S Component Of Staphylococcus Aureus Induces Apoptosis And Cycle Arrest Of Non-small Cell Lung Cancer Cells Through The P38/ERK MAPK Signaling Pathway

Objectives Non-small cell lung cancer(NSCLC)is the most common histological subtype of lung cancer,accounting for about 80% of lung cancer.The expression of the complement C5 a receptor(C5a R)in the tumor is often related to the severity of the disease and the prognosis of the patient,its expression in non-small cell lung cancer tissues is higher than that in adjacent tissues.Panton-valentine leukocidin(PVL)secreted by staphylococcus aureus was composed of two components,Luk F-PV and LukS-PV,which could bind C5 a R,inhibit proliferation and invasion of leukemia cells,and induce apoptosis and differentiation.We speculated that LukS-PV might play a similar biological role in non-small cell lung cancer cells with increased C5 a R expression.In this study,the cell proliferation,migration,apoptosis and cell cycle were studied to investigate the effect and mechanism of LukS-PV on non-small cell lung cancer cells A549 and H460.Methods(1)Normal lung epithelial cells(16-HBE)and non-small cell lung cancer cells(A549,H460)were cultured in vitro,and stimulated with 0,0.25,0.5,0.75,1?M concentrations of LukS-PV for different times(0,12,24,36,48H),respectively.(1)The effect of LukS-PV on cell viability was determined by CCK-8 method.(2)The effect of LukS-PV on the proliferation of A549 and H460 cells was detected by Ed U test.(2)The effect of LukS-PV on the migration of NSCLC cells was detected by transwell assay,and Western blot was used to detect the expression of migration-related protein MMP-2.(3)FCM assay was used to detect the effect of LukS-PV on the apoptosis and cell cycle of A549 and H460 cells,RT-q PCR was used to detect the expression of cellcycle-related proteins(P21,Cyclin D1,Cyclin A2),and Western blot was used to detect the expression changes of apoptosis-related proteins(Bax,bcl-2)and cyclins(P21,Cyclin D1,CDK2).(4)The expression levels of p38,ERK and phosphorylated p38 and ERK in MAPK signaling pathway were measured by Western blot assay.(5)NSCLC cells A549 and H460 were pretreated with ERK inhibitor LY3214996 and p38 MAPK inhibitor SB203580 for 2H,and stimulated with LukS-PV for another 24 H.Then,they were divided into control group,LukS-PV-stimulated group,LukS-PV+SB203580group,LukS-PV+LY3214996 group and LukS-PV+SB203580+LY3214996 group,respectively.FCM assay was used to detected cell cycle and apoptosis in each group,and the phosphorylated p38,ERK as well as the expression levels of cell cycle and apoptosis-related proteins in each group were detected by Western blot.Results(1)LukS-PV can inhibit the proliferation of non-small cell lung cancer cells.(2)LukS-PV can down-regulate the expression of MMP-2 and inhibit the migration of non-small cell lung cancer cells.(3)LukS-PV can down-regulate the expression of bcl-2 and up-regulate the expression of Bax,inducing the apoptosis of non-small cell lung cancer cells.(4)LukS-PV can increase the expression of P21 and decrease the expression of Cyclin D1,Cyclin A2 and CDK2,inducing cell cycle arrest in the S phase.(5)LukS-PV can increase the expression of phosphorylated p38 and ERK,while the ERK inhibitor LY3214996 and the p38 MAPK inhibitor SB203580 antagonized the apoptosis and cycle arrest of non-small cell lung cancer cells induced by LukS-PV to some extent.Conclusions(1)LukS-PV has the effect of inhibiting proliferation as well as migration,and inducing apoptosis and cycle arrest of non-small cell lung cancer cells.(2)LukS-PV induces apoptosis and cycle arrest of non-small cell lung cancer cells through the p38/ERK MAPK signaling pathway.