Laboratory of Medicinal Chemistry, CHU de Québec (CHUL, T4) - Research Center and Laval University (Faculty of Medicine), Québec, Québec G1V 4G2, Canada.
Laboratory of Medicinal Chemistry, CHU de Québec (CHUL, T4) - Research Center and Laval University (Faculty of Medicine), Québec, Québec G1V 4G2, Canada.
J Steroid Biochem Mol Biol. 2014 May;141:44-51. doi: 10.1016/j.jsbmb.2013.12.019. Epub 2014 Jan 13.
17β-Hydroxysteroid dehydrogenase type 3 (17β-HSD3 or HSD17B3) catalyzes the last step in the biosynthesis of the potent androgen testosterone (T), by stereoselectively reducing the C17 ketone of 4-androstene-3,17-dione (4-dione), with NADPH as cofactor. Since T plays an important role in androgen-sensitive diseases, this enzyme is thus an interesting therapeutic target. In an attempt to design compounds to lower the level of T, we synthesized androsterone derivatives substituted at position 3 as inhibitors of 17β-HSD3, and selected one of the most potent compounds for additional studies. In an enzymatic assay in homogenized and whole HEK-293 cells overexpressing 17β-HSD3, the inhibitor RM-532-105 efficiently inhibited the conversion of natural substrate 4-dione (50nM) into T with an IC50 of 26nM and 5nM, respectively. Moreover, the inhibitor RM-532-105 (10mg/kg) reached a plasma concentration of 250ng/mL at 7h (AUC 24h: 3485ngh/mL) after subcutaneous (s.c.) injection in the rat. In order to mimic the human situation in which 4-dione is converted to T in the testis, we used intact rats. Treatment for 7 days with 17β-HSD3 inhibitor RM-532-105 by s.c. injection or oral gavage exerted no effect on the testis, prostate and seminal vesicle weight and no modification in the levels of plasma steroids. However, after this treatment, the concentration of inhibitor in plasma increased depending on the dose. We thereafter determined the concentration of inhibitor in the testis and we discovered that the compound was slightly present. In fact, at 10mg/kg, the inhibitor RM-532-105 seems to have difficulty penetrating inside the testis and was found to be concentrated in the testicular capsule, and therefore unable to inhibit the 17β-HSD3 located inside the testis. However, with a higher dose of 50mg/kg injected s.c. in rats, RM-532-105 significantly decreased the level of T and dihydrotestosterone measured in plasma at 2h.
17β-羟甾脱氢酶 3 型（17β-HSD3 或 HSD17B3）通过立体选择性还原 4-雄烯二酮（4-dione）的 C17 酮，以 NADPH 为辅因子，催化强效雄激素睾酮（T）的生物合成的最后一步。由于 T 在雄激素敏感疾病中起着重要作用，因此该酶是一个有趣的治疗靶标。为了设计降低 T 水平的化合物，我们合成了 3 位取代的雄甾酮衍生物作为 17β-HSD3 的抑制剂，并选择了一种最有效的化合物进行进一步研究。在匀浆和过表达 17β-HSD3 的整个 HEK-293 细胞的酶促测定中，抑制剂 RM-532-105 分别以 26nM 和 5nM 的 IC50 有效抑制天然底物 4-dione（50nM）转化为 T。此外，抑制剂 RM-532-105（10mg/kg）在大鼠皮下（s.c.）注射后 7 小时达到 250ng/mL 的血浆浓度（AUC 24h：3485ngh/mL）。为了模拟 4-dione 在睾丸中转化为 T 的人类情况，我们使用了完整的大鼠。通过 s.c.注射或口服灌胃用 17β-HSD3 抑制剂 RM-532-105 治疗 7 天对睾丸、前列腺和精囊的重量没有影响，也没有改变血浆类固醇的水平。然而，在此治疗后，抑制剂在血浆中的浓度会增加，这取决于剂量。此后，我们测定了睾丸中抑制剂的浓度，发现该化合物略有存在。实际上，在 10mg/kg 时，抑制剂 RM-532-105 似乎难以穿透睾丸内部，并且在睾丸囊中浓缩，因此无法抑制位于睾丸内部的 17β-HSD3。然而，在大鼠中以更高剂量 50mg/kg 皮下注射，RM-532-105 可显著降低 2 小时时血浆中 T 和二氢睾酮的水平。
