EphB2蛋白在结直肠癌中的表达及意义

Expression of EphB2 in colonrectal carcinoma and its significance

目的:研究EphB2蛋白在不同临床病理分期的结直肠癌组织以及在不同转移能力的结直肠癌细胞株中的表达差异,并初步探讨EphB2对结直肠癌作用的相关机制。方法:运用免疫组织化学法检测43例结直肠癌和10例正常组织中EphB2受体的表达及间质微血管密度(microvascular density,MVD);体外培养SW480、HT29、HCT116和LoVo等4种具有不同转移能力的结直肠癌细胞株,Western印迹法检测EphB2蛋白的表达,RT-PCR法检测EphB2 mRNA水平的表达。结果:EphB2在大多数结直肠癌细胞质中表达,EphB2受体的表达和肿瘤的浸润深度以及远处转移呈负相关,与肿瘤组织的分化程度呈正相关,EphB2蛋白的表达与肿瘤的MVD呈正相关;高转移性结直肠癌细胞株HCT116和LoVo中EphB2蛋白及EphB2 mRNA的表达均较低转移性细胞株SW480和HT29明显降低。结论:EphB2表达对肿瘤的生长可能起抑制作用,EphB2表达的减少能促进肿瘤的形成和演进。影响肿瘤血管形成的功能可能是EphB2抑制肿瘤生长机制中的一种。

Objective：To investigate the differentiated expressions of EphB2 protein in colorectal carcinoma at different clinicopathologic staging and in different colorectal carcinoma cell lines with varying metastasis potential and explore the effect of EphB2 on colorectal cancer and its action mechanism. Methods： Immunohistochemistry was used to detect the expression of EphB2 and mierovaseular density （MVD） in coloreetal carcinoma tissues （n = 43 ） and normal colon tissues （n = 10） was detected. Four colorectal carcinoma cell lines with varying metastasis potential, SW480, HT29, HCT116, and LoVo cells, were cultured in vitro. The expression of EphB2 protein was measured by Western blotting and the transcription of EphB2 mRNA was determined by RT-PCR. Results： EphB2 was expressed in the cytoplasm of the most colon carcinomas. EphB2 receptor expression was negatively related with tumor infiltration depth and distant metastasis; EphB2 receptor expression was positively related with the differentiation degree of colon cancer. Expression of EphB2 protein had positive correlation with MVD in tumor tissues ; the expression level of EphB2 was decreased in high-metastatic HCT116 and LoVo cells compared with low-metastatic SW480 and HT29 cells. Conclusion： Decreased expression of EphB2 may promote the carcinogenesis and progression of colorectal carcinoma. One of the explanations for the effect of EphB2 is its regulaion on tumor angiogenesis.