Downregulation of O-linked N-acetylglucosamine transferase by RNA interference decreases MMP9 expression in human esophageal cancer cells

Abstract

O-linked N-acetylglucosamine transferase (OGT) catalyzes O-linked glycosylation (O-GlcNAcylation). O-GlcNAcylation is a post-translational carbohydrate modification of diverse nuclear and cytosolic proteins by the addition of O-linked β-N-acetylglucosamine. It was recently demonstrated that OGT and the level of O-GlcNAcylation are upregulated in esophageal cancer; however, the physiological consequences of this upregulation remain unknown. The current study reports that OGT knockdown by short hairpin RNA (shRNA) did not affect cell viability; however, cell migration in esophageal cancer Eca‐109 cells was significantly reduced. OGT‐specific shRNA vectors efficiently decreased the protein and mRNA levels of OGT and the RL2 level (a marker of O-GlcNAcylation levels) in Eca-109 esophageal cancer cells. In addition, colony formation and cell proliferation assays demonstrated that OGT‐specific shRNA decreased the proliferation of Eca-109 cells; however, there was no significant statistical difference between OGT‐specific shRNA and control shRNA. Notably, transwell assays demonstrated that the migratory ability of Eca‐109 cells was significantly suppressed following knockdown of the OGT gene. Correspondingly, western blot analyses demonstrated that OGT knockdown significantly downregulated the expression of matrix metalloproteinase 9 (MMP9) in Eca-109 cells. These results suggest that OGT may promote the migration, invasion and metastasis of esophageal cancer cells by enhancing the stability or expression of MMP9. Introduction Esophageal cancer is one of the most common types of cancer worldwide with >480,000 new cases diagnosed annually (1,2). Globally, the disease accounts for ~400,000 cancer-associated mortalities annually (3) with a 5-year survival rate of <20% (4). According to the National Comprehensive Cancer Network guidelines (5), surgery is the optimal treatment choice, however, chemotherapy and radiotherapy may also be administered (6). Squamous cell carcinoma is one of the most common types of cancer and this reacts poorly to common chemotherapy compared with other types of cancer, such as adenocarcinoma (7). Novel studies are required to provide evidence for effective therapy on this disease. Glycolysis and the uptake of glucose are enhanced in cancer cells in order to meet the increased energy requirements of the rapidly proliferating cells, including esophageal caner cells, which are known of elevated Wurberg Effects. A fraction of the glucose in cancer cells is metabolized by the hexosamine biosynthetic pathway (HBP) (8-10). The HBP regulates enzymatic O-linked glycosylation (O-GlcNAcylation), a post-translational carbohydrate modification of diverse nuclear and cytosolic proteins by the addition of O-linked β-N-acetylglucosamine (O-GlcNAc). O-GlcNAcylation of a protein alters the protein's stability, intracellular localization and function. O-GlcNAcylation serves important roles in an array of normal biological processes, and its dysregulation is involved in a variety of human diseases, including diabetes mellitus (11,12) and various neurological disorders (13). Several GlcNAcylated tumor-associated proteins have recently been identified, including c‐Myc (14) and p53 (15), each one of the most important oncogenes and tumor suppressor genes, respectively. These findings suggest that O-GlcNAcylation serves a significant role in oncogenesis and tumor progression (16-18). In our previous study, OGT and a marker of O-GlcNAcylation levels, mouse monoclonal anti-O-linked N-acetylglucosamine antibody (RL2), were observed to be upregulated in esophageal cancer (19). However, the physiological consequences of this upregulation remain to be determined. In the current study, RNA interference (RNAi) was used to knock down OGT in esophageal cancer Eca-109 cells, and Downregulation of O‐linked N‐acetylglucosamine transferase by RNA interference decreases MMP9 expression in human esophageal cancer cells ZHE QIAO1, CHENGXUE DANG2, BIN ZHOU1, SHAOMIN LI1, WEI ZHANG1, JIANTAO JIANG1, JIN ZHANG1, YUEFENG MA1, RANRAN KONG1 and ZHENCHUAN MA1 1Department of Thoracic Surgery, The Second Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710004; 2Department of Surgical Oncology, The First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China Received January 7, 2015; Accepted January 21, 2016 DOI: 10.3892/ol.2016.4428 Correspondence to: Dr Zhe Qiao, Department of Thoracic Surgery, The Second Affiliated Hospital, Xi'an Jiaotong University, 157 Five West Street, Xi'an, Shaanxi 710004, P.R. China E-mail: qiaozhe5921@163.com

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@inproceedings{Qiao2016DownregulationOO, title={Downregulation of O-linked N-acetylglucosamine transferase by RNA interference decreases MMP9 expression in human esophageal cancer cells}, author={Zhe Qiao and Cheng-xue Dang and Bin Zhou and Shaomin Li and Wei Zhang and Jiantao Jiang and Jin Zhang and Yuefeng Ma and Ranran Kong and Zhenchuan Ma}, year={2016} }