1
<h4>Background</h4>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 Rad51-dependent homologous recombination (HR) DNA repair in regulating radiosensitivity in two NSCLC cell lines with different EGFR mutation status.<h4>Methods</h4>NSCLC cell lines, wild-type EGFR A549 and mutant EGFR H820 with an in-frame deletion in exon 19 of EGFR (ΔE746-E750), were cultured ...[more]