DNA Damage Induced By Human CD40 Ligand Mutant Promotes Senescence And Induces Demethylation Of GATA4 In Lung Cancer

Subject: To explore the effects and possible mechanism of CD40L-M on cellular senescence in CD40-positive NSCLC cell lines.Methods: Western blot was used to investigate the level of CD40L?p-p65?p65?I?B??p53?p21?p-Chk2?Chk2?p-Chk1 and Chk1.SA-?-gal staining was used to examine senescence.Cell cycle assay was performed to evaluate the effect of CD40L?M on cell cycle progression.CCK-8 assay was used to examine the effect of CD40L-M on the growth viability.MS-PCR assay was used to determine the methylation status of GATA4.Results: We found that CD40L-M-expressing cells had senescent characteristics,including reduced cell proliferation and enlargement,increased SA-?-gal staining activity,and overexpression of several cell cycle regulators p53 and p21.In addition,expression of GATA4 was restored,and the NF-?B signaling pathway was activated in CD40L-M-induced senescent cells.Mechanistic analyses revealed that CD40L-M expression triggered the ATM/Chk2 DNA damage response,which mediated cell senescence and induced GATA4 demethylation.Knockdown of GATA4 reversed CD40L-M-induced senescence and decreased NF-?B activity.Conclusion: CD40L-M induces senescence,inhibits cell proliferation and promote cell cycle arrest in CD40-positive NSCLC cells.We predict that CD40L-M transgene may represent a unique target with potential clinical applications in lung cancer.