Methylation-mediated regulation of tumor-suppressor function of the miR-379/656 (C14MC) cluster and its clinical utility in hepatocellular carcinoma

Furthermore, we demonstrated that the loss of C14MC tumor suppressor function is directly regulated by the hypermethylation of promoter-bound CpGs, as shown in artificial methylation experiments. The reactivation of specific C14MC miRNAs, like miR-299-5p and miR-376c-3p via mimics, abrogated the expression of several target oncogenes, including PARP1, SPP1, RAD21, and CENPA that regulate critical molecular pathways such as the p53 signaling and NF-kappa B signaling pathways in HCC.

Additionally, overexpression of miR-299-5p and miR-376c-3p inhibited HCC cell migration and invasion, suggesting that overexpression of candidate C14MC miRNAs can mitigate cancer hallmarks in HCC cells. Additionally, we have performed whole transcriptomic sequencing for RNA isolated from HCC spheroids generated from HepG2 cells to identify the DEGs regulated by C14MC. Furthermore, we checked for the clinical correlation of C14MC targets and their target genes in terms of survival outcomes and identified the key genes associated with prognostic potential in HCC.

We conclude from our experimental findings that C14MC is a tumor-suppressor miRNA cluster and is regulated epigenetically by methylation in HCC. Several of these miRNAs and their targets can be used for early HCC diagnosis and prognosis. Thus, targeting C14MC can be useful in HCC management.