PML/RARα-Regulated miR-181a/b Cluster Targets the Tumor Suppressor RASSF1A in Acute Promyelocytic Leukemia

Cancer Res. 2015 Aug 15;75(16):3411-24. doi: 10.1158/0008-5472.CAN-14-3521. Epub 2015 Jun 3.

Abstract

In acute promyelocytic leukemia (APL), all-trans retinoic acid (ATRA) treatment induces granulocytic maturation and complete remission of leukemia. microRNAs are known to be critical players in the formation of the leukemic phenotype. In this study, we report downregulation of the miR-181a/b gene cluster in APL blasts and NB4 leukemia cells upon ATRA treatment as a key event in the drug response. We found that miR-181a/b expression was activated by the PML/RARα oncogene in cells and transgenic knock-in mice, an observation confirmed and extended by evidence of enhanced expression of miR-181a/b in APL patient specimens. RNA interference (RNAi)-mediated attenuation of miR-181a/b expression in NB4 cells was sufficient to reduce colony-forming capacity, proliferation, and survival. Mechanistic investigations revealed that miR-181a/b targets the ATRA-regulated tumor suppressor gene RASSF1A by direct binding to its 3'-untranslated region. Enforced expression of miR-181a/b or RNAi-mediated attenuation of RASSF1A inhibited ATRA-induced granulocytic differentiation via regulation of the cell-cycle regulator cyclin D1. Conversely, RASSF1A overexpression enhanced apoptosis. Finally, RASSF1A levels were reduced in PML/RARα knock-in mice and APL patient samples. Taken together, our results define miR-181a and miR-181b as oncomiRs in PML/RARα-associated APL, and they reveal RASSF1A as a pivotal element in the granulocytic differentiation program induced by ATRA in APL.

Publication types

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

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Proliferation / genetics
  • Flow Cytometry
  • Gene Expression Regulation, Leukemic / drug effects
  • HEK293 Cells
  • HL-60 Cells
  • Humans
  • Immunoblotting
  • Leukemia, Promyelocytic, Acute / genetics*
  • Leukemia, Promyelocytic, Acute / metabolism
  • Leukemia, Promyelocytic, Acute / pathology
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • MicroRNAs / genetics*
  • Multigene Family
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Oncogene Proteins, Fusion / genetics*
  • Oncogene Proteins, Fusion / metabolism
  • Promyelocytic Leukemia Protein
  • Receptors, Retinoic Acid / genetics
  • Receptors, Retinoic Acid / metabolism
  • Retinoic Acid Receptor alpha
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Tretinoin / pharmacology
  • Tumor Suppressor Proteins / genetics*
  • Tumor Suppressor Proteins / metabolism
  • U937 Cells

Substances

  • Antineoplastic Agents
  • MIrn181 microRNA, human
  • MicroRNAs
  • Nuclear Proteins
  • Oncogene Proteins, Fusion
  • Promyelocytic Leukemia Protein
  • RARA protein, human
  • RASSF1 protein, human
  • Rara protein, mouse
  • Receptors, Retinoic Acid
  • Retinoic Acid Receptor alpha
  • Transcription Factors
  • Tumor Suppressor Proteins
  • promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein
  • PML protein, human
  • Tretinoin