Resistance to Imatinib Mesylate-induced apoptosis in acute lymphoblastic leukemia is associated with PTEN down-regulation due to promoter hypermethylation

Leuk Res. 2008 May;32(5):709-16. doi: 10.1016/j.leukres.2007.09.005. Epub 2007 Oct 17.


The aim of our study was to determine the potential mechanism(s) implicated in Imatinib resistance in patients with Ph+ ALL. Resistance of Ph+ ALL cells to Imatinib-induced apoptosis was associated with lack of inhibition of Akt phosphorylation. Addition of the PI3K inhibitor LY294002 to Imatinib significantly increased apoptosis of Ph+ ALL cells. Interestingly, expression of PTEN was reduced in Ph+ ALL cells which was due to PTEN promoter hypermethylation. Treatment of Ph+ ALL cells with 5-Aza-2'-deoxycytidine was associated with an increased expression of PTEN and an increase in cell apoptosis. These results suggest that Imatinib resistance in patients with ALL may be dependent at least in part to PTEN down-regulation due to the abnormal promoter hypermethylation and support the potential role of de-methylating agents for the treatment of patients with Ph+ ALL.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects*
  • Benzamides
  • Cell Line, Tumor
  • DNA Methylation*
  • Down-Regulation
  • Drug Resistance, Neoplasm
  • Fusion Proteins, bcr-abl / physiology
  • Humans
  • Imatinib Mesylate
  • PTEN Phosphohydrolase / genetics*
  • Phosphatidylinositol 3-Kinases / physiology
  • Piperazines / pharmacology*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / drug therapy*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / genetics
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / pathology
  • Promoter Regions, Genetic*
  • Proto-Oncogene Proteins c-akt / physiology
  • Pyrimidines / pharmacology*


  • Antineoplastic Agents
  • Benzamides
  • Piperazines
  • Pyrimidines
  • Imatinib Mesylate
  • Phosphatidylinositol 3-Kinases
  • Fusion Proteins, bcr-abl
  • Proto-Oncogene Proteins c-akt
  • PTEN Phosphohydrolase
  • PTEN protein, human