Effects of WNT/beta-catenin pathway activation on signaling through T-cell factor and androgen receptor in prostate cancer cell lines

Int J Oncol. 2005 Apr;26(4):1033-40. doi: 10.3892/ijo.26.4.1033.

Abstract

Dysregulation of the WNT/beta-catenin pathway is thought to contribute to prostate cancer progression. Mutations of beta-catenin occurring in 5-7% of advanced prostate cancers may act by stimulating TCF-dependent and/or androgen receptor (AR)-dependent transcription. Using a reporter gene approach we found overexpressed mutated beta-catenin to enhance AR-regulated probasin-promoter activity in the AR-positive prostate cancer cell line 22Rv1, particularly at low androgen levels. In 22Rv1 cells mutated beta-catenin was able to stimulate TCF-dependent transcription but was unable to do so in LNCaP cells where it activates the AR. Since beta-catenin mutations are rare in vivo, we studied further possible routes of WNT-pathway modulation. Higher concentrations of LiCl, a GSK3beta-inhibitor, were required to activate TCF-dependent rather than AR-dependent reporter constructs. In 22Rv1 overexpression of E-cadherin repressed androgen-dependent transcription, but did not inhibit transcription of TCF-dependent reporter genes as in bladder cancer cell lines. Interestingly, Wnt-3a stimulated proliferation selectively in the AR-positive prostate cancer cell lines 22Rv1 and LNCaP, even though TCF-dependent reporter gene transcription was not induced in LNCaP cells. In summary, the data from our study support the idea that activation of WNT/beta-catenin signaling in AR-positive prostate cancer cells may predominantly act through AR-dependent mechanisms rather than classical TCF-dependent mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Proliferation
  • Cytoskeletal Proteins / biosynthesis*
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / pharmacology*
  • Disease Progression
  • Gene Expression Regulation, Neoplastic*
  • Genes, Reporter
  • Humans
  • Intercellular Signaling Peptides and Proteins / biosynthesis*
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / pharmacology*
  • Male
  • Mutation
  • Prostatic Neoplasms / pathology*
  • Receptors, Androgen / drug effects*
  • Receptors, Androgen / physiology*
  • Signal Transduction
  • Trans-Activators / biosynthesis*
  • Trans-Activators / genetics
  • Trans-Activators / pharmacology*
  • Transcription Factors / pharmacology*
  • Tumor Cells, Cultured
  • Urinary Bladder Neoplasms / pathology
  • Wnt Proteins
  • beta Catenin

Substances

  • CTNNB1 protein, human
  • Cytoskeletal Proteins
  • Intercellular Signaling Peptides and Proteins
  • Receptors, Androgen
  • Trans-Activators
  • Transcription Factors
  • Wnt Proteins
  • beta Catenin