4249

MGAT5

mannosyl (alpha-1,6-)-glycoprotein beta-1,6-N-acetyl-glucosaminyltransferase;MGAT5;mannosyl (alpha-1,6-)-glycoprotein beta-1,6-N-acetyl-glucosaminyltransferase

N-acetylglucosaminyl-transferase V|alpha-1,6-mannosylglycoprotein 6-beta-N-acetylglucosaminyltransferase A|alpha-mannoside beta-1,6-N-acetylglucosaminyltransferase|glcNAc-T V|mannoside acetylglucosaminyltransferase 5

2q21.3

protein-coding

metastatic and invasive potential is a barrier to the successful treatment of gastric cancer. N-acetylgluco-saminyltransferase V (GnT-V), a key enzyme catalyzing the formation of 1,6 N-acetylglucosamine (GlcNAc), has been demonstrated to display a distinct function in different types of tumors. The aim of this study was to investigate the role of GnT-V in the invasive potential of BGC823 human gastric cancer cells in vitro and the possible underlying mechanism. GnT-V was downregulated in BGC823 cells by oligo-siRNA transfection. Cell proliferation and invasiveness were assessed by CCK-8 assay, Tunel assay, scratch-wound assay as well as transwell assay. The products of GnT-V, beta1-6 branching of asparagine-linked oligosaccharides, were determined by L-PHA lectin blot analysis. The expression of EGFRs, E-cadherin/vimentin and MMP-2/MMP-9 was analyzed both at the mRNA and protein levels. The results showed that downregulation of GnT-V decreased proliferation and the metastatic/invasive potential of BGC823 cells. The expression of EGFRs, E-cadherin/vimentin and MMP-9, molecules related to cancer metastasis and invasion in various tumors, were influenced correspondingly. These findings suggest that downregulation of GnT-V inhibited cell metastasis and invasion of BGC823 cells via EGFR signaling-initiated EMT phenotype and MMP-9 expression. These results provide a novel mechanism to explain the role of GnT-V in cell metastasis and invasion.

Previous studies have identified a subclone cell line (PC-J) which was isolated from a metastatic human prostate cell line, PC-3. In vitro matrigel invasion assays and xenograft animal studies suggested that matriptase was a putative metastatic gene in human prostate carcinoma cells. Although low metastatic prostate tumor cells, LNCaP, also expressed high levels of matriptase mRNA, gelatin zymography indicated that LNCaP cells had extremely low matriptase activity. Further studies using RT-PCR and lectin blotting assays revealed that the expression of N-acetylglucosaminyltransferase V (MGAT5), a glycoprotein that stabilizes matriptase, was low in LNCaP cells compared to PC-3 and PC-J cells. The transient overexpression of MGAT5 significantly enhanced the activity of matriptase and the invasion ability in the LNCaP cells. Knock-down of MGAT5 in PC-3 cells attenuated the metastatic ability of the cells, as determined by the in vitro invasion assay and the xenograft animal studies. Matriptase and MGAT5 may play important role in the metastasis of prostate cancer.