CD44基因拼接体、p53基因突变和染色体倍性与大肠癌转移之间关系的机理研究

A preliminary study on CD44 gene splice, p^(53) mutation and chromosome ploidy in relation with metastasis of colorectal cancer

目的:探讨大肠癌ＣＤ４４ｖ６表达、ｐ(53)基因突变和染色体倍性与大肠癌转移之间的关系和作用机理。方法：流式细胞仪测定大肠癌细胞倍性及其在细胞周期各相中的分布；ＲＴ－ＰＣＲ方法及特异探针Ｄ３对大肠癌细胞进行Ｓｏｕｔｈｅｒｎ Ｂｌｏｔ，并对杂交条带进行辉度扫描；银染ＰＣＲ单链构象多态性（ＳＳＣＰ）技术检测大肠癌细胞ｐ(53)基因突变。结果：正常对照、良性腺瘤、肿瘤未转移和肿瘤转移组其ＣＤ４４ｖ６阳性率和ｐ(53)基因突变率呈逐渐上升趋势，ＣＤ４４ｖ６辉度扫描表明肿瘤未转移组（２３１７．２６±１９８．７３）和转移组（１００２４．１６±８５５．４０）相比较，表达量有显著差异（Ｐ＜０．０２）；ＣＤ４４ｖ６阳性和阴性两组中Ｇ２Ｍ期细胞均值分别占６．２４％和５．４８％（Ｐ＞０．０５），异倍体细胞分别为６２．１６％和６０．００％（Ｐ＞０．５）；而ｐ(53)基因突变和未突变两组中Ｇ２Ｍ细胞占１０．３３％和４．０１％（Ｐ＜０．０５），异倍体细胞分别为８５．２０％和３０，００％（Ｐ＜０．００５）；肿瘤异倍体细胞转移率显著高于二倍体细胞。结论：ＣＤ４４ｖ６的表达与转移高度相关，ＣＤ４４ｖ６和ｐ(53)基因突变与肿瘤转移关系可能涉及不同的作用机理。Ｃ?

Objective:To explore the relationship between D44v6 expression, p53 gene mutation, cell ploidy and colorectal metastasis.Methods: Tumor cell ploidy and the distribution of tumor cells in each stage of cell cycle were detected by flow cytometry. By using techniquessuch as RT-PCR, Southern Blot and image analysis, the quatitative and qualitiative expression of CD44v6 were determined. The mutation of p53gene in the colorectal carcinomas was also determined by PCR-SSCP with silver staining. Results: Expression of CD44v6 and mutation of p53gene were increased gradually in the normal colorectal specimen, polys, non-metastatic and metastatic carcinomas , the mean dark density in thenon-metastasis(2 317.26± 198.73)and metastasis(10 024. 16± 855 .40) groups was rather different(P < 0.02). In the CD44v6 positive andnegative groups,the tumor cell mean fraction at the G2M stage was 6.24% and 5 .48% (P > 0.05), aneuploidy tumor cell mean fraction was62. 16% and 60.00 %(P > 0.5) separately, in the mutated and nunmutated p53 gene groups, their mean fraction at the G2M stage was10.33% and 4.01 % (P < 0.05),aneuploidy tumor cell mean fraction was 85.20% and 30.00 % (P < 0.00 5) separately. Aneuploidy tumorcases were much easier to metastasize than diploid tumor cases. Conclusion: The expression of CD44v6 is closely allaied to tumor metastasis.The relationship between CD44v6 expression, p53 gene mutation and tumor metastasis can be involved in the different mechanism. As comparedas mutated p53 gene, CD44v6 is more suitabe to be used as a tumor marker for clinical diagnosis than mutated p53 gene.