蛋白质组学检测β-原肌球蛋白在结肠癌组织中的表达

目的：通过比较结肠腺癌与正常结肠黏膜的蛋白质组表达差异，寻找与结肠腺癌发生相关的蛋白质，筛选结肠癌诊断的分子标志物。方法: 运用蛋白质组学技术，对8例结肠腺癌组织和8例正常结肠黏膜组织进行胶内差异双向电泳（2-D），选择差异表达超过2倍的蛋白质进行MALDI-TOF/TOF质谱分析和生物信息学分析，并对结肠癌组织中表达下调的蛋白β-原肌球蛋白(TM β)进行Western blotting验证。结果: 成功建立结肠腺癌和正常结肠黏膜的双向凝胶电泳图谱，结肠腺癌和正常黏膜组织凝胶电泳图谱中平均蛋白质斑点数分别为3 289和3 066，其中表达差异超过2倍的斑点共有31个，质谱分析和数据库检索共鉴定出18种蛋白质，包括cytokeratin 8、cytokeratin 10、S100A6、TM β、protein disulfide isomerase 等。从功能分析，这些差异蛋白与癌细胞的发生、增殖、分化、转移等相关；TM β在结肠癌组织中的表达水平Western blotting结果与电泳结果一致。结论: 蛋白质组学能有效地分离和鉴定结肠腺癌组织与正常结肠组织间的差异表达蛋白质，结肠癌组织中表达下降的TMβ，可能成为结肠癌诊断的分子标记物。

Downregulation of beta tropomyosin protein expression in colon adenocarcinoma

AIM: To investigate the cancer associated proteins and sensitive biomakers for early diagnosis in colon adenocarcinoma by using proteomic technique.METHODS: Two-dimensional gel electrophoresis was used to define patterns of protein expression in adenocarcinoma tissue from 8 patients with matched normal colonic mucosa. Proteins expressed differently of a 2-fold change were cut and analyzed by MALDI-TOF/TOF mass spectrometry. RESULTS: Two-dimensional protein maps of adenocarcinoma and normal colonic mucosa were gained successfully. Gel-analysis software identified an average of 3 289 spots in adenocarcinoma while 3 066 in normal mucosa and statistical filtering yielded 31 spots of a 2-fold change, 18 of which were identified by using mass spectrometry, including cytokeratin 8, cytokeratin 10, S100A6, beta tropomyosin (TMβ), protein disulfide isomerase, etc. Functional analysis revealed that these proteins were associated with adenocarcinoma cellular oncogenesia, proliferation, differentiation, metastasis and so on. The results of Western blotting validated that the expression level of TM β in colon adenocarcinoma was much lower than that in matched normal colonic mucosa.CONCLUSION: Proteomic analysis can identify the proteins with variance of colon adenocarcinoma versus normal colonic mucosa. Downregulation of TM β might serve as a new biomarker of colon adenocarcinoma.