1. ¹Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
2. ²The Vanderbilt Prostate Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA
3. ³Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, TN, USA
4. ⁴The Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN, USA
5. ⁵Department of Pathology, Vanderbilt University Medical Center, Nashville, TN, USA
6. ⁶Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, USA
7. ⁷Center for Reproductive Biology Research, Vanderbilt University Medical Center, Nashville, TN, USA

Correspondence: Dr RJ Matusik, PhD, Department of Urologic Surgery, A-1302 Medical Center North, Vanderbilt University Medical Center, Nashville, TN 37232-2765, USA. E-mail: robert.matusik@vanderbilt.edu

^*Current address: Vaxin Inc., 2800 Milan Court, Birmingham, AL, USA.

^†Current address: Department of Reparative and Regenerative Medicine, Mie University, 2–174 Edobashi, Tsu, Mie, Japan.

Received 3 June 2006; Revised 7 July 2006; Accepted 8 July 2006; Published online 7 August 2006.

Abstract

Cell cultures representing different stages of prostatic carcinoma will be a useful tool allowing a more complete understanding of the role of individual genes in tumorigenesis. We used the androgen-regulated probasin promoter linked to the neomycin phosphotransferase (Neo) gene, to generate the ARR₂PBneo transgenic mouse model. Development was normal and all six ARR₂PBneo transgenic founder lines expressed the Neo gene in a prostate-specific manner. Line C, which expressed high levels of neo, was crossbred to LPB-Tag 12T-7f transgenic mice (in which the SV40 large T antigen (Tag) was targeted to the prostate by the large probasin (LPB) promoter). Three bigenic males (carrying both Neo and Tag transgenes) were identified. Prostatic lesions developed in these mice in a predictable and heritable manner, indicating that Neo did not alter Tag-induced prostate tumor development and progression. Three separate NeoTag epithelial cell strains were established from three bigenic mice. G418 selection was used to obtain immortalized epithelial cells in culture. Selected cells expressed the Neo and Tag transgenes, cytokeratins 8 and 18, and were androgen responsive for growth. To determine if these NeoTag cells maintained a similar in vivo phenotype to the 12T–7f transgenic line, tissue recombinations were made with rat urogenital sinus mesenchyme (rUGM) and grafted under the renal capsule of male nude mouse hosts. In recombinants, the three NeoTag strains developed PIN lesions and/or more extensive adenocarcinoma than seen in the 12T–7f mouse. Androgen ablation demonstrated that the grafts were androgen responsive. NeoTag cells grafted without rUGM developed undifferentiated adenocarcinoma demonstrating that prostatic stroma dictates the glandular architecture seen in the well-differentiated adenocarcinoma.