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Second-generation tyrosine kinase inhibitors reduce telomerase activity in K562 cells

Saar Shapira1, Galit Granot, Rahav Mor-Tzuntz

  • 1Felsenstein Medical Research Center, Beilinson Hospital, Sackler School of Medicine, Tel Aviv University, Israel.

Cancer Letters
|May 5, 2012
PubMed

Insights

Nilotinib and dasatinib reduce telomerase activity by decreasing human telomerase reverse transcriptase (hTERT) mRNA expression and inhibiting Sp1 and AKT phosphorylation. This study reveals novel mechanisms of tyrosine kinase inhibitor action on telomerase regulation.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Oncology

Background:

  • Telomerase is a key enzyme in cell proliferation and cancer.
  • Tyrosine kinase inhibitors (TKIs) like nilotinib and dasatinib target specific signaling pathways in cancer treatment.
  • The precise mechanisms by which TKIs affect telomerase activity are not fully understood.

Purpose of the Study:

  • To investigate the effects of nilotinib and dasatinib on telomerase activity and its regulatory mechanisms.
  • To determine if the impact of these TKIs on telomerase is independent of their known targets.

Main Methods:

  • Assessing telomerase activity in BCR-ABL-positive and negative cell lines.
  • Measuring human telomerase reverse transcriptase (hTERT) mRNA expression.
  • Analyzing Sp1 and AKT phosphorylation and nuclear translocation.
  • Evaluating Sp1 binding to the hTERT promoter.

Main Results:

  • Nilotinib and dasatinib significantly reduced telomerase activity in both BCR-ABL-positive and negative cells.
  • A substantial decrease in hTERT mRNA expression was observed.
  • The drugs reduced Sp1 nuclear expression and binding to the hTERT promoter.
  • Reduced phosphorylation of Map kinase and AKT was detected, along with decreased nuclear hTERT.

Conclusions:

  • Nilotinib and dasatinib inhibit telomerase activity through both transcriptional and post-translational mechanisms.
  • These effects are uncoupled from the TKIs' known targets, suggesting novel pathways of action.
  • The findings provide new insights into the anticancer potential of nilotinib and dasatinib via telomerase inhibition.

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