Characterisation of steroid receptor expression in the human prostate carcinoma cell line 22RV1 and quantification of androgen effects on mRNA regulation of prostate-specific genes.

In this study, the effect of natural androgens on the expression of androgen-regulated genes in the human prostate carcinoma cell line 22RV1 was characterised. To clarify the usefulness of the cells for in vitro studies concerning activation of androgen responsive genes by various steroidal compounds steroid receptor expression patterns had to be characterised intensively. Expression of androgen receptor (AR), estrogen receptor alpha (ERalpha) and beta (ERbeta), progestin receptor (PR) and glucocorticoid receptor alpha and beta was investigated by the means of RT-PCR, immunocytochemistry, ligand binding or Western blot. 22RV1 cells were proved to express androgen receptor and less glucocorticoid receptor beta on mRNA level. The confirmed mutation of the androgen receptor at codon H874 slightly apart from the steroid binding pocket seemed not to cause alteration of natural steroid hormone binding. mRNA expression of all progestin and estrogen receptor isoforms as well as glucocorticoid receptor alpha could not be detected. To study functional relevance of above-mentioned findings nine androgen-regulated genes were chosen to characterise the cell line and to determine androgenic effects using highly sensitive real-time RT-PCR. Addition of the three natural steroids dihydrotestosterone (DHT), testosterone, and 19-nortestosterone significantly influenced mRNA expression profiles. All compounds under study showed clear time-dependent and androgen-specific effects on transcriptional level. The results demonstrate that the cultivated human prostate carcinoma epithelial cells have a hormonal sensitivity correlated with the presence of specific receptors and can, therefore, serve as a selective model to study hormone action.