半乳糖凝素-3在结肠癌肝转移中的表达及改良柑橘果胶对其抑制作用

目的 探讨半乳糖凝素-3(galectin-3,Gal-3)在小鼠结肠癌肝转移中的表达及改良柑橘果胶(MCP)对它的抑制作用.方法 75只Balb/c小鼠随机分为阴性对照组、阳性对照组和低、中、高浓度MCP组.阳性对照组和各MCP治疗组小鼠经脾脏下极包膜注入CT26结肠癌细胞建立结肠癌肝转移模型.MCP加入饮用水,浓度分别为0、0、0.01、0.025、0.05mg/ml.3周后观察各组小鼠肝转移情况.采用ELISA方法检测小鼠血清Gal-3浓度;制作肝转移瘤组织芯片,用免疫组化方法检测肝转移瘤组织中Gal-3的表达.结果 (1)除阴性对照组外各组肝转移率分别为100%、80%、73.3%和60%.高浓度MCP组肝转移灶数目明显低于对照组(P＜0.05).(2)除阴性对照组外各组脾脏原发瘤体积中位数分别为1.51、0.93、0.77和0.70 cm3.高浓度MCP组肿瘤体积较对照组明显缩小(P＜0.05).(3)阳性对照组和各治疗组血荊al-3浓度均明显高于阴性对照组(P＜0.01);阳性对照组与各治疗组比较无明显差异(P＞0.05).(4)除阴性对照组外各组肝转移瘤组织中Gal-3表达相互间比较无明显差异(P＞0.05).结论 Gal-3在结肠癌肝转移中呈高水平表达,MCP能明显抑制结肠癌肝转移.

Expression of galectin-3 in liver metastasis of colon cancer and the inhibitory effect of modified citrus pectin

OBJECTIVE:To observe the expression of galectin-3 in the liver metastasis of colon cancer in mice and the inhibitory effect of modified citrus pectin (MCP) on galectin-3 expression. METHODS: Seventy-five Balb/c mice were randomized into 5 groups, namely the negative control, positive control, low-concentration MCP, moderate-concentration MCP and high-concentration MCP groups. CT26 colon cancer cells were injected into the subcapsule of the mouse spleen to establish liver metastasis models of colon cancer, but the mice in the negative control group received no tumor cell injection. MCP was added into the drinking water of the mice at the concentrations of 0, 1.0%, 2.5% and 5.0% (m/V). The liver metastasis was observed 3 weeks after tumor cell inoculation. Enzyme-linked immunosorbent assay was performed to determine the serum galectin-3 level. A tissue microarray of the liver metastasis was prepared for immunohistochemical detection of galectin-3 expression in the liver metastasis.RESULTS: In the positive control, low-, moderate- and high-concentration MCP groups, the rates of liver metastasis were 100%, 80%, 73.3% and 60%, respectively. The number of liver metastases in high-concentration MCP group was significantly smaller than that in the positive control group (P<0.05). In the 4 groups with tumor cell inoculation, the median volume of the primary lesions in the spleen was 1.51, 0.93, 0.77 and 0.70 cm(3), respectively, which were significantly smaller in the moderate- and high-concentration MCP groups than in the positive control group (P<0.05). The serum galectin-3 level in the positive control group and MCP-treated groups were significantly higher than that in the negative control group (P<0.01), but similar between the positive control group and the MCP-treated groups (P>0.05). In the positive control and the MCP-treated groups, the expression of galectin-3 in the liver metastases showed no significant differences (P>0.05). CONCLUSION: The expression of galetin-3 is significantly increased in the liver metastasis of colon cancer, and MCP can effectively inhibit the liver metastasis.