MEG3-derived miR-493-5p overcomes the oncogenic feature of IGF2-miR-483 loss of imprinting in hepatic cancer cells

Cell Death Dis. 2019 Jul 18;10(8):553. doi: 10.1038/s41419-019-1788-6.

Abstract

Numerous studies have described the critical role played by microRNAs (miRNAs) in cancer progression and the potential of these small non-coding RNAs for diagnostic or therapeutic applications. However, the mechanisms responsible for the altered expression of miRNAs in malignant cells remain poorly understood. Herein, via epigenetic unmasking, we identified a group of miRNAs located in the imprinted delta like non-canonical Notch ligand 1 (DLK1)-maternally expressed 3 (MEG3) locus that were repressed in hepatic tumor cells. Notably, miR-493-5p epigenetic silencing was correlated with hypermethylation of the MEG3 differentially regulated region (DMR) in liver cancer cell lines and tumor tissues from patients. Experimental rescue of miR-493-5p promoted an anti-cancer response by hindering hepatocellular carcinoma (HCC) cell growth in vitro and tumor progression in vivo. We found that miR-493-5p mediated part of its tumor-suppressor activity by abrogating overexpression of insulin-like growth factor 2 (IGF2) and the IGF2-derived intronic oncomir miR-483-3p in HCC cells characterized by IGF2 loss of imprinting (LOI). In summary, this study describes an unknown miRNA-dependent regulatory mechanism between two distinct imprinted loci and a possible therapeutic window for liver cancer patients exhibiting IGF2-miR-483 LOI and amplification.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carcinoma, Hepatocellular / genetics*
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Survival / genetics
  • DNA Methylation
  • Epigenesis, Genetic
  • Female
  • Gene Expression Regulation, Neoplastic / genetics
  • Genes, Tumor Suppressor
  • Genomic Imprinting / genetics*
  • Humans
  • Insulin-Like Growth Factor II / genetics*
  • Insulin-Like Growth Factor II / metabolism
  • Introns
  • Liver Neoplasms / genetics*
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • Mice
  • Mice, Nude
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • RNA, Long Noncoding / genetics
  • RNA, Long Noncoding / metabolism*
  • Transplantation, Heterologous

Substances

  • IGF2 protein, human
  • MEG3 non-coding RNA, human
  • MIRN483 microRNA, human
  • MIRN493 microRNA, human
  • MicroRNAs
  • RNA, Long Noncoding
  • Insulin-Like Growth Factor II