Androgen signaling and post-transcriptional downregulation of Bcl-2 in androgen-unresponsive prostate cancer

Prostate Cancer Prostatic Dis. 2004;7(2):158-64. doi: 10.1038/sj.pcan.4500717.

Abstract

We previously characterized the LNCaP prostate cancer progression model and showed that despite loss of Bcl-2 protein in the androgen-unresponsive LNCaP-unresponsive (UR) cells, these cells maintained an increased resistance to the induction of apoptosis. Since the loss of Bcl-2 protein coincided with the progression to androgen-unresponsiveness, we sought to determine if Bcl-2 expression was regulated through androgen signaling pathways. LNCaP-responsive (R) and -UR cells grown in charcoal-stripped serum conditions for 3 months differentiated to a neuroendocrine (NE)-like morphology. Under these conditions, LNCaP-UR cells regained Bcl-2 protein expression, and LNCaP-R cells overexpressed Bcl-2. Chronic exposure to casodex resulted in differentiation of both LNCaP-R and -UR cells to the NE-type morphology accompanied by a marked downregulation of Bcl-2 protein, while Bax protein levels were unchanged. Downregulation of Bcl-2 was post-transcriptional since Bcl-2 message levels were unchanged in LNCaP cells treated with casodex. These data suggest that Bcl-2 is post-transcriptionally modulated by androgen signaling pathways in LNCaP cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis
  • Blotting, Western
  • Caspase 3
  • Caspases / analysis
  • Down-Regulation
  • Gene Expression Profiling*
  • Humans
  • Male
  • Prostatic Neoplasms / drug therapy
  • Prostatic Neoplasms / genetics*
  • Prostatic Neoplasms / pathology*
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis*
  • Proto-Oncogene Proteins c-bcl-2 / pharmacology
  • RNA Interference
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction
  • Tumor Cells, Cultured

Substances

  • Proto-Oncogene Proteins c-bcl-2
  • CASP3 protein, human
  • Caspase 3
  • Caspases