GATA3 in the urinary bladder: suppression of neoplastic transformation and down-regulation by androgens

Yi Li1, Hitoshi Ishiguro2, Takashi Kawahara2

  • 1Department of Pathology and Laboratory Medicine, University of Rochester Medical Center Rochester, NY, USA ; Department of Urology, 2nd Affiliated Hospital, Zhejiang University School of Medicine Hangzhou, China.

Insights

GATA3 acts as a tumor suppressor in bladder cancer, with androgens decreasing its expression and estrogens increasing it. This suggests a role for sex hormones in bladder cancer development and potential androgen deprivation therapies.

Area of Science:

  • Urothelial Carcinogenesis
  • Endocrinology
  • Molecular Biology

Background:

  • Sex hormone receptors are implicated in bladder cancer initiation.
  • The precise roles of androgens and estrogens in bladder cancer development are unclear.
  • GATA3, a transcription factor and urothelial marker, is downregulated in bladder cancer.

Purpose of the Study:

  • To investigate if GATA3 suppresses bladder tumorigenesis.
  • To determine how androgens and estrogens influence GATA3 expression in normal urothelial cells.

Main Methods:

  • Treated immortalized normal urothelial cells (SVHUC) with androgens (R1881, dihydrotestosterone) and estrogens (17β-estradiol).
  • Assessed GATA3 expression at mRNA and protein levels.
  • Utilized short hairpin RNA (shRNA) for GATA3 silencing and performed in vitro transformation assays with a chemical carcinogen (3-methylcholanthrene).

Main Results:

  • Androgen treatment decreased GATA3 expression, while estrogen treatment increased it.
  • GATA3 silencing promoted cell proliferation and in vitro tumor transformation, especially with androgen exposure.
  • GATA3 knockdown altered the expression of tumor suppressors (e.g., PTEN, p53) and oncogenes (e.g., c-myc, cyclins).

Conclusions:

  • GATA3 functions as a suppressor of urothelial cell neoplastic transformation.
  • Sex hormones oppositely regulate GATA3 expression in the bladder.
  • Findings provide insights into gender-specific bladder cancer incidence and suggest androgen deprivation as a chemopreventive strategy.