SNC73基因在结肠癌细胞中的表达及重组的研究

Expression and recombination mechanism of SNC73(IgHα1) in human epithelial cancer cell line

目的 观察上皮来源的肿瘤细胞SNC73(IgHα1)基因的表达 ,探讨其在上皮细胞中的重组机理。方法 采用逆转录聚合酶链反应 (RT PCR)和Western印迹杂交方法 ,分析经无血清培养基培养的大肠癌细胞系SW4 80中SNC73和重组激活基因 (RAG1和RAG2 )的表达 ,并对RT PCR产物进行序列分析 ;利用免疫组织化学方法检测IgHα1、Igλ和Igκ在SW 4 80中的表达。 结果 SNC73、RAG1、RAG2、IgHα1和Igκ在SW 4 80细胞系中表达阳性 ,而Igλ则为阴性。对SNC73RT PCR产物的序列进行分析 ,发现SW 4 80中表达的SNC73基因的恒定区序列与免疫球蛋白A1完全一致。对RAG1和RAG2RT PCR产物的序列进行分析以及Western印迹杂交检测 ,表明其与前B淋巴细胞表达的完全相同。结论 上皮来源的肿瘤细胞表达免疫球蛋白A1,且轻链为κ;RAG1和RAG2在上皮来源的肿瘤细胞中的表达 。

Objective To study if the gene SNC73 (IgHα1) is expressed in human epithelial cancer cell line and to interpret the recombination mechanism. Methods Human epithelial cancer cells of SW480 line were cultured. RT PCR and Western blotting were used to examine the expression of SNC73, recombination activating gene 1(RAG1), and RAG2. The RT PCR products were confirmed by sequencing. Immunohistochemistry was used to detect the expression of IgHα1, Igκ, and Igλ in these epithelial cancer cells. Results The human epithelial cancer cell line (SW480) positively expressed SNC73, RAG1, and RAG2. IgHα1 and Igκ was strongly expressed in SW480 cells, but Igλ was undetectable. The sequence of the constant region of SNC73 in SW480 cells is identical to that of IgA1. Both sequencing and Western blotting showed that the RAG1 and RAG2 expressed in SW480 cells were identical to that expressed in pre B lymphocytes. Conclusion Immunoglobulin alpha 1 gene is expressed in non lymphoid cells, which may be a potential genetic marker for the development of colorectal cancer. Recombination signal sequence (RSS) mediated recombination may take part in the rearrangement of immunoglobulin alpha 1 gene in human epithelial cancer cell line.