O-GlcNAc Glycosylation Level Positively Regulates Ang-2 Expression and Promotes Tumor Angiogenesis in Mice with Liver Cancer

doi:10.3969/j.issn.1674-5817.2020.01.007

Abstract

Abstract: Objective To explore the relationship between O-linked N-acetylglucosamine (O-GlcNAc) glycosylation and Angiopoietin-2(Ang-2) expression in the development of hepatocellular carcinoma. Methods C57BL/6 mice model of hepatocellular carcinoma was induced by Diethylnitroamine (DEN) to detect the changes of O-GlcNAc glycosylation, Ang-2 and cell adhesion molecule-1 (CD31) expression in hepatocellular carcinoma. HepG2 cells were intervened with O-linked Glc NAc-transferase (OGT) inhibitors and O-Glc NAcase (OGA) inhibitors to detect whether the expression of Ang-2 changed with the changes of O-GlcNAc glycosylation level. MTT was used to detect the relationship between O-GlcNAc glycosylation level and proliferation of hepatocellular carcinoma cells. Transwell method was used to detect relationship between the level of O-GlcNAc glycosylation and cell migration and invasion in HUVEC cells. Results In the DEN-induced hepatocarcinoma model, the liver volume of mice increased significantly, and tumors of different sizes could be seen in the liver. The results of immunohistochemistry showed that the glycosylation level of O-GlcNAc and the expression of Ang-2 increased significantly in the liver of the model group compared with the control group (P<0.05). The results of qRT-PCR showed that the level of O-GlcNAc glycosylation affected the expression of Ang-2 by detecting the levels of OGT, OGA and Ang-2. Western blotting showed that the expression of Ang-2 decreased with the decrease of the glycosylation level of O-GlcNAc after the intervention of OGT inhibitors on HepG2 cells. After the intervention of HepG2 cells with OGA inhibitors, the expression of Ang-2 increased with the decrease of the glycosylation level of O-GlcNAc. MTT results showed that the glycosylation level of O-GlcNAc was closely related to the proliferation of hepatocellular carcinoma cells. The proliferation ability of hepatocellular carcinoma cells was stronger when the glycosylation level of O-GlcNAc was higher,. The proliferation ability of hepatocellular carcinoma cells was significantly inhibited, when the glycosylation level of O-GlcNAc was low,. Transwell results showed that HUVEC cell migration and invasion ability was positively correlated with O-GlcNAc glycosylation level. Conclusions During the development of hepatocellular carcinoma, the glycosylation level of O-GlcNAc increases gradually, and the expression level of Ang-2 positively regulated by the glycosylation of O-GlcNAc, thus promoting neovascularization.

Key words: Hepatocellular carcinoma, O-linked N-acetylglucosamine (O-GlcNAc), Glycosylation, HepG2 cell, Angiopoietin-2(Ang-2), Neovascularization of tumors

CLC Number:

Q95-33

WANG Aihong, WANG Mingquan, DU Juan. O-GlcNAc Glycosylation Level Positively Regulates Ang-2 Expression and Promotes Tumor Angiogenesis in Mice with Liver Cancer[J]. Laboratory Animal and Comparative Medicine, 2020, 40(1): 39-46.

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