O-GlcNAcylation of RACK1 promotes hepatocellular carcinogenesis

• Published in: Journal of hepatology 2018-06, Vol.68 (6), p.1191-1202
• Main Authors: Duan, Fangfang, Wu, Hao, Jia, Dongwei, Wu, Weicheng, Ren, Shifang, Wang, Lan, Song, Shushu, Guo, Xinying, Liu, Fenglin, Ruan, Yuanyuan, Gu, Jianxin
• Format: Article
• Language: English
• Subjects: Amino acids; Angiogenesis; Carcinogenesis; Carcinogens; Chemoresistance; Chemotherapy; Diethylnitrosamine; Hepatocellular carcinoma; Liver cancer; Localization; Mass spectroscopy; Metastases; mRNA; O-GlcNAcylation; Patients; Phosphorylation; PKCβII; Protein kinase; Protein kinase C; Proteins; RACK1; Ribosomal DNA; Ribosome; Transgenic mice; Translation; Tumor cells; Tumorigenesis
• ISSN: 0168-8278; 1600-0641
• DOI: 10.1016/j.jhep.2018.02.003

[Display omitted] •RACK1 acts as key mediator linking O-GlcNAcylation to protein translation in HCC.•RACK1 O-GlcNAcylation induces its stability, ribosome attachment and PKCβII binding.•RACK1 O-GlcNAcylation is critical for oncogene translation and tumorigenesis in HCC.•RACK1 O-GlcNAcylation is correlated with HCC development and recurrence in patients. Aberrant oncogenic mRNA translation and protein O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) are general features during tumorigenesis. Nevertheless, whether and how these two pathways are interlinked remain unknown. Our previous study indicated that ribosomal receptor for activated C-kinase 1 (RACK1) promoted chemoresistance and growth in hepatocellular carcinoma (HCC). The aim of this study is to examine the role of RACK1 O-GlcNAcylation in oncogene translation and HCC carcinogenesis. The site(s) of RACK1 for O-GlcNAcylation was mapped by mass spectrometry analysis. HCC cell lines were employed to examine the effects of RACK1 O-GlcNAcylation on the translation of oncogenic factors and behaviors of tumor cells in vitro. Transgenic knock-in mice were used to detect the role of RACK1 O-GlcNAcylation in modulating HCC tumorigenesis in vivo. The correlation of RACK1 O-GlcNAcylation with tumor progression and relapse were analyzed in clinical HCC samples. We found that ribosomal RACK1 was highly modified by O-GlcNAc at Ser122. O-GlcNAcylation of RACK1 enhanced its protein stability, ribosome binding and interaction with PKCβII (PRKCB), leading to increased eukaryotic translation initiation factor 4E phosphorylation and translation of potent oncogenes in HCC cells. Genetic ablation of RACK1 O-GlcNAcylation at Ser122 dramatically suppressed tumorigenesis, angiogenesis, and metastasis in vitro and in diethylnitrosamine (DEN)-induced HCC mouse model. Increased RACK1 O-GlcNAcylation was also observed in HCC patient samples and correlated with tumor development and recurrence after chemotherapy. These findings demonstrate that RACK1 acts as key mediator linking O-GlcNAc metabolism to cap-dependent translation during HCC tumorigenesis. Targeting RACK1 O-GlcNAcylation provides promising options for HCC treatment. O-GlcNAcylation of ribosomal receptor for activated C-kinase 1 at the amino acid serine122 promotes its stability, ribosome localization and interaction with the protein kinase, PKCβII, thus driving the translation of oncogenes and tumorigenesis of hepatocellular carcinoma. Increased O-GlcNAcylation