N-乙酰氨基葡萄糖转移酶III在转化生长因子β1诱导的上皮间质转化中的作用

The epithelial-to-mesenchymal transition (EMT) plays crucial roles in the embryonic development, wound healing, tissue repair and cancer progression. In the present study, we demonstrate that transforming growth factor β (TGF-β) down-regulated expression of N-acetylglucosaminyltransferase III (GnT-III) during EMT. The treatment with TGF-β1 resulted in a decrease in E-cadherin expression and GnT-III expression as well as its product, the bisected N-glycans, which was confirmed by E4-PHA lectin blot in human MCF-10A and mouse GE11 cells. To understand roles of GnT-III expression in EMT, the MCF-10A cell was stably transfected with GnT-III. Of particular interesting, overexpression of GnT-III partially, but did inhibit EMT induced by TGF-β1, which were confirmed by cell morphological changes of phase-contrast, immunochemical staining patterns of E-cadherin and actin. In addition, GnT-III modified E-cadherin, which contributed to prolong E-cadherin turnover on cell surface examined by biotinylation and pulse-chase experiments. Consistently, GnT-III expression inhibited β-catenin translocation from cell-cell contact into cytoplasm and nucleus. Furthermore, the transwell assay showed that GnT-III expression suppresses TGF-β-induced cell motility. Taken together, these observations are the first to clearly demonstrate that GnT-III plays important roles in EMT, and explain a molecular mechanism for inhibitory effects of GnT-III on cancer metastasis.The epithelial-to-mesenchymal transition (EMT) plays crucial roles in the embryonic development, wound healing, tissue repair and cancer progression. In the present study, we demonstrate that transforming growth factor β (TGF-β) down-regulated expression of N-acetylglucosaminyltransferase III (GnT-III) during EMT. The treatment with TGF-β1 resulted in a decrease in E-cadherin expression and GnT-III expression as well as its product, the bisected N-glycans, which was confirmed by E4-PHA lectin blot in human MCF-10A and mouse GE11 cells. To understand roles of GnT-III expression in EMT, the MCF-10A cell was stably transfected with GnT-III. Of particular interesting, overexpression of GnT-III partially, but did inhibit EMT induced by TGF-β1, which were confirmed by cell morphological changes of phase-contrast, immunochemical staining patterns of E-cadherin and actin. In addition, GnT-III modified E-cadherin, which contributed to prolong E-cadherin turnover on cell surface examined by biotinylation and pulse-chase experiments. Consistently, GnT-III expression inhibited β-catenin translocation from cell-cell contact into cytoplasm and nucleus. Furthermore, the transwell assay showed that GnT-III expression suppresses TGF-β-induced cell motility. Taken together, these observations are the first to clearly demonstrate that GnT-III plays important roles in EMT, and explain a molecular mechanism for inhibitory effects of GnT-III on cancer metastasis