Expression of transforming growth factor-? receptor type I and type II in rat ventral prostate and Dunning R3327 PAP adenocarcinoma in response to castration and oestrogen treatment

Abstract

In the normal prostate, transforming growth factor-β1 (TGF-β1) inhibits epithelial cell growth and is associated with apoptosis. The role of TGF-β1 in prostate cancer remains, however, unclear. In this work, the expression of TGF-β receptor type I and II (TGFβ-RI and TGFβ-RII) in the Dunning R3327 PAP adenocarcinoma was studied, after castration and oestrogen treatment. Since castration induces apoptosis in the rat ventral prostate (VP) [21], but not in the Dunning R3327 PAP tumour [46], the TGF-β receptor levels in the tumour were compared to the receptor levels in the VP. Methods used were competitive reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. In the VP, TGFβ-RI and TGFβ-RII expressions were increased after castration, indicating a negative regulation of TGFβ receptors by androgens. In the Dunning tumour, TGFβ-RI and TGFβ-RII levels were elevated and only TGFβ-RI showed a clear-cut increase after castration. The receptors were located in epithelial and smooth muscle cells in the VP and mainly in epithelial cells in the Dunning tumour. In conclusion, the elevated TGFβ receptor levels and the diminished androgen regulation of TGFβ-RII in the tumour distinguish the Dunning R3327 PAP tumour from the normal prostate and need to be further elucidated.