Adenosine <scp> A ₃ </scp> receptor antagonists as anti‐tumor treatment in human prostate cancer: an <i>in vitro</i> study

Prostate cancer (PCa) is one of the most common cancers in men, and for patients with PCa that cannot be surgically resected or treated, androgen suppression therapy often results in significant adverse effects. Recent studies have shown that A3 adenosine receptors (A₃ARs) are overexpressed in prostate cancer (PCa), and several A₃AR agonists and antagonists have been investigated as potential anticancer drugs. In this study, we investigated the potential therapeutic effects of the A₃AR antagonists AR 292 and AR 357 in human PCa cell lines. LNCaP, DU-145, and PC3 cell lines were treated with AR 292 and AR 357 compounds, and their cytotoxic effects were determined using viability assays, flow cytometry, and western blotting. Moreover, the drug transporter gene profile was evaluated using RT-PCR in untreated and A₃AR antagonist-treated PCa cells. Both AR 292 and AR 357 showed antiproliferative effects with significant cell cycle arrest and induced DNA damage leading to cell death. AR 292 and especially AR 357 modulated the expression of drug transporter genes involved in chemoresistance, ferroptosis, and the hypoxia response. Ferroptosis was induced in DU-145 cells treated with both compounds as well as in PC3 cells treated with AR 357. However, the treatment of PC3 cells with AR 292 and the treatment of LNCaP cells with both AR 292 and AR 357 resulted in necrotic cell death. In conclusion, our study showed that A₃AR ligands exert anticancer effects via different mechanisms on PCa cell lines through the activation of multiple molecular pathways.