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Transcriptional upregulation of BAG3 upon proteasome inhibition

Hua-Qin Wang1, Hai-Mei Liu, Hai-Yan Zhang

  • 1Department of Biochemistry & Molecular Biology, China Medical University, Shenyang 110001, China. wanghq_doctor@hotmail.com

Biochemical and Biophysical Research Communications
|November 13, 2007
PubMed

Insights

Proteasome inhibitors can induce BAG3, a protein that promotes cancer cell survival. Inhibiting BAG3 enhances the effectiveness of these drugs, suggesting a new therapeutic strategy against tumors.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Drug Discovery

Background:

  • Proteasome inhibitors show antitumoral effects in various cancers.
  • Upregulation of antiapoptotic factors and survival signaling can limit proteasome inhibitor efficacy.
  • The Bcl-2-associated athanogene (BAG) family proteins modulate cell proliferation and death.

Purpose of the Study:

  • To investigate the role of BAG family proteins in cancer cells treated with proteasome inhibitors.
  • To determine if BAG3 is induced by proteasome inhibitors and contributes to drug resistance.

Main Methods:

  • Treatment of various cancer cells with proteasome inhibitors.
  • Analysis of BAG3 expression at the transcriptional level.
  • BAG3 knockdown using small interfering RNA (siRNA).
  • Assessment of apoptosis induction following proteasome inhibitor treatment.

Main Results:

  • Proteasome inhibitors induce the expression of BAG3 in cancer cells.
  • BAG3 functions as an antiapoptotic molecule in this context.
  • Knockdown of BAG3 sensitizes cancer cells to proteasome inhibitor-induced apoptosis (e.g., MG132).

Conclusions:

  • BAG3 is a novel antiapoptotic factor induced by proteasome inhibitors.
  • BAG3 induction represents a mechanism of resistance to proteasome inhibitors.
  • Targeting BAG3 may enhance the therapeutic efficacy of proteasome inhibitors in cancer treatment.

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