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Androgenic dependence of exophytic tumor growth in a transgenic mouse model of bladder cancer: a role for thrombospondin-1.

Publication ,  Journal Article
Johnson, AM; O'Connell, MJ; Miyamoto, H; Huang, J; Yao, JL; Messing, EM; Reeder, JE
Published in: BMC Urol
April 23, 2008

BACKGROUND: Steroid hormones influence mitogenic signaling pathways, apoptosis, and cell cycle checkpoints, and it has long been known that incidence of bladder cancer (BC) in men is several times greater than in women, a difference that cannot be attributed to environmental or lifestyle factors alone. Castration reduces incidence of chemically-induced BC in rodents. It is unclear if this effect is due to hormonal influences on activation/deactivation of carcinogens or a direct effect on urothelial cell proliferation or other malignant processes. We examined the effect of castration on BC growth in UPII-SV40T transgenic mice, which express SV40 T antigen specifically in urothelium and reliably develop BC. Furthermore, because BC growth in UPII-SV40T mice is exophytic, we speculated BC growth was dependent on angiogenesis and angiogenesis was, in turn, androgen responsive. METHODS: Flat panel detector-based cone beam computed tomography (FPDCT) was used to longitudinally measure exophytic BC growth in UPII-SV40T male mice sham-operated, castrated, or castrated and supplemented with dihydrotestosterone (DHT). Human normal bladder and BC biopsies and mouse bladder were examined quantitatively for thrombospondin-1 (TSP1) protein expression. RESULTS: Mice castrated at 24 weeks of age had decreased BC volumes at 32 weeks compared to intact mice (p = 0.0071) and castrated mice administered DHT (p = 0.0233; one-way ANOVA, JMP 6.0.3, SAS Institute, Inc.). Bladder cancer cell lines responded to DHT treatment with increased proliferation, regardless of androgen receptor expression levels. TSP1, an anti-angiogenic factor whose expression is inhibited by androgens, had decreased expression in bladders of UPII-SV40T mice compared to wild-type. Castration increased TSP1 levels in UPII-SV40T mice compared to intact mice. TSP1 protein expression was higher in 8 of 10 human bladder biopsies of normal versus malignant tissue from the same patients. CONCLUSION: FPDCT allows longitudinal monitoring of exophytic tumor growth in the UPII-SV40T model of BC that bypasses need for chemical carcinogens, which confound analysis of androgen effects. Androgens increase tumor cell growth in vitro and in vivo and decrease TSP1 expression, possibly explaining the therapeutic effect of castration. This effect may, in part, explain gender differences in BC incidence and implies anti-androgenic therapies may be effective in preventing and treating BC.

Duke Scholars

Published In

BMC Urol

DOI

EISSN

1471-2490

Publication Date

April 23, 2008

Volume

8

Start / End Page

7

Location

England

Related Subject Headings

  • Urology & Nephrology
  • Urinary Bladder Neoplasms
  • Thrombospondin 1
  • Orchiectomy
  • Mice, Transgenic
  • Mice
  • Disease Models, Animal
  • Cell Proliferation
  • Animals
  • Androgens
 

Citation

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Johnson, A. M., O’Connell, M. J., Miyamoto, H., Huang, J., Yao, J. L., Messing, E. M., & Reeder, J. E. (2008). Androgenic dependence of exophytic tumor growth in a transgenic mouse model of bladder cancer: a role for thrombospondin-1. BMC Urol, 8, 7. https://doi.org/10.1186/1471-2490-8-7
Johnson, Aimee M., Mary J. O’Connell, Hiroshi Miyamoto, Jiaoti Huang, Jorge L. Yao, Edward M. Messing, and Jay E. Reeder. “Androgenic dependence of exophytic tumor growth in a transgenic mouse model of bladder cancer: a role for thrombospondin-1.BMC Urol 8 (April 23, 2008): 7. https://doi.org/10.1186/1471-2490-8-7.
Johnson AM, O’Connell MJ, Miyamoto H, Huang J, Yao JL, Messing EM, et al. Androgenic dependence of exophytic tumor growth in a transgenic mouse model of bladder cancer: a role for thrombospondin-1. BMC Urol. 2008 Apr 23;8:7.
Johnson, Aimee M., et al. “Androgenic dependence of exophytic tumor growth in a transgenic mouse model of bladder cancer: a role for thrombospondin-1.BMC Urol, vol. 8, Apr. 2008, p. 7. Pubmed, doi:10.1186/1471-2490-8-7.
Johnson AM, O’Connell MJ, Miyamoto H, Huang J, Yao JL, Messing EM, Reeder JE. Androgenic dependence of exophytic tumor growth in a transgenic mouse model of bladder cancer: a role for thrombospondin-1. BMC Urol. 2008 Apr 23;8:7.
Journal cover image

Published In

BMC Urol

DOI

EISSN

1471-2490

Publication Date

April 23, 2008

Volume

8

Start / End Page

7

Location

England

Related Subject Headings

  • Urology & Nephrology
  • Urinary Bladder Neoplasms
  • Thrombospondin 1
  • Orchiectomy
  • Mice, Transgenic
  • Mice
  • Disease Models, Animal
  • Cell Proliferation
  • Animals
  • Androgens