17-Allylamino-17-demethoxygeldanamycin Induces Downregulation of Critical Hsp90 Protein Clients and Results in Cell Cycle Arrest and Apoptosis of Human Urinary Bladder Cancer Cells

BMC Cancer. 2010 Sep 9;10:481. doi: 10.1186/1471-2407-10-481.

Abstract

Background: 17-Allylamino-17-demethoxygeldanamycin (17-AAG), a benzoquinone ansamycin antibiotic, specifically targets heat shock protein 90 (Hsp90) and interferes with its function as a molecular chaperone that maintains the structural and functional integrity of various protein clients involved in cellular signaling. In this study, we have investigated the effect of 17-AAG on the regulation of Hsp90-dependent signaling pathways directly implicated in cell cycle progression, survival and motility of human urinary bladder cancer cell lines.

Methods: We have used MTT-based assays, FACS analysis, Western blotting, semi-quantitative RT-PCR, immunocytochemistry and scratch-wound assay in RT4, RT112 and T24 human urinary bladder cancer cell lines.

Results: We have demonstrated that, upon 17-AAG treatment, bladder cancer cells are arrested in the G1 phase of the cell cycle and eventually undergo apoptotic cell death in a dose-dependent manner. Furthermore, 17-AAG administration was shown to induce a pronounced downregulation of multiple Hsp90 protein clients and other downstream effectors, such as IGF-IR, Akt, IKK-α, IKK-β, FOXO1, ERK1/2 and c-Met, resulting in sequestration-mediated inactivation of NF-κB, reduced cell proliferation and decline of cell motility.

Conclusions: In total, we have clearly evinced a dose-dependent and cell type-specific effect of 17-AAG on cell cycle progression, survival and motility of human bladder cancer cells, due to downregulation of multiple Hsp90 clients and subsequent disruption of signaling integrity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Benzoquinones / pharmacology*
  • Blotting, Western
  • Cell Adhesion / drug effects
  • Cell Cycle / drug effects*
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Fluorescent Antibody Technique
  • HSP90 Heat-Shock Proteins / antagonists & inhibitors*
  • HSP90 Heat-Shock Proteins / genetics
  • HSP90 Heat-Shock Proteins / metabolism*
  • Humans
  • Lactams, Macrocyclic / pharmacology*
  • RNA, Messenger / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • Tumor Cells, Cultured
  • Urinary Bladder Neoplasms / drug therapy
  • Urinary Bladder Neoplasms / metabolism*
  • Urinary Bladder Neoplasms / pathology
  • Wound Healing / drug effects

Substances

  • Benzoquinones
  • HSP90 Heat-Shock Proteins
  • Lactams, Macrocyclic
  • RNA, Messenger
  • tanespimycin