Use of tissue recombination to predict phenotypes of transgenic mouse models of prostate carcinoma

Abstract

Transgenic mouse models of cancer represent a powerful approach for exploring disease processes and testing potential therapeutic interventions. Currently, it is difficult to predict if a specific genetic manipulation will result in a desirable phenotype. The present study tests the idea that tissue recombinants recapitulate the pathologic features of the neoplastic prostate seen in transgenic mice, and would thus be suitable predictive models for new mouse design. The large probasin-large T-antigen (LPB-Tag) transgenic lines 12T-7f and 12T-10 were used as a basis for this study. Tissue recombinants of bladder epithelium (BlE) and urogenital sinus mesenchyme (UGM) were implanted under the renal capsule of athymic mice. Recombinants composed of BlE from 12T-10 LPB-Tag and wild-type (wt) UGM faithfully recapitulated the histopathologic and temporal features of intact transgenic mice of this line. Tissue recombinants using BlE from 12T-7f mice and wt UGM developed epithelial proliferation with atypia that lacked the associated hypercellular stroma seen in the intact 12T-7f line. Recombinants using 12T-7f UGM demonstrated that the hypercellular stroma results from stromal cell expression of the SV40 large T antigen. Corresponding to the recombinant phenotypes, stromal Tag immunostaining was observed in prostate tissues from intact 12T-7f but not 12T-10 mice. Similar stromal expression of Tag was also noted in the hypercellular TRAMP prostatic stroma. Further analysis revealed a previously unreported pattern of SV40T expression in the LADY and TRAMP models including ductus deferens and seminal vesicle stroma as well as region and cell type-specific patterns in the epididymis. The present study demonstrates the utility of using tissue recombination to explore organ-specific phenotypes. Recombination strategies should enable quick and cost-effective screening for likely phenotypes in transgenic animals. This comparison of tissue recombination to existing models shows that this approach can elicit new information on well-characterized models.

Bladder tissue formation from cultured bladder urothelium

“…The use of tissue recombination as a model to study the bladder has been underutilized and, indeed, has been primarily used to derive prostatic tissue from transgenic mice using the prostatic inductive urogenital sinus mesenchyme or seminal vesicle mesenchyme (Neubauer et al, 1983;Donjacour and Cunha, 1993;Ishii et al, 2005). Multiple investigators have reported the successful in vitro growth of bladder urothelium and have refined the culture conditions required to grow bladder urothelial cells (Roszell et al, 1977;Chlapowski and Haynes, 1979;Johnson et al, 1985;Liebert et al, 1990;Hutton et al, 1993;Southgate et al, 1994;Kurzrock et al, 2005).…”

Tumor-secreted Hsp90 Subverts Polycomb Function to Drive Prostate Tumor Growth and Invasion

“…Collagen plugs were incubated overnight at 37°C and grafted under the kidney capsule of adult male SCID mice (Harlan Sprague-Dawley, Indianapolis, IN), as described (34). Two replicates/kidney from each experiment were xenografted in three mice (total of six replicates).…”

“…Animal Studies-Equivalent cell numbers (1 ϫ 10 6 ) from each experimental group were resuspended in 50 l of type I rat collagen as described previously (34). Collagen plugs were incubated overnight at 37°C and grafted under the kidney capsule of adult male SCID mice (Harlan Sprague-Dawley, Indianapolis, IN), as described (34).…”

Cross-talk between Paracrine-Acting Cytokine and Chemokine Pathways Promotes Malignancy in Benign Human Prostatic Epithelium

“…All work involving animals was done under protocols reviewed and approved by the Vanderbilt Institutional Animal Care and Use Committee. Rat urogenital sinus mesenchyme (rUGM) was prepared from 18-day embryonic fetuses of pregnant Sprague-Dawley rats (Harlan) as previously described (30). UGM was then additionally reduced to single cells by a 90-min digestion at 37jC with 187 units/mL collagenase (Life Technologies).…”