Synthesis and activity of novel 16-dehydropregnenolone acetate derivatives as inhibitors of type 1 5α-reductase and on cancer cell line SK-LU-1

Testosterone (T) plays a crucial role in prostate growth. In androgen-dependent tissues T is reduced to dihydrotestosterone (DHT) because of the presence of the 5α-reductase enzyme. This androgen is more active than T, since it has a higher affinity for the androgen receptor (AR). When this mechanism is altered, androgen-dependent diseases, including prostate cancer, could result. The aim of this study was to synthesize several 16-dehydropregnenolone acetate derivatives containing a triazole ring at C-21 and a linear or alicyclic ester moiety at C-3 of the steroidal skeleton. These steroids were designed as potential inhibitors of the activity of both types (1 and 2) of 5α-reductase. The cytotoxic activity of these compounds was also evaluated on a panel of PC-3, MCF7, and SK-LU-1 human cancer cell lines. The results from this study showed that with the exception of steroids 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-propionate and 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-pentanoate, the compounds exhibit a lower inhibitory activity for both isoenzymes of 5α-reductase than finasteride. Furthermore the 3β-hydroxy-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-20-one and 20-oxo-21-(1H-1,2,4-triazole-1-yl)pregna-5,16-dien-3β-yl-acetate derivatives display 80% cytotoxic activity on the SK-LU-1 cell line. These results also indicated that the triazole derivatives, which have a hydroxyl or acetoxy group at C-3, could have an anticancer effect, whereas the derivatives with a alicyclic ester group at C-3 do not show biological activity.