The Expression Of Cdk5 And Its Effect On PD-L1 In Non-small Cell Lung Cancer

Objective: To detect the expressionof cyclin-dependent kinase-5(Cdk5)on the malignant biological function of non-small cell lung cancer(NSCLC)cell lines and the effect on PD-L1 expression.Methods:1 Quantificational real-time polymerase chain reaction(qRT-PCR)and Western blot assays were used to evaluate Cdk5 expression levels in five NSCLC cell lines(H1975,H1299,A549,H520,H460)and the embryo lung cell line 2BS.2 RNA interfere method were used to constructedCdk5 low-expression cells(shCdk5),empty vector group(shNS)and blank control group(WT)were set up simultaneously.MTS and clone formation assays were used to detect the effect of Cdk5 on cell proliferation ability.FCM assay was performed to evaluate the effect of Cdk5 on cell cycle.Wound healing and transwell chamber experiments were used to evaluate the effect of Cdk5 on cell migration and cell invasion.3(qRT-PCR)and Western were used to detected the expresssion of PDL1 on five NSCLC cell lines(H1975,H1299,A549,H520,H460)and the embryo lung cell line 2BS.The effect of shCdk5 on the expression of PD-L1 was examined by qRT-PCR and Western blot assays.Results:1.The expression of Cdk5 in H460,A549,H1299,H520,H1975 cells was higher compared to that of 2BS.Among these cells,Cdk5 expression was highest inH460 and A549,while lowest in H1299.2.The H460 cell line with stable low-expression of Cdk5 was obtained by flow cytometry.The results of MTS showed that cell proliferation activity in shCdk5 cell was inhibited compared to control groups(P<0.05).Colony formation assay results showed that the clone efficiency of shCdk5 cells was significantly inhibited(P<0.05).Cell cycle experiments showed that the ratio of G0/G1 phase in shCdk5 cells increased significantly(P<0.05).The results of apoptosis experiments showed that the number of apoptotic cells in shCdk5 group was significantly increased(P<0.05).The results of wound healing assay showed that the distance of migration was significantly decreased in shCdk5 group(P<0.05).Transwell assay showed that the number of transmembrane cells in shCdk5 group was significantly decreased(P<0.05).3.The expression of PD-L1 gene and protein in H1975,H520,H460 and A549 cells was higher compared to that of 2BS(P<0.05).The expression of PD-L1 in H460 cells was significantly down-regulated in shCdk5 group compared to that of control groups(P<0.05).Conclusions:1.Compared to 2BS,Cdk5 was overexpress in NSCLC cells H1975,H1650,A549,H460.Cdk5 stably expressed H460 cells was constructed successfully.Low expression of Cdk5 could inhibit the abilities of proliferation,migration,invasion and apoptosis.2.The expression of Cdk5 was high in 5 different NSCLC cells.Knockdown the expression of Cdk5 could downregulate the expression of PD-L1,which indicate that Cdk5 might affect on tumor immune escape through PD-L1 pathway.