Effects of MicroRNAs on Fucosyltransferase 8 (FUT8) Expression in Hepatocarcinoma Cells

Abstract

Fucosyltransferase 8 (FUT8) catalyzes the transfer of α1,6-linked fucose to the first N-acetylglucosamine in N-linked glycans (core fucosylation). Increased core fucosylation has been reported during hepatocarcinogenesis, in both cell-associated and secreted proteins. Accordingly, increased core fucosylation of α-fetoprotein and α1-antitrypsin is currently used as a diagnostic and prognostic indicator. The present study provides new evidences that FUT8 can be regulated also through miRNA-mediated mechanisms. Using microRNA/target prediction programs, we identified miR-122 and miR-34a seed regions in the 3′ untranslated region (3′UTR) of FUT8. Then we used human and rodents hepatocarcinoma cell lines to evaluate the impact of transfection of miR-122 and miR-34a mimics on FUT8 mRNA and protein levels. This study demonstrated that forced expression of these miRNAs is able to induce a decrease of FUT8 levels and also to affect core fucosylation of secreted proteins. The ability of miR-122 and miR-34a to specifically interact with and regulate the 3′UTR of FUT8 was demonstrated via a luciferase reporter assay. Since miR-122 and miR-34a downregulation is a common feature in spontaneous human hepatocarcinoma, our finding that these miRNAs are able to target FUT8 3′UTR suggests that, together with transcriptional and other post-transcriptional systems, a miRNA-mediated mechanism could also be involved in the increased core fucosylation observed in liver tumors. Moreover, these findings also point out that miRNAs may be widely involved in the regulation of glycosylation machinery.

A Systems Biology Approach Identifies FUT8 as a Driver of Melanoma Metastasis

“…This is in agreement with previous evidence that TGIF2 inhibition by miR-34a blocks bone metastasis and melanoma invasive growth (Krzeszinski et al, 2014; Yamazaki et al, 2012). FUT8 has also been described as a miR-34a target (Bernardi et al, 2013; Cheng et al, 2016) opening the possibility that miR-34a controls FUT8 both directly and indirectly, via TGIF2 suppression. Multiple datasets of melanoma patient samples support TGIF2 upregulation in metastasis highlighting the clinical relevance of the TGIF2-FUT8 axis.…”

Multi-level regulation of cellular glycosylation: from genes to transcript to enzyme to structure

“…For example, miR-34a, a microRNA associated with hepatocellular carcinoma, targets FUT8. This miRNA did no impact FUT8 transcripts in human HepG2 cells, although it concomitantly altered FUT8 protein expression and core fucosylation levels [30]. miRNA regulate biological pathways by regulating sets of gene transcripts.…”

Insights into miRNA regulation of the human glycome

“…Alterations in core fucosylation have been linked to cancer and emphysema [11,39,40] and recent data points to a role in controlling TGFβ signaling [41]. Our analysis predicts that FUT8 is “highly regulated” by miRNA.…”

“…Recently, work by several groups has pointed to a role for microRNA in controlling glycosylation [5,6,7,8,9]. To date, seven human glycogenes (C1GALT1[6], MANEA [10], FUT4 [9], FUT8 [11], GALNT1 [8], GALNT7 [7,8] and NDST1 [5]) have been validated as miRNA targets. A role for miRNA as a major regulator of glycan biosynthesis has been suggested by work in C. elegans [12] and by unpublished results in human cell lines from our laboratory.…”