Effects Of PMS2 Regulation Of PCNA/MMR Pathway On SW-480 Biological Behavior In Colon Cancer Cells

To investigate the effect of PMS2 on the invasion,proliferation and platinum sensitivity of colorectal cancer cell line SW-480,and to elucidate its mechanism through the detection of MMR pathway protein.Methods1.First,TIMER database was used to analyze PMS2 for pan-cancer,and then TCGA database was used to download a data containing 696 samples and carry out bioinformatics analysis to analyze the predictive ability and clinical significance of PMS2 for colorectal cancer;The appropriate cell line SW-480 was selected by detecting the expression level of PMS2 by fluorescence quantitative PCR and immunofluorescence blotting.The si-RNA and overexpression plasmid for PMS2 were designed,and the SW-480 was transfected by transient transfection.2.The biological behavior of the cells after knockout and overexpression was detected.The transfected cells were divided into knockout group(si-PMS2)and control group(si-NC);Overexpression group: experimental group(PMS2-mini cs),control group(PMS2-mini cs NC).3.The proliferative ability of cells was detected by CCK8 method;Transwell method was used to detect the invasiveness of cells;The median lethal concentration of SW-480 cells to cisplatin was detected,and the sensitivity of cells to cisplatin was detected by flow cytometry and CCK8 method.4.The protein interaction website STRING predicts that PMS2 plays a key role in the mismatch repair pathway(MMR).Western blot is used to detect the expression level of the downstream pathway protein of MMR after PMS2 knockdown and overexpression.Results1.TIMER analysis showed that the expression level of PMS2 in most cancer tissues was higher than that in normal tissues or adjacent tissues;Through the analysis of colorectal cancer data downloaded by TCGA,it was also found that the expression level of PMS2 in colorectal cancer tissue was higher than that in normal tissue.In the analysis of the ROC curve of PMS2 in the sample,it was found that the cut-off value of the ROC curve was 2.867,and PMS2 had certain statistical significance for the prognosis of the tumor(AUC=0.791,CI=0.751-0.831).2.After transfection of si-RNA,RT-PCR and western blot were performed in si-PMS2 group and control group.The expression level of PMS2 in si-PMS2 group was much lower than that in si-NC group(P<0.05).Western blot was performed in PMS2-mics group and control group.The expression level of PMS2-mics group was higher than that in PMS2-mics NC group(P<0.05).3.After the deletion of PMS2,the proliferation ability,invasion ability and migration ability of SW-480 were enhanced(P<0.05),and the sensitivity of cisplatin was decreased(P<0.05);However,overexpression would weaken the proliferation ability(P<0.05),migration ability(P<0.05)and increase the sensitivity of cisplatin(P<0.05).4.The expression level of PCNA,RPa1 and Lig1 protein decreased significantly after the deletion of PMS2(P<0.05);After overexpression of PMS2,the expression levels of PCNA,RPa1 and Lig1 protein were significantly increased(P<0.05).Conclusions1.Overexpression of PMS2 will weaken the proliferation and invasion ability of SW-480 in colon cancer cells,and enhance cisplatin sensitivity.Knockdown will enhance the proliferation and invasion ability of SW-480,and the sensitivity of cisplatin will be weakened.2.PMS2 regulates the biological behavior of SW-480 in colon cancer cells through PCNA/MMR pathway.