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Hsp27 overexpression inhibits doxorubicin-induced apoptosis in human breast cancer cells

R K Hansen1, I Parra, P Lemieux

  • 1Department of Medicine, The University of Texas Health Science Center, San Antonio, USA.

Breast Cancer Research and Treatment
|November 26, 1999
PubMed

Insights

Heat shock protein 27 (hsp27) overexpression enhances resistance to doxorubicin chemotherapy in breast cancer cells. Hsp27 protects cells from apoptosis by altering topoisomerase II expression, a key drug target.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Pharmacology

Background:

  • Heat shock protein 27 (hsp27) is implicated in cellular stress responses and drug resistance.
  • Doxorubicin is a widely used chemotherapeutic agent that induces apoptosis in cancer cells.
  • MDA-MB-231 breast cancer cells are a relevant model for studying drug resistance mechanisms.

Purpose of the Study:

  • To investigate the role of hsp27 overexpression in doxorubicin-induced apoptosis in MDA-MB-231 breast cancer cells.
  • To determine the effect of hsp27 on the expression of topoisomerase II (topo II), a key doxorubicin target.

Main Methods:

  • Generation of stable MDA-MB-231 transfectants overexpressing hsp27.
  • Assessment of doxorubicin-induced apoptosis in control and hsp27-overexpressing cells.
  • Quantitative analysis of topoisomerase II alpha and beta expression levels.

Main Results:

  • Hsp27 overexpression significantly protected MDA-MB-231 cells from doxorubicin-induced apoptosis.
  • Cells overexpressing hsp27 exhibited reduced levels of both topo IIalpha and topo IIbeta compared to controls.
  • A correlation was observed between hsp27 overexpression, altered topo II expression, and apoptotic resistance.

Conclusions:

  • Hsp27 confers resistance to doxorubicin in breast cancer cells by inhibiting apoptosis.
  • Altered expression of topoisomerase II is a key mechanism underlying the protective effect of hsp27 against doxorubicin.
  • Targeting hsp27 or modulating topo II levels may represent novel therapeutic strategies for overcoming doxorubicin resistance.

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