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Updated: Aug 12, 2026

A Method for Screening and Validation of Resistant Mutations Against Kinase Inhibitors
12:40

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Published on: December 7, 2014

In BCR-ABL-positive cells, STAT-5 tyrosine-phosphorylation integrates signals induced by imatinib mesylate and Ara-C

T Kindler1, F Breitenbuecher, S Kasper

  • 1III Medical Department (Hematology/Oncology), Johannes Gutenberg-University Mainz, Langenbeckstrasse 1, Mainz 55101, Germany.

Leukemia
|May 24, 2003
PubMed

Insights

Imatinib mesylate and cytosine arabinoside (Ara-C) suppress STAT-5 phosphorylation in BCR-ABL-positive cells. Combination therapy shows synergistic effects, suggesting STAT-5 inhibition is key for treating these cancers.

Area of Science:

  • Oncology
  • Molecular Biology
  • Hematology

Background:

  • Constitutive STAT-5 activation by tyrosine phosphorylation drives BCR-ABL-positive cell survival.
  • Activated STAT-5 upregulates bcl-X(L), conferring resistance to apoptosis.

Purpose of the Study:

  • To investigate the effects of imatinib mesylate and Ara-C on STAT-5 signaling.
  • To evaluate their impact on proliferation and apoptosis in BCR-ABL-positive cells.
  • To explore combination therapy effects.

Main Methods:

  • Treatment of K562 cells and primary CML blasts with imatinib mesylate and/or Ara-C.
  • Assessment of STAT-5 tyrosine phosphorylation, DNA binding, and Hck phosphorylation.
  • Evaluation of cellular proliferation and apoptosis induction via caspase activation.

Main Results:

  • Imatinib mesylate significantly suppressed STAT-5 tyrosine phosphorylation and K562 cell proliferation.
  • Ara-C downregulated STAT-5 tyrosine phosphorylation and inhibited DNA binding.
  • Combination therapy exhibited synergistic effects on STAT-5 signaling, proliferation, and apoptosis.

Conclusions:

  • STAT-5 tyrosine phosphorylation is a specific target for imatinib mesylate and Ara-C.
  • Combined inhibition of STAT-5 may enhance therapeutic efficacy in BCR-ABL-positive malignancies.
  • Synergistic effects observed suggest a promising combination strategy.

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