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Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics
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Ex Vivo Treatment Response of Primary Tumors and/or Associated Metastases for Preclinical and Clinical Development of Therapeutics

Published on: October 2, 2014

Down-regulation of ICBP90 contributes to doxorubicin resistance

Jingxuan Wang1, Ying Song, Shanqi Xu

  • 1Department of Medical Oncology, The Third Hospital of Harbin Medical University, Harbin, China.

European Journal of Pharmacology
|February 8, 2011
PubMed

Insights

Acquired resistance to doxorubicin in breast cancer is linked to decreased ICBP90 and Topo IIα. Restoring Topo IIα levels can re-sensitize resistant cells to doxorubicin treatment.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Research

Background:

  • Acquired resistance to doxorubicin presents a significant challenge in breast cancer therapy.
  • The precise mechanisms underlying doxorubicin resistance remain incompletely understood.

Purpose of the Study:

  • To investigate the roles of ICBP90 and Topo IIα in acquired doxorubicin resistance in breast cancer.
  • To elucidate the molecular mechanisms connecting ICBP90, Topo IIα, and doxorubicin chemoresistance.

Main Methods:

  • Development of a doxorubicin-resistant MCF-7/Dox cell line.
  • Comparative analysis of ICBP90 and Topo IIα expression profiles and cell growth.
  • RNA interference (RNAi) and forskolin stimulation experiments.
  • Immunohistochemical analysis of patient samples.

Main Results:

  • Doxorubicin-resistant cells exhibited decreased expression of ICBP90 and Topo IIα.
  • Down-regulation of ICBP90 and Topo IIα was associated with impaired doxorubicin-induced cell growth inhibition and G1 phase arrest.
  • Forskolin-induced increase in Topo IIα expression restored doxorubicin sensitivity.
  • In patient samples, ICBP90 expression correlated with tumor proliferation, advanced disease, and Topo IIα levels.

Conclusions:

  • Down-regulation of ICBP90 leads to decreased expression of Topo IIα, a key enzyme targeted by doxorubicin.
  • ICBP90 and Topo IIα play crucial roles in the development of acquired doxorubicin resistance in breast cancer.
  • Targeting ICBP90 or restoring Topo IIα expression may represent potential therapeutic strategies to overcome doxorubicin resistance.

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