Human bladder as a novel target for vitamin D receptor ligands

J Clin Endocrinol Metab. 2005 Feb;90(2):962-72. doi: 10.1210/jc.2004-1496. Epub 2004 Nov 30.

Abstract

Human prostate is now considered a target for vitamin D receptor (VDR) ligands, such as BXL-628. Because BXL-628 inhibited prostate growth without interfering with androgen signaling, it represents a new option for benign prostate hyperplasia (BPH) therapy. However, BPH symptoms are related not only to prostate size, but also to compensatory bladder hypertrophy and eventual overactivity. We now report that human bladder expresses VDR (determined by real-time PCR immunohistochemistry and Western blot) and responds to VDR agonists, such as the natural ligand, calcitriol, and its synthetic and less hypercalcemic derivative, BXL-628. Experiments were conducted with stromal cells derived from human bladder neck obtained at surgery from BPH patients. BXL-628 counteracted keratinocyte growth factor (KGF) and androgen-induced cell proliferation and stimulated apoptosis with a parallel reduced expression of the survival oncoprotein Bcl-2. Prolonged serum starvation time-dependently pushed bladder stromal cells to express activated myofibroblast markers, such as desmin and smoothelin, without changing other contractile-related proteins and intermediate filaments, such as vimentin. Chronic exposure to BXL-628 prevented starvation-induced cell phenotype modification. Because hypertrophy and starvation-induced bladder remodeling are supposed to underlie bladder overactivity, it is possible that BXL-628 might be helpful in reducing not only cumbersome symptoms related to prostate overgrowth, but also those related to bladder irritation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone and Bones / drug effects
  • Bone and Bones / embryology
  • Calcitriol / analogs & derivatives*
  • Calcitriol / pharmacology*
  • Calcitriol / therapeutic use
  • Cells, Cultured
  • Humans
  • Ligands
  • Male
  • Prostatic Hyperplasia / drug therapy
  • Prostatic Hyperplasia / surgery
  • Receptor, Fibroblast Growth Factor, Type 2
  • Receptors, Calcitriol / physiology*
  • Receptors, Fibroblast Growth Factor / drug effects
  • Receptors, Fibroblast Growth Factor / genetics
  • Receptors, Fibroblast Growth Factor / physiology
  • Urinary Bladder / drug effects
  • Urinary Bladder / physiology*

Substances

  • BXL628
  • Ligands
  • Receptors, Calcitriol
  • Receptors, Fibroblast Growth Factor
  • Receptor, Fibroblast Growth Factor, Type 2
  • keratinocyte growth factor receptor
  • Calcitriol