Abstract:

Objective To discuss the effect of the expression of post-meiotic segregated protein 2 （PMS2） on the biological behaviors of colon cancer SW480 cells， and to clarify the relationships between PMS2 and excision repair cross-complementation group 1（ERCC1） and extracellular regulated protein kinase （ERK） signal transduction pathway. Methods The PMS2 siRNA and PMS2 over-expression plasmids were respectively transfected into the colon cancer SW480 cells （knockdown group and PMS2 over-expression group）. The PMS2 knockdown control group （siRNA-NC group） and PMS2 over-expression control group （PMS2 control group） were wet up.Real-time fluorescence quantitative PCR（RT-qPCR） method was used to detect the expression levels of PMS2 mRNA in cells in various groups； the expression levels of PMS2 protein in the cells in various groups were detected by Western blotting method； the proliferation activities of cells in various groups were detected by CCK-8 assay； cell scratch test was used to detect the migration rates of cells in various groups；the numbers of invasion cells in various groups were detected by Transwell chamber assay； the apoptotic rates of cells in various groups after cisplatin treatment were detected by flow cytometry；bioinformatics analysis was performed on the relationship between upstream and downstream proteins of PMS2， ERCC1， and ERK by using String Database；the PMS2 and ERCC1 knockdown in the SW480 cells were treated with 3 siRNA.The RT-qPCR method was used to verify the reaction between PMS2 and ERCC1；the expression levels of PMS2，extracellular regulated protein kinases 1/2（ERK1/2）， and phosphorylated ERK1/2（p-ERK1/2） proteins in the cells in various groups were detected by Western blotting method. Results The RT-qPCR and Western blotting results showed that the cell model of PMS2 gene knockdown and over-expression was successfully established. Compared with siRNA-NC group， the cell proliferative activity and cell migration rate in PMS2 knockdown group were increased（P<0.05 or P<0.01）， the number of invasion cells was increased（P<0.01），the apoptotic rate was decreased after cisplatin treatment （P<0.05）； compared with PMS2 control group， the cell proliferative activity and cell migration rate in PMS2 over-expression group were decreased（P<0.05）， the number of invasion cells was decreased（P<0.01）， and the apoptotic rate was increased after cisplatin treatment （P<0.05）.The protein-protein interaction （PPI） enrichment P value was 2.09e-07， including a total of 13 interaction nodes such as ERCC1 and ERK1/2， suggesting that there might be a regulatory effect between PMS2， ERCC1 and ERK1/2. Compared with siRNA-NC group， the expression levels of ERCC1 mRNA in the cells in various PMS2-knockout groups were significantly decreased （P<0.05 or P<0.01）. There was no significant difference in the expression of PMS2 mRNA in the cells between various ERCC1 knockdown groups and siERCC1-NC group （P>0.05）. Compared with siRNA-NC group， the expression levels of PMS2， ERK1/2， and p-ERK1/2 proteins in the cells in PMS2 knockdown group were decreased （P<0.05 or P<0.01）； compared with PMS2 control group， the expression levels of PMS2， ERK1/2，and p-ERK1/2 proteins in the cells in PMS2 over-expression group were increased （P<0.05）. Conclusion PMS2 expression can affect the proliferation， migration， invasion，and anti-apoptotic abilities of the colon cancer SW480 cells.PMS2 interacts with ERCC1 and participates in ERK signaling transduction pathway by regulating ERCC1.

Key words: Colon neoplasms, SW480 cells, Posteiotic segregation increased 2, Excision repair cross-complementation group 1, Extracellular regulated protein kinases 1/2, Signaling pathway