Background: Angiogenesis is important for prostate organogenesis and prostate cancer progression. It is not yet known whether androgens promote part of their control of prostate structure and function by influencing angiogenesis. The aim of this study was to explore the possible androgenic regulation of the angiogenic factor vascular endothelial growth factor (VEGF) and its receptors flt-1 and flk-1/KDR in the rat ventral prostate (VP) and Dunning R3327 PAP adenocarcinoma.
Methods: RNA was prepared from VP and tumors of intact and castrated rats. VEGF, flt-1, and flk-1/KDR mRNA levels were determined using competitive RT-PCR.
Results: VEGF121, VEGF165, and VEGF189 together with flt-1 and flk-1/KDR mRNA were detected. The VEGF, but not flt-1 mRNA levels were significantly decreased in the VP after castration. The Dunning tumor expressed high levels of mRNA for VEGF and its receptors compared to the VP. The flt-1 mRNA level in the tumor increased after castration, while the VEGF mRNA levels were unchanged.
Conclusions: Decreased mRNA expression of VEGF, but not flt-1, was found in the rat VP after castration. However, in the Dunning tumor, castration did not alter the expression of VEGF mRNA. Moreover, elevated levels of both mRNA for VEGF and its receptors relative to the VP were observed, indicating that the VEGF system may be important for Dunning tumor development.