Synthesis, biological evaluation and SAR of naftopidil-based arylpiperazine derivatives

For the development of potential anti-prostate cancer agents, 24 kinds of novel naftopidil-based arylpiperazine derivatives have been synthesized and characterized by spectroscopic methods. Their antitumor activities were evaluated against several classical prostate cancer cell lines including PC-3, LNCaP, and DU145. Among all the compounds, 9, 13, 17, 21 and 27 showed strong cytotoxic activities against DU145 cells (IC₅₀ < 1 μM). Further testing confirmed that compound 17 inhibited the growth of DU145 cells by inducing cell cycle arrest at G0/G1 phase. Besides, antagonistic activities of compounds (9, 13, 17, 21 and 27) towards a₁-ARs (α_1A, α_1B, and α_1D) were further evaluated using dual-luciferase reporter assays, and the compounds 13 and 17 exhibited better a₁-ARs subtype selectivity. The structure-activity relationship (SAR) of these developed arylpiperazine derivatives was rationally discussed. Taken together, these results suggested that further development of such compounds may be of great interest.