Loss of MiR-192 Initiates a Hyperglycolysis and Stemness Positive Feedback in Hepatocellular Carcinoma

Abstract

Background: Emerging studies revealed that cancer stem cells (CSCs) possessed peculiar metabolic properties, which however remained largely unknown in hepatocellular carcinoma (HCC). Genetic silencing of liver-abundant miR-192 was a key feature for multiple groups of CSC-positive primary HCCs. We thus aimed to investigate essential metabolic features of hepatic CSCs via using HCCs with miR-192 silencing as a model. Methods: Data integration analyses of miR-192 with metabolome and mRNA transcriptome in HCC cohort 1 were performed to investigate miR-192 related metabolic features. Cellular and molecular assays were performed to examine whether and how miR-192 regulated the identified metabolic feature. Co-culture systems consisting of HCC and non-HCC cells were established to explore effects of the metabolomic property on stemness features in HCC cells via interacting with non-HCC cells. Results: High expression of glycolysis-related metabolites and genes presented in HCCs with low miR-192 and CSC-positive HCCs in two independent HCC cohorts. miR-192 knock-out cells displayed CSC features and miR-192 loss led to an enhanced glycolytic phenotype via targeting three glycolysis regulators, i.e., Glut1, Pfkfb3, and c-Myc. Meanwhile, c-Myc suppressed miR-192 transcription, ensuring a low-miR-192/high-c-Myc loop to maintain hyperglycolysis. Moreover, over-produced lactic acid from hyperglycolytic HCC cells stimulated the Erk phosphorylation of co-cultured non-HCC cells partially via NDRG3 and MCT1, which in turn promoted cell malignancy and stemness of HCC cells. Conclusions: In CSC-positive HCCs, miR-192 loss enhanced glycolysis via a c-Myc/miR-192/glycolysis regulators signal loop, allowing HCC cells to actively coordinate with their environment non-HCC cells for further increased stemness and malignancy.