Triggering of transient receptor potential vanilloid type 1 (TRPV1) by capsaicin induces Fas/CD95-mediated apoptosis of urothelial cancer cells in an ATM-dependent manner

Carcinogenesis. 2009 Aug;30(8):1320-9. doi: 10.1093/carcin/bgp138. Epub 2009 Jun 5.

Abstract

Herein, we provide evidence on the expression of transient receptor potential vanilloid type 1 (TRPV1) on human urothelial cancer (UC) cells and its involvement in the apoptosis induced by the selective agonist capsaicin (CPS). We analyzed TRPV1 messenger RNA and protein expression on human UC cell lines demonstrating its progressive decrease in high-grade UC cells. Treatment of RT4 cells with CPS induced cell cycle arrest in G(0)/G(1) phase and apoptosis. These events were associated with rapid co-ordinated transcription of pro-apoptotic genes including Fas/CD95, Bcl-2 and caspase families and ataxia telangiectasia mutated (ATM)/CHK2/p53 DNA damage response pathway. CPS induced Fas/CD95 upregulation, but more importantly Fas/CD95 ligand independent, TRPV1-dependent death receptor clustering and triggering of both extrinsic and intrinsic mitochondrial-dependent pathways. Moreover, we observed that CPS activates ATM kinase that is involved in Ser15, Ser20 and Ser392 p53 phosphorylation as shown by the use of the specific inhibitor KU55933. Notably, ATM activation was also found to control upregulation of Fas/CD95 expression and its co-clustering with TRPV1 as well as RT4 cell growth and apoptosis. Altogether, we describe a novel connection between ATM DNA damage response pathway and Fas/CD95-mediated intrinsic and extrinsic apoptotic pathways triggered by TRPV1 stimulation on UC cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Ataxia Telangiectasia Mutated Proteins
  • Blotting, Western
  • Capsaicin / pharmacology*
  • Cell Cycle / drug effects
  • Cell Cycle Proteins / metabolism*
  • Cell Proliferation / drug effects
  • Cells, Cultured
  • DNA-Binding Proteins / metabolism*
  • Flow Cytometry
  • Fluorescent Antibody Technique
  • Humans
  • Membrane Potential, Mitochondrial / drug effects
  • Neoplasm Invasiveness
  • Protein-Serine-Threonine Kinases / metabolism*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sensory System Agents / pharmacology
  • TRPV Cation Channels / metabolism*
  • Tumor Suppressor Proteins / metabolism*
  • Urinary Bladder Neoplasms / drug therapy
  • Urinary Bladder Neoplasms / metabolism
  • Urinary Bladder Neoplasms / pathology*
  • Urothelium / drug effects
  • Urothelium / metabolism
  • fas Receptor / metabolism*

Substances

  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • FAS protein, human
  • RNA, Messenger
  • Sensory System Agents
  • TRPV Cation Channels
  • TRPV1 protein, human
  • Tumor Suppressor Proteins
  • fas Receptor
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Protein-Serine-Threonine Kinases
  • Capsaicin