线粒体细胞色素B在胃癌组织的表达及临床意义

Expression of mitochondrial cytochrome B in gastric cancer and clinical implication

目的 应用蛋白质组学方法筛选有转移和无转移的患者胃癌标本差异蛋白表达.方法 收集经病理检查证实为胃癌的手术患者12例,其中淋巴结转移标本6例,无淋巴结转移标本6例.应用双向凝胶电泳、胶图分析、质谱分析及国家生物技术信息中心（NCBI）数据库筛查并鉴定差异蛋白,并采用荧光定量聚合酶链反应（FQ-PCR）检测证实.结果 通过双向凝胶电泳、质谱分析及数据库查询,发现转移组与无转移组共存在10种差异表达蛋白,其中1种差异蛋白为线粒体细胞色素B（CytB）,其在转移组中表达水平明显降低;FQ-PCR检测证实CytB转移组明显降低（P＜0.05）;原位缺口末端标记法（TUNEL）凋亡检测发现,有淋巴转移的胃癌组织细胞凋亡率为（14.42±3.62）％,明显少于无淋巴转移组[（22.32±0.02）％,P＜0.05].结论 CytB的异常表达可能是促进胃细胞发生转移的重要因素,其作用机制可能是通过破坏呼吸链,引起继发性氧自由基（ROS）产生增加,从而促进肿瘤细胞增殖和转移.

Objective To screen the differentially expressed proteins in gastric cancer specimens with or without metastasis by proteomics methods.Metbods The resected specimens from 12 patients with gastric cancer confirmed pathologically were collected,including 6 cases of specimens with lymph node metastasis,and 6 cases of specimens without lymph node metastasis.The differentially expressed proteins were screened and identified by two-dimensional gel electrophoresis,glue diagram analysis,mass spectrometry and National Center for Biotechnology Information （NCBI） database,and confirmed by real-time fluorescent quantitative polymerase chain reaction （FQ-PCR）.Results Two-dimensional gel electrophoresis,mass spectrometry and database queries revealed that there were l0 differentially expressed proteins between metastasis group and non-metastasis group,and one of the differentially expressed proteins was mitochondrial cytochrome B （CytB） encoded by the right of mitochondrial proteins.The CytB expression was significantly reduced in the metastasis group.TdT-mediated dUTP nick end labeling （TUNEL） assay showed that apoptosis rate was significantly decreased in the metastasis group as compared with non-metastasis group [（14.42 ± 3.62） % vs.（22.32±0.02）%,P〈0.05].Conclusion Abnormal expression of CytB may be an important factor in promoting metastasis of gastric cancer cells,and the mechanism may be that the depressed CytB destroyed the respiratory chain,which leads to increased secondary reactive oxygen species （ROS） production,thereby promoting the proliferation and metastasis of tumor cells.