甲状腺乳头状癌与交界性病变的差异蛋白质组学研究

Differential proteomic study of papillary thyroid carcinoma and thyroid borderline lesion

目的:分析和鉴定甲状腺乳头状癌(papillary thyroid carcinoma,PTC)与交界性病变的差异表达蛋白,筛选新的蛋白标志物。方法:收集2013年4月至2015年2月云南省第一人民医院手术切除的甲状腺标本118例。实验组分别为PTC 43例(含经典型40例、滤泡亚型3例)、交界性病变33例(具有PTC样细胞核及乳头状结构,而缺乏包膜、血管侵犯,未发生转移的病例。其中8例合并非典型腺瘤),对照组为癌旁正常甲状腺组织42例。每组用10例冰冻样本提取总蛋白进行双向凝胶电泳(two-dimensional electrophoresis,2-DE),经PDQUEST 7.3图像分析软件检测3组的表达差异点,利用基质辅助激光解吸电离串联飞行时间质谱(MALDI-TOF/TOFMS)和Swiss-Prot数据库对差异蛋白进行鉴定,选择其中6种差异表达蛋白用118例样本通过免疫组织化学(immunohistochemistry,IHC)染色进行验证。结果:3组样本两两比较共发现24个蛋白差异点,通过质谱分析鉴定出18种差异表达蛋白。IHC染色显示6种蛋白keratin,typeⅡcytoskeletal 8(CK8)、keratin,typeⅠcytoskeletal 18(CK18)、60 k Da heat shock protein(HSP60)、actin,cytoplasmic 2(γ-Actin)、14-3-3 protein beta/alpha(14-3-3β/α)和14-3-3 protein epsilon(14-3-3ε)定位于细胞浆;在PTC中6种蛋白的表达均高于正常甲状腺组织(P<0.001),同时CK8、CK18、HSP60和γ-actin的表达高于交界性病变组(P<0.01);在交界性病变中,除CK8无明显变化外,其它5种蛋白的表达均高于正常对照组(P<0.001)。结论:蛋白质组学分析有助于发现新的PTC和交界性病变的蛋白标志物,IHC染色进一步确认这些蛋白在组织细胞中的表达模式,更有利于PTC的早期病理诊断。

Objective： To search for potential protein biomarkers of papillary thyroid carcinoma （PTC） and thyroid borderline lesion. Differentially expressed proteins between the two were analyzed and identified. Methods： A total of 118 cases of thyroid resection samples were obtained from patients who underwent surgery at the First People＇s Hospital of Yunnan Province from April 2013 to February 2015. Experimental groups included 43 PTCs （40 classic and 3 follicular variants） and 33 thyroid borderline lesions （with equivocal PTC type nuclear features and papillary structure, but without metastasis, and lacking capsular or vascular invasion; 8 cases with atypical adenoma）, respectively. The control group included 42 normal thyroid tissues adjacent to carcinoma. The total protein extracts from frozen thyroid samples of 10 cases in each group were profiled with 2D electrophoresis. The differential protein spots were then revealed by PDQUEST 7.3 software and identified by matrix-assisted laser desorption ionization time-of-fight/time-of-fight mass spectrometry and Swiss-Prot database search. Six differentially expressed proteins of these spots were further validated using 118 samples through immunohistochemistry. Results： A set of 24 differentially expressed spots significant in discriminating between the sample groups were found, and 18 proteins were identified. Immunohistochemistry revealed the following six proteins located in the cytoplasm： keratin, type II cytoskeletal 8 （CK8）; keratin, type I cytoskeletal 18 （CK18）; 60 kDa heat shock protein （HSP60）; actin, cytoplasmic 2 （y-actin）; 14-3-3 protein beta/alpha （14-3-3 β/a）; and 14-3-3 protein epsilon （14-3-3ε）. All six proteins were overexpressed in PTC compared with normal tissues （P〈0.001）. Meanwhile, CK8, CK18, HsP60, and -y-actin were overexpressed in PTC compared with borderline lesions （P〈0.01）. Except for CKg, the five other proteins were overexpressed in borderline lesions compared with normal tissues （P〈0.001）. Conclusion： Proteomic analysis is useful in searching for new biomarkers of PTC and thyroid borderline lesion. The ex- pression patterns of these differentially expressed proteins can be further validated using immunohistochemistry. The newly identified protein biomarkers can positively contribute to early PTC diagnosis.