Role Of Liver Specific MiR-192 In Regulating Cancer Stem Cell Features Of Hepatocellular Carcinoma

Primary liver cancer is one of the most deadly human malignancy with high tumor heterogeneity.Approximately 90%of them are hepatocellular carcinomas(HCCs).Various cancer stem cell(CSC)biomarkers have been identified for HCCs,but the metabolic phenotypes and shared molecular networks within CSC populations are poorly understood.Thererfore,this project is focused on CSC in HCCs with following two directions.Part 1:The expression of miR-192-5p(miR-192)is significantly silenced in multiple groups of HCC expressing high levels of CSC markers.Through miRNA profile analysis in an HCC cohort(n=241)for five groups of CSC~+HCC tissues,i.e.,EpCAM~+,CD90~+,CD133~+,CD44~+,and CD24~+HCC and corresponding CSC~-HCCs,14 unique miRNAs were found to be significantly commonly downregulated in the five groups of CSC~+HCC cases and related to tumor recurence.Among them,miR-192-5p was the top candidate,which was liver-abundant and-specific and markedly downregulated in all five groups of CSC~+HCC from another two independent cohorts in the following studies(n=613).Moreover,over-expression of miR-192 significantly reduced while suppressing miR-192promited the HCC cell malignant features including cell migration,invasion and spheroid formation etc.The silencing of miR-192 was further confirmed in CSC~+primary HCCs and found be regulated through the methylation of miR-192 promoter region.Part 2:Loss of miR-192 ensures hyperglycolysis in cancer stem cell-positive hepatocellular carcinoma.In a cohort with 304 HCC patients,an integration analysis of miR-192 with global metabolome and mRNA transcriptome identified high expression levels of glycolysis-related metabolites and genes in HCCs with low miR-192 expression.miR-192 knockout HCC cell lines were then established and we found that loss of miR-192 led to an enhanced glycolytic phenotype by targeting three glycolysis regulators,Glut1,Pfkfb3,and c-Myc.Moreover,c-Myc could suppress miR-192 transcription,ensuring a low-miR-192/high-c-Myc loop to maintain hyperglycolysis feature of CSC~+HCC cells.Further,overproduced lactic acid from hyperglycolytic CSC~+HCC cells stimulated Erk phosphorylation of environmental non-HCC cells partially via NDRG3 and MCT1;in turn,phosphorylated Erk promoted CSC+HCC cell malignancy and stemness.Taken together,miR-192,a liver-specific and-abundant miRNA,was significantly downregulated in CSC~+HCCs;loss of miR-192 fueled CSC~+HCC cells via enhanced glycolysis,promoting malignant phenotype and at the same time allowing CSC~+HCC cells to actively coordinate with their environment for further increased stemness and malignancy.