Dysregulation of the miR-325–3p/DPAGT1 axis supports HBV-positive HCC chemoresistance

Abstract

BackgroundChemotherapeutic resistance in hepatitis B virus (HBV)-positive hepatocellular carcinoma (HCC) patients is an unfortunate side effect of standard chemotherapy. This situation necessitates a better understanding of the molecular pathways underlying HBV + HCC chemoresistance in order to aid the development of novel chemotherapeutic targets. MethodsWe generated two doxorubicin (DOX)-resistant HBV + HCC sublines HepG2.2.15 and Huh7–1.3. qRT-PCR was used to evaluate dysregulation in hexosamine pathway genes in chemosensitive and chemoresistant HBV + HCC cell lines in vitro. Western blots, luciferase reporter assays, and in vivo xenograft tumor studies were conducted to reveal the role of the miRNA-325–3p/DPAGT1 axis in HBV + HCC chemoresistance. ResultsThe hexosamine pathway gene dolichyl-phosphate N-acetylglucosamine phosphotransferase 1 (DPAGT1) was found to be upregulated in both DOX-resistant cell lines. Enhancing DPAGT1 activity significantly improved the survival of DOX-resistant cells. Silencing or pharmacological inhibition of DPAGT1 inhibited xenograft tumor growth under DOX-treated conditions. DPAGT1 upregulation was associated with higher levels of stemness-related markers and ATP-binding cassette (ABC) drug efflux transporters in DOX-resistant cell lines. miR-325–3p was found to negatively modulate DPAGT1 expression and phenocopied the effects of DPAGT1 silencing in vitro and in vivo. In HBV + HCC patients treated with transarterial chemoembolization (TACE), high and low levels of tumor DPAGT1 and miR-325–3p expression, respectively, were associated with a poor chemotherapeutic response. ConclusionsOur findings provide novel insights into the role of miR-325–3p/DPAGT1 axis dysregulation in supporting HBV + HCC chemoresistance.