Day Joanna M, Tutill Helena J, Foster Paul A, Bailey Helen V, Heaton Wesley B, Sharland Christopher M, Vicker Nigel, Potter Barry V L, Purohit Atul, Reed Michael J
Oncology Drug Discovery & Women's Health Group, Department of Endocrinology & Metabolic Medicine, & Sterix Ltd., Imperial College London, London W2 1NY, UK.
Mol Cell Endocrinol. 2009 Mar 25;301(1-2):251-8. doi: 10.1016/j.mce.2008.08.014. Epub 2008 Aug 22.
17beta-Hydroxysteroid dehydrogenases (17beta-HSDs) are responsible for the pre-receptor reduction/oxidation of steroids at the 17-position into active/inactive hormones, and the 15 known enzymes vary in their substrate specificity, localisation, and directional activity. 17beta-HSD Type 3 (17beta-HSD3) has been seen to be over-expressed in prostate cancer, and catalyses the reduction of androstenedione (Adione) to testosterone (T), which stimulates prostate tumour growth. Specific inhibitors of 17beta-HSD3 may have a role in the treatment of hormone-dependent prostate cancer and benign prostate hyperplasia, and also have potential as male anti-fertility agents. A 293-EBNA-based cell line with stable expression of transfected human 17beta-HSD3 was created and used to develop a whole cell radiometric TLC-based assay to assess the 17beta-HSD3 inhibitory potency of a series of compounds. STX2171 and STX2624 (IC(50) values in the 200-450nM range) were two of several active inhibitors identified. In similar TLC-based assays these compounds were found to be inactive against 17beta-HSD1 and 17beta-HSD2, indicating selectivity. A novel proof of concept model was developed to study the efficacy of the compounds in vitro using the androgen receptor positive hormone-dependent prostate cancer cell line, LNCaPwt, and its derivative, LNCaP[17beta-HSD3], transfected and selected for stable expression of 17beta-HSD3. The proliferation of the parental cell line was most efficiently stimulated by 5alpha-dihydrotestosterone (DHT), but the LNCaP[17beta-HSD3] cells were equally stimulated by Adione, indicating that 17beta-HSD3 efficiently converts Adione to T in this model. Adione-stimulated proliferation of LNCaP[17beta-HSD3] cells was inhibited in the presence of either STX2171 or STX2624. The compounds alone neither stimulated proliferation of the cells nor caused significant cell death, indicating that they are non-androgenic with low cytotoxicity. STX2171 inhibited Adione-stimulated growth of xenografts established from LNCaPwt cells in castrated mice in vivo. In conclusion, a primary screening assay and proof of concept model have been developed to study the efficacy of 17beta-HSD3 inhibitory compounds, which may have a role in the treatment of hormone-dependent cancer. Active compounds are selective for 17beta-HSD3 over 17beta-HSD1 and 17beta-HSD2, non-androgenic with low toxicity, and efficacious in both an in vitro proof of concept model and in an in vivo tumour model.
17β-羟基类固醇脱氢酶（17β-HSDs）负责在受体前将17位的类固醇还原/氧化为活性/非活性激素，已知的15种酶在底物特异性、定位和方向活性方面存在差异。17β-HSD3型（17β-HSD3）在前列腺癌中过度表达，催化雄烯二酮（Adione）还原为睾酮（T），从而刺激前列腺肿瘤生长。17β-HSD3的特异性抑制剂可能在激素依赖性前列腺癌和良性前列腺增生的治疗中发挥作用，并且也有作为男性抗生育剂的潜力。创建了一种基于293-EBNA的细胞系，其稳定表达转染的人17β-HSD3，并用于开发一种基于全细胞放射性TLC的测定方法，以评估一系列化合物对17β-HSD3的抑制效力。STX2171和STX2624（IC(50)值在200 - 450 nM范围内）是鉴定出的几种活性抑制剂中的两种。在类似的基于TLC的测定中，发现这些化合物对17β-HSD1和17β-HSD2无活性，表明具有选择性。开发了一种新的概念验证模型，使用雄激素受体阳性的激素依赖性前列腺癌细胞系LNCaPwt及其衍生物LNCaP[17β-HSD3]（转染并选择用于稳定表达17β-HSD3）在体外研究这些化合物的功效。亲代细胞系的增殖最有效地受到5α-二氢睾酮（DHT）的刺激，但LNCaP[17β-HSD3]细胞同样受到Adione的刺激，表明在该模型中17β-HSD3有效地将Adione转化为T。在存在STX2171或STX2624的情况下，Adione刺激的LNCaP[17β-HSD3]细胞增殖受到抑制。这些化合物单独既不刺激细胞增殖也不引起明显的细胞死亡，表明它们是非雄激素性的，细胞毒性低。STX2171在体内抑制了去势小鼠中由LNCaPwt细胞建立的异种移植物的Adione刺激的生长。总之，已经开发了一种初步筛选测定和概念验证模型来研究17β-HSD3抑制性化合物的功效，这些化合物可能在激素依赖性癌症的治疗中发挥作用。活性化合物对17β-HSD3具有选择性，优于17β-HSD1和17β-HSD2，是非雄激素性的，毒性低，并且在体外概念验证模型和体内肿瘤模型中均有效。
