Aldo-keto reductases (AKRs) are soluble NAD(P)(H) oxidoreductases that primarily reduce aldehydes and ketones to primary and secondary alcohols, respectively. The ten known human AKR enzymes can turnover a vast range of substrates, including drugs, carcinogens, and reactive aldehydes. They play central roles in the metabolism of these agents, and this can lead to either their bioactivation or detoxication. AKRs are Phase I drug metabolizing enzymes for a variety of carbonyl-containing drugs and are implicated in cancer chemotherapeutic drug resistance. They are involved in tobacco-carcinogenesis because they activate polycyclic aromatic trans-dihydrodiols to yield reactive and redox active o-quinones, but they also catalyze the detoxication of nicotine derived nitrosamino ketones. They also detoxify reactive aldehydes formed from exogenous toxicants, e.g., aflatoxin, endogenous toxicants, and those formed from the breakdown of lipid peroxides. AKRs are stress-regulated genes and play a central role in the cellular response to osmotic, electrophilic, and oxidative stress.

The source of NADPH-dependent cytosolic 3␤-hydroxysteroid dehydrogenase (3␤-HSD) activity is unknown to date. This important reaction leads e.g. to the reduction of the potent androgen 5␣-dihydrotestosterone (DHT) into inactive 3␤-androstanediol (3␤-Diol). Four human cytosolic aldo-keto reductases (AKR1C1-AKR1C4) are known to act as non-positional-specific 3␣-/ 17␤-/20␣-HSDs. We now demonstrate that AKR1Cs catalyze the reduction of DHT into both 3␣-and 3␤-Diol (established by 1 H NMR spectroscopy). The rates of 3␣-versus 3␤-Diol formation varied significantly among the isoforms, but with each enzyme both activities were equally inhibited by the nonsteroidal anti-inflammatory drug flufenamic acid. In vitro, AKR1Cs also expressed substantial 3␣[17␤]-hydroxysteroid oxidase activity with 3␣-Diol as the substrate. However, in contrast to the 3-ketosteroid reductase activity of the enzymes, their hydroxysteroid oxidase activity was potently inhibited by low micromolar concentrations of the opposing cofactor (NADPH). This indicates that in vivo all AKR1Cs will preferentially work as reductases. Human hepatoma (HepG2) cells (which lack 3␤-HSD/⌬ 5-4 ketosteroid isomerase mRNA expression, but express AKR1C1-AKR1C3) were able to convert DHT into 3␣-and 3␤-Diol. This conversion was inhibited by flufenamic acid establishing the in vivo significance of the 3␣/3␤-HSD activities of the AKR1C enzymes. Molecular docking simulations using available crystal structures of AKR1C1 and AKR1C2 demonstrated how 3␣/3␤-HSD activities are achieved. The observation that AKR1Cs are a source of 3␤-tetrahydrosteroids is of physiological significance because: (i) the formation of 3␤-Diol (in contrast to 3␣-Diol) is virtually irreversible, (ii) 3␤-Diol is a pro-apoptotic ligand for estrogen receptor ␤, and (iii) 3␤-tetrahydrosteroids act as ␥-aminobutyric acid type A receptor antagonists.Two classes of 3␤-hydroxysteroids, i.e. the ⌬ 5 -3␤-hydroxysteroids and the fully saturated 3␤-tetrahydrosteroids, represent pivotal intermediates in steroid hormone metabolism. In steroidogenic glands, ⌬ 5 -3␤-hydroxysteroid precursors are converted into ⌬ 4 -3-ketosteroids to produce active steroid hormones (1, 2), whereas 3-ketosteroid reduction of 5␣/5␤-dihydrosteroids into 3␤-tetrahydrosteroids is an important catabolic step in steroid hormone transformation.Human steroid hormone target tissues like the prostate express membrane attached and/or cytosolic 3␣-HSD 1 and 3␤-HSD activity (3-9). One key example of the catabolic function of these HSDs is the 3-ketosteroid reduction of the potent androgen 5␣-dihydrotestosterone (DHT, 17␤-hydroxy-5␣-androstan-3-one) into the inactive androgens 5␣-androstane-3␣,17␤-diol (3␣-Diol; Fig. 1) and 5␣-androstane-3␤,17␤-diol (3␤-Diol) (10 -12). In vivo, the formation of 3␤-Diol is virtually irreversible, whereas 3␣-Diol can be converted back to DHT via 3␣-hydroxysteroid oxidase activity (13-17). Reformation of DHT from 3␤-Diol is prevented, because 3␤-Diol is either irreversibly hydroxylated at the C-6 and/or C-7 position or ...

Cryptococcosis is caused by either Cryptococcus neoformans or C. gattii. While cryptococcal meningoencephalitis is caused mostly by C. neoformans in immunocompromised patients, the risk factors remain unclear for patients with no known immune defect. Recently, anti-granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies were detected in the plasma of seven “immunocompetent” cryptococcosis patients, and the cryptococcal strains from these patients were reported as C. neoformans (three strains), C. gattii (one strain), and Cryptococcus (three strains not identified to the species level). We identified all three strains that had not been identified to the species level as C. gattii. Notably, the three strains that were reported as C. neoformans but were unavailable for species confirmation originated from Sothern California and Thailand where C. gattii is endemic. Most clinical laboratories designate C. neoformans without distinguishing between the two species; hence, these three strains could have been C. gattii. Since C. gattii infects more immunocompetent patients than C. neoformans, we pursued the possibility that this antibody may be more prevalent in patients infected with C. gattii than in those infected with C. neoformans. We screened the plasma of 20 healthy controls and 30 “immunocompetent” patients with cryptococcal meningoencephalitis from China and Australia (multiple ethnicities). Anti-GM-CSF autoantibodies were detected only in the plasma of seven patients infected by C. gattii and one healthy volunteer and in none infected by C. neoformans. While plasma from these C. gattii patients completely prevented GM-CSF-induced p-STAT5 in normal human peripheral blood mononuclear cells (PBMCs), plasma from one healthy volunteer positive for anti-GM-CSF autoantibodies caused only partial blockage. Our results suggest that anti-GM-CSF autoantibodies may predispose otherwise immunocompetent individuals to meningoencephalitis caused by C. gattii but not necessarily to that caused by C. neoformans.

There is considerable interest in the development of an inhibitor of aldo-keto reductase (AKR) 1C3 (type 5 17β-hydroxysteroid dehydrogenase and prostaglandin F synthase) as a potential therapeutic for both hormone-dependent and hormone-independent cancers. AKR1C3 catalyzes the reduction of 4-androstene-3,17-dione to testosterone and estrone to 17β-estradiol in target tissues, which will promote the proliferation of hormone dependent prostate and breast cancers, respectively. AKR1C3 also catalyzes the reduction of prostaglandin (PG) H 2 to PGF 2α and PGD 2 to 9α,11β-PGF 2 , which will limit the formation of anti-proliferative prostaglandins, including 15-deoxy-Δ 12,14 -PGJ 2 , and contribute to proliferative signaling. AKR1C3 is overexpressed in a wide variety of cancers, including breast and prostate cancer. An inhibitor of AKR1C3 should not inhibit the closely related isoforms AKR1C1 and AKR1C2, as they are involved in other key steroid hormone biotransformations in target tissues. Several structural leads have been explored as inhibitors of AKR1C3, including non-steroidal anti-inflammatory drugs, steroid hormone analogues, flavonoids, cyclopentanes, and benzodiazepines. Inspection of the available crystal structures of AKR1C3 with multiple ligands bound, along with the crystal structures of the other AKR1C isoforms, provides a structural basis for the rational design of isoform specific inhibitors of AKR1C3. We find that there are subpockets involved in ligand binding that are considerably different in AKR1C3 relative to the closely related AKR1C1 or AKR1C2 isoforms. These pockets can be used to further improve the binding affinity and selectivity of the currently available AKR1C3 inhibitors. KeywordsAldo-keto reductase; steroid hormones; prostaglandins; nuclear receptors; structure-based inhibitor design The Aldo-Keto Reductase (AKR) protein superfamily nomenclature was developed to annotate family members based on sequence homology rather than enzymatic activity. This is because the same enzyme was given different trivial names based on the enzymatic reaction measured and led to considerable confusion. For example, aldo-keto reductase 1C3 (AKR1C3) has been referred to as: type 5 17β-hydroxysteroid dehydrogenase, prostaglandin F synthase, type 2 3α-hydroxysteroid dehydrogenase; and dihydrodiol dehydrogenase X. The nomenclature was originally adopted by the 6 th International Workshop on the Enzymology and Molecular Biology of Carbonyl Metabolism held in Deadwood, South Dakota in 1996 (see, Jez et al., Biochem. Pharmacol. 54 (1997. It has since been adopted by the Human Genome Project (please visit: www.med.upenn.edu/akr).Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors m...

Aldo-keto reductase 1C3 (AKR1C3; type 5 17β-hydroxysteroid dehydrogenase) is overexpressed in castrate resistant prostate cancer (CRPC) and is implicated in the intratumoral biosynthesis of testosterone and 5α-dihydrotestosterone. Selective AKR1C3 inhibitors are required since compounds should not inhibit the highly related AKR1C1 and AKR1C2 isoforms which are involved in the inactivation of 5α-dihydrotestosterone. NSAIDs, N-phenylanthranilates in particular are potent but non-selective AKR1C3 inhibitors. Using flufenamic acid, 2-{[3-(trifluoromethyl)phenyl]amino}benzoic acid as lead compound, five classes of structural analogs were synthesized and evaluated for AKR1C3 inhibitory potency and selectivity. Structure activity relationship (SAR) studies revealed that a meta-carboxylic acid group relative to the amine conferred pronounced AKR1C3 selectivity without loss of potency, while electron withdrawing groups on the phenylamino B-ring were optimal for AKR1C3 inhibition. Lead compounds did not inhibit COX-1 or COX-2 but blocked the AKR1C3 mediated production of testosterone in LNCaP-AKR1C3 cells. These compounds offer promising leads towards new therapeutics for CRPC.

Human aldo-keto reductases (AKRs) regulate nuclear receptors by controlling ligand availability. Enzymes implicated in regulating ligand occupancy and trans-activation of the nuclear receptors belong to the AKR1C family (AKR1C1-AKR1C3). Nuclear receptors regulated by AKR1C members include the steroid hormone receptors (androgen, estrogen, and progesterone receptors) and the orphan peroxisome proliferator-activated receptor (PPAR␥). In human myeloid leukemia (HL-60) cells, ligand access to PPAR␥ is regulated by AKR1C3, which diverts PGD 2 metabolism away from J-series prostanoids (Desmond et al., 2003). Inhibition of AKR1C3 by indomethacin, a nonsteroidal anti-inflammatory drug (NSAID), caused PPAR␥-mediated terminal differentiation of the HL-60 cells. To discriminate between antineoplastic effects of NSAIDs that are mediated by either AKR1C or cyclooxygenase (COX) isozymes, selective inhibitors are required. We report a structural series of N-phenylanthranilic acid derivatives and steroid carboxylates that selectively inhibit recombinant AKR1C isoforms but do not inhibit recombinant COX-1 or COX-2. The inhibition constants, IC 50 , K I values, and inhibition patterns were determined for the NSAID analogs and steroid carboxylates against AKR1C and COX isozymes. Lead compounds, 4-chloro-N-phenylanthranilic acid and 4-benzoyl-benzoic acid for the N-phenylanthranilic acid analogs and most steroid carboxylates, exhibited IC 50 values that had greater than 500-fold selectivity for AKR1C isozymes compared with COX-1 and COX-2. Crystallographic and molecular modeling studies showed that the carboxylic acid of the inhibitor ligand was tethered by the catalytic Tyr55-OH 2 ϩ and explained why A-ring substituted N-phenylanthranilates inhibited only AKR1C enzymes. These compounds can be used to dissect the role of the AKR1C isozymes in neoplastic diseases and may have cancer chemopreventive roles independent of COX inhibition.

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Background:Health education has been considered as the effectiveness method to increase the self-care skills of diabetes patients. However, limited studies to investigate the association of health education via Wechat platform on increased the basic self-care skills and glycemic control rate in patients with type 2 diabetes.Methods:A total number of 120 type 2 diabetes patients were randomized into intervention (health education by Wechat platform plus usual care) and the control group (usual care). Biochemical parameters including fasting plasma glucose (FPG), 2-hour plasma glucose (2hPG), glycosylated hemoglobin A1c (HbA1c) were measured among the 2 groups at baseline 6-month and 12-month. Diabetes Management Self-Efficacy (SE) Scale was completed at baseline 6-month and 12-month.Results:Significant difference of HbA1c concentration and SE were found between intervention and control groups at 6-month and 12-month (P <.05). The effect of groups and health education duration times was found on reduced HbA1c concentration and increased the total score of SE (P <.05). No significant difference of FPG and 2hPG concentrations were found between intervention and control groups at 6 months and 12 months (P >.05).Conclusion:Health education of diabetic individuals via Wechat platform in conjunction with conventional diabetes treatment could improve glycemic control and positively influence other aspects of diabetes self-care skills.