应用荧光差异显示法对胃癌及癌前病变相关基因的研究

Study of Genes Related to Gastric Cancer and Its Premalignant Lesions with Fluorescent Differential Display

背景与目的:一般认为胃癌是由癌前病变(慢性萎缩性胃炎、肠化生和不典型增生)逐步发展形成的。mRNA差异显示法是筛选肿瘤发生、发展中差异表达基因的有用方法。在胃癌、癌前病变中寻找差异表达的基因将有助于确定胃癌发生前的胃粘膜组织的分子变化。方法:应用荧光mRNA差异显示技术分析胃癌(2例)、癌前病变(2例)和正常胃粘膜(2例)组织,鉴别并分离差异表达的基因片段,进行PCR再扩增。将扩增cDNA片段克隆后进行测序,测序结果提交GenBank,经BLAST软件检索以进行同源性分析。RT-PCR检测血影蛋白基因在胃癌(7例)、癌前病变(7例)和正常胃粘膜(7例)的表达。结果:发现4个差异表达的cDNA片段,其中3个cDNA片段在胃癌中高表达,1个cDNA片段在正常组织和癌前病变组织中高表达。1个在胃癌组织中高表达的cDNA片段与血影蛋白基因(SPTAN1)同源,RT-PCR检测也发现血影蛋白基因在胃癌组织中高表达。另外3个与GenBank中已知的基因序列同源,但其功能目前尚不清楚。结论:所发现的4个差异表达的基因有3个在胃癌组织中高表达,其中SPTAN1基因在胃癌组织的表达比正常胃粘膜及胃异型增生组织表达明显高。

BACKGROUND & OBJECTIVE: It is generally recognized that developm ent of gastric cancer arises gradually from premalignant lesions (chronic atroph ic gastritis, intestinal metaplasia and dysplasia). Differential display of mRNA is a valuable tool for the identification of differentially expressed gene s in human carcinogenesis and development. The search for differentially express ed genes in gastric cancer and its premalignant lesions may help to define molec ular alterations in the gastric mucosa tissue that may precede the development o f gastric cancer. METHODS: The differentially expressed cDNA bands were isolated and identified by fluorescent differential display in 2 gastric cancer, 2 prema lignant lesions, and 2 normal gastric mucosa tissues and then reamplified by PCR . After being cloned, all cDNA fragments were sequenced. Through BLAST software, the sequencing results were compared with GenBank database for homology analysi s. Expression of SPTAN1 in 7 gastric cancer tissues, 7 premalignant lesions, and 7 normal gastric mucosa tissues were identified by RT-PCR. RESULTS: Four diffe rentially expressed cDNA fragments were found. Three of them were over-expresse d in the gastric cancer tissue. One of them was over-expressed in premalignant lesions and normal gastric mucosa tissue. One cDNA fragment over-expressed in g astric cancer was homologous to SPTAN1 and its over-expression in gastric cance r was confirmed by RT-PCR. The other three cDNA fragments showed significant ho mology to known gene sequences in GenBank but their functions are unknown. CONCL USION: Three of the four differentially expressed genes over-expressed in gastr ic cancer. SPTAN1gene was significantly higher in gastric cancer tissue than in normal gastric mucosa tissue and dysplasia tissue.