Inhibitory effect of modified citrus pectin on liver metastases in a mouse colon cancer model

摘要

AIM: To discuss the expression of glactin-3 in liver metastasis of colon cancer and its inhibition by modi- fied citrus pectin (MCP) in mice. METHODS: Seventy-five Balb/c mice were randomly di- vided into negative control group (n = 15), positive con- trol group (n = 15), low MCP concentration group (n = 15), middle MCP concentration group (n = 15) and high MCP concentration group (n = 15). CT26 colon cancer cells were injected into the subcapsule of mouse spleen in positive control group, low, middle and high MCP concentrations groups, except in negative control, to set up a colon cancer liver metastasis model. The concen- tration of MCP in drinking water was 0.0%, 0.0%, 1.0%, 2.5% and 5.0% (wt/vol), respectively. Liver metastasis of colon cancer was observed after 3 wk. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentration of galectin-3 in serum. Expression of ga- lectin-3 in liver metastasis was detected by immunohis- tochemistry. RESULTS: Except for the negative group, the percent- age of liver metastasis in the other 4 groups was 100%, 80%, 73.3% and 60%, respectively. The number of liver metastases in high MCP concentration group was significantly less than that in positive control group (P = 0.008). Except for the negative group, the median volume of implanted spleen tumor in the other 4 groups was 1.51 cm3, 0.93 cm3, 0.77 cm3 and 0.70 cm3, respec- tively. The volume of implanted tumor in middle and high MCP concentration groups was significantly smaller than that in positive control group (P = 0.019; P = 0.003). The concentration of serum galectin-3 in positive control and MCP treatment groups was significantly higher than that in the negative control group. However, there was no significant difference between them. Except for the negative control group, the expression of galectin-3 in liver metastases of the other 4 groups showed no sig- nificant difference. CONCLUSION: Expression of galetin-3 increases sig- nificantly in liver metastasis of colon cancer, which can be effectively inhibited by MCP.