Jiang Zhi, Liu Zhenhua, Zou Shitao, Ni Jianlong, Shen Li, Zhou Yinghui, Hua Dong, Wu Shiliang
Department of Biochemistry and Molecular Biology, School of Medicine, Soochow University, Suzhou, Jiangsu 215123, P.R. China.
Department of Inspection, Suzhou Health College, Suzhou, Jiangsu 215001, P.R. China.
Oncol Rep. 2016 Sep;36(3):1353-60. doi: 10.3892/or.2016.4959. Epub 2016 Jul 21.
Aberrant glycosylation, a common feature of malignant alteration, is partly due to changes in the expression of glycosyltransferases, including β1,3-N-acetyl-glucosaminyltrans-ferase 8 (β3Gn‑T8), which synthesizes poly-N-acetyllactosamine (poly-LacNAc) chains on β1,6 branched N‑glycans. Although the role of β3Gn‑T8 in tumors has been reported, the regulation of β3Gn‑T8 expression, however, is still poorly understood. In the present study, we used three online bioinformatic software tools to identify multiple c‑jun binding sites in the promoter of the β3Gn‑T8 gene. Using luciferase reporter assay, chromatin immunoprecipitation (ChIP) analysis, RT‑PCR and western blot analysis, we revealed that c‑jun could bind to and activate the β3Gn‑T8 promoter, thus upregulating β3Gn‑T8 expression. This was also confirmed by changes in β3Gn‑T8 activity as demonstrated by flow cytometry, immunofluorescence and lectin blot analysis using LEA lectin. Moreover, expression of glycoprotein HG‑CD147, the substrate of β3Gn‑T8, was also regulated by c‑jun. In addition, c‑jun and β3Gn‑T8 were more highly expressed in the gastric cancer tissues when compared to these levels in the adjacent non‑tumor gastric tissues, and β3Gn‑T8 expression was positively correlated with c‑jun expression. These results suggest that c‑jun plays a significant role in regulating the expression of β3Gn‑T8 in the SGC‑7901 cell line and may be involved in the development of malignancy via the activity of β3Gn‑T8.
异常糖基化是恶性改变的一个常见特征，部分归因于糖基转移酶表达的变化，包括β1,3-N-乙酰葡糖胺基转移酶8（β3Gn-T8），它在β1,6分支的N-聚糖上合成多聚N-乙酰乳糖胺（多聚LacNAc）链。尽管β3Gn-T8在肿瘤中的作用已有报道，但其表达调控仍知之甚少。在本研究中，我们使用了三种在线生物信息学软件工具来鉴定β3Gn-T8基因启动子中的多个c-jun结合位点。通过荧光素酶报告基因检测、染色质免疫沉淀（ChIP）分析、RT-PCR和蛋白质印迹分析，我们发现c-jun可以结合并激活β3Gn-T8启动子，从而上调β3Gn-T8的表达。使用LEA凝集素进行的流式细胞术、免疫荧光和凝集素印迹分析所显示的β3Gn-T8活性变化也证实了这一点。此外，β3Gn-T8的底物糖蛋白HG-CD147的表达也受c-jun调控。另外，与相邻的非肿瘤胃组织相比，c-jun和β3Gn-T8在胃癌组织中的表达更高，且β3Gn-T8的表达与c-jun的表达呈正相关。这些结果表明，c-jun在调控SGC-7901细胞系中β3Gn-T8的表达方面发挥着重要作用，并且可能通过β3Gn-T8的活性参与恶性肿瘤的发生发展。
