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Characterization of HSP27 phosphorylation induced by microtubule interfering agents: implication of p38 signalling

Pedro Casado1, Pedro Zuazua-Villar, Miguel A Prado

  • 1Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, 33071 Oviedo, Spain.

Archives of Biochemistry and Biophysics
|March 21, 2007
PubMed

Insights

Vincristine triggers significant HSP27 phosphorylation at three sites via the p38 pathway. Paclitaxel shows minimal effect, and can block vincristine

Area of Science:

  • Cell Biology
  • Molecular Pharmacology
  • Cancer Research

Background:

  • Vincristine and paclitaxel are microtubule-targeting anticancer drugs.
  • HSP27 phosphorylation is a known cellular response to stress.

Purpose of the Study:

  • To investigate the specific phosphorylation sites of HSP27 induced by vincristine.
  • To elucidate the signaling pathways involved in vincristine-induced HSP27 phosphorylation.
  • To compare the effects of vincristine and paclitaxel on HSP27 phosphorylation.

Main Methods:

  • MCF-7 cells were treated with vincristine and paclitaxel.
  • Phosphorylation of HSP27 at specific serine residues (78, 82, 15) was analyzed.
  • Involvement of p38 and JNK signaling pathways was assessed.

Main Results:

  • Vincristine induces phosphorylation of HSP27 at serines 78, 82, and 15.
  • The p38 signaling pathway mediates vincristine-induced HSP27 phosphorylation; JNK is not implicated.
  • Paclitaxel causes weak phosphorylation at serine 78 only and does not affect serines 82 or 15.
  • Paclitaxel pre-treatment inhibits vincristine-induced HSP27 phosphorylation.

Conclusions:

  • Vincristine differentially phosphorylates HSP27 at multiple sites through the p38 pathway.
  • Distinct mechanisms govern HSP27 phosphorylation by vincristine and paclitaxel.
  • Paclitaxel can interfere with vincristine's effects on HSP27 phosphorylation.

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