Selective leukemia cell death by activation of the double-stranded RNA-dependent protein kinase PKR

Int J Mol Med. 2011 Aug;28(2):215-22. doi: 10.3892/ijmm.2011.666. Epub 2011 Apr 4.

Abstract

Deregulated activity of the BCR-ABL tyrosine kinase encoded by the Bcr-Abl oncogene represents an important therapeutic target for all the chronic myelogenous leukemia (CML) phases. In this study, we sought to identify targeted PKR activation by Bcr-Abl AS RNA, an anti-sense RNA complementary to the unique mRNA fragments flanking the fusion point of Bcr-Abl, which can be used as an effective anti-leukemia strategy in K562 cells. Moreover, we observed expression of Bcr-Abl AS RNA in K562 cells which resulted in selective apoptosis induction through specific activation of PKR, leading to phosphorylation of eIF2α, global inhibition of protein synthesis, caspase-8 activation and BAX up-regulation. The targeted PKR activation and induced apoptosis were reversed by the PKR inhibitor 2-aminopurine. Taken together, our results indicate that targeted PKR activation led to selective apoptosis induction in K562 cells, which correlated with caspase-8 activity and enhanced expression of BAX.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Caspases / metabolism
  • Cell Cycle
  • Cell Death*
  • Cell Line, Tumor
  • Enzyme Activation / physiology
  • Fusion Proteins, bcr-abl / genetics
  • Fusion Proteins, bcr-abl / metabolism
  • Gene Expression Regulation, Leukemic
  • Gene Silencing
  • Humans
  • K562 Cells
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / enzymology*
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / pathology
  • Models, Biological
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • RNA, Antisense / genetics
  • RNA, Antisense / metabolism
  • Signal Transduction
  • bcl-2-Associated X Protein / metabolism
  • eIF-2 Kinase / genetics
  • eIF-2 Kinase / metabolism*

Substances

  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Antisense
  • bcl-2-Associated X Protein
  • Fusion Proteins, bcr-abl
  • eIF-2 Kinase
  • Caspases