6PGD Activity Research Articles

The role of 6-phosphogluconate dehydrogenase in vascular smooth muscle cell phenotypic switching and angioplasty-induced intimal hyperplasia

BackgroundRestenosis poses a significant challenge for individuals afflicted with peripheral artery diseases, often leading to considerable morbidity and necessitating repeated interventions. The primary culprit behind the pathogenesis of restenosis is intimal hyperplasia (IH), in which the hyperproliferative and migratory vascular smooth muscle cell (VSMC) accumulate excessively in the tunica intima. 6-Phosphogluconate dehydrogenase (6PGD), sometimes referred to as PGD, is one of the critical enzymes in pentose phosphate pathway (PPP). In this study, we sought to probe whether 6PGD is aberrantly regulated in IH and contributes to VSMC phenotypic switching. MethodsWe used clinical specimens of diseased human coronary arteries with IH lesions and observed robust upregulation of 6PGD at protein level in both the medial and intimal layers in comparison with healthy arterial segments. Results6PGD activity and protein expression were profoundly stimulated upon platelet-derived growth factor-induced VSMC phenotypic switching. Using gain-of-function (dCas9-mediated transcriptional activation) and loss-of-function (small interfering RNA-mediated) silencing, we were able to demonstrate the pathogenic role of 6PGD in driving VSMC hyperproliferation, migration, dedifferentiation, and inflammation. Finally, we conducted a rat model of balloon angioplasty in the common carotid artery, with Pluronic hydrogel-assisted perivascular delivery of Physcion, a selective 6PGD inhibitor with poor systemic bioavailability, and observed effective mitigation of IH. ConclusionsWe contend that aberrant 6PGD expression and activity—indicative of a metabolic shift toward pentose phosphate pathway—could serve as a new disease-driving mechanism and, hence, an actionable target for the development of effective new therapies for IH and restenosis after endovascular interventions.

Hydroxyethyl starch-based self-reinforced nanomedicine inhibits both glutathione and thioredoxin antioxidant pathways to boost reactive oxygen species-powered immunotherapy

The adaptive antioxidant systems of tumor cells, predominantly glutathione (GSH) and thioredoxin (TRX) networks, severely impair photodynamic therapy (PDT) potency and anti-tumor immune responses. Here, a multistage redox homeostasis nanodisruptor (Phy@HES-IR), integrated by hydroxyethyl starch (HES)-new indocyanine green (IR820) conjugates with physcion (Phy), an inhibitor of the pentose phosphate pathway (PPP), is rationally designed to achieve PDT primed cancer immunotherapy. In this nanodisruptor, Phy effectively depletes intracellular GSH of tumor cells by inhibiting 6-phosphogluconate dehydrogenase (6PGD) activity. Concurrently, it is observed for the first time that the modified IR820-NH2 molecule not only exerts PDT action but also interferes with TRX antioxidant pathway by inhibiting thioredoxin oxidase (TRXR) activity. The simultaneous weakening of two major antioxidant pathways of tumor cells is favorable to maximize the PDT efficacy induced by HES-IR conjugates. By virtue of the excellent protecting ability of the plasma expander HES, Phy@HES-IR can remain stable in the blood circulation and efficiently enrich in the tumor region. Consequently, PDT and metabolic modulation synergistically induced immunogenic cell death, which not only suppressed primary tumors but also stimulated potent anti-tumor immunity to inhibit the growth of distant tumors in 4T1 tumor-bearing mice.

The effects of morin and methotrexate on pentose phosphate pathway enzymes and GR/GST/TrxR enzyme activities: An in vivo and in silico study.

In this study, the mechanisms by which the enzymes glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione-S-transferase (GST), and thioredoxin reductase (TrxR) are inhibited by methotrexate (MTX) were investigated, as well as whether the antioxidant morin can mitigate or prevent these adverse effects in vivo and in silico. For 10 days, rats received oral doses of morin (50 and 100 mg/kg body weight). On the fifth day, a single intraperitoneal injection of MTX (20 mg/kg body weight) was administered to generate toxicity. Decreased activities of G6PD, 6PGD, GR, GST, and TrxR were associated with MTX-related toxicity while morin treatment increased the activity of the enzymes. The docking analysis indicated that H-bonds, pi-pi stacking, and pi-cation interactions were the dominant interactions in these enzyme-binding pockets. Furthermore, the docked poses of morin and MTX against GST were subjected to molecular dynamic simulations for 200 ns, to assess the stability of both complexes and also to predict key amino acid residues in the binding pockets throughout the simulation. The results of this study suggest that morin may be a viable means of alleviating the enzyme activities of important regulatory enzymes against MTX-induced toxicity.

Effects of Arbutin on Potassium Bromate-Induced Erythrocyte Toxicity in Rats: Biochemical Evaluation of Some Metabolic Enzyme Activities In Vivo and In Vitro.

In the present study, the inhibitory effect of potassium bromate on the pentose phosphate pathway and intracellular antioxidant systems enzymes (glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR), glutathione S-transferase (GST), and thioredoxin reductase (TrxR)) and the role of arbutin in ameliorating this inhibition were investigated. In the in vivo phase of the study, Wistar Albino rats (28 male adults) were randomly divided into four groups. Control (n = 7): isotonic serum (0.5 mL, i.p), potassium bromate group (n = 7): potassium bromate (100 mg/kg), arbutin group (n = 7): arbutin (i.p.) (50 mg/kg/day), potassium bromate + arbutin, and Group (n = 7): potassium bromate (100 mg/kg) + arbutin (50 mg/kg/day) (i.p). The results of in vivo study showed that the activities of G6PD, 6PGD, GR, and TrxR enzymes were strongly inhibited in potassium bromate groups (p < 0.05). It was determined that GST enzyme activity decreased in the potassium bromate group, but this decrease was not statistically significant compared to the control group (p ⩾ 0.05). A statistically significant increase was found in G6PD, 6PGD, GST, and TrxR enzyme activities in the arbutin group compared to the control group (p < 0.05). The increase in GR enzyme activity was not statistically significant (p ⩾ 0.05). The potassium bromate + arbutin group's enzyme activity increased in comparison to the potassium bromate group and was discovered to be closer to the control group. It was found that potassium bromate inhibited the 6PGD enzyme obtained from rat erythrocyte tissues with IC50 = 346 μM value and Ki = 434.4 μM ± 6.1 value, and the inhibition was noncompetitive.

The Effects of Sodium Tetraborate against Lead Toxicity in Rats: The Behavior of Some Metabolic Enzymes.

This study was planned to research the in vivo effects of lead (Pb) ions and sodium tetraborate (Na2B4O7) on G6PD and 6PGD, which are some of the enzymes of the pentose phosphate pathway, which carries vital importance for metabolism, and GR and GST, which are glutathione metabolism enzymes, and the in vitro effects of the same agents on the 6PGD enzyme. According to the in vivo analysis results, in comparison to the control group, the rat liver G6PD (p < 0.05), and 6PGD (p < 0.01) enzyme activities in the Na2B4O7 group were significantly lower. In addition, GR and GST enzyme activities were insignificantly lower in the Na2B4O7 group compared to the control group (p > 0.05). The Pb group had lower G6PD and 6PGD enzyme activity levels and higher GR and GST enzyme activity levels compared to the control group, while these changes did not reach statistical significance (p > 0.05). In the in vitro analyses of the effects of Pb ions on the 6PGD enzyme that was purified out of rat liver with the 2',5'-ADP-Sepharose 4B affinity chromatography method, it was determined that Pb ions (200-1200 μM) increased the rat liver 6PGD enzyme activity levels by 33%. On the other hand Na2B4O7 was not significantly effective on 6PGD activity. These results will also contribute to future studies in understanding the physiopathology of the states triggered by Pb ions and sodium tetraborate (Na2B4O7).

PCNA regulates primary metabolism by scaffolding metabolic enzymes

The essential roles of proliferating cell nuclear antigen (PCNA) as a scaffold protein in DNA replication and repair are well established, while its cytosolic roles are less explored. Two metabolic enzymes, alpha-enolase (ENO1) and 6-phosphogluconate dehydrogenase (6PGD), both contain PCNA interacting motifs. Mutation of the PCNA interacting motif APIM in ENO1 (F423A) impaired its binding to PCNA and resulted in reduced cellular levels of ENO1 protein, reduced growth rate, reduced glucose consumption, and reduced activation of AKT. Metabolome and signalome analysis reveal large consequences of impairing the direct interaction between PCNA and ENO1. Metabolites above ENO1 in glycolysis accumulated while lower glycolytic and TCA cycle metabolite pools decreased in the APIM-mutated cells; however, their overall energetic status were similar to parental cells. Treating haematological cancer cells or activated primary monocytes with a PCNA targeting peptide drug containing APIM (ATX-101) also lead to a metabolic shift characterized by reduced glycolytic rate. In addition, we show that ATX-101 treatments reduced the ENO1 - PCNA interaction, the ENO1, GAPDH and 6PGD protein levels, as well as the 6PGD activity. Here we report for the first time that PCNA acts as a scaffold for metabolic enzymes, and thereby act as a direct regulator of primary metabolism.

Combined resveratrol and vitamin D treatment ameliorate inflammation-related liver fibrosis, ER stress, and apoptosis in a high-fructose diet/streptozotocin-induced T2DM model.

A high fructose diet is a major cause of diabetes and various metabolic disorders, including fatty liver. In this study, we investigated the effects of resveratrol and vitamin D (VitD) treatments on endoplasmic reticulum (ER) stress, oxidative stress, inflammation, apoptosis, and liver regeneration in a rat model of type 2 diabetes mellitus, namely, T2DM Sprague-Dawley rats. This T2DM rat model was created through a combination treatment of a 10% fructose diet and 40mg/kg streptozotocin (STZ). Resveratrol (1mg/kg/day) and VitD (170/IU/week) were administered alone and in combination to both the diabetic and control groups. Immunohistochemical staining was performed to evaluate PCNA, NF-κB, TNF-α, IL-6, IL-1β, GRP78, and active caspase-3 in liver tissue. The TUNEL method and Sirius red staining were used to determine apoptosis and fibrosis, respectively. G6PD, 6-PGD, GR, and GST activities were measured to determine oxidative stress status. We found that the expressions of cytokines (TNF-α, IL-6, and IL-1β) correlated with NF-κB activation and were significantly increased in the T2DM rats. Increased GRP78 expression, indicating ER stress, increased in apoptotic cells, enhanced caspase-3 activation, and collagen accumulation surrounding the central vein were observed in the T2DM group compared with the other groups. The combination VitD + resveratrol treatment improved antioxidant defense via increasing G6PD, 6-PGD, GR, and GST activities compared to the diabetic groups. We concluded that the combined administration of resveratrol with VitD ameliorates the adverse effects of T2DM by regulating blood glucose levels, increasing antioxidant defense mechanisms, controlling ER stress, enhancing tissue regeneration, improving inflammation, and reducing apoptosis in liver cells. In conclusion, this study indicates that the combination treatment of resveratrol + VitD can be a beneficial option for preventing liver damage in fructose-induced T2DM.

Sıçan Eritrositlerinde Karbon Tetraklorürün(CCl4) ve Kuersetinin Bazı Metabolik Enzim Aktiviteleri Üzerine İn Vivo Etkisinin İncelenmesi

In the study; the purpose was to investigate the in vivoimpact of carbon tetrachloride (CCl4) and quercetin (Qu) on activities of important metabolic enzymes such as Glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), glutathione reductase (GR) and glutathione S-transferase (GST) in rat erythrocytes. At the experimental stage, rats were divided into 4 groups. 1.Group (Control): Pure olive oil at a dose determined according to their body weight (1mL/kg) was given to the rats in this group, 2.Group (CCl4: 1.0 mL/kg (ip)(1:1), 3.Group (Ku: 25) mg/kg (ip), 4.Group (CCl4(1.0 ml/kg (ip)+ Ku (25 mg/kg (ip) was injected. The study was continued for 3 days.The results revealed that the activities of; G6PD (p˂0.01), 6PGD (p˂0.01), GR(p˂0.001) and GST (p˃0.05) enzyme activities were decreased in the CCl4group compared to the control group. It was determined that enzyme activities were higher in CCl4+Qu applied groups compared to CCl4group.The application of Qu caused an increase in the enzyme activity value. This can be accepted as an indication that the inhibition caused by CCI4has disappeared. Consequently; It is thought that Qu may be effective in preventing oxidative damage due to CCl4administration.

The effect of brimonidine and proparacaine on metabolic enzymes: Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and glutathione reductase.

Oxidative stress is to upregulate the pentose phosphate pathway (PPP). The PPP consists of two functional branches, glucose-6-phosphate dehydrogenase (G6PD) and 6-phosphogluconaste dehydrogenase (6PGD). Glutathione reductase (GR) has a significant role in catalyzing an oxidized glutathione form into a reduced form. The purpose of this study is to investigate the effects of brimonidine and proparacaine on the activity of 6PGD, G6PD, and GR enzymes purified from human erythrocytes. Brimonidine displayed considerable inhibition profile against G6PD with IC50 value and KI constant of 29.93±3.56 and 48.46±0.66μM, respectively. On the other hand, proparacaine had no inhibitory effect against G6PD. KI values were found to be 66.06±0.78 and 811.50±11.13μM for brimonidine and proparacaine, respectively, for 6PGD. KI values were found to be 144.10±2.01 and 1,654.00±26.29μM for brimonidine and proparacaine, respectively, for GR. Herein, also in silico molecular docking studies were performed between drugs and enzymes.

Alterations in Enzyme Activity of Carbonic Anhydrase, 6-phosphogluconate Dehydrogenase and Thioredoxin Reductase in Rats Exposed to Doxorubicin and Morin

Objective: Carbonic anhydrase (CA), 6-phosphogluconate dehydrogenase (6PGD) and thioredoxin reductase (TrxR) enzymes are the essential biological molecules needed for metabolic processes in all living cells. This study was designed to investigate the activities of CA, 6PGD and TrxR enzymes in the brain, kidney, liver, heart and testis tissues of the rats exposed to Dox and morin. Methods: Male Wistar albino rats were randomly divided into three groups as control, morin and DOX, each of them containing 7 rats. At the end of the experimental procedure, CA, 6PGD and TrxR enzyme activities in tissues of rats were determined spectrophotometrically. Results: In our study, we observed that DOX activated CA enzyme in liver and kidney tissues while inhibiting CA enzyme in the other tissues, activated 6PGD enzyme in the kidney, liver and heart tissues, and inhibited the TrxR enzyme in all the tissues. In addition, morin activated CA enzyme in the liver tissue while inhibiting CA enzyme in the brain, heart and testis tissues. Morin activated 6PGD enzyme activity while it inhibited TrxR enzyme in all the tissues. Conclusion: The findings showed that doxorubicin and morin had similar properties in the tissues as to their effect on enzyme activities.

Effects of butylparaben on antioxidant enzyme activities and histopathological changes in rat tissues.

Butyl p-hydroxybenzoic acid, also known as butylparaben (BP), is one of the most common parabens absorbed by the skin and gastrointestinal tract and metabolised in the liver and kidney. Recent in vivo and in vitro studies have raised concern that BP causes reproductive, development, and teratogenic toxicity. However, BP-induced oxidative stress and its relation to tissue damage has not been widely investigated before. Therefore, we aimed to investigate the effects of butyl 4-hydroxybenzoate on enzyme activities related to the pentose phosphate pathway and on glutathione-dependent enzymes such as glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6-PGD), glutathione reductase (GR), glutathione peroxidase (GPx), and glutathione-S-transferase (GST) in kidney, liver, brain, and testis tissues. Male rats were randomly divided into four groups to orally receive corn oil (control) or 200, 400, or 800 mg/kg/day of BP for 14 days. Then we measured G6PD, GR, GST, 6-PGD, and GPx enzyme activities in these tissues and studied histopathological changes. BP treatment caused imbalance in antioxidant enzyme activities and tissue damage in the liver, kidney, brain, and testis. These findings are the first to show the degenerative role of BP on the cellular level. The observed impairment of equivalent homeostasis and antioxidant defence points to oxidative stress as a mechanism behind tissue damage caused by BP.

Abstract 1837: Tyr phosphorylation activates and inhibits upstream acetyltransferases and deacetylase of 6PGD, respectively, to promote cancer metabolism and tumor growth

Abstract Background: We recently reported that 6-phosphogluconate dehydrogenase (6PGD), the third enzyme in the oxidative pentose phosphate pathway (PPP), is commonly activated by lysine acetylation in EGF-stimulated cells but “hijacked” in human cancer cells. Acetylation at K76 and K294 enhances 6PGD activation and is commonly observed in diverse human cancer cells, which is important for coordination of anabolic biosynthesis, redox homeostasis, and glycolysis in cells, providing an overall metabolic advantage to cancer cell proliferation and tumor growth. Moreover, we identified DLAT and ACAT2 as upstream acetyltransferases of K76 and K294, respectively, and HDAC4 as the deacetylase of both sites. However, it remains unclear how oncogenic signals regulate the activity of these acetyltransferases and deacetylase to control 6PGD activity and consequently contribute to tumor cell metabolism and tumor growth. Methods: Tyrosine phosphorylation sites were identified in Mass Spec-based studies using recombinant purified ACAT2, DLAT and HDAC4 treated with active recombinant oncogenic tyrosine kinases in diverse in vitro kinase assays. Mutational analysis was performed to determine tyrosine phosphorylation sites that are crucial to activate ACAT2 and DLAT or inhibit HDAC4, and/or promote or attenuate 6PGD binding to ACAT2 and DLAT or HDAC4, respectively. Results: We found that, although tyrosine phosphorylation does not affect 6PGD catalytic activity or binding to its upstream acetyltransferases and deacetylase, diverse growth factor receptors as well as oncogenic tyrosine kinases commonly phosphorylate ACAT2, DLAT and HDAC4, leading to catalytic activation of ACAT2 and DLAT but inhibition of HDAC4. Moreover, tyrosine phosphorylation promotes binding of 6PGD to ACAT2 and DLAT but attenuates HDAC4-6PGD association. Conclusions: Our findings provide insight into the molecular mechanisms underlying 6PGD regulation, which responds to growth factor stimulation or oncogenic tyrosine kinases through activation and inhibition of upstream 6PGD acetyltransferases and deacetylase, respectively, via tyrosine phosphorylation. Moreover, our studies showcase the beauty of complex signal transduction-based regulation of cellular processes, where hierarchical, distinct posttranslational modifications act in concert to provide precise regulation of a series of sequential events to control catalytic activity of acetyltransferases ACAT2 and DLAT and deacetylase HDAC4 and kinetic formation of protein complex to regulate 6PGD in cancer cells, and subsequently contribute to cancer metabolism and tumor growth. Note: This abstract was not presented at the meeting. Citation Format: Siyuan Xia, Changliang Shan, Jun Fan, Jing Chen. Tyr phosphorylation activates and inhibits upstream acetyltransferases and deacetylase of 6PGD, respectively, to promote cancer metabolism and tumor growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1837.

Tyrosine phosphorylation activates 6-phosphogluconate dehydrogenase and promotes tumor growth and radiation resistance

6-Phosphogluconate dehydrogenase (6PGD) is a key enzyme that converts 6-phosphogluconate into ribulose-5-phosphate with NADP+ as cofactor in the pentose phosphate pathway (PPP). 6PGD is commonly upregulated and plays important roles in many human cancers, while the mechanism underlying such roles of 6PGD remains elusive. Here we show that upon EGFR activation, 6PGD is phosphorylated at tyrosine (Y) 481 by Src family kinase Fyn. This phosphorylation enhances 6PGD activity by increasing its binding affinity to NADP+ and therefore activates the PPP for NADPH and ribose-5-phosphate, which consequently detoxifies intracellular reactive oxygen species (ROS) and accelerates DNA synthesis. Abrogating 6PGD Y481 phosphorylation (pY481) dramatically attenuates EGF-promoted glioma cell proliferation, tumor growth and resistance to ionizing radiation. In addition, 6PGD pY481 is associated with Fyn expression, the malignancy and prognosis of human glioblastoma. These findings establish a critical role of Fyn-dependent 6PGD phosphorylation in EGF-promoted tumor growth and radiation resistance.

6PGD inhibition sensitizes hepatocellular carcinoma to chemotherapy via AMPK activation and metabolic reprogramming

Better understanding of the molecular mechanism involved in hepatocellular carcinoma (HCC) progression is essential for the development of therapeutic strategies to overcome chemoresistance in HCC patients. In this work, we show that 6-phosphogluconate dehydrogenase (6PGD), a key enzyme of the oxidative pentose phosphate pathway, is important for HCC growth and survival. Compared to normal liver tissues, we demonstrate that 6PGD expression is upregulated in HCC tissues. 6PGD overexpression increases 6PGD activity and promotes growth in normal liver cells. In contrast, targeting 6PGD using both genetic and pharmacological approaches inhibits HCC growth and survival. Combination of chemotherapeutic agents with 6PGD inhibition achieves greater efficacy in inhibiting HCC growth and survival than chemotherapeutic agent alone. We further show that inhibition of 6PGD activates AMP-activated protein kinase (AMPK) and acetyl-coenzyme A carboxylase 1 (ACC1), and decreases level of NADPH/NAD + and NADH in HCC, leading to SIRT1 activity reduction and oxidative stress. Conversely, AMPK depletion significantly abolishes the effects of physcion (a selective small-molecule 6PGD inhibitor) in decreasing NADPH/NAD + ratio, growth and survival, confirming the role of AMPK as the relevant upstream activator with 6PGD inhibition in HCC cells. Our work is the first to demonstrate the upregulation of 6PGD and its critical involvement in growth and survival in HCC. Our findings suggest 6PGD as a promising therapeutic target to overcome chemoresistance in HCC.

SREBP-1 and LXRα pathways mediated Cu-induced hepatic lipid metabolism in zebrafish Danio rerio

The present study was performed to explore the underlying molecular mechanism of Cu-induced disorder of lipid metabolism in fish. To this end, adult zebrafish were exposed to three waterborne Cu concentrations (0 (control), 8 and 16 μg Cu/L, respectively) for 60 days. Hepatic Cu content and hepatosomatic index increased after waterborne Cu exposure. H&E and oil red O stainings showed extensive steatosis in the liver of Cu-exposed fish. Cu exposure up-regulated lipogenic enzymes activities of ME, ICDH, 6PGD, G6PD and FAS, but down-regulated CPTI activities. Transcriptomic analysis indicated that lipid metabolism related pathways were significantly enriched in both low-dose and high-dose Cu exposure group. Genes involved in lipogenic process from fatty acid biosynthesis, fatty acid elongation, fatty acid desaturation to glycerolipid biosynthesis were up-regulated by Cu. To elucidate the mechanism, LXRα inhibitor SR9243 and SREBP1 inhibitor fatostatin were used to verify the role of LXRα and SREBP1 in Cu-induced disorder of lipid metabolism. Both SR9243 and fatostatin significantly attenuated the Cu-induced increase of TG accumulation of hepatocytes. Meanwhile, SR9243 significantly attenuated the Cu-induced up-regulation of expression of lipogenic genes (acaca, fas, icdh, dgat1, moat2 and moat3), and fatostatin significantly attenuated the up-regulation of expression of acaca, fas, g6pd, dgat1 and moat2. Enzymes analysis showed both SR9243 and fatostatin blocked the Cu-induced increase of lipogenic enzymes activities. Taken together, our findings highlight the importance of LXRα and SREBP1 in Cu-induced hepatic lipid deposition, which proposed a novel mechanism for elucidating metal element exposure inducing the disorder of lipid metabolism in aquatic vertebrates.

The effect of astaxanthin and cadmium on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzymes activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro.

In this study, the effects of astaxanthin (AST) that belongs to carotenoid family and cadmium (Cd), which is an important heavy metal, on rat erythrocyte G6PD, 6PGD, GR, and TrxR enzyme activities in vivo and on rat erythrocyte 6PGD enzyme activity in vitro were studied. In in vitro studies, 6PGD enzyme was purified from rat erythrocytes with 2',5'-ADP Sepharose4B affinity chromatography. Results showed inhibition of enzyme by Cd at IC50 ; 346.5μM value and increase of 6PGD enzyme activity by AST. In vivo studies showed an increase in G6PD, 6PGD, and GR enzyme activities (P˃0.05) and no chance in TrxR enzyme activity by AST. Cd ion inhibited G6PD, 6PGD, and GR enzyme activities (P˂0.05) and also decreased TrxR enzyme activity (P˃0.05). AST+Cd group G6PD enzyme activity was statistically low compared with control group (P˂0.05). 6PGD and TrxR enzyme activities decreased without statistical significance (P˃0.05); however, GR enzyme activity increased statistically significantly (P˂0.05).

The synthesis of new oxindoles as analogs of natural product 3,3′-bis(indolyl)oxindole and in vitro evaluation of the enzyme activity of G6PD and 6PGD

Natural and synthetic derivatives that contain an indole core are being used in medical treatments and technological processes. Therefore, the development of new synthetic methods for the synthesis of indole derivatives is very popular. In this study, new oxindoles with reaction of 4,7-dihydro-1$H$-indole (2) and isatin (4) were synthesized as analogs of natural product 3,3$^\prime $-bis(indolyl)oxindole. The biological properties of the compounds obtained during this study were also studied, showing that compounds 5, 7, and 12 inhibited the activity of G6PD with an IC$_{50}$ of 99 $\mu $M, 231 $\mu $M, and 304 $\mu $M respectively. The activity of rat erythrocyte 6PGD was increased in the presence of 5 and 7 and was inhibited in the presence of 12. As indole derivative 5 was an activator of 6PGD and inhibitor of G6PD, it was selected for docking studies to understand the mechanism of activation and inhibition.

Impact of the Di(2-Ethylhexyl) Phthalate Administration on Trace Element and Mineral Levels in Relation of Kidney and Liver Damage in Rats.

Di(2-ethylhexyl) phthalate (DEHP) is a widely used synthetic polymer in the industry. DEHP may induce reproductive and developmental toxicity, obesity, carcinogenesis and cause abnormal endocrine function in both human and wildlife. The aim of this study was to investigate trace element and mineral levels in relation of kidney and liver damage in DEHP-administered rats. Therefore, prepubertal male rats were dosed with 0, 100, 200, and 400mg/kg/day of DEHP. At the end of the experiment, trace element and mineral levels, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6-PGD), glutathione reductase (GR) and glutathione S-transferase (GST) enzyme activities were evaluated in the serum, liver, and kidney samples of rats. Furthermore, serum clinical biochemistry parameters, organ/body weight ratios and histological changes were investigated to evaluate impact of DEHP more detailed. Our data indicated that sodium (Na), calcium (Ca), potassium (K), lithium (Li), rubidium (Rb) and cesium (Cs) levels significantly decreased, however iron (Fe) and selenium (Se) concentrations significantly increased in DEHP-administered groups compared to the control in the serum samples. On the other hand, upon DEHP administration, selenium concentration, G6PD and GR activities were significantly elevated, however 6-PGD activity significantly decreased compared to the control group in the kidney samples. Decreased G6PD activity was the only significant change between anti-oxidant enzyme activities in the liver samples. Upon DEHP administration, aberrant serum biochemical parameters have arisen and abnormal histological changes were observed in the kidney and liver tissue. In conclusion, DEHP may induce liver and kidney damage, also result abnormalities in the trace element and mineral levels.

The impacts of Elaeagnus umbellata Thunb. leaf and fruit aqueous extracts on mice hepatic, extrahepatic antioxidant and drug metabolizing enzymes related structures

ABSTRACT In this work, the potential chemopreventive activities of Elaeagnus umbellata fruit aqueous (EUFA) and leaf aqueous (EULA) extracts focusing on the modulatory influence of xenobiotic metabolizing enzymes (XMEs), antioxidant enzymes, glucose-6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6PGD), lactate dehydrogenase (LDH) activity, lipid peroxidation (LP), sulfhydryl groups were investigated in the hepatic and extrahepatic organs of Swiss albino mice (50 and 100 mg/kg body wt given orally for 14 days) and compared with BHA (0.75 % in diet). The modulatory and chemopreventive properties of two different doses EUFA and EULA were observed for cytochrome P450, cytochrome b5, sulfhydryl groups, NADPH-cytochrome P450 reductase, NADH-cytochrome b5 reductase, 7-ethoxyresorufin-deethylase and N,N-dimethylaniline N-oxidase activities in the liver and compared with BHA as a standard. The activities of glutathione S-transferase (GST) and DT-diaphorase (DTD) showed a significant increase in the kidney, forestomach, heart and brain at both doses of EUFA and EULA. The results of EULA-treated groups were found a notable increase in LDH, G6PD, 6PGD, GST and DTD activities. Superoxide dismutase level in liver, kidney and heart exhibited a significant increase at both doses of EULA. Glutathione reductase activity was a remarkable level at high dose of EUFA in liver, kidney and EULA in kidney. Both doses of EUFA were effective in inducing glutathione peroxidase activitiy in heart. The levels of LP at low and high doses of EULA-treated and EUFA-treated were effective in liver and kidney, respectively. The present results demonstrate that significant effects in the level of XMEs and antioxidant enzymes of EUFA and EULA are remarkable for modulating roles and natural chemoprevention properties and therefore is considered for a valuable natural source.

Inhibiting 6-phosphogluconate dehydrogenase selectively targets breast cancer through AMPK activation.

6-phosphogluconate dehydrogenase (6PGD), a key enzyme of the oxidative pentose phosphate pathway, is involved in tumor growth and metabolism. Although high 6PGD activity has been shown to be associated with poor prognosis, its role and therapeutic value in breast cancer remain unknown. The levels and roles of 6PGD were analyzed in breast cancer cells and their normal counterparts. The underlying mechanisms of 6PGD's roles are also analyzed. We found that 6PGD is aberrantly activated in breast cancer as shown by its increased transcriptional and translational levels as well as enzyme activity in breast cancer tissues and cell lines compared to normal counterparts. Although similar degree of enzyme activity inhibition was achieved in both breast cancer and normal breast cells, 6PGD inhibition by siRNA-mediated knockdown or pharmacological inhibitor physcion is more effective in inhibiting growth and survival in breast cancer than normal breast cells. Moreover, inhibiting 6PGD significantly sensitizes breast cancer response to chemotherapeutic agents in in vitro cell culture system and in vivo xenograft breast cancer model. We further show that 6PGD inhibition activates AMPK and its downstream substrate ACC1, leading to reduction of ACC1 activity and lipid biosynthesis. AMPK depletion significantly reverses the inhibitory effects of physcion in breast cancer cells, confirming that 6PGD inhibition targets breast cancer cell via AMPK activation. Our work provides experimental evidence on the association of 6PGD with poor prognosis in breast cancer and suggests that 6PGD inhibition may represent a potential therapeutic strategy to augment chemotherapy efficacy in breast cancer.