Liver cancer stem cells (CSCs) were involved in tumorigenesis, progression, recurrence, and drug resistance of hepatocellular carcinoma (HCC). miR-365 was downregulated in hepatocellular carcinoma and inhibited HCC cell proliferation and invasion. However, the role of miR-365 in liver cancer stem cells was unknown. Herein, we observed a remarkable decrease of miR-365 expression in CD133 or EpCAM-positive liver CSCs as well as in CSC-enriched hepatoma spheres. Up-regulated miR-365 suppressed liver CSC expansion by inhibiting the dedifferentiation of hepatoma cells and decreasing the self-renewal ability of liver CSCs. Mechanistically, bioinformatic and luciferase reporter analysis identified Ras-related C3 botulinum toxin substrate 1 (RAC1) as a direct target of miR-365. Overexpression of miR-365 in hepatoma cells downregulated the RAC1 mRNA and protein expression. RAC1 also could promote the expansion of liver CSCs. The special RAC1 inhibitor EHop-106 or RAC1 overexpression abolished the discrepancy in liver CSC proportion and the self-renewal capacity between miR-365 overexpression hepatoma cells and control cells, which further confirmed that RAC1 was required in miR-365-suppressed liver CSCs expansion. miR-365 was downregulated in liver CSCs and could inhibit HCC cells dedifferentiation and liver CSCs expansion by targeting RAC1 signaling.
Hepatocellular carcinoma (HCC) was the second most common malignant tumor with a poor prognostic condition. We aimed to identify novel methylation signatures to predict HCC patients at their early stages. Differentially expressed methylated genes between HCC patients and normal liver tissues retrieved from TCGA were screened out by SAM. Genes highly related to patients' survival were figured out by COX. The signatures that could identify relapse HCC patients were identified by the forwarding search algorithm. Besides, functional enrichment analysis was performed on the methylation genes in the signature. A total of 5,392 CPG sites that differentially methylated expressed were found out and 4,294 differentially expressed genes were obtained. A total of 197 genes among were associated with RFS of HCC patients at both stage I and stage II. Signature composed of 21 pairs was obtained to predict the prognostic situation by C-index forward search method. The function of these genes was figured out by functional enrichment analysis. To summary, the signature composed of 21 gene pairs that can predict the prognostic situation of HCC patients at both stage I and stage II, provided a reference standard for the adjuvant therapy of HCC patients after surgery.
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