Abstract:

AIM: To investigate the effects and mechanisms of exrtacellular-signal regulated protein kinase in gastrin-induced cell proliferation of colorectal cancer cells by using RNA interference technology.  METHODS: CCK-BR positive cell strain CACO2 was constructed lentivirus infection. Detection of gastrin receptor (CCK-BR) expression in colorectal cancer cell line CACO2 by qRT-PCR. RNA interference was used to silence the ERK1/2 gene, and the expression of total ERK protein and its phosphorylation level were analyzed. The experiment was divided into four groups: The control group, negative interference group, gastrin group and plasmid interference group. Changes of proliferation index of CACO2 cells were detected by cell cytometry. The protein of ERKl/2 and phosphorylation levels were detected by Western blot. RESULTS: After chronic viral infection, the target strip membrane protein and mRNA expression of CCK-BR were detected in the CACO2 cells. The amplified product was 185 bp. The interference plasmid was selected, the ratio of plasmid and liposome was 1∶2, the transfection efficiency was 40%-50%, and the expression level of ERK protein in the transfected plasmid was decreased. From the protein level,the constructed plasmid was observed effective. The proliferation index of the gastrin group was significantly higher than that of the plasmid interference group,the negative interference group and the blank control group, the difference was statistically significant (P<0.01). The expression of ERK1/2 protein and phosphorylation level in the four groups were significantly different (P<0.01). The protein expression and phosphorylation level of ERK1/2 in gastrin group were significantly higher than those in the plasmid interference group, the negative interference group and the blank control group, the difference was statistically significant (P<0.01). CONCLUSION: Gastrin can promote the proliferation of CACO2 cells in vitro by ERK signaling pathway. RNA interference can effectively block the phosphorylation of ERK protein in ERK signaling pathway, which is expected to provide a new approach for the treatment of colorectal cancer.

Key words: gastrin, ERK1/2, colorectal cancer, RNAi, lentivirus infection