Aldo-keto reductases (AKRs) are monomeric NAD(P)(H) dependent oxidoreductases that play pivotal roles in the biosynthesis and metabolism of steroids in humans. AKR1C enzymes acting as 3-keto-, 17-keto- and 20-keto-steroid reductases are involved in the pre-receptor regulation of ligands for the androgen, estrogen and progesterone receptor and are considered drug targets to treat steroid hormone dependent malignancies and endocrine disorders. By contrast AKR1D1 is the only known steroid 5β-reductase and is essential for bile-acid biosynthesis, the generation of ligands for the farnesoid-X-receptor, and the 5β-dihydrosteroids that have their own biological activity. This article will review the crystal structures of these AKRs, their kinetic and catalytic mechanisms, AKR genomics (gene expression, splice variants, polymorphic variants, and inherited genetic deficiencies), distribution in steroid target tissues, roles in steroid hormone action and disease, and inhibitor design.
Evaluation of a series of MetAP inhibitors in an in vitro enzyme activity assay led to the first identification of potent molecules that show significant growth inhibition against Burkholderia pseudomallei. Nitroxoline analogs show excellent inhibition potency in the BpMetAP1 enzyme activity assay with the lowest IC50 of 30 nM, and inhibit the growth of B. pseudomallei and B. thailandensis at concentrations ≥ 31 μM.
Type 5 17β-hydroxysteroid dehydrogenase, aldo-keto reductase 1C3 (AKR1C3) converts Δ4-androstene-3,17-dione and 5α-androstane-3,17-dione to testosterone (T) and 5α-dihydrotestosterone, respectively, in castration resistant prostate cancer (CRPC). In CRPC, AKR1C3 is implicated in drug resistance, and enzalutamide drug resistance can be surmounted by indomethacin a potent inhibitor of AKR1C3. We examined a series of naproxen analogues and find that (R)-2-(6-methoxynaphthalen-2-yl)butanoic acid (in which the methyl group of R-naproxen was replaced by an ethyl group) acts as a potent AKR1C3 inhibitor that displays selectivity for AKR1C3 over other AKR1C enzymes. This compound was devoid of inhibitory activity on COX isozymes and blocked AKR1C3 mediated production of T and induction of PSA in LNCaP-AKR1C3 cells as a model of a CRPC cell line. R-Profens are substrate selective COX-2 inhibitors and block the oxygenation of endocannabinoids and in the context of advanced prostate cancer R-profens could inhibit intratumoral androgen synthesis and act as analgesics for metastatic disease.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.