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目的:通过蛋白质组学技术筛选出结直肠癌(CRC)组织中差异表达最显著的蛋白,并探讨其与CRC疾病特征的关系。方法:收集83例CRC患者手术标本,包括患者的CRC组织,正常大肠黏膜组织,转移的淋巴结以及部分患者同时长有的大肠良性息肉。用二维差异凝胶电泳(2D DIGE)及基质辅助激光解析飞行时间质谱(MALDI-TOF-MS)对新鲜的CRC与正常黏膜组织以行蛋白质组学分析。找出兴趣蛋白后,用Western blot法在新鲜的CRC与正常黏膜组织,以及不同的CRC细胞株中验证;用免疫组化检测石蜡包埋的CRC、正常黏膜、良性息肉和转移淋巴结组织中该蛋白的表达。用Western blot法检测CRC细胞株在丁酸钠(NaB)诱导分化后该蛋白的表达改变。结果:2D-DIGE分析和MALDI-TOF-MS鉴定结果显示,CRC组织中硒结合蛋白1(SELENBP1)表达丰度比正常黏膜组织明显降低2.54倍(P<0.01)。Western blot示,CRC组织中SELENBP1的表达水平明显低于其配对的正常黏膜组织[(0.76±0.37)vs.(1.46±0.56)](P<0.001),SELENBP1的表达在CRC细胞株中普遍降低。免疫组化示,SELENBP1的表达评分在CRC组织与正常黏膜组织中分别为1.25±0.78和2.02±0.77,组间差异有统计学意义(P<0.001);在高、中、低分化的CRC组织中分别为1.75±0.53,1.29±0.41,0.89±0.49,组间差异有统计学意义(P<0.05);在不同分期的CRC组织间、良性息肉与正常黏膜间、转移淋巴结与其配对的原发癌间,差异均无统计学意义(均P>0.05)。各CRC细胞株经NaB分化诱导后,SELENBP1表达均明显增高(均P<0.05)。结论:CRC组织SELENBP1表达降低,SELENBP1表达降低与CRC低分化程度有关,但与疾病进展及淋巴结转移无关。
OBJECTIVE: To screen out the most differentially expressed proteins in colorectal cancer (CRC) tissues by proteomics and to explore their relationship with CRC disease characteristics. METHODS: Totally 83 surgical specimens of CRC patients were collected, including CRC tissues of patients, normal colorectal mucosa, metastatic lymph nodes and some patients with benign polyps of large intestine. Fresh CRC and normal mucosal tissues were subjected to proteomic analysis using 2D DIGE and MALDI-TOF-MS. The protein of interest was identified by Western blot in fresh CRC and normal mucosa as well as in different CRC cell lines. Immunohistochemistry was used to detect the expression of paraffin-embedded CRC, normal mucosa, benign polyps and metastatic lymph node tissue Protein expression. Western blot was used to detect the expression changes of CRC cells after sodium butyrate (NaB) -induced differentiation. Results: The results of 2D-DIGE and MALDI-TOF-MS showed that the expression of SELENBP1 in CRC tissues was significantly decreased by 2.54-fold (P <0.01) compared with normal mucosa. Western blot showed that the expression of SELENBP1 in CRC tissues was significantly lower than that in matched normal mucosa [(0.76 ± 0.37) vs. (1.46 ± 0.56)] (P <0.001), and the expression of SELENBP1 was generally lower in CRC cell lines . Immunohistochemistry showed that the expression score of SELENBP1 in CRC tissue and normal mucosa were 1.25 ± 0.78 and 2.02 ± 0.77, respectively. The difference between the two groups was statistically significant (P <0.001). In high, moderate and poorly differentiated CRC tissues (P <0.05). Among the different stages of CRC, benign polyps and normal mucosa, lymph node metastasis and its matched primary There was no significant difference between the two groups (all P> 0.05). The expression of SELENBP1 was significantly increased in all CRC cell lines induced by NaB differentiation (all P <0.05). Conclusion: The expression of SELENBP1 is decreased in CRC tissues. The decreased expression of SELENBP1 is associated with the poorly differentiated CRC, but not with the progression of disease and lymph node metastasis.