胃癌线粒体D-loop(CA)n和ND1及ND5基因突变的研究

Gene mutation of mitochondrial D-loop-(CA)n,ND1 and ND5 in gastric carcinoma

目的:探讨胃癌线粒体DNA(mitochondrial DNA,mtDNA)突变在胃癌发生发展中的作用。方法:利用激光显微切割技术分离胃癌组织及其切缘的正常组织,应用变性高效液相色谱技术DHPLC对胃癌线粒体D-loop调控区D-loop-(CA)n及电子传递链酶复合体Ⅰ的ND1和ND5基因进行突变筛查及测序分析。结果:胃癌组织样本中D-loop-(CA)n调控区、ND1和ND5基因突变率分别为50.8%(31/61)、39.3%(24/61)和21.3%(13/61),正常组织均未见有序列改变。胃癌组织D-loop-(CA)n调控区、ND1和ND5基因突变率与正常组织相比差异均有统计学意义,χ2值分别为41.560、29.878和14.550,P值均<0.001。测序共鉴定出17个突变位点,11个位点为同义突变未引起氨基酸改变,6个位点为错义突变发生了氨基酸改变。mtDNA突变类型主要为碱基替代(76.5%,13/17),其中碱基转换和颠换各占23.5%(4/17)和52.9%(9/17)。结论:胃癌mtDNA突变参与了肿瘤的发生发展。

OBJECTIVE： To investigate the mechanisms of the mitochondrial DNA mutation in the pathogenesis of gastric carcinoma. METHODS： The mitochondrial mutation from tumor and paired normal DNA was examined by tissue laser capture microdissection and denaturing high performance liquid chromatogragh （DHPLC）. RESULTS： The mitochondrial genetic mutation was detected in D-loop region,ND1 and ND5 genes which belong to electron respiratory chain complex I . The mutation frequencies among them were 50.8%（31/61） ,39.3%（24/61） and 21.3%（13/61） respectively while the control group of paired normal tissues found no mitochondriai genetic mutation, X2 were 41. 560,29. 878 and 14. 550,all P were 〈0. 001. According to the sequencing results, there were seventeen mitochondrial mutation locus. Among of them, eleven mutation locus were same sense mutation which did not change amino acid; six mutation locus were mis-sense mutation which can change amino acid. Base substitution was main type accounting for 76.5% （13/17） in mitochondrial mutation. Base transition and base transversion were 23.5 % （4/17） and 52.9 % （9/17） respectively in the seventeen base substitution. CONCLUTION： Mitochondrial DNA mutation may be one of important reasons for tumorgenesis of gastric carcinoma. [