α2,6-唾液酸转移酶(ST6GalI)的表达对结肠癌细胞唾液酸化的影响

A Study of α2,6-Sialyltransferase (ST6Gal I) Expression for the Sialylation of Colon Carcinoma Cells

目的 研究结肠癌细胞LS174T转染正义和反义的α2 ,6唾液酸转移酶 (ST6GalI)cDNA对结肠癌细胞表面唾液酸化及肿瘤细胞粘附功能的影响 .方法 结肠癌细胞株LS174T转染正义ST6GalIcDNA或反义ST6GalIcDNA的部分序列的表达载体pcDNA3 .1,以RT -PCR检测转染子ST6GalImRNA的表达 ,流式细胞仪检测细胞表面α2 ,6唾液酸含量 .结果 转染正义ST6GalIcDNA的克隆显示ST6GalImRNA的表达增强以及接骨木凝集素 (SNA)与细胞表面成分的结合增加 ;而转染反义ST6GalIcDNA的部分序列的细胞克隆的ST6GalImRNA的表达减少 ,SNA与细胞表面成分的结合力降低 .结论 ST6GalI的表达直接影响细胞表面α2 ,6-连接的唾液酸水平并调节肿瘤细胞的粘附功能 .利用反义核酸技术抑制ST6GalI的表达并降低肿瘤细胞表面α2 。

Objectives To study the sialylation of colon carcinoma cells LS174T transfected with sialyltransferase ST6Gal I cDNA in sense- or antisense direction and evaluate the effect of sialylation of cell surface for the adhesion of tumor cells. Methods Colon carcinoma cells LS174T were sense-transfected with ST6Gal I cDNA or antisense-transfected with different parts of the ST6Gal I sequence inserted into pcDNA 3.1 vector. The ST6Gal I mRNA expression of transfectants were determined by RT-PCR, and the α2,6-sialylation of cell surface were measured by FACS. Results Clones transfected with ST6Gal I in sense direction showed an enhanced ST6Gal I mRNA expression as well as an increased binding of the lectin SNA (sambucus nigra agglutinin, a specific lectin recognizes α2,6-linked sialic acid) to cell surface components. Transfection with ST6Gal I in antisense direction resulted in a lower ST6Gal I mRNA expression, less SNA-reactivity. Conclusions Expression of sialyltransferase ST6Gal I of tumor cells directly affects α2,6-sialylation of cell surface and further regulates the adhesion properties of tumor cells. Application of antisense technique to inhibit ST6Gal I expression and decrease the α2,6-sialylation of cell surface might be a way to reduce the metastases of carcinoma cells.