胃泌素受体拮抗剂丙谷胺和选择性COX2抑制剂塞来昔布对人胃癌细胞株BGC-823增殖和PGE2分泌的影响

Expression of gastrin in colon cancer and its effect on human colon cancer cell proliferation and P38 signal transduction pathway

BACKGROUND

Colon cancer (CC) is a common malignant tumor of the digestive system in China. The early diagnosis is low due to nonspecific symptoms, which leads to the loss of chance of radical surgery and a high mortality rate, greatly harming patients' life and health. Gastrin is a hormone that is mainly secreted from G cells in the gastrointestinal tract. Upon binding to gastrin receptors, it stimulates gastric acid secretion and promotes gastrointestinal mucosal growth. Mitogen-activated protein kinases (MAPKs) are a group of serine-threonine protein kinases that are activated by hormones such as gastrin and are responsible for signal transduction between the cell surface and the nucleus.

AIM

To analyze the expression of gastrin in CC patients, and to investigate the inhibitory effect of gastrin receptor antagonist on human CC cell line and the P38 signal transduction pathway.

METHODS

From January 2016 to October 2018, 30 CC specimens collected from the Department of Pathology of our hospital were divided into poorly, moderately, and highly differentiated specimens according to the criteria of the World Health Organization's malignant tumor differentiation. The immunohistochemical technique was used to detect the expression of gastrin in these specimens. The human CC cell line SW480 was cultured in vitro, and the cells were divided into a control group (no drug treatment), a gastrin group (6.25-200.00 mg/L of gastrin was added), a proglumide group (8.00-256.00 mg/L of proglumide for treatment), and a gastrin plus proglumide group (12.5 mg/L gastrin and 8.00-256.00 mg/L proglumide for treatment). The expression of gastrin receptor/cholecystokinin-B receptor in SW480 cells was detected, and SW480 cell viability, proliferation index, and expression of P38 signal transduction pathway molecules (P38 protein, phosphorylated P38 protein, Bcl-2, and BAX) in different groups were compared.

RESULTS

The higher the degree of differentiation of CC tissues, the higher the positive rate of gastrin expression. The OD values of SW480 cells treated with gastrin at concentrations ranging from 6.25 to 200.00 mg/L were significantly higher than those in control cells (P < 0.05). Gastrin at a concentration of 12.50 mg resulted in the highest OD value in SW480 cells (P < 0.05). There was no significant difference in OD values of SW480 cells treated with gastrin at concentrations between 25.00 and 200.00 mg/L (P > 0.05). There was no significant difference in OD values of SW480 cells treated with glutamine at concentrations of 8.00-256.00 mg/L (P > 0.05). Gastrin at 12.50 mg/L combined with 16.00 mg/L of proglumide resulted in the lowest OD value in SW480 cells, which was significantly lower than that in the control group (P < 0.05), but this significant difference disappeared with the increase of proglumide concentration (P > 0.05). The cell proliferation index of the gastrin group (12.50 mg/L) was significantly higher than those of the proglumide group (16.00 mg/L) and the gastrin plus proglumide group (12.5 mg/L + 16.00 mg/L) (P < 0.05). The levels of P38 protein expression and phosphorylation and BAX protein expression in the gastrin group (12.50 mg/L) were significantly lower than those of the control group, proglumide group (16.00 mg/L), and gastrin plus proglumide group (12.5 mg/L + 16.00 mg/L), while Bcl-2 protein expression was significantly higher that in the control group, proglumide group (16.00 mg/L), and gastrin plus proglumide group (12.5 mg/L + 16.00 mg/L) (P < 0.05).

CONCLUSION

Gastrin can inhibit the apoptosis of human CC cell line SW480, and its expression in CC is related to the degree of tumor differentiation. The higher the degree of differentiation, the higher the expression level. Gastrin receptor antagonist can antagonize the proliferative effect of gastrin via mechanisms possibly related to up-regulation of P38 expression, phosphorylation of P38, and BAX expression and down-regulation of Bcl-2 expression.