Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Although diagnostic measures and surgical interventions have improved in recent years, the five-year survival rate for patients with advanced HCC remains bleak-a reality that is largely attributable to an absence of early stage symptoms, lack of adequate diagnostic and prognostic biomarkers, and the common occurrence of acquired resistance to chemotherapeutic agents during HCC treatment. A limited understanding of the molecular mechanisms underlying HCC pathogenesis also presents a challenge for the development of specific and efficacious pharmacological strategies to treat, halt, or prevent progression to advanced stages. Over the past decade, aldo-keto reductase family 1 member 10 (AKR1B10) has emerged as a potential biomarker for the diagnosis and prognosis of HCC, and experimental studies have demonstrated roles for this enzyme in biological pathways underlying the development and progression of HCC and acquired resistance to chemotherapeutic agents used in the treatment of HCC. Here we provide an overview of studies supporting the diagnostic and prognostic utility of AKR1B10, summarize the experimental evidence linking AKR1B10 with HCC and the induction of chemoresistance, and discuss the clinical value of AKR1B10 as a potential target for HCC-directed drug development. We conclude that AKR1B10-based therapies in the clinical management of specific HCC subtypes warrant further investigation.

Members of human aldo-keto reductase (AKR) superfamily have been reported to be involved in cancer progression, whereas the final conclusion is not generally accepted. Herein, we propose a quantitative method to measure human AKR proteins in cells using mTRAQ-based multiple reaction monitoring (MRM). AKR peptides with multiple transitions were carefully selected upon tryptic digestion of the recombinant AKR proteins, while AKR proteins were identified by SDS-PAGE fractionation coupled with LC-MS/MS. Utilizing mTRAQ triplex labeling to produce the derivative peptides, calibration curves were generated using the mixed lysate as background, and no significantly different quantification of AKRs was elicited from the two sets of calibration curves under the mixed and single lysate as background. We employed this approach to quantitatively determine the 6 AKR proteins, AKR1A1, AKR1B1, AKR1B10, AKR1C1/C2, AKR1C3, and AKR1C4, in 7 different cancer cell lines and for the first time to obtain the absolute quantities of all the AKR proteins in each cell. The cluster plot revealed that AKR1A and AKR1B were widely distributed in most cancer cells with relatively stable abundances, whereas AKR1Cs were unevenly detected among these cells with diverse dynamic abundances. The AKR quantitative distribution in different cancer cells, therefore, may assist further exploration toward how the AKR proteins are involved in tumorigenesis.

The aldose reductase (AR; human AKR1B1/mouse Akr1b3) has been the focus of many research because of its role in diabetic complications. The starting point of these alterations is the massive entry of glucose in polyol pathway where it is converted into sorbitol by this enzyme. However, the issue of AR function in non-diabetic condition remains unresolved. AR-like enzymes (AKR1B10, Akr1b7, and Akr1b8) are highly related isoforms often co-expressed with bona fide AR, making functional analysis of one or the other isoform a challenging task. AKR1B/Akr1b members share at least 65% protein identity and the general ability to reduce many redundant substrates such as aldehydes provided from lipid peroxidation, steroids and their by-products, and xenobiotics in vitro. Based on these properties, AKR1B/Akr1b are generally considered as detoxifying enzymes. Considering that divergences should be more informative than similarities to help understanding their physiological functions, we chose to review specific hallmarks of each human/mouse isoforms by focusing on tissue distribution and specific mechanisms of gene regulation. Indeed, although the AR shows ubiquitous expression, AR-like proteins exhibit tissue-specific patterns of expression. We focused on three organs where certain isoforms are enriched, the adrenal gland, enterohepatic, and adipose tissues and tried to connect recent enzymatic and regulation data with endocrine and metabolic functions of these organs. We presented recent mouse models showing unsuspected physiological functions in the regulation of glucido-lipidic metabolism and adipose tissue homeostasis. Beyond the widely accepted idea that AKR1B/Akr1b are detoxification enzymes, these recent reports provide growing evidences that they are able to modify or generate signal molecules. This conceptually shifts this class of enzymes from unenviable status of scavenger to upper class of messengers.

Sulindac has been identified as a competitive inhibitor of aldo-keto reductase 1B10 (AKR1B10), an enzyme that plays a key role in carcinogenesis. AKR1B10 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and exhibits lipid substrate specificity, especially for farnesyl and geranylgeranyl. There have been no studies though showing that the inhibition of PDAC by sulindac is via inhibition of AKR1B10, particularly the metabolism of farnesyl/geranylgeranyl and Kras protein prenylation. To determine the chemopreventive effects of sulindac on pancreatic carcinogenesis, 5-week-old LSL-Kras(G12D)-LSL-Trp53(R172H)-Pdx-1-Cre mice (Pan(kras/p53) mice) were fed an AIN93M diet with or without 200 p.p.m. sulindac (n = 20/group). Kaplan-Meier survival analysis showed that average animal survival in Pan(kras/p53) mice was 143.7 ± 8.8 days, and average survival with sulindac was increased to 168.0 ± 8.8 days (P < 0.005). Histopathological analyses revealed that 90% of mice developed PDAC, 10% with metastasis to the liver and lymph nodes. With sulindac, the incidence of PDAC was reduced to 56% (P < 0.01) and only one mouse had lymph node metastasis. Immunochemical analysis showed that sulindac significantly decreased Ki-67-labeled cell proliferation and markedly reduced the expression of phosphorylated extracellular signal-regulated kinases 1 and 2 (ERK1/2), c-Raf and mitogen-activated protein kinase kinase 1 and 2. In in vitro experiments with PDAC cells from Pan(kras/p53) mice, sulindac exhibited dose-dependent inhibition of AKR1B10 activity. By silencing AKR1B10 expression through small interfering RNA or by sulindac treatment, these in vitro models showed a reduction in Kras and human DNA-J homolog 2 protein prenylation, and downregulation of phosphorylated C-raf, ERK1/2 and MEK1/2 expression. Our results demonstrate that sulindac inhibits pancreatic carcinogenesis by the inhibition of Kras protein prenylation by targeting AKR1B10.

A human member of the aldo-keto reductase (AKR) superfamily, AKR1B10, shares high sequence identity with aldose reductase (AR), and was recently identified as a therapeutic target in the treatment of several types of cancer. We have compared the inhibitory effects of plant components on recombinant AKR1B10 and AR. AKR1B10 was inhibited by curcuminoids, magnolol, honokiol and resveratrol, with IC(50) values of 0.06-5 microM, which were lower than their values for AR. Among them, bisdemethoxycurcumin was the most potent competitive inhibitor (K(i)=22 nM) with the highest selectivity (85-fold versus AR), and acted as an effective inhibitor in cellular level. In contrast, demethoxycurcumin and curcumin showed >3-fold less potency and selectivity. Molecular docking studies of the curcuminoids in the AKR1B10-NADP(+) complex and site-directed mutagenesis of the putative binding residues suggest that Gln114, Val301 and Gln303 are important for determining the inhibitory potency and selectivity of the curcuminoids.

A human aldose reductase-like protein, AKR1B10 in the aldo-keto reductase (AKR) superfamily, was recently identified as a therapeutic target in the treatment of several types of cancer. In order to identify potential leads for new inhibitors of AKR1B10, we adopted the virtual screening approach using the automated program icm, which resulted in the discovery of several chromene-3-carboxamide derivatives as potent competitive inhibitors. The most potent (Z)-2-(4-methoxyphenylimino)-7-hydroxy-N-(pyridin-2-yl)-2H-chromene-3-carboxamide inhibited the reductase activity of AKR1B10 with a K(i) value of 2.7nM, and the metabolism of farnesal and 4-hydroxynonenal in the AKR1B10-overexpressed cells from 0.1microM with an IC(50) value equal to 0.8microM.

The reversible thiol/disulfide exchange is an important regulatory mechanism of protein enzymatic activity. Many protein enzymes are susceptible to S-thiolation induced by reactive oxygen species (ROS); and the glutathione (GSH) and free amino acid cysteine (Cys) are critical cellular thiol anti-oxidants, protecting proteins from irreversible oxidative damage. In this study, we found that aldo-keto reductase family 1 member B10 (AKR1B10) contains 4 Cys residues, i.e., Cys45, Cys187, Cys200, and Cys299. Exposing AKR1B10 to ROS mixtures resulted in significant decrease of its free sulfhydryl groups, up to 40-50% in the presence of physiological thiol cysteine at 0.5 or 1.0 mM; and accordingly, AKR1B10 enzymatic activity was reversibly decreased, in parallel with the oxidation of the sulfhydryl groups. ROS-induced thiolation also affected the sensitivity of AKR1B10 to inhibitors EBPC, epalrestat, and statil. Together our results showed for the first time that AKR1B10's enzymatic activity and inhibitor sensitivity are modulated by thiol/disulfide exchanges.

To understand the changes in the metabolome of hepatitis C virus (HCV)-infected persons, we conducted a metabolomic investigation in both plasma and urine of 30 HCV-positive individuals using plasmas from 30 HCV-negative blood donors and urines from 30 healthy volunteers. Samples were analysed by gas chromatography-mass spectrometry and data subjected to multivariate analysis. The plasma metabolomic phenotype of HCV-positive persons was found to have elevated glucose, mannose and oleamide, together with depressed plasma lactate. The urinary metabolomic phenotype of HCV-positive persons comprised reduced excretion of fructose and galactose combined with elevated urinary excretion of 6-deoxygalactose (fucose) and the polyols sorbitol, galactitol and xylitol. HCV-infected persons had elevated galactitol/galactose and sorbitol/glucose urinary ratios, which were highly correlated. These observations pointed to enhanced aldose reductase activity, and this was confirmed by real-time quantitative polymerase chain reaction with AKR1B10 gene expression elevated sixfold in the liver. In contrast, AKR1B1 gene expression was reduced 40% in HCV-positive livers. Interestingly, persons who were formerly HCV infected retained the metabolomic phenotype of HCV infection without reverting to the HCV-negative metabolomic phenotype. This suggests that the effects of HCV on hepatic metabolism may be long lived. Hepatic AKR1B10 has been reported to be elevated in hepatocellular carcinoma and in several premalignant liver diseases. It would appear that HCV infection alone increases AKR1B10 expression, which manifests itself as enhanced urinary excretion of polyols with reduced urinary excretion of their corresponding hexoses. What role the polyols play in hepatic pathophysiology of HCV infection and its sequelae is currently unknown.

Endometrial and cervical cancers, uterine myoma, and endometriosis are very common uterine diseases. Worldwide, more than 800,000 women are affected annually by gynecological cancers, as a result of which, more than 360,000 die. During their reproductive age, about 70% of women develop uterine myomas and 10-15% suffer from endometriosis. Uterine diseases are associated with aberrant inflammatory responses and concomitant increased production of prostaglandins (PG). They are also related to decreased differentiation, due to low levels of protective progesterone and retinoic acid, and to enhanced proliferation, due to high local concentrations of estrogens. The pathogenesis of these diseases can thus be attributed to disturbed PG, estrogen, and retinoid metabolism and actions. Five human members of the aldo-keto reductase 1B (AKR1B) and 1C (AKR1C) superfamilies, i.e., AKR1B1, AKR1B10, AKR1C1, AKR1C2, and AKR1C3, have roles in these processes and can thus be implicated in uterine diseases. AKR1B1 and AKR1C3 catalyze the formation of PGF2α, which stimulates cell proliferation. AKR1C3 converts PGD2 to 9α,11β-PGF2, and thus counteracts the formation of 15-deoxy-PGJ2, which can activate pro-apoptotic peroxisome-proliferator-activated receptor γ. AKR1B10 catalyzes the reduction of retinal to retinol, and thus lessens the formation of retinoic acid, with potential pro-differentiating actions. The AKR1C1-AKR1C3 enzymes also act as 17-keto- and 20-ketosteroid reductases to varying extents, and are implicated in increased estradiol and decreased progesterone levels. This review comprises an introduction to uterine diseases and AKR1B and AKR1C enzymes, followed by an overview of the current literature on the AKR1B and AKR1C expression in the uterus and in uterine diseases. The potential implications of the AKR1B and AKR1C enzymes in the pathophysiologies are then discussed, followed by conclusions and future perspectives.

In addition to its well-characterized role in the regulation of drug metabolism and transport by xenobiotics, pregnane X receptor (PXR) critically impacts on lipid homeostasis. In mice, both ligand-dependent activation and knockout of PXR were previously shown to promote hepatic steatosis. To elucidate the respective pathways in human liver, we generated clones of human hepatoma HepG2 cells exhibiting different PXR protein levels, and analyzed effects of PXR activation and knockdown on steatosis and expression of lipogenic genes. Ligand-dependent activation as well as knockdown of PXR resulted in increased steatosis in HepG2 cells. Activation of PXR induced the sterol regulatory element-binding protein (SREBP) 1-dependent lipogenic pathway via PXR-dependent induction of SREBP1a, which was confirmed in primary human hepatocytes. Inhibiting SREBP1 activity by blocking the cleavage-dependent maturation of SREBP1 protein impaired the induction of lipogenic SREBP1 target genes and triglyceride accumulation by PXR activation. On the other hand, PXR knockdown resulted in up-regulation of aldo-keto reductase (AKR) 1B10, which enhanced the acetyl-CoA carboxylase (ACC)-catalyzed reaction step of de novo lipogenesis. In a cohort of human liver samples histologically classified for non-alcoholic fatty liver disease, AKR1B10, SREBP1a and SREBP1 lipogenic target genes proved to be up-regulated in steatohepatitis, while PXR protein was reduced. In summary, our data suggest that activation and knockdown of PXR in human hepatic cells promote de novo lipogenesis and steatosis by induction of the SREBP1 pathway and AKR1B10-mediated increase of ACC activity, respectively, thus providing mechanistic explanations for a putative dual role of PXR in the pathogenesis of steatohepatitis.

Biological activity of natural retinoids requires the oxidation of retinol to retinoic acid (RA) and its binding to specific nuclear receptors in target tissues. The first step of this pathway, the reversible oxidoreduction of retinol to retinaldehyde, is essential to control RA levels. The enzymes of retinol oxidation are NAD-dependent dehydrogenases of the cytosolic medium-chain (MDR) and the membrane-bound short-chain (SDR) dehydrogenases/reductases. Retinaldehyde reduction can be performed by SDR and aldo-keto reductases (AKR), while its oxidation to RA is carried out by aldehyde dehydrogenases (ALDH). In contrast to SDR, AKR and ALDH are cytosolic. A common property of these enzymes is that they only use free retinoid, but not retinoid bound to cellular retinol binding protein (CRBP). The relative contribution of each enzyme type in retinoid metabolism is discussed in terms of the different subcellular localization, topology of membrane-bound enzymes, kinetic constants, binding affinity of CRBP for retinol and retinaldehyde, and partition of retinoid pools between membranes and cytoplasm. The development of selective inhibitors for AKR enzymes 1B1 and 1B10, of clinical relevance in diabetes and cancer, granted the investigation of some structure-activity relationships. Kinetics with the 4-methyl derivatives of retinaldehyde isomers was performed to identify structural features for substrate specificity. Hydrophilic derivatives were better substrates than the more hydrophobic compounds. We also explored the inhibitory properties of some synthetic retinoids, known for binding to retinoic acid receptors (RAR) and retinoid X receptors (RXR). Consistent with its substrate specificity towards retinaldehyde, AKR1B10 was more effectively inhibited by synthetic retinoids than AKR1B1. A RARβ/γ agonist (UVI2008) inhibited AKR1B10 with the highest potency and selectivity, and docking simulations predicted that its carboxyl group binds to the anion-binding pocket.

Several studies have identified genes that are differentially expressed in atopic dermatitis (AD) compared to normal skin. However, there is also considerable variation in the list of differentially expressed genes (DEGs) reported by different groups and the exact cause of AD is still not fully understood. Using a rank-based approach, we analyzed gene expression data from five different microarray studies, comprising a total of 127 samples and more than 250,000 transcripts. A total of 89 AD gene expression signatures '89ADGES', including FLG gene, were identified to show dysregulation consistently across these studies. Using a Support Vector Machine, we showed that the '89ADGES' discriminates AD from normal skin with 98% predictive accuracy. Functional annotation of these genes implicated their roles in immune responses (e.g., betadefensin, microseminoprotein), keratinocyte differentiation/epidermal development (e.g., FLG, CORIN, AQP, LOR, KRT16), inflammation (e.g., IL37, IL27RA, CCL18) and lipid metabolism (e.g., AKR1B10, FAD7, FAR2). Subsequently, we validated a subset of signature genes using quantitative PCR in a mouse model. Using a bioinformatic approach, we identified keratinocyte pathway over-represented (P = <0.0006) among the 89 signature genes. Keratinocytes are known to play a major role in barrier function due to their location in the epidermis. Our result suggests that besides immune- mediated pathway, skin barrier pathways such as the keratinocyte differentiation pathway play a key role in AD pathogenesis. A better understanding of the role of keratinocytes in AD will be important for developing novel "barrier therapy" for this disease.

Anthracyclines are an important reagent in many chemotherapy regimes for treating a wide range of tumors. One of the primary mechanisms of anthracycline action involves DNA damage caused by inhibition of topoisomerase II. Enzymatic detoxification of anthracycline is a major critical factor that determines anthracycline resistance. Natural product, daunorubicin a toxic analogue of anthracycline is reduced to less toxic daunorubicinol by the AKR1B10, enzyme, which is overexpressed in most cases of smoking associate squamous cell carcinoma (SCC) and adenocarcinoma. In addition, AKR1B10 was discovered as an enzyme overexpressed in human liver, cervical and endometrial cancer cases in samples from uterine cancer patients. Also, the expression of AKR1B10 was associated with tumor recurrence after surgery and keratinization of squamous cell carcinoma in cervical cancer and estimated to have the potential as a tumor intervention target colorectal cancer cells (HCT-8) and diagnostic marker for non-small-cell lung cancer. This article presents the mechanism of daunorubicin action and a method to improve the effectiveness of daunorubicin by modulating the activity of AKR1B10.

The total expression profiles of two medulloblastoma cell lines resistant to the preactivated form of cyclophosphamide (4-hydroperoxycyclophosphamide, 4-HC) were examined using the Affymetrix GeneChip U133A array. Our primary objective was to look for possible genes, other than the well-studied aldehyde dehydrogenases (ALDH) that may be involved in cyclophosphamide (CP) resistance in medulloblastomas. We present here the lists of the most highly upregulated [30 for D341 MED (4-HCR); 20 for D283 MED (4-HCR)] and downregulated [19 for D341 MED (4-HCR); 15 for D283 MED (4-HCR)] genes which may be involved in conferring CP-resistance to the two medullobalstoma cell lines. The lists of genes from the two sublines almost had no overlap, suggesting different mechanisms of CP-resistance. One of the most noteworthy upregulated gene is TAP1 [90-fold increase in D341 MED (4-HCR) relative to D341 MED]. TAP1, a protein belonging to the ABC transporter family is normally involved in major histocompatibility class I (MHC I) antigen processing. This suggests the possible role of multidrug resistance (MDR), albeit atypical (which means it does not involve the usual MDR1 and MRP glycoproteins), in medulloblastoma's CP-resistance. Apart from TAP1, a number of other genes involved in MHC1 processing were upregulated in D341 MED (4HCR). D341 MED (4-HCR) also had a 20-fold increase in the expression of the aldo-keto reductase gene, AKR1B10, which may deactivate the reactive cyclophosphamide metabolite, aldophosphamide. For D283 MED (4-HCR), the most notable increase in expression is that of ALDH1B1, a member of the aldehyde dehydrogenase (ALDH) family of proteins.

This prospective study explored the relationship between expression of AKR1B10 mRNA and various clinical parameters in non-small-cell lung cancer (NSCLC) in terms of its validation as a marker for NSCLC. Tumour tissue samples were collected from 229 patients with NSCLC. Tissue samples from adjacent non-malignant lung tissue >> 5 cm from the tumour) of 89 of these patients and samples from 20 patients with benign lung disease were used as controls. Quantitative reverse transcription- polymerase chain reaction showed significantly higher levels of AKR1B10 mRNA expression in NSCLC tumour tissue than in adjacent non-malignant lung tissue and benign lung tissue. Statistically significant factors for AKR1B10 mRNA over-expression were found to be male gender, smoking, squamous cell carcinoma and moderate or poor cell differentiation. It is concluded that AKR1B10 seems to have potential as a prognostic marker for NSCLC and warrants further investigation.

The Aldo Keto Reductases (AKRs) are a superfamily of enzymes that catalyze the reduction of biogenic and xenobiotic aldehydes and ketones. AKR1B family has 2 known members in humans and 3 in rodents. Two novel gene loci, hereafter referred to as AKR1B15 in human and Akr1b16 in mouse have been predicted to exist within the AKR1B clusters. AKR1B15 displays 91% and 67% sequence identity with human genes AKR1B10 and AKR1B1, respectively while Akr1b16 shares 82-84% identity with murine Akr1b8 and Akr1b7. We tested the hypothesis that AKR1B15 and Akr1b16 genes are expressed as functional proteins in human and murine tissues, respectively. Using whole tissue mRNA, we were able to clone the full-length open reading frames for AKR1B15 from human eye and testes, and Akr1b16 from murine spleen, demonstrating that these genes are transcriptionally active. The corresponding cDNAs were cloned into pET28a and pIRES-hrGFP-1α vectors for bacterial and mammalian expression, respectively. Both genes were expressed as 36kDa proteins found in the insoluble fraction of bacterial cell lysate. These proteins, expressed in bacteria showed no enzymatic activity. However, lysates from COS-7 cells transfected with AKR1B15 showed a 4.8-fold (with p-nitrobenzaldehyde) and 3.3-fold (with dl-glyceraldehyde) increase in enzyme activity compared with untransfected COS-7 cells. The Akr1b16 transcript was shown to be ubiquitously expressed in murine tissues. Highest levels of transcript were found in heart, spleen, and lung. From these observations we conclude that the predicted AKR1B15 and 1b16 genes are expressed in several murine and human tissues. Further studies are required to elucidate their physiological roles.

The incidence of lung cancer (LC) is markedly increased among patients with usual interstitial pneumonia (UIP), and tobacco smoking is its superimposed risk factor. AKR1B10 (aldo-keto reductase 1B10) is frequently overexpressed in pulmonary squamous cell carcinoma and adenocarcinoma in smokers. To investigate the role of AKR1B10 in the pulmonary carcinogenesis in UIP with correlation to tobacco smoking, we examined 13 UIP cases with LC, 13 UIP cases without LC, and 30 cases of non-UIP LC using AKR1B10 immunohistochemistry. AKR1B10 immunoreactivity was confined to squamous metaplasia in honeycomb lesions of UIP and neoplastic cells of LC. Squamous metaplastic foci showed AKR1B10 immunoreactivity more frequently in UIP with LC (24/36 foci, 67%) than in UIP without LC (16/44 foci, 37%) (P<0.01). AKR1B10 expression in UIP was also more frequent in squamous metaplastic foci in smokers (38/67 foci, 57%) than in non-smokers (2/13 foci, 15%) (P<0.01). AKR1B10 expression was frequently observed in both UIP-associated LC (10/13 foci, 77%) and non-UIP LC (18/30 foci, 60%). Ki-67 labeling index was significantly higher in AKR1B10-positive squamous metaplasia of UIP than in AKR1B10-negative squamous metaplasia of UIP. Our results demonstrate that AKR1B10 is involved in the development of LC in UIP in association with smoking. AKR1B10 might be useful as a new marker for identification of high LC risk patients in UIP.

Advanced prostate cancer has significant long-term morbidity, and there is a growing interest in alternative and complimentary forms of therapy that will improve the outcomes of patients. Azadirachta indica (common name: neem) contains multiple active compounds that have potent anti-inflammatory and anticancer properties. The present study investigates the novel targets of the anticancer activity of ethanol extract of neem leaves (EENL) in vitro and evaluates the in vivo efficacy in the prostate cancer models. Analysis of the components in the EENL by mass spectrometry suggests the presence of 2',3'-dehydrosalannol, 6-desacetyl nimbinene, and nimolinone. Treatment of C4-2B and PC-3M-luc2 prostate cancer cells with EENL inhibited the cell proliferation. Genome-wide expression profiling, using oligonucleotide microarrays, revealed genes differentially expressed with EENL treatment in prostate cancer cells. Functional analysis unveiled that most of the up-regulated genes were associated with cell death, and drug metabolism, and the down-regulated genes were associated with cell cycle, DNA replication, recombination, and repair functions. Quantitative PCR confirmed significant up-regulation of 40 genes and immunoblotting revealed increase in the protein expression levels of HMOX1, AKR1C2, AKR1C3, and AKR1B10. EENL treatment inhibited the growth of C4-2B and PC-3M-luc2 prostate cancer xenografts in nude mice. The suppression of tumor growth is associated with the formation of hyalinized fibrous tumor tissue and the induction of cell death by apoptosis. These results suggest that EENL-containing natural bioactive compounds could have potent anticancer property and the regulation of multiple cellular pathways could exert pleiotrophic effects in prevention and treatment of prostate cancer.

The human aldo-keto reductase (AKR) 1B10 is suggested as a tumor marker in various solid tumors. Using colon cancer cells, we found that AKR1B10 was induced with acquisition of resistance to the anticancer drug mitomycin-c (MMC). In the resistant cells, treatment with an AKR1B10 inhibitor decreased their MMC tolerance. In the nonresistant cells, overexpression and silencing of AKR1B10 decreased and increased, respectively, susceptibility to cytotoxic effects of MMC and 4-hydroxy-2-nonenal, which was formed as a product of lipid peroxidation by MMC treatment. These results suggest a role of AKR1B10 in the development of MMC resistance, which may be mediated by its ability to detoxify cytotoxic aldehydes including 4-hydroxy-2-nonenal.

Aldo-keto reductase family 1 member B10 (AKR1B10), over-expressed in multiple human cancers, might be implicated in cancer development and progression via detoxifying cytotoxic carbonyls and regulating fatty acid synthesis. In the present study, we investigated the ortholog of AKR1B10 in mice, an ideal modeling organism greatly contributing to human disease investigations. In the mouse, there are three aldo-keto reductase family 1 subfamily B (AKR1B) members, i.e., AKR1B3, AKR1B7, and AKR1B8. Among them, AKR1B8 has the highest similarity to human AKR1B10 in terms of amino acid sequence, computer-modeled structures, substrate spectra and specificity, and tissue distribution. More importantly, similar to human AKR1B10, mouse AKR1B8 associates with murine acetyl-CoA carboxylase-α and mediates fatty acid synthesis in colon cancer cells. Taken together, our data suggest that murine AKR1B8 is the ortholog of human AKR1B10.

Leprosy, an infectious disease caused by Mycobacterium leprae, affects millions of people worldwide. However, little is known regarding its molecular pathophysiological mechanisms. In this study, a comprehensive assessment of human mRNA was performed on leprosy skin lesions by using DNA chip microarrays, which included the entire spectrum of the disease along with its reactional states. Sixty-six samples from leprotic lesions (10TT, 10BT, 10BB, 10BL, 4LL, 14R1, and 10R2) and nine skin biopsies from healthy individuals were used as controls (CC) (ages ranged from 06 to 83 years, 48 were male and 29 female). The evaluation identified 1580 differentially expressed mRNAs [Fold Change (FC) ≥ 2.0, p ≤ 0.05] in diseased lesions vs. healthy controls. Some of these genes were observed in all forms of the disease (CD2, CD27, chit1, FA2H, FAM26F, GZMB, MMP9, SLAMF7, UBD) and others were exclusive to reactional forms (Type "1" reaction: GPNMB, IL1B, MICAL2, FOXQ1; Type "2" reaction: AKR1B10, FAM180B, FOXQ1, NNMT, NR1D1, PTX3, TNFRSF25). In literature, these mRNAs have been associated with numerous pathophysiological processes and signaling pathways and are present in a large number of diseases. The role of these mRNAs maybe studied in the context of developing new diagnostic markers and therapeutic targets for leprosy.

The different stages of the metastatic cascade present distinct metabolic challenges to tumour cells and an altered tumour metabolism associated with successful metastatic colonisation provides a therapeutic vulnerability in disseminated disease. We identify the aldo-keto reductase AKR1B10 as a metastasis enhancer that has little impact on primary tumour growth or dissemination but promotes effective tumour growth in secondary sites and, in human disease, is associated with an increased risk of distant metastatic relapse. AKR1B10^High tumour cells have reduced glycolytic capacity and dependency on glucose as fuel source but increased utilisation of fatty acid oxidation. Conversely, in both 3D tumour spheroid assays and in vivo metastasis assays, inhibition of fatty acid oxidation blocks AKR1B10^High-enhanced metastatic colonisation with no impact on AKR1B10^Low cells. Finally, mechanistic analysis supports a model in which AKR1B10 serves to limit the toxic side effects of oxidative stress thereby sustaining fatty acid oxidation in metabolically challenging metastatic environments.

NADP(H)-dependent cytosolic aldo-keto reductases (AKR) are mostly monomeric enzymes which fold into a typical (α/β)(8)-barrel structure. Substrate specificity and inhibitor selectivity are determined by interaction with residues located in three highly variable loops (A, B, and C). Based on sequence identity, AKR have been grouped into families, namely AKR1-AKR15, containing multiple subfamilies. Two human enzymes from the AKR1B subfamily (AKR1B1 and AKR1B10) are of special interest. AKR1B1 (aldose reductase) is related to secondary diabetic complications, while AKR1B10 is induced in cancer cells and is highly active with all-trans-retinaldehyde. Residues interacting with all-trans-retinaldehyde and differing between AKR1B1 and AKR1B10 are Leu125Lys and Val131Ala (loop A), Leu301Val, Ser303Gln, and Cys304Ser (loop C). Recently, we demonstrated the importance of Lys125 as a determinant of AKR1B10 specificity for retinoids. Residues 301 and 304 are also involved in interactions with substrates or inhibitors, and thus we checked their contribution to retinoid specificity. We also extended our study with retinoids to rodent members of the AKR1B subfamily: AKR1B3 (aldose reductase), AKR1B7 (mouse vas deferens protein), AKR1B8 (fibroblast-growth factor 1-regulated protein), and AKR1B9 (Chinese hamster ovary reductase), which were tested against all-trans isomers of retinaldehyde and retinol. All enzymes were active with retinaldehyde, but with k(cat) values (0.02-0.52 min(-1)) much lower than that of AKR1B10 (27 min(-1)). None of the enzymes showed oxidizing activity with retinol. Since these enzymes (except AKR1B3) have Lys125, other residues should account for retinaldehyde specificity. Here, by using site-directed mutagenesis and molecular modeling, we further delineate the contribution of residues 301 and 304. We demonstrate that besides Lys125, Ser304 is a major structural determinant for all-trans-retinaldehyde specificity of AKR1B10.

There is a spectacular rise in the global prevalence of type 2 diabetes mellitus (T2DM) due to the worldwide obesity epidemic. However, a significant proportion of T2DM patients are non-obese and they also have an increased risk of cardiovascular diseases. As the Goto-Kakizaki (GK) rat is a well-known model of non-obese T2DM, the goal of this study was to investigate the effect of non-obese T2DM on cardiac alterations of the transcriptome in GK rats.

Fasting blood glucose, serum insulin and cholesterol levels were measured at 7, 11, and 15 weeks of age in male GK and control rats. Oral glucose tolerance test and pancreatic insulin level measurements were performed at 11 weeks of age. At week 15, total RNA was isolated from the myocardium and assayed by rat oligonucleotide microarray for 41,012 genes, and then expression of selected genes was confirmed by qRT-PCR. Gene ontology and protein-protein network analyses were performed to demonstrate potentially characteristic gene alterations and key genes in non-obese T2DM.

Fasting blood glucose, serum insulin and cholesterol levels were significantly increased, glucose tolerance and insulin sensitivity were significantly impaired in GK rats as compared to controls. In hearts of GK rats, 204 genes showed significant up-regulation and 303 genes showed down-regulation as compared to controls according to microarray analysis. Genes with significantly altered expression in the heart due to non-obese T2DM includes functional clusters of metabolism (e.g. Cyp2e1, Akr1b10), signal transduction (e.g. Dpp4, Stat3), receptors and ion channels (e.g. Sln, Chrng), membrane and structural proteins (e.g. Tnni1, Mylk2, Col8a1, Adam33), cell growth and differentiation (e.g. Gpc3, Jund), immune response (e.g. C3, C4a), and others (e.g. Lrp8, Msln, Klkc1, Epn3). Gene ontology analysis revealed several significantly enriched functional inter-relationships between genes influenced by non-obese T2DM. Protein-protein interaction analysis demonstrated that Stat is a potential key gene influenced by non-obese T2DM.

Non-obese T2DM alters cardiac gene expression profile. The altered genes may be involved in the development of cardiac pathologies and could be potential therapeutic targets in non-obese T2DM.