Department of Biochemistry & Biophysics, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA 19104, United States.
Department of Systems Pharmacology & Translational Therapeutics, Perelman School of Medicine University of Pennsylvania, Philadelphia, PA 19104, United States.
J Steroid Biochem Mol Biol. 2022 Jul;221:106121. doi: 10.1016/j.jsbmb.2022.106121. Epub 2022 Apr 28.
Aldo-keto reductase (AKR) 1C3, also known as type 5 17β-hydroxysteroid dehydrogenase and prostaglandin F synthase, is a member of the AKR superfamily that reduces aldehydes and ketones to primary and secondary alcohols. It plays an essential role in the peripheral formation of androgens and is implicated in several steroid hormone dependent diseases including prostate cancer, breast cancer, and polycystic ovary syndrome (PCOS). AKR1C3 has 14 nonsynonymous single nucleotide polymorphisms (nsSNPs) with different global frequencies and ethnic distributions. Association studies support their role in disease, but a detailed functional genomic analysis of these variants is lacking. One study examined five AKR1C3 nsSNPs for their ability to reduce exemestane, an aromatase inhibitor used to treat breast cancer, to 17β-dihydroexemestane, and reported a 17-250-fold reduction in catalytic efficiency of H5Q, E77G, K104D, and R258C variants compared to wild type (WT). This observation provided the impetus to examine the impact of these variants on AKR1C3 function. Here, we purified AKR1C3 WT, and the top four most frequently occurring nsSNPs, H5Q, E77G, K104D, and R258C, from E. coli to expand upon their characterization and illuminate functional differences that could affect disease outcome and treatment. While we found negligible deviations in steady state kinetics, the K104D variant showed reduced thermal stability compared to WT. The presence of NAD(P) restored the stability of the variant. As it is unlikely that the apoenzyme will exist within the cell without cofactor bound the K104D is not expected to manifest a phenotype.
醛酮还原酶（AKR）1C3，也称为 5 型 17β-羟甾脱氢酶和前列腺素 F 合酶，是 AKR 超家族的一员，可将醛和酮还原为伯醇和仲醇。它在雄激素的外周形成中起着重要作用，与几种类固醇激素依赖性疾病有关，包括前列腺癌、乳腺癌和多囊卵巢综合征（PCOS）。AKR1C3 有 14 个非同义单核苷酸多态性（nsSNP），具有不同的全球频率和种族分布。关联研究支持它们在疾病中的作用，但这些变体的详细功能基因组分析尚缺乏。一项研究检查了 5 个 AKR1C3 nsSNP 降低芳香酶抑制剂依西美坦（用于治疗乳腺癌）为 17β-二氢依西美坦的能力，并报告 H5Q、E77G、K104D 和 R258C 变体的催化效率比野生型（WT）降低了 17-250 倍。这一观察结果为研究这些变体对 AKR1C3 功能的影响提供了动力。在这里，我们从大肠杆菌中纯化了 AKR1C3 WT 和最常发生的前 4 个 nsSNP，即 H5Q、E77G、K104D 和 R258C，以扩展其特征描述并阐明可能影响疾病结局和治疗的功能差异。虽然我们发现稳态动力学的偏差可以忽略不计，但 K104D 变体的热稳定性比 WT 降低。NAD（P）的存在恢复了变体的稳定性。由于在没有辅助因子结合的情况下细胞内不太可能存在脱辅基酶，因此预计 K104D 不会表现出表型。
