Aldo-keto reductases:Role in cancer development and theranostics

Aldo-keto reductases(AKRs)are a superfamily of enzymes that play crucial roles in various cellular processes,including the metabolism of xenobiotics,steroids,and carbohydrates.A growing body of evidence has unveiled the involvement of AKRs in the development and progression of various cancers.AKRs are aberrantly expressed in a wide range of malignant tumors.Dysregulated expression of AKRs enables the acquisition of hallmark traits of cancer by activating oncogenic signaling pathways and contributing to chemoresistance.AKRs have emerged as promising oncotherapeutic targets given their pivotal role in cancer development and progression.Inhibition of aldose reductase(AR),either alone or in combination with chemotherapeutic drugs,has evolved as a pragmatic therapeutic option for cancer.Several classes of synthetic aldo-keto reductase(AKR)inhibitors have been developed as potential anticancer agents,some of which have shown promise in clinical trials.Many AKR inhibitors from natural sources also exhibit anticancer effects.Small molecule inhibitors targeting specific AKR isoforms have shown promise in preclinical studies.These inhibitors disrupt the activation of oncogenic signaling by modulating transcription factors and kinases and sensitizing cancer cells to chemotherapy.In this review,we discuss the physiological functions of human AKRs,the aberrant expression of AKRs in malignancies,the involvement of AKRs in the acquisition of cancer hallmarks,and the role of AKRs in oncogenic signaling,and drug resistance.Finally,the potential of aldose reductase inhibitors(ARIs)as anticancer drugs is summarized.

Aldo-keto reductase family member C3(AKR1C3)promotes hepatocellular carcinoma cell growth by producing prostaglandin F2α

Hepatocellular carcinoma(HCC)is a leading cause of death worldwide.Current therapies are effective for HCC patients with early disease,but many patients suffer recurrence after surgery and have a poor response to chemotherapy.Therefore,new therapeutic targets are needed.We analyzed gene expression profiles between HCC tissues and normal adjacent tissues from public databases and found that the expression of genes involved in lipid metabolism was significantly different.The analysis showed that AKR1C3 was upregulated in tumors,and high AKR1C3 expression was associated with a poorer prognosis in HCC patients.In vitro,assays demonstrated that the knockdown of AKR1C3 or the addition of the AKR1C3 inhibitor indomethacin suppressed the growth and colony formation of HCC cell lines.Knockdown of AKR1C3 in Huh7 cells reduced tumor growth in vivo.To explore the mechanism,we performed pathway enrichment analysis,and the results linked the expression of AKR1C3 with prostaglandin F2 alpha(PGF2a)downstream target genes.Suppression of AKR1C3 activity reduced the production of PGF2a,and supplementation with PGF2a restored the growth of indomethacin-treated Huh7 cells.Knockdown of the PGF receptor(PTGFR)and treatment with a PTGFR inhibitor significantly reduced HCC growth.We showed that indomethacin potentiated the sensitivity of Huh7 cells to sorafenib.In summary,our results indicate that AKR1C3 upregulation may promote HCC growth by promoting the production of PGF2α,and suppression of PTGFR limited HCC growth.Therefore,targeting the AKR1C3-PGF2a-PTGFR axis may be a new strategy for the treatment of HCC.

The use of 5-alpha reductase inhibitors in the treatment of benign prostatic hyperplasia

Benign prostatic hyperplasia(BPH)is characterized by an enlarged prostate,lower urinary tract symptoms(LUTS),and a decreased urinary flow rate.Common in older men,BPH is a progressive disease that can eventually lead to complications including acute urinary retention(AUR)and the need for BPH-related surgery.Both normal and abnormal prostate growth is driven by the androgen dihydrotestosterone(DHT),which is formed from testosterone under the influence of 5-alpha reductase.Thus,5-alpha reductase inhibitors(5-ARIs)effectively reduce the serum and intraprostatic concentration of DHT,causing an involution of prostate tissue.Two 5-ARIs are currently available for the treatment of BPHdfinasteride and dutasteride.Both have been demonstrated to decrease prostate volume,improve LUTS and urinary flow rates,which ultimately reduces the risk of AUR and BPH-related surgery.Therefore,either alone or in combination with other BPH medications,5-ARIs are a mainstay of BPH management.

Changes in aortic endothelium ultrastructure in male rats following castration, replacement with testosterone and administration of 50α-reductase inhibitor

Aim： To investigate the relationship between low androgen level and ultrastructure of vascular endothelium. Methods： Forty-eight male Sprague-Dawley rats were randomly divided into four groups： group A, normal rats with sham castration; group B, castrated rats; group C, castrated rats given testosterone （T） undecanoate; and group D, intact rats treated with 5α-reductase inhibitor. After 10 weeks of treatment or castration, rats in different groups were killed and serum T, free T （FT） and dihydrotestosterone （DHT） were measured. The aortic endothelia were scanned under electron microcopy and the Vascular Endothelium Structure Score （VESS） was computed. Results： Serum T and FT concentrations of rats in group B were significantly lower than those of the other three groups （P 〈 0.01）; DHT concentrations of group D rats were significantly decreased （P 〈 0.01 ） when compared with those of groups A and C. Rats in groups B and D rats （with low androgen levels） had obvious damage to their endothelial surfaces, which appeared crimpled, rough, adhesive and ruptured, and had high destruction of VESS. Conclusion： These results suggest that low concentrations of T and DHT are associated with ultrastructural damage of the aortic endothelia in male rats.

Medical therapy for clinical benign prostatic hyperplasia:α1 Antagonists,5α reductase inhibitors and their combination

Medical therapy for clinical benign prostatic hyperplasia(BPH)has advanced significantly in the last 2 decades.Many new a1 antagonists and 5a reductase inhibitors(5ARi)are now commercially available.The practicing urologist must decide on the most appropriate medication for his patients,taking into consideration various factors like efficacy,dosing regime,adverse effects,cost,patient’s socioeconomic background,expectations,drug availability and his own clinical experience.The use of combination therapy added further to the complexity in clinical judgment when prescribing.We highlight some of the key points in prescribing a1 antagonists,5ARi and their combination,based on our viewpoints and experience as urologists in an Asian clinical setting.

A novel thioredoxin reductase inhibitor inhibits cell growth and induces apoptosis in HL-60 and K562 cells

Human thioredoxin reductase (TrxR) system is associated with cancer cell growth and anti-apoptosis process. Effects of 1,2-bis(1,2-benzisoselenazolone-3(2H)-ketone)ethane (BBSKE),a novel TrxR inhibitor,were investigated on human leu-kemia cell lines HL-60 and K562. BBSKE treatment induced cell growth inhibition and apoptosis in both cell lines. Apoptosis induced by BBSKE is through Bcl-2/Bax and caspase-3 pathways. Ehrlich's ascites carcinoma-bearing mice were used to inves-tigate the anti-tumor effect of BBSKE in vivo. Tumor-bearing mice treated with BBSKE showed an increase of life span with a comparable effect to cyclophosphamide (CTX). These results suggest a potential usage of BBSKE as a therapeutic agent against non-solid tumors.

A systematic review of the effects and mechanisms of preoperative 5α-reductase inhibitors on intraoperative haemorrhage during surgery for benign prostatic hyperplasia

5α-reductase inhibitors （5α-RIs）, including finasteride and dutasteride, are commonly used medical therapies for benign prostatic hyperplasia （BPH）. Many studies reported that preoperative 5α-RI had impact on intraoperative haemorrhage during surgery for BPH, but it was still in controversial. So, we conducted a systematic review of the effects and mechanisms of 5α-RIs on intraoperative bleeding for BPH. MEDLINE, EMBASE, the Cochrane Controlled Trail Register of Controlled Trials and the reference lists of retrieved studies were searched in the analysis. Sixteen publications involving 15 different randomized controlled trials （RCTs） and a total of 1156 patients were used in the analysis, including 10 RCTs for finasteride and five RCTs for dutasteride. We found that preoperative finasteride treatment decreases microvessel density （MVD） in resected prostate specimens. Total blood loss, blood loss per gram of resected prostate tissue and decreases in haemoglobin were all greatly reduced in the finasteride group as compared to controls. Dutasteride appeared to have no effect on bleeding. This meta-analysis shows that preoperative finasteride treatment could decrease intraoperative haemorrhage during surgery for BPH. Preoperative dutasteride had no effect on intraoperative haemorrhage, but further high-qualitv prospective studies are still needed to confirm this observation.

Screening of traditional Chinese medicine monomers as ribonucleotide reductase M2 inhibitors for tumor treatment

BACKGROUND Ribonucleotide reductase(RR)is a key enzyme in tumor proliferation,especially its subunit-RRM2.Although there are multiple therapeutics for tumors,they all have certain limitations.Given their advantages,traditional Chinese medicine(TCM)monomers have become an important source of anti-tumor drugs.Therefore,screening and analysis of TCM monomers with RRM2 inhibition can provide a reference for further anti-tumor drug development.AIM To screen and analyze potential anti-tumor TCM monomers with a good binding capacity to RRM2.METHODS The Gene Expression Profiling Interactive Analysis database was used to analyze the level of RRM2 gene expression in normal and tumor tissues as well as RRM2's effect on the overall survival rate of tumor patients.TCM monomers that potentially act on RRM2 were screened via literature mining.Using AutoDock software,the screened monomers were docked with the RRM2 protein.RESULTS The expression of RRM2 mRNA in multiple tumor tissues was significantly higher than that in normal tissues,and it was negatively correlated with the overall survival rate of patients with the majority of tumor types.Through literature mining,we discovered that berberine,ursolic acid,gambogic acid,cinobufagin,quercetin,daphnetin,and osalmide have inhibitory effects on RRM2.The results of molecular docking identified that the above TCM monomers have a strong binding capacity with RRM2 protein,which mainly interacted through hydrogen bonds and hydrophobic force.The main binding sites were Arg330,Tyr323,Ser263,and Met350.CONCLUSION RRM2 is an important tumor therapeutic target.The TCM monomers screened have a good binding capacity with the RRM2 protein.

Expression Analysis of Aldo-Keto Reductase 1 (AKR1) in Foxtail Millet (Setaria italica L.) Subjected to Abiotic Stresses

Foxtail millet (Setaria italica L.) is a drought-tolerant millet crop of arid and semi-arid regions. Aldo-keto reductases (AKRs) are significant part of plant defence mechanism, having an ability to confer multiple stress tolerance. In this study, AKR1 gene expression was studied in roots and leaves of foxtail millet subjected to different regimes of PEG- and NaCl-stress for seven days. The quantitative Real-time PCR expression analysis in both root and leaves showed upregulation of AKR1 gene during PEG and salt stress. A close correlation exits between expression of AKR1 gene and the rate of lipid peroxidation along with the retardation of growth. Tissue-specific differences were found in the AKR1 gene expression to the stress intensities studied. The reduction in root and shoot growth under both stress conditions were dependent on stress severity. The level of lipid peroxidation as indicated by MDA formation was significantly increased in roots and leaves along with increased stress levels. Finally, these findings support the early responsive nature of AKR1 gene and seem to be associated at least in part with its ability to contribute in antioxidant defence related pathways which could provide a better protection against oxidative stress under stress conditions.

Aspects of Antithrombotic Effect of HMG-CoA Reductase Inhibitors

Statins, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are widely used for the treatment of hypercholesteremia and have showed remarkable activity in preventing cardiovascular morbidity and mortality. Recent studies demonstrated that statins have significant antithrombotic effect in addition to cholesterollowering action. Although the efficacy of statins for reducing cardiovascular events has historically been ascribed to their inhibitory activity on cholesterol synthesis, the degree of low-density lipoprotein cholesterol reduction by statins generally does not correlate with the magnitude of coronary risk reduction.

Nrf2-inducing and HMG-CoA reductase inhibitory activities of a polyphenol-rich fraction of Guazuma ulmifolia leaves

Objective: To fractionate and identify polyphenols from Guazuma ulmifolia Lam. leaves, and to explore their antioxidant, 5-hydroxy-3-methylglutaryl-coenzyme A(HMG-Co A) reductase inhibitory, and Nrf2 modulatory activities.Methods: The 1,1-diphenyl-2-picrylhydrazyl assay was used to evaluate the antioxidant activity of a polyphenolic fraction of the extract of Guazuma ulmifolia Lam. leaves. THP-1 gene reporter cell lines constructed with a transcriptional response element specific for Nrf2 and a minimal promoter for the firefly luciferase–green fluorescent protein transgene were used to determine the effect of the polyphenolic fraction on the Nrf2 signaling pathway. Furthermore, an assay of HMG-Co A reductase inhibitory activity was performed by using a commercial enzyme kit. Polyphenolic compounds were identified by liquid chromatographytandem mass spectrometry.Results: The polyphenolic fraction showed fairly strong antioxidant activity [IC50 =(14.90 ± 4.70) μg/m L] and inhibited HMG-Co A reductase activity by 69.10%, which was slightly lower than that by pravastatin(84.37%) and quercetin(84.25%). Additionally, the polyphenolic fraction activated the Nrf2 antioxidant signaling pathway at 500 μg/m L. Eleven subfractions resulting from the column chromatography separation of the polyphenolic fraction also showed relatively strong antioxidant activities(IC50: 17.46–217.14 μg/m L). The subfraction(F6) stimulated the Nrf2 signaling pathway and had HMG-Co A reductase inhibitory activity(65.43%). Moreover, the subfraction contained two main flavonoids: quercetin and quercimeritrin.Conclusions: The polyphenolic fraction of Guazuma ulmifolia could induce antioxidant genes via the Nrf2/antioxidant regulatory elements pathway, and is a promising candidate for an inhibitor of HMG-Co A reductase.

Pre-Androgen Ablation Prostate Cancer Patients Who Bleed Do Well with 5 Alpha Reductase Inhibitors

Background: Patients with gross haematuria are sometimes found to have prostate cancer after clinical evaluation. The treatment of such haematuria could be very challenging. Use of a 5 alpha reductase inhibitor like dutasteride has been found helpful in bleeding prostate cancer patients if they have not undergone hormonal manipulation before they developed haematuria. Patients and Method: 26 patients with gross haematuria of prostatic origin who had histologic confirmation of adenocarcinoma of the prostate but who have not had chemical or surgical castration were randomized to receive daily dutasteride in addition to vigorous saline irrigation and antibiotics on one arm and vigorous saline irrigation and antibiotics only as control on the other arm. The time taken before haematuria resolved and the amount of irrigation fluid used were noted. Statistical analysis was done using SPSS. Student’s t-test and Kaplan Meier survival analysis were used to test various variables at 0.5 significant levels. Results: Of the 26 patients 12(46.2%) received 0.5 mg oral dutasteride in addition to saline irrigation while 14 (53.8%) received saline irrigation only. Haematuria stopped in all of 12 (100%) patients on dutasteride arm but on 12 (85.7%) of the 14 patients on the control arm. It took significantly shorter time and lesser volume of irrigation fluid before haematuria resolved in those treated with dutasteride than in those on the control arm. Conclusion: Dutasteride is effective in the control of acute haematuria in pre-androgen ablation prostate cancer patients.

Relation between Baseline Lipid Levels and Effectiveness of HMG-CoA Reductase Inhibitors in Patients with Hyperlipidemia

Objective To evaluate whether the effects of HMG - CoA reductase inhibitors on patients with hyperlipidemia are closely related to baseline lipid levels. Methods The data analyzed originated from 3 separate multicenter clinical trials with similar designs during 1994 to 1999. 166 patients with mean age 58. 9±9. 2 years were involved in Simvastatin Clinical Trial with simvastatin 10 mg once daily for 8 weeks. 146 patients with mean age 57. 9±8. 7years were involved in Lovastatin Clinical Trial with lovastatin 20 mg once daily for 8 weeks. 105 patients with mean age 57. 8±9. 3 years were involved in Atorvastatin Clinical Trial with atorvastatin 10 mg once daily for 6 weeks. Baseline total cholesterol (TC) was more than 5. 98 mmol. L - 1, and baseline triglyceride (TG) was less than 4. 52 mmo. L - 1. The patients were grouped by baseline lipid levels. Results The higher the baseline TC, low density lipoprotein cholesterol (LDL - C) and TG levels were, the more effective the simvastatin, lovastatin, or atorvastatin was in reducing serum TC, LDL - C, and TG, respectively. A positive linear correlation was found between baseline values and effects of simvastatin, lovastatin, or atorvastatin in reducing serum TC, LDL - C, and TG, respectively. Conclusion The changes of reduction on serum lipid with HMG - CoA reductase inhibitors in patients with hyperlipidemia were influenced by baseline lipid levels.

High-throughput fluorescent screening of thioredoxin reductase inhibitors to inhibit Mycobacterium tuberculosis

Tuberculosis(TB)is a chronic infectious disease,which is caused by the pathogen Mycobacterium tuberculosis(Mtb)and reemerged as a global health risk with a significant proportion of multi-drug resistant and extensively drug resistant TB cases.It is very urgent to find some novel high-confidence drug targets in Mtb for discovering the effective anti-TB agents.Thioredoxin reductase(TrxR)has been identified to be a highly viable target for anti-TB drugs for its important role in protecting the pathogen from thiol-specific oxidizing stress,regulating intracellular dithiol/disulfide homeostasis and DNA replication and repair.In the present work,a near-infrared(NIR)fluorescent probe DDAT was developed for the detection of TrxR activity and used to high-throughput screen the TrxR inhibitors from natural products.Two screened TrxR inhibitors from Sappan Lignum and microbial metabolites that were further used to inhibit Mycobacterium tuberculosis.All the results indicate that DDAT is a practical fluorescent molecular tool for the discovery of potential anti-TB drugs.

Differential expression of 5-alpha reductase sozymes in the prostate and its clinical implications

The development of human benign or malignant prostatic diseases is closely associated with androgens, primarily testosterone （T） and dihydrotestosterone （DHT）. T is converted to DHT by 5-alpha reductase （5-AR） isozymes. Differential expression of 5-AR isozymes is observed in both human benign and malignant prostatic tissues. 5-AR inhibitors （5-ARI） are commonly used for the treatment of benign prostatic hyperplasia （BPH） and were once promoted as chemopreventive agents for prostate cancer （PCa）. This review discusses the role of the differential expression of 5-AR in the normal development of the human prostate and in the pathogenesis and progression of BPH and PCa.

Primary 4-3-oxosteroid 5β-reductase deficiency:Two cases in China

Aldo-keto reductase 1D1(AKR1D1) deficiency,a rare but life-threatening form of bile acid deficiency,has not been previously described in China.Here,we describe the first two primary 4-3-oxosteroid 5β-reductase deficiency patients in China's Mainland diagnosed by fast atom bombardment-mass spectroscopy of urinary bile acids and confirmed by genetic analysis.A high proportion of atypical 3-oxo-4-bile acids in the urine indicated a deficiency in 4-3-oxosteroid 5β-reductase.All of the coding exons and adjacent intronic sequence of the AKR1D1 gene were sequenced using peripheral lymphocyte genomic DNA of two patients and one of the patient's parents.One patient exhibited compound heterozygous mutations:c.396C>A and c.722A>T,while the other was heterozygous for the mutation c.797G>A.Based on these mutations,a diagnosis of primary 4-3-oxosteroid 5β-reductase deficiency could be confirmed.With ursodeoxycholic acid treatment and fat-soluble vitamin supplements,liver function tests normalized rapidly,and the degree of hepatomegaly was markedly reduced in both patients.

新型醛糖还原酶抑制1-乙酰基-1H-吲哚-3-乙酸酯的合成及其抑制活性

醛糖还原酶抑制剂(ARIs)抑制多元醇途径的醛糖还原酶是治疗糖尿病并发症的重要策略。以2-氯苯甲酸为起始原料,在碱性条件下经铜催化,与甘氨酸反应生成氯代邻羧基苯基甘氨酸,再与乙酸酐反应,生成N-乙酰基邻羧基苯甲酸。然后在吡啶催化下合环,生成1-乙酰基-^(1)H-吲哚-3-乙酸酯(AIA),总收率为79.0%,纯度为99.0%。通过^(1)H NMR、^(13)C NMR和MS(ESI)对其结构进行表征,并对该化合物的的醛糖还原酶抑制活性进行测定,IC 50=9.4×10^(-2)μM。

Human AKR1A1 involves in metabolic activation of carcinogenic aristolochic acidⅠ

OBJECTIVE To investigate whether aldo-keto reductases(AKRs)can act as a nitrore⁃ductase(NR)and bioactivate aristolochic acidⅠ(AA-Ⅰ)to produce AA-Ⅰ-DNA adducts.METHODS①Human-induced hepatocytes(hiHeps)and human bladder RT4 cells were used as tool cells and treated with AA-Ⅰ0,0.5,1.0 and 2μmol·L^(-1)for 24 h.Cell viability was detected using the CCK-8 method,and the half maximal inhibition concentration(IC_(50))was calculated using the CCK-8 method and the level of DNA adduct production was calculated.②hiHeps and RT4 cells were treated with AKR inhibitor luteotin(0,5,10 and 25μmol·L^(-1))+AA-Ⅰ0.2 and 1.0μmol·L^(-1)for 24 h,respectively,and the levels of DNA adducts were detected by a liquid chromatography-tandem mass spectrometer(LC-MS/MS).③hiHeps cells were incubated with 80 nmol·L^(-1)small interfering RNAs(si-AKRs)for 48 h and treated with AA-Ⅰ1.0μmol·L^(-1)for 24 h.Real-time qualitative PCR(RT-qPCR)method was used to detect the mRNA expression of AKRs gene and LC-MS/MS technology was used to investigate the effect of specific AKR gene knockdown on DNA adduct levels.④500 nmol·L^(-1)human AKR recombinant proteins AKR1A1 and AA-Ⅰwere incubated in vitro under anaerobic conditions and the formation of AA-Ⅰ-DNA adducts was detected.RESULTS①The IC_(50)of AA-Ⅰto hiHeps and RT4 cells was 1.9 and 0.42μmol·L^(-1),respec⁃tively.The level of DNA adduct production of the two cell lines was significantly different(P<0.01).②Luteolin≥5μmol·L^(-1)significantly inhibited the production of AA-Ⅰ-DNA adducts in both cells(P<0.05),and there was a concentration-dependent effect in hiHeps cells(P<0.01,R=0.84).③In the AKR family,the knockdown of AKR1A1 gene up to 80%inhibited the generation of AA-Ⅰ-DNA adducts by 30%-40%.④The AA-Ⅰ-DNA adducts were detected in the incubation of recombinant protein AKR1A1 and AA-Ⅰunder anaerobic conditions in vitro,approximately 1 adduct per 107 nucleotides.CONCLU⁃SION AKR1A1 is involved in AA-Ⅰbioactivation,providing a reference for elucidation of the carcino⁃genic mechanism of AA-Ⅰ.

硫氧还蛋白还原酶结构与肿瘤治疗的研究进展

硫氧还蛋白还原酶(thioredoxin reductase,TrxR)是硫氧还蛋白(thioredoxin,Trx)系统里主要的功能蛋白,在调节多种细胞氧化还原信号通路中起关键作用。近年来,TrxR/Trx被越来越多地认为是肿瘤发展的重要调节剂,因此靶向TrxR/Trx是一种很有前景的肿瘤治疗策略。该文对TrxR的结构特点、与肿瘤相关的生理功能、TrxR抑制剂进行综述,以对TrxR的研究提供参考。

预防对比剂相关性急性肾损伤的研究进展

对比剂相关性急性肾损伤(CA-AKI)是在诊断或介入手术中使用对比剂所引起的一种严重并发症,目前已成为住院患者新发急性肾功能不全的主要原因之一。选择相对低毒的对比剂,减少对比剂暴露的时间和剂量对CA-AKI有一定的预防作用,他汀等药物以及术前术后的水化能够降低CA-AKI的风险,目前纳米药物已被证明在动物模型中获益。该文就当前CA-AKI的防治进行综述,为进一步深入研究新的干预措施奠定基础,并为临床治疗提供理论依据。