MicroRNA-99 family members suppress Homeobox A1 expression in epithelial cells

PLoS One. 2013 Dec 3;8(12):e80625. doi: 10.1371/journal.pone.0080625. eCollection 2013.

Abstract

The miR-99 family is one of the evolutionarily most ancient microRNA families, and it plays a critical role in developmental timing and the maintenance of tissue identity. Recent studies, including reports from our group, suggested that the miR-99 family regulates various physiological processes in adult tissues, such as dermal wound healing, and a number of disease processes, including cancer. By combining 5 independent genome-wide expression profiling experiments, we identified a panel of 266 unique transcripts that were down-regulated in epithelial cells transfected with miR-99 family members. A comprehensive bioinformatics analysis using 12 different sequence-based microRNA target prediction algorithms revealed that 81 out of these 266 down-regulated transcripts are potential direct targets for the miR-99 family. Confirmation experiments and functional analyses were performed to further assess 6 selected miR-99 target genes, including mammalian Target of rapamycin (mTOR), Homeobox A1 (HOXA1), CTD small phosphatase-like (CTDSPL), N-myristoyltransferase 1 (NMT1), Transmembrane protein 30A (TMEM30A), and SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 5 (SMARCA5). HOXA1 is a known proto-oncogene, and it also plays an important role in embryonic development. The direct targeting of the miR-99 family to two candidate binding sequences located in the HOXA1 mRNA was confirmed using a luciferase reporter gene assay and a ribonucleoprotein-immunoprecipitation (RIP-IP) assay. Ectopic transfection of miR-99 family reduced the expression of HOXA1, which, in consequence, down-regulated the expression of its downstream gene (i.e., Bcl-2) and led to reduced proliferation and cell migration, as well as enhanced apoptosis. In summary, we identified a number of high-confidence miR-99 family target genes, including proto-oncogene HOXA1, which may play an important role in regulating epithelial cell proliferation and migration during physiological disease processes, such as dermal wound healing and tumorigenesis.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Gene Expression Profiling
  • Gene Expression Regulation / physiology*
  • Genome-Wide Association Study
  • Homeodomain Proteins / biosynthesis*
  • Homeodomain Proteins / genetics
  • Humans
  • MicroRNAs / biosynthesis*
  • MicroRNAs / genetics
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins / biosynthesis*
  • Proto-Oncogene Proteins / genetics
  • Transcription Factors / biosynthesis*
  • Transcription Factors / genetics

Substances

  • Homeodomain Proteins
  • MAS1 protein, human
  • MIRN99 microRNA, human
  • MicroRNAs
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins
  • Transcription Factors
  • homeobox A1 protein