不同亚型的半乳凝素-9对结肠癌LoVo细胞和内皮细胞体外黏附作用的影响

Galectin-9 isoforms influence the adhesion between colon carcinoma LoVo cells and human umbilical vein endothelial cells in vitro by regulating the expression of E-selectin in LoVo cells

目的研究不同亚型的半乳凝素-9对结肠癌LoVo细胞侵袭转移相关分子表达的调节作用，以及该调节作用对LoVo细胞与内皮细胞体外黏附作用的影响。方法半乳凝素-9基因不同亚型的表达载体转染结肠癌LoVo细胞24h后，分别用逆转录聚合酶链反应（RT—PCR）和Westernblot方法检测整合素B1、钙黏着素E、选择素E、细胞间黏附分子-1、CD44和基质金属蛋白酶-9表达的变化。LoVo细胞分别在转染半乳凝素-9、转染半乳凝素-9＋半乳凝素-9抗体、转染半乳凝素-9＋选择素E抗体和转染半乳凝素-9＋β-乳糖条件下进行体外LoVo细胞与内皮细胞的黏附实验。结果半乳凝素-9L能下调选择素EmRNA和蛋白的表达，半乳凝素-9M和半乳凝素-9S能上调选择素EmRNA和蛋白的表达。体外黏附实验中，转染空载体、转染半乳凝素-9L、转染半乳凝素-9M和转染半乳凝素-9S组的平均荧光强度分别为0．90±0．20、0．94±0．24、1．60±0．11和1．45±0．13。半乳凝素-9M和半乳凝素-9S可促进LoVo细胞黏附于内皮细胞（P〈0．05），而半乳凝素-9抗体、选择素E抗体和β-乳糖均可抑制此作用。结论3种不同亚型的半乳凝素-9通过不同的方式调节LoVo细胞选择素EmRNA和蛋白的表达，影响LoVo细胞与内皮细胞的体外黏附；3种不同亚型的半乳凝素-9在介导肿瘤细胞转移过程中的作用可能是不同的。

Objective To study the regulatory effect of galectin-9 isoforms on some molecules involved in cell adhesion/invasion, and the influence of this regulation action on the adhesion between colon carcinoma LoVo cells and human umbilical vein endothelial cells （HUVECs） in vitro. Methods Various expression vectors of galectin-9 isoforms were transfected into LoVo cells. 24 h after transfection, the expression of integrin-β, E-cadherin, E-selectin, ICAM-1, CD44 and MMP-9 was detected by RT-PCR and Western blot analysis. LoVo cell-HUVEC adhesion assay was performed under conditions of galectin-9 transfection, galectin-9 transfection ＋ galectin-9 antibody, galectin-9 transfection ＋ E-selectin antibody and galectin-9 transfection ＋ β-lactose, respectively. Results Galectin-9L down-regulates the mRNA and protein levels of E-selectin while galectin-9M and galectin-9S up-regulate the expression of E-selectin. In LoVo cell-HUVEC adhesion assay, the average fluorescence intensity of vector transfection group, galectin- 9L transfection group, galectin-9M transfection group and galectin-9S transfection group was 0.90 ± 0.20, 0.94 ±0. 24, 1.60 ± 0. 11 and 1.45 ± 0. 13, respectively, indicating that galectin-9M and galectin-9S facilitated the adherence of LoVo cells to HUVECs （ P 〈 0.05）. E-selectin antibody, galectin-9 antibody or β-lactose inhibited that effect. Conclusion Galectin-9 isoforms regulate the E-selectin expression in LoVo cells differently and thus influence the adhesion between LoVo cells and HUVECs in vitro in different modes. The mechanisms through which galectin-9 isoforms participate in the metastasis process of colon cancer may not be the same.