大肠癌肝转移相关基因mRNA的表达差异

DifferentialdisplayofmRNAforhepaticmetastatic associatedgenesoflargeintestinalcarcinoma

目的：对比、研究大肠癌肝转移过程中相关基因的表达及其作用，探讨大肠癌肝转移的分子机理。方法：采用DD-PCR(differential display PCR)方法，对比大肠癌原发灶、癌旁肠粘膜、肝转移灶组织mRNA的表达差异，克隆肝转移灶中差异片段。经Northern杂交、测序、同源性比较、临床标本检测，研究差异表达基因在大肠癌肝转移中的作用。结果：在大肠癌原发灶、癌旁肠粘膜、肝转移灶中存在明显的基因表达差异，其中在肝转移灶中发现10条差异表达条带和5条缺失条带。对其中CHm1、CHm8差异带进行克隆、测序，经序列分析和同源性比较，确认CHm1（395bp）与FasL基因99％同源；CHm8（423bp）有60％与IKKα基因同源，40％与线粒体DNA序列同源。在28例大肠癌肝转移灶中全部检测出FasL和IKKα表达。结论：大肠癌肝转移的mRNA差异显示证明FasL、IKKα基因表达在大肠癌肝转移过程中起着重要作用；线粒体DNA的插入可能与肝转移相关基因的表达有密切关系。

Objective： To study expression and function of hepatic metastasis associated genes of large intestine cancer, and to seek for the mechanisms of hepatic metastasis. Methods： Differential display PCR (DD PCR) was used to display the differential expression of mRNA among primary foci, paratumoral intestine mucosa and hepatic metastasis of large intestine carcinoma. Molecular cloning techniques were applied to the differential segments in hepatic metastasis. And the expression and function of the differential genes in hepatic metastasis were studied with Northen hybridization, sequencing, homologous comparison and detection of clinical specimens. Results： Significant differential expressions were found among primary foci, paratumoral intestine mucosa and hepatic metastasis of large intestine carcinoma. Ten segments of differential expression and 5 pieces of loss were discovered in hepatic metastasis. And two differential segments of CHm1 and CHm8 in hepatic metastasis were cloned and sequenced. By comparison with database, CHm1 was homology of FasL gene(99％ ), and CHm8 was similar to IKK α gene(60％ ) and to mitochondria DNA(40％ ). Positive expressions of FasL and IKK α genes were detected in all 28 hepatic metastasis. Conclusion： The present investigation with mRNA differential display suggests that expressions of FasL and IKK α play an important role in hepatic metastasis of large intestinal carcinoma and that the insertion of mitochondria DNA has an affinity with the expression of hepatic metastatic associated genes.