miR-93/106b and their host gene, MCM7, are differentially expressed in leiomyomas and functionally target F3 and IL-8

Mol Endocrinol. 2012 Jun;26(6):1028-42. doi: 10.1210/me.2012-1075. Epub 2012 May 3.

Abstract

miR-93/106b and their host gene minichromosome maintenance complex component 7 (MCM7) reside at chr7q22, a region frequently rearranged in leiomyomas. We explored the expression of miR-93/106b in leiomyoma and paired myometrium (n = 63) from untreated and patients exposed to hormonal therapies (GnRH agonist, Depo-Provera, and oral contraceptives) from African-Americans and Caucasians and their regulatory functions in isolated paired (n = 15) leiomyoma and myometrial smooth muscle cells and the leiomyosarcoma cell line. At tissue level leiomyomas expressed significantly lower levels of miR-93 and elevated MCM7 as compared with myometrium with limited racial influence or hormonal exposure on their expression. Assessing the regulatory function of miR-93/106b through doxycycline-inducible lentiviral transduction in a microarray analysis, tissue factor (F3) and IL8 were identified as their possible targets. At the tissue level, leiomyomas expressed a significantly lower level of F3 and an elevated IL-8 level, which exhibited an inverse relationship with miR-93 but with limited racial or hormonal influences. The gain of function of miR-93/106b in leiomyoma smooth muscle cells, myometrial smooth muscle cells, and the leiomyosarcoma cell line dose dependently repressed F3 and IL8 through direct interactions with their respective 3'-untranslated region and indirectly through F3 repression inhibited IL8, CTGF, and PAI-1 expression, confirmed by using small interfering RNA silencing or factor Vlla (FVIIa) activation of F3, as well as reducing the rate of proliferation, while increasing caspase-3/7 activity. We concluded that differential expression of miR-93/106b and their direct and/or indirect regulatory functions on F3, IL8, CTGF, and PAI-1 expression, with key roles in inflammation and tissue turnover may be of significance in the outcome of leiomyoma growth and associated symptoms.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Caspases / metabolism
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Proliferation
  • Cell Survival
  • Cells, Cultured
  • Cluster Analysis
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Female
  • Gene Expression
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Interleukin-8 / genetics*
  • Leiomyoma / metabolism*
  • Menstrual Cycle
  • MicroRNAs / genetics
  • MicroRNAs / metabolism*
  • Middle Aged
  • Minichromosome Maintenance Complex Component 7
  • Myometrium / metabolism
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism*
  • RNA Interference
  • Thromboplastin / genetics*
  • Uterine Neoplasms / metabolism*
  • Young Adult

Substances

  • CXCL8 protein, human
  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • Interleukin-8
  • MIRN106 microRNA, human
  • MIRN93 microRNA, human
  • MicroRNAs
  • Nuclear Proteins
  • Thromboplastin
  • Caspases
  • MCM7 protein, human
  • Minichromosome Maintenance Complex Component 7