Silencing AML1-ETO gene expression leads to simultaneous activation of both pro-apoptotic and proliferation signaling

Leukemia. 2014 Nov;28(11):2222-8. doi: 10.1038/leu.2014.130. Epub 2014 Apr 14.

Abstract

The t(8;21)(q22;q22) rearrangement represents the most common chromosomal translocation in acute myeloid leukemia (AML). It results in a transcript encoding for the fusion protein AML1-ETO (AE) with transcription factor activity. AE is considered to be an attractive target for treating t(8;21) leukemia. However, AE expression alone is insufficient to cause transformation, and thus the potential of such therapy remains unclear. Several genes are deregulated in AML cells, including KIT that encodes a tyrosine kinase receptor. Here, we show that AML cells transduced with short hairpin RNA vector targeting AE mRNAs have a dramatic decrease in growth rate that is caused by induction of apoptosis and deregulation of the cell cycle. A reduction in KIT mRNA levels was also observed in AE-silenced cells, but silencing KIT expression reduced cell growth but did not induce apoptosis. Transcription profiling of cells that escape cell death revealed activation of a number of signaling pathways involved in cell survival and proliferation. In particular, we find that the extracellular signal-regulated kinase 2 (ERK2; also known as mitogen-activated protein kinase 1 (MAPK1)) protein could mediate activation of 23 out of 29 (79%) of these upregulated pathways and thus may be regarded as the key player in establishing the t(8;21)-positive leukemic cells resistant to AE suppression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / genetics*
  • Cell Cycle / genetics
  • Cell Line, Tumor
  • Cell Proliferation
  • Core Binding Factor Alpha 2 Subunit / genetics*
  • Down-Regulation / genetics
  • Gene Expression Regulation, Leukemic*
  • HEK293 Cells
  • Humans
  • Leukemia, Myeloid, Acute / genetics*
  • Leukemia, Myeloid, Acute / pathology
  • Models, Genetic
  • Oncogene Proteins, Fusion / genetics*
  • Proto-Oncogene Proteins c-kit / genetics*
  • RNA, Small Interfering / genetics
  • RUNX1 Translocation Partner 1 Protein
  • Signal Transduction / genetics*

Substances

  • AML1-ETO fusion protein, human
  • Core Binding Factor Alpha 2 Subunit
  • Oncogene Proteins, Fusion
  • RNA, Small Interfering
  • RUNX1 Translocation Partner 1 Protein
  • Proto-Oncogene Proteins c-kit