Abstract：
AKR1C3 is an enzyme that is overexpressed in several types of radiotherapy- and chemotherapy-resistant cancers. Despite AKR1C3 is a validated target for drug development, no inhibitor has been approved for clinical use. In this manuscript, we describe our study of a new series of potent AKR1C3-targeting 3-hydroxybenzoisoxazole based inhibitors that display high selectivity over the AKR1C2 isoform and low micromolar activity in inhibiting 22Rv1 prostate cancer cell proliferation. In silico studies suggested proper substituents to increase compound potency and provided with a mechanistic explanation that could clarify their different activity, later confirmed by X-ray crystallography. Both the in-silico studies and the crystallographic data highlight the importance of 90° rotation around the single bond of the biphenyl group, in ensuring that the inhibitor can adopt the optimal binding mode within the active pocket. The p-biphenyls that bear the meta-methoxy, and the ortho- and meta-trifluoromethyl substituents (in compounds 6a, 6e and 6f respectively) proved to be the best contributors to cellular potency as they provided the best IC50 values in series (2.3, 2.0 and 2.4 μM respectively) and showed no toxicity towards human MRC-5 cells. Co-treatment with scalar dilutions of either compound 6 or 6e and the clinically used drug abiraterone led to a significant reduction in cell proliferation, and thus confirmed that treatment with both CYP171A1-and AKR1C3-targeting compounds possess the potential to intervene in key steps in the steroidogenic pathway. Taken together, the novel compounds display desirable biochemical potency and cellular target inhibition as well as good in-vitro ADME properties, which highlight their potential for further preclinical studies.
摘要：
AKR1C3是一种在几种类型的放疗和化疗抗性癌症中过表达的酶。尽管AKR1C3是药物开发的有效靶点，尚未批准将抑制剂用于临床。在这份手稿中,我们描述了我们对一系列有效的AKR1C3靶向3-羟基苯并异恶唑抑制剂的研究，这些抑制剂对AKR1C2亚型具有高选择性，并且在抑制22Rv1前列腺癌细胞增殖方面具有低的微摩尔活性。在计算机研究中提出了适当的取代基以增加化合物的效力，并提供了可以阐明其不同活性的机械解释，后来通过X射线晶体学证实。计算机内研究和晶体学数据都强调了围绕联苯基团单键旋转90°的重要性，以确保抑制剂可以在活性口袋内采用最佳结合模式。带有间甲氧基的对联苯，和邻-和间-三氟甲基取代基(在化合物6a中，6e和6f）分别被证明是细胞效力的最佳贡献者，因为它们提供了最佳的IC50值（分别为2.3、2.0和2.4μM），并且对人MRC-5细胞没有毒性。用化合物6或6e的标量稀释液和临床使用的药物阿比特龙共同治疗导致细胞增殖显着降低，因此证实用CYP171A1和AKR1C3靶向化合物治疗具有干预类固醇生成途径关键步骤的潜力。一起来看,新化合物显示出理想的生化效力和细胞靶标抑制以及良好的体外ADME特性，这凸显了他们进一步临床前研究的潜力。
