Li Wei, Zhang Xuede, Wang Wei, Sun Ruiying, Liu Boxuan, Ma Yuefeng, Zhang Wei, Ma Li, Jin Yaofeng, Yang Shuanying
Department of Respiratory Medicine, Second Affiliated Hospital of Xi'an Jiaotong UniversityXi'an 710004, Shaanxi Province, P. R. China.
Department of Oncology, Shandong Provincial Qianfoshan Hospital, Shandong UniversityJinan 250014, Shandong Province, P. R. China.
Am J Transl Res. 2017 Sep 15;9(9):3918-3934. eCollection 2017.
Lung adenocarcinoma is the most common type of lung cancer. Unfortunately, lung adenocarcinoma has a poor prognosis and the pathogenesis remains unclear. Mitochondria are important mediators of tumorigenesis. However, the proteomics profile of lung adenocarcinoma mitochondrial proteins has not been elucidated. In this study, we investigated differences in the mitochondrial protein profiles between lung adenocarcinomas and normal tissue. Laser capture microdissection (LCM) was used to isolate the target cells from lung adenocarcinomas and normal tissue. The differential expression of mitochondrial proteins was determined using isobaric tags for relative and absolute quantitation (iTRAQ) combined with two-dimensional liquid chromatography-tandem mass spectrometry (2D-LC-MS/MS). Bioinformatics analysis was performed using Gene Ontology and KEGG databases. As a result, 510 differentially expressed proteins were identified, 315 of which were upregulated and 195 that were downregulated. Of these proteins, 35.5% were mitochondrial or mitochondrial-related and were involved in binding, catalysis, molecular transduction, transport, and molecular structure. Based on the differentially expressed proteins, 63 pathways were significantly enriched through KEGG. The overexpression and cellular distribution of the mitochondrial protein C1QBP in the lung cancer samples was confirmed and verified by Western blotting. The relationship between C1QBP expression and clinicopathological features in lung cancer patients was likewise evaluated using immunohistochemistry, which revealed that the upregulation of C1QBP was associated with lymph node metastasis, pathological grade and clinical stage of TNM. The results indicate that the iTRAQ 2D-LC-MS/MS technique is a potential method for comparing mitochondrial protein profiles between tumor and normal tissue and could aid in identifying novel biomarkers and the mechanisms underlying carcinogenesis.
肺腺癌是肺癌最常见的类型。不幸的是，肺腺癌预后较差，其发病机制仍不清楚。线粒体是肿瘤发生的重要介质。然而，肺腺癌线粒体蛋白的蛋白质组学特征尚未阐明。在本研究中，我们调查了肺腺癌与正常组织之间线粒体蛋白质谱的差异。使用激光捕获显微切割（LCM）从肺腺癌和正常组织中分离目标细胞。使用相对和绝对定量的等压标签（iTRAQ）结合二维液相色谱-串联质谱（2D-LC-MS/MS）来确定线粒体蛋白的差异表达。使用基因本体论和KEGG数据库进行生物信息学分析。结果，鉴定出510种差异表达蛋白，其中315种上调，195种下调。在这些蛋白质中，35.5%是线粒体或与线粒体相关的，并且参与结合、催化、分子转导、转运和分子结构。基于差异表达蛋白，通过KEGG显著富集了63条通路。通过蛋白质印迹法证实并验证了肺癌样本中线粒体蛋白C1QBP的过表达和细胞分布。同样使用免疫组织化学评估了C1QBP表达与肺癌患者临床病理特征之间的关系，结果显示C1QBP的上调与TNM的淋巴结转移、病理分级和临床分期相关。结果表明，iTRAQ 2D-LC-MS/MS技术是一种比较肿瘤组织与正常组织线粒体蛋白质谱的潜在方法，有助于识别新的生物标志物和致癌机制。
