Phosphodiesterase Type-5 Inhibitor Tadalafil Modulates Steroid Hormones Signaling in a Prostate Cancer Cell Line

Background: The androgen receptor (AR) plays a key role in normal prostate homeostasis and in prostate cancer (PCa) development, while the role of aromatase (Cyp19a1) is still unclear. We evaluated the effects of a treatment with Tadalafil (TAD) on both these proteins. Methods: Androgen-sensitive human PCa cell line (LnCAP) was incubated with/without TAD (10&minus
6 M) and bicalutamide (BCT) (10&minus
4 M) to evaluate a potential modulation on cell proliferation, protein and mRNA expression of Cyp19a, AR and estrogen receptor-&beta
(ER&beta
), respectively. Results: TAD increased early AR nuclear translocation (p &lt
0.05, after 15 min of exposure), and increased AR transcriptional activity (p &lt
0.05) and protein expression (p &lt
0.05) after 24 h. Moreover, after 24 h this treatment upregulated Cyp19a1 and ER&beta
mRNA (p &lt
0.05 and p &lt
0.005 respectively) and led to an increase in protein expression of both after 48 h (p &lt
0.05). Interestingly, TAD counteracted Cyp19a1 stimulation induced by BCT (p &lt
0.05) but did not alter the effect induced by BCT on the AR protein expression. Conclusion: We demonstrate for the first time that TAD can significantly modulate AR expression and activity, Cyp19a1 and ER&beta
expression in PCa cells, suggesting a specific effect of these proteins. In addition, TAD potentiates the antiproliferative activity of BCT, opening a new clinical scenario in the treatment of PCa.