Purpose To investigate the expression of POLR2M in colorectal cancer(CRC)and its effects on cell growth,apoptosis and invasion.Methods GEPIA2.0,TCGA and Kaplan-Meier Plotter databases were used to ana-lyze the differential expression of POLR2M in CRC tissues and normal adjacent tissues,and to evaluate its prognostic significance using the Log-rank test.Quantitative real-time PCR(qRT-PCR)was used to detect the expression of POLR2M in human colorectal cancer cell lines SW480,HCT-8,RKO,LOVO,DLD-1,HCT-116,SW620 and human normal colorectal cell line FHC.DLD-1 and RKO cells were stably transfected with lentivirus,and the POLR2M groups were up-regulated into the control group(LV-NC)and experimental group(LV-POLR2M),and the transient transfec-tion of SW620 and SW480 cells with interfering fragments of SiRNA was used to down-regulate the POLR2M groups into the control group(Si-NC)and experimental group(Si-POLR2M),and the transfection efficiency of each group was verified.CCK-8,plate cloning,Transwell and scratch healing assays were used to detect cell proliferation,invasion and migration.Flow cytometry was used to detect the effects of POLR2M on cell cycle and apoptosis.Results GE-PIA2.0,TCGA and Kaplan-Meier Plotter database analysis showed that the expression of POLR2M in colorectal cancer was significantly higher than in normal adjacent tissues(P＜0.05),and the expression of POLR2M was closely associ-ated with the histological type of colorectal cancer and lymph node metastasis(P＜0.05),but not with the age,gen-der,tumor grade and vascular invasion of patients(P＞0.05).The prognosis of patients with POLR2M overexpression was poor(P＜0.05).The results of qRT-PCR showed that compared with FHC cells,the mRNA expression of POLR2M in SW480,HCT-8,RKO,LOVO,DLD-1,HCT-116 and SW620 cell lines was increased(F=97.7,P＜0.05),and POLR2M stable overexpression and interference cell lines were successfully constructed.Compared with the LV-NC group,the viability,colony number,number of cells passing through the chamber and cell mobility of DLD-1 and RKO cells in the LV-POLR2M group were significantly increased(P＜0.05).Compared with the Si-NC group,the viability,colony number,number of cells passing through the chamber,and cell mobility of SW620 and SW480 cells in the Si-POLR2M group were significantly decreased(P＜0.05).Downregulation of POLR2M induced cell cycle arrest in G1 phase and promotes apoptosis(P＜0.05).Conclusion POLR2M may play a role as a pro-tumor gene in CRC,and its high expression can significantly promote the proliferation and invasion of CRC cells.

Purpose To investigate the expression of POLR2M in colorectal cancer(CRC)and its effects on cell growth,apoptosis and invasion.Methods GEPIA2.0,TCGA and Kaplan-Meier Plotter databases were used to ana-lyze the differential expression of POLR2M in CRC tissues and normal adjacent tissues,and to evaluate its prognostic significance using the Log-rank test.Quantitative real-time PCR(qRT-PCR)was used to detect the expression of POLR2M in human colorectal cancer cell lines SW480,HCT-8,RKO,LOVO,DLD-1,HCT-116,SW620 and human normal colorectal cell line FHC.DLD-1 and RKO cells were stably transfected with lentivirus,and the POLR2M groups were up-regulated into the control group(LV-NC)and experimental group(LV-POLR2M),and the transient transfec-tion of SW620 and SW480 cells with interfering fragments of SiRNA was used to down-regulate the POLR2M groups into the control group(Si-NC)and experimental group(Si-POLR2M),and the transfection efficiency of each group was verified.CCK-8,plate cloning,Transwell and scratch healing assays were used to detect cell proliferation,invasion and migration.Flow cytometry was used to detect the effects of POLR2M on cell cycle and apoptosis.Results GE-PIA2.0,TCGA and Kaplan-Meier Plotter database analysis showed that the expression of POLR2M in colorectal cancer was significantly higher than in normal adjacent tissues(P＜0.05),and the expression of POLR2M was closely associ-ated with the histological type of colorectal cancer and lymph node metastasis(P＜0.05),but not with the age,gen-der,tumor grade and vascular invasion of patients(P＞0.05).The prognosis of patients with POLR2M overexpression was poor(P＜0.05).The results of qRT-PCR showed that compared with FHC cells,the mRNA expression of POLR2M in SW480,HCT-8,RKO,LOVO,DLD-1,HCT-116 and SW620 cell lines was increased(F=97.7,P＜0.05),and POLR2M stable overexpression and interference cell lines were successfully constructed.Compared with the LV-NC group,the viability,colony number,number of cells passing through the chamber and cell mobility of DLD-1 and RKO cells in the LV-POLR2M group were significantly increased(P＜0.05).Compared with the Si-NC group,the viability,colony number,number of cells passing through the chamber,and cell mobility of SW620 and SW480 cells in the Si-POLR2M group were significantly decreased(P＜0.05).Downregulation of POLR2M induced cell cycle arrest in G1 phase and promotes apoptosis(P＜0.05).Conclusion POLR2M may play a role as a pro-tumor gene in CRC,and its high expression can significantly promote the proliferation and invasion of CRC cells.