病毒学报

人巨细胞病毒(Human cytomegalovirus,HCMV)的US28基因在结肠癌内呈高表达趋势且与淋巴结转移、Dukes分期进展密切相关,癌细胞过度的迁移和侵袭是造成淋巴结转移、Dukes分期进展的重要物学环节,US28基因表达的变化提示US28可能参与了结肠癌细胞迁移、侵袭的调控,但具体的作用及机制均未阐明。为研究HCMV US28基因促进结肠癌细胞迁移、侵袭的作用及机制,本研究培养结肠癌COLO205细胞株并分组,阴性对照组(NC组)用不含药物和质粒的DMEM处理,空白对照质粒组(NC质粒组)转染空白的pcDNA3.1质粒,US28质粒组转染过表达US28基因的pcDNA3.1质粒,US28质粒+YC-1组转染过表达US28基因的pcDNA3.1质粒、同时加入缺氧诱导因子-1α(HIF-1α)的抑制剂YC-1。检测细胞的迁移活力、侵袭活力、细胞中HIF-1α及下游迁移基因(HIF-1α、Snail)、侵袭基因(MMP1、MMP9)的表达量。结果显示,与NC组、NC质粒组比较,US28质粒组的迁移细胞数目、侵袭细胞数目及细胞中HIF-1α、Snail、MMP1、MMP9的蛋白表达水平均明显增多(P<0.05),细胞中E-cadherin、TIMP2的蛋白表达水平均明显减少(P<0.05);与US28质粒组比较,US28质粒+YC-1组的迁移细胞数目、侵袭细胞数目及细胞中HIF-1α、Snail、MMP1、MMP9的蛋白表达水平明显减少(P<0.05),细胞中E-cadherin、TIMP2的蛋白表达水平均明显增多(P<0.05)。综上,HCMV US28基因能够促进结肠癌细胞的迁移、侵袭且该作用与激活HIF-1α途径、调节下游迁移及侵袭基因表达有关。

US28 from the human cytomegalovirus(HCMV)shows high expression in colonic cancer,is closely associated with lymph-node metastasis,and is used for Dukes' staging. Excessive migration and invasion of cancer cells are important biological behaviors associated with lymph-node metastasis and the Dukes staging.Changes in US28 expression suggest that it may be involved in colonic cancer. However,effect and mechanism of US28 expression,the biological behaviors of cancer cells have not been clarified. To study the role and mechanism of US28 in the HCMV in promoting migration and invasion of colonic cancer cells,the colonic cancer cell line COLO205 was cultured and grouped. The negative control(NC) group was treated with Dulbecco's modified Eagle's medium(DMEM)without drugs or plasmids. The negative plasmid control(NC plasmid)group was transfected with blank pcDNA3.1 plasmid. The US28 plasmid group was transfected with pcDNA3.1 plasmid containing US28. The US28+YC-1 group was transfected with pcDNA3.1 plasmid containing US28 and an inhibitor of hypoxia inducible factor(HIF)-1α,YC-1,was added. Migration and invasion of cells,expression of HIF-1α,downstream migration genes and invasive genes were detected. Results showed that,compared with the NC group and NC plasmid group,the number of migrating cells and invading cells,expression of HIF-1α,Snail,matrix metallopeptidase(MMP)1 and MMP9 in cells of the US28 plasmid group were increased significantly,whereas expression of E-cadherin and tissue inhibitor of metalloproteinases(TIMP)2 in cells was decreased significantly(P<0.05). Compared with the US28 plasmid group,the number of migrating cells and invading cells,expression of HIF-1α,Snail,MMP1 and MMP9 in cells of the US28 plasmid+YC-1 group were increased significantly(P<0.05),whereas expression of E-cadherin and TIMP2 in cells was increased significantly(P<0.05). The present study suggested that US28 from the HCMV can promote the migration and invasion of colonic cancer cells,which is related to activation of the HIF-1α pathway.