Identification of MicroRNAs Specific for EpCAM + Tumor Cells in Hepatocellular Carcinoma

Therapies that target cancer stem cells (CSCs) hold promise in eliminating cancer burden. However, normal stem cells are likely to be targeted due to their similarities to CSCs. It is established that EpCAM is a biomarker for normal hepatic stem cells and EpCAM + AFP + hepatocellular carcinoma (HCC) cells have enriched hepatic CSCs. We sought to determine if specific miRNAs exist in hepatic CSCs that are not expressed in normal hepatic stem cells. We performed a pair-wised comparison of the miRNA transcriptome of EpCAM + and corresponding EpCAM − cells isolated from two primary HCC specimens, as well as from two fetal livers and three healthy adult liver donors via small RNA deep sequencing. We found that miR-150, miR-155 and miR-223 were preferentially highly expressed in EpCAM + HCC cells, which was further validated. Their gene surrogates, identified using miRNA and mRNA profiling in a cohort of 292 HCC patients, were associated with patient prognosis. We further demonstrated that miR-155 was highly expressed in EpCAM + HCC cells compared to corresponding EpCAM − HCC cells, fetal livers with enriched normal hepatic progenitors, and normal adult livers with enriched mature hepatocytes. Suppressing miR-155 resulted in a decreased EpCAM + fraction in HCC cells and reduced HCC cell colony formation, migration and invasion in vitro . The reduced levels of identified miR-155 targets predicted the shortened overall survival and time to recurrence of HCC patients. Conclusion: MiR-155 was highly elevated in EpCAM + HCC cells and might serve as a molecular target to eradicate the EpCAM + CSC population in human HCCs. unique in compared hepatocyte We that is a biomarker for both normal hepatic cells hepatic CSCs. Here, we focus on the difference between EpCAM + hepatic CSCs and EpCAM + normal hepatic stem cells. Small RNA next-generation sequencing was used to globally and unbiasedly detect and quantify miRNAs. Our study compared the stemness-related miRNAs in EpCAM + HCC cells vs. EpCAM + hepatic normal stem cells. We have found the difference of cancer and normal hepatic stem cells according to their miRNA expression profiling, and that a small group of miRNAs were remarkably altered in EpCAM + HCC cells compared to EpCAM − HCC cells, but not in normal stem cells compared to hepatocytes. EpCAM − HCC cells have been showed to have less malignancy features but mature hepatocyte features 5). Meanwhile, the gene surrogates of these EpCAM + HCC cells specific miRNAs were significantly associated with clinical outcome of HCC patients. The presence of these miRNAs suggests the biological distinctions between