University of Manitoba

Other

Robert J Matusik

Jeffrey M Rosen

Norman M Greenberg

A DNA sequence (-426 to +28 base pairs) cloned from the probasin (PB) gene promoter region confers androgen regulation in cell culture and prostate specific expression in transgenic non-human eukaryotic animals. Various PB promoter fragments impart preferential regulation by androgens compared to other steroid hormones on fused transgenes. Alteration of the DNA sequences and/or combinations of the sequences offer improvements on the sensitivity of the bioassay for androgenic and anti-androgenic materials where androgenic is defined as any ligand or pathway that leads to the activation of androgen action. This assay also measures the significance of alteration of amino acids in the androgen receptor on its bioactivity or ability to bind to DNA sequences. In transgenic non-human eukaryotic animals, the PB sequence directs fused transgene expression to the prostate which then can control the growth or function of prostatic cells. Expression of any gene specifically in prostatic cells or cells prostate in origin, can change the characteristics of those cells. Animal models for prostatic hyperplasia and prostate cancer can be developed as well as cells isolated from these new animal models can be placed into culture to develop new cell cultures models. Exposure of either animal or culture models to any material can determine effectiveness of therapies on prostatic disease for a cure or relief of symptoms. These same animal or culture models may test any material for carcinogenicity or protection against development of prostatic neoplasms. Further, the ability of PB to target trangenes to prostatic cells permits the targeting of genes to human prostatic cells for the treatment of human benign prostatic hyperplasia and human prostate cancer.

Androgen regulation with DNA sequences of rat probasin gene

Several lines of transgenic mice have been generated using the prostate-specific rat probasin (PB) gene promoter to drive expression of the SV40 T antigen (Tag) coding region. Mice expressing high levels of the transgene specifically display progressive forms of prostatic cancer that histologically resemble human prostate cancer ranging from mild prostatic intraepithelial neoplasia (PIN) to large multinodular malignant adenocarcinoma with metastasis. Adenocarcinomas of the prostate have been detected as early as 10 weeks of age with extracapsular extension (ECE) and seminal vesicle invasion (SVI). Immunohistochemical analysis of tumor tissue has demonstrated that dorsolateral prostate-specific secretory proteins were confined to well differentiated ductal epithelial cells adjacent to, or within the poorly differentiated tumor mass. Prostate tumors in the mice also display elevated levels of nuclear p53, and a decreased heterogenous pattern of androgen receptor (AR) expression as observed in advanced human prostate cancer. The establishment of breeding lines of transgenic mice that reproducibly develop prostate cancer with metastasis provides a unique animal model system to study the molecular basis of transformation of normal prostatic cells and the factors influencing the progression to metastatic prostate cancer.

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Winnipeg, Canada

Robert J Matusik