engleski

5-aza-2'-deoxycytidine up-regulates expression of MGAT3 gene in HepG2 cells and causes significant changes in N-glycome of secreted proteins

Protein N-glycosylation is an important posttranslational modification which affects protein structure and function. Majority of plasma proteins are synthesized in liver and changes in their glycosylation are often associated with different types of liver diseases, including hepatocellular carcinoma (HCC). HepG2 cell line is a hepatocellular carcinoma cell line which secretome is comparable with secretomes of HCC patients. This cell line can serve as a model to study epigenetically induced changes in glycosylation of secreted proteins. Using epigenetic inhibitor 5-aza-2’-deoxycytidine we have induced global hypomethylation in HepG2 cells. A panel of 84 glyco-genes was analysed and around 20% of the genes changed the expression level following the epigenetic treatment. Change in glyco-gene expression level was correlated with preferential appearance of particular glycan structures in the HepG2 secretome. The overexpression of MGAT3 gene explained the majority of the changes observed in the glycosylation profile. GNT-III, enzyme coded by MGAT3 gene, is responsible for the addition of bisecting GlcNAc, which prevents further core fucosylation and branching. When methylation and the expression level of MGAT3 was specifically analysed and correlated with glycome composition from secretome of HepG2 cells following 5-aza-2’-deoxycytidine treatment we were able to detect decrease of glycan structures with core fucose and highly branched structures. Many epigenetic inhibitors are currently explored as part of a therapeutic strategy or are already used in cancer treatment. The present work contributes to our understanding of their efficiency in altering the N- glycan profiles of secreted proteins.

glycome ; HepG2 ; MGAT3

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