Eugenol and its liposome-based nano carrier reduce anxiety by inhibiting glyoxylase-1 expression in mice / Eugenol e seu nanocarreador à base de lipossoma reduzem a ansiedade ao inibir a expressão de glioxalase 1 em camundongos

Abstract The most common form of psycho-social dysfunction is anxiety with depression being related closely without any age bar. They are present with combined state of sadness, confusion, stress, fear etc. Glyoxalase system contains enzyme named glyoxalase 1 (GLO1).It is a metabolic pathway which detoxifies alpha-oxo-aldehydes, particularly methylglyoxal (MG). Methylglyoxal is mainly made by the breakdown of the glycolytic intermediates, glyceraldehyde-3-phosphates and dihydroxyacetone phosphate. Glyoxylase-1 expression is also related with anxiety behavior. A casual role or GLO-1 in anxiety behavior by using viral vectors for over expression in the anterior cingulate cortex was found and it was found that local GLO-1 over expression increased anxiety behavior. The present study deals with the molecular mechanism of protective activity of eugenol against anxiolytic disorder. A pre-clinical animal study was performed on 42 BALB/c mice. Animals were given stress through conventional restrain model. The mRNA expression of GLO-1 was analyzed by real time RT-PCR. Moreover, the GLO-1 protein expression was also examined by immunohistochemistry in whole brain and mean density was calculated. The mRNA and protein expressions were found to be increased in animals given anxiety as compared to the normal control. Whereas, the expressions were decreased in the animals treated with eugenol and its liposome-based nanocarriers in a dose dependent manner. However, the results were better in animals treated with nanocarriers as compared to the compound alone. It is concluded that the eugenol and its liposome-based nanocarriers exert anxiolytic activity by down-regulating GLO-1 protein expression in mice.

Resumo A forma mais comum de disfunção psicossocial é a ansiedade intimamente relacionada com a depressão, sem qualquer barreira de idade. Elas estão presentes em um estado combinado de tristeza, confusão, estresse, medo etc. O sistema de glioxalase contém uma enzima chamada glioxalase 1 (GLO1). É uma via metabólica que desintoxica alfa-oxo-aldeídos, particularmente metilglioxal (MG). O metilglioxal é produzido principalmente pela quebra dos intermediários glicolíticos, gliceraldeído-3-fosfatos e fosfato de diidroxiacetona. A expressão da glioxalase 1 também está relacionada ao comportamento de ansiedade. Um papel casual ou GLO1 no comportamento de ansiedade usando vetores virais para superexpressão no córtex cingulado anterior foi encontrado e descobriu-se que a superexpressão local de GLO1 aumentava o comportamento de ansiedade. O presente estudo trata do mecanismo molecular da atividade protetora do eugenol contra o transtorno ansiolítico. Um estudo pré-clínico em animais foi realizado em 42 camundongos BALB / c. Os animais foram submetidos ao estresse por meio do modelo de contenção convencional. A expressão de mRNA de GLO1 foi analisada por RT-PCR em tempo real. Além disso, a expressão da proteína GLO1 também foi examinada por imuno-histoquímica em todo o cérebro e a densidade média foi calculada. Verificou-se que as expressões de mRNA e proteínas estavam aumentadas em animais que receberam ansiedade em comparação com o controle normal. Considerando que as expressões foram diminuídas nos animais tratados com eugenol e seus nanocarreadores baseados em lipossomas de forma dependente da dose. No entanto, os resultados foram melhores em animais tratados com nanocarreadores em comparação com o composto sozinho. Conclui-se que o eugenol e seus nanocarreadores baseados em lipossomas exercem atividade ansiolítica por regulação negativa da expressão da proteína GLO1 em camundongos.

Nordihydroguaiaretic acid inhibits glyoxalase I, and causes the accumulation of methylglyoxal followed by cell-growth inhibition.

BACKGROUND: Methylglyoxal (MGO) is a known toxic byproduct of glycolysis, with MGO-induced cytotoxicity believed to contribute to the pathogenesis of several diseases. Glyoxalase I (GLO1) is a key enzyme for eliminating MGO in mammalian cells, therefore, compounds affecting GLO1 activity are potential therapeutic agents for MGO-induced disorders. Previously, we found nordihydroguaiaretic acid (NDGA) as a potent GLO1 inhibitor. METHODS: The inhibitory characteristics of NDGA were determined spectrophotometrically with recombinant GLO1. NDGA-induced growth-inhibition and accumulation of MGO-derived advanced glycation end products (AGEs) were examined in EA.hy926 cells. RESULTS: NDGA showed significant inhibition of GLO1 enzymatic activity in a dose-dependent manner. Its Ki value was estimated to be 146-fold lower than that of myricetin, a known GLO1 inhibitor. The co-addition of MGO with NDGA to the cells resulted in significant growth inhibition, suggesting that MGO accumulation, sufficient to affect cell growth, was caused by NDGA inhibiting GLO1. These findings were supported by the observations that the addition of aminoguanidine, a typical MGO scavenger, significantly reversed cell-growth inhibition by co-addition of MGO with NDGA, and that an increase in intracellular MGO-derived AGEs was observed during incubation with the co-addition of MGO with NDGA. CONCLUSION: NDGA was found to be a novel and potent inhibitor of GLO1. The co-addition of NDGA with MGO to the cells resulted in increased intracellular MGO accumulation followed by enhanced cell-growth inhibition.

Emerging Glycation-Based Therapeutics-Glyoxalase 1 Inducers and Glyoxalase 1 Inhibitors.

The abnormal accumulation of methylglyoxal (MG) leading to increased glycation of protein and DNA has emerged as an important metabolic stress, dicarbonyl stress, linked to aging, and disease. Increased MG glycation produces inactivation and misfolding of proteins, cell dysfunction, activation of the unfolded protein response, and related low-grade inflammation. Glycation of DNA and the spliceosome contribute to an antiproliferative and apoptotic response of high, cytotoxic levels of MG. Glyoxalase 1 (Glo1) of the glyoxalase system has a major role in the metabolism of MG. Small molecule inducers of Glo1, Glo1 inducers, have been developed to alleviate dicarbonyl stress as a prospective treatment for the prevention and early-stage reversal of type 2 diabetes and prevention of vascular complications of diabetes. The first clinical trial with the Glo1 inducer, trans-resveratrol and hesperetin combination (tRES-HESP)-a randomized, double-blind, placebo-controlled crossover phase 2A study for correction of insulin resistance in overweight and obese subjects, was completed successfully. tRES-HESP corrected insulin resistance, improved dysglycemia, and low-grade inflammation. Cell permeable Glo1 inhibitor prodrugs have been developed to induce severe dicarbonyl stress as a prospective treatment for cancer-particularly for high Glo1 expressing-related multidrug-resistant tumors. The prototype Glo1 inhibitor is prodrug S-p-bromobenzylglutathione cyclopentyl diester (BBGD). It has antitumor activity in vitro and in tumor-bearing mice in vivo. In the National Cancer Institute human tumor cell line screen, BBGD was most active against the glioblastoma SNB-19 cell line. Recently, potent antitumor activity was found in glioblastoma multiforme tumor-bearing mice. High Glo1 expression is a negative survival factor in chemotherapy of breast cancer where adjunct therapy with a Glo1 inhibitor may improve treatment outcomes. BBGD has not yet been evaluated clinically. Glycation by MG now appears to be a pathogenic process that may be pharmacologically manipulated for therapeutic outcomes of potentially important clinical impact.

Eugenol and its liposome-based nano carrier reduce anxiety by inhibiting glyoxylase-1 expression in mice.

The most common form of psycho-social dysfunction is anxiety with depression being related closely without any age bar. They are present with combined state of sadness, confusion, stress, fear etc. Glyoxalase system contains enzyme named glyoxalase 1 (GLO1).It is a metabolic pathway which detoxifies alpha-oxo-aldehydes, particularly methylglyoxal (MG). Methylglyoxal is mainly made by the breakdown of the glycolytic intermediates, glyceraldehyde-3-phosphates and dihydroxyacetone phosphate. Glyoxylase-1 expression is also related with anxiety behavior. A casual role or GLO-1 in anxiety behavior by using viral vectors for over expression in the anterior cingulate cortex was found and it was found that local GLO-1 over expression increased anxiety behavior. The present study deals with the molecular mechanism of protective activity of eugenol against anxiolytic disorder. A pre-clinical animal study was performed on 42 BALB/c mice. Animals were given stress through conventional restrain model. The mRNA expression of GLO-1 was analyzed by real time RT-PCR. Moreover, the GLO-1 protein expression was also examined by immunohistochemistry in whole brain and mean density was calculated. The mRNA and protein expressions were found to be increased in animals given anxiety as compared to the normal control. Whereas, the expressions were decreased in the animals treated with eugenol and its liposome-based nanocarriers in a dose dependent manner. However, the results were better in animals treated with nanocarriers as compared to the compound alone. It is concluded that the eugenol and its liposome-based nanocarriers exert anxiolytic activity by down-regulating GLO-1 protein expression in mice.

Molecular docking and dynamic studies of a potential therapeutic target inhibiting glyoxalase system: Metabolic action of the 3, 3 '- [3- (5-chloro-2-hydroxyphenyl) -3-oxopropane-1, 1-diyl] - Bis-4-hydroxycoumarin leads overexpression of the intracellular level of methylglyoxal and induction of a pro-apoptotic phenomenon in a hepatocellular carcinoma model.

Methylglyoxal is a dicarbonyl compound recruited as a potential cytotoxic marker, initially presents in cells and considered as a metabolite of the glycolytic pathway. Our aim is to demonstrate the inhibitory effect of 3, 3'-[3-(5-chloro-2-hydroxyphenyl)-3-oxopropane-1, 1-diyl] Bis (4-hydroxycoumarin) on the glyoxalase system, and indirectly its anticancer activity. The docking of OT-55 was conducted by using Flexible docking protocol, ChiFlex and libdock tools inside the active site of Glo-I indicated that both hydrogen bonding and hydrophobic interactions contributed significantly in establishing potent binding with the active site which is selected as a strong inhibitor with high scoring values and maximum Gibbs free energy. Coumarin-liposome formulation was characterized and evaluated in vivo against chemically induced hepatocarcinoma in Wistar rats. After Diethylnitrosamine (DEN) induction, microscopic assessment was realized; precancerous lesions were developed showing an increase of both tumor-associated lymphocyte and multiple tumor acini supported by the blood investigation. Our finding also suggested a preferential uptake of liposomes respectively in liver, kidney, lung, brain and spleen in the DEN-treated animals. OT-55 has also been shown to inhibit the activity of Glo-I in vitro as well as in DEN-treated rats. An abnormal high level of MGO of up to 50% was recorded followed by a reduction in glucose consumption and lactate dehydrogenase production validated in the positive control. MGO generates apoptosis as depicted by focal hepatic lesions. Also, no deleterious effects in the control group were observed after testing our coumarin but rather a vascular reorganization leading to nodular regenerative hyperplasia. Involved in the detoxification process, liver GSH is restored in intoxicated rats, while no changes are seen between controls. At the endothelial cell, OT-55 appears to modulate the release of NO only in the DEN-treated group. OT-55 would behave both as an anticancer agent but also as an angiogenic factor regarding results obtained.

Addition of hydrophobic side chains improve the apoptosis inducibility of the human glyoxalase I inhibitor, TLSC702.

Glyoxalase I (GLO I) is a known therapeutic target in cancer. Even though TLSC702, a GLO I inhibitor that we discovered, induces apoptosis in tumor cells, exceptionally higher doses are required compared with those needed to inhibit GLO I activity in vitro. In this work, structure-activity optimization studies were conducted on four sections of the TLSC702 molecule to determine the partial structural features necessary for the inhibition of GLO I. Herein, we found that the carboxy group in TLSC702 was critical for binding with the divalent zinc at the active site of GLO I. In contrast, the side chain substituents in the meta- and para- positions of the benzene ring had little influence on the in vitro inhibition of GLO I. The CLogP values of the TLSC702 derivatives showed a positive correlation with the antiproliferative effects on NCI-H522 cells. Thus, two derivatives of TLSC702, which displayed either high or low lipophilicity due to the types of substituents at the phenyl position, were selected. Even though both derivatives showed comparable inhibitory effects as that of their parent compound, the derivative with the high CLogP value was distinctly more antiproliferative than TLSC702. In contrast, the derivative with the low CLogP value did not decrease cell viability in NCI-H522 and HL-60 cells. These findings suggested that structural improvements, such as the addition of hydrophobic moieties to the phenyl group, enhanced the ability of TLSC702 to induce apoptosis by increasing cell membrane permeability.

Yeasts as Complementary Model Systems for the Study of the Pathological Repercussions of Enhanced Synphilin-1 Glycation and Oxidation.

Synphilin-1 has previously been identified as an interaction partner of α-Synuclein (αSyn), a primary constituent of neurodegenerative disease-linked Lewy bodies. In this study, the repercussions of a disrupted glyoxalase system and aldose reductase function on Synphilin-1 inclusion formation characteristics and cell growth were investigated. To this end, either fluorescent dsRed-tagged or non-tagged human SNCAIP, which encodes the Synphilin-1 protein, was expressed in Saccharomyces cerevisiae and Schizosaccharomyces pombe yeast strains devoid of enzymes Glo1, Glo2, and Gre3. Presented data shows that lack of Glo2 and Gre3 activity in S. cerevisiae increases the formation of large Synphilin-1 inclusions. This correlates with enhanced oxidative stress levels and an inhibitory effect on exponential growth, which is most likely caused by deregulation of autophagic degradation capacity, due to excessive Synphilin-1 aggresome build-up. These findings illustrate the detrimental impact of increased oxidation and glycation on Synphilin-1 inclusion formation. Similarly, polar-localised inclusions were observed in wild-type S. pombe cells and strains deleted for either glo1+ or glo2+. Contrary to S. cerevisiae, however, no growth defects were observed upon expression of SNCAIP. Altogether, our findings show the relevance of yeasts, especially S. cerevisiae, as complementary models to unravel mechanisms contributing to Synphilin-1 pathology in the context of neurodegenerative diseases.

Ellagic acid: A potent glyoxalase-I inhibitor with a unique scaffold.

The glyoxalase system, particularly glyoxalase-I (GLO-I), has been approved as a potential target for cancer treatment. In this study, a set of structurally diverse polyphenolic natural compounds were investigated as potential GLO-I inhibitors. Ellagic acid was found, computationally and experimentally, to be the most potent GLO-I inhibitor among the tested compounds which showed an IC50 of 0.71 mmol L-1. Its binding to the GLO-I active site seemed to be mainly driven by ionic interaction via its ionized hydroxyl groups with the central Zn ion and Lys156, along with other numerous hydrogen bonding and hydrophobic interactions. Due to its unique and rigid skeleton, it can be utilized to search for other novel and potent GLO-I inhibitors via computational approaches such as pharmacophore modeling and similarity search methods. Moreover, an inspection of the docked poses of the tested compounds showed that chlorogenic acid and dihydrocaffeic acid could be considered as lead compounds worthy of further optimization.

Glyoxalase system: A systematic review of its biological activity, related-diseases, screening methods and small molecule regulators.

The glyoxalase system is a ubiquitous enzymatic network which plays important roles in biological life. It consists of glyoxalase 1 (GLO1), glyoxalase 2 (GLO2), and reduced glutathione (GSH), which perform an essential metabolic function in cells by detoxifying methylglyoxal (MG) and other endogenous harmful metabolites into non-toxic d-lactate. MG and MG-derived advanced glycation endproducts (AGEs) are associated with various diseases, such as diabetes, cardiovascular disease, neurodegenerative disorders and cancer, and GLO1 is a key rate-limiting enzyme in the anti-glycation defense. The abnormal activity and expression of GLO1 in various diseases make this enzyme a promising target for drug design and development. This review focuses on the regulatory mechanism of GLO1 in diverse pathogenic conditions with a thorough discussion of GLO1 regulators since their discovery, including GLO1 activators and inhibitors. The different classes, chemical structure and structure-activity relationship are embraced. Moreover, assays for the discovery of small molecule regulators of the glyoxalase system are also introduced in this article. Compared with spectrophotometer-based assay, microplate-based assay is a more simple, rapid and quantitative high-throughput method. This review will be useful to design novel and potent GLO1 regulators and hopefully provide a convenient reference for researchers.

Design, synthesis and biological evaluation of novel glyoxalase I inhibitors possessing diazenylbenzenesulfonamide moiety as potential anticancer agents.

The enzyme glyoxalase-I (Glo-I) is an essential therapeutic target in cancer treatment. Significant efforts have been made to discover competitive inhibitors of Glo-I as potential anticancer agents. Herein, we report the synthesis of a series of diazenylbenzenesulfonamide derivatives, their in vitro evaluation against Glo-I and the resulting structure-activity relationships. Among the compounds tested, compounds 9h and 9j exhibited the highest activity with IC50 1.28 µM and 1.13 µM, respectively. Docking studies to explore the binding mode of the compounds identified key moieties that may contribute to the observed activities. The active compounds will serve as suitable leads for further chemical optimization.

The Putative Glyoxalase 1 Inhibitor Piceatannol Exhibits Both Anxiolytic-like and Antitumor Effects in Mice.

BACKGROUND/AIM: This study aimed to determine the anxiolytic effect of a putative glyoxalase 1 inhibitor, piceatannol, as well as its antitumor activities on the stress-induced tumor growth of Lewis lung carcinoma. MATERIALS AND METHODS: The anxiolytic activities of piceatannol (1-30 mg/kg) were assessed using the elevated plus maze (EPM) test. We also evaluated the pharmacological modulation of stress-induced tumor growth; the mice were treated with piceatannol (3 and 30 mg/kg) from the 10th day till the 19th day after administration of the LLC cells. RESULTS: At the low dose (3 mg/kg), piceatannol significantly increased the time spent in the open arms of the EPM test when compared with the vehicle. At higher doses (30 mg/kg), it significantly suppressed the stress-induced enhancement of tumor growth. CONCLUSION: A low dose of piceatannol exerts an anxiolytic effect, and high doses have an antitumor effect.

Chemoproteomic Profiling of a Pharmacophore-Focused Chemical Library.

Pharmacophore-focused chemical libraries are continuously being created in drug discovery programs, yet screening assays to maximize the usage of such libraries are not fully explored. Here, we report a chemical proteomics approach to reutilizing a focused chemical library of 1,800 indole-containing molecules for discovering uncharacterized ligand-protein pairs. Gel-based protein profiling of the library using a photo-affinity indole probe 1 enabled us to find new ligands for glyoxalase 1 (Glo1), an enzyme involved in the detoxification of methylglyoxal. Structure optimization of the ligands yielded an inhibitor for Glo1 (9). Molecule 9 increased the cellular methylglyoxal levels in human cells and suppressed the osteoclast formation of mouse bone marrow-derived macrophages. X-ray structure analyses revealed that the molecule lies at a site abutting the substrate binding site, which is consistent with the enzyme kinetic profile of 9. Overall, this study exemplifies how chemical proteomics can be used to exploit existing focused chemical libraries.

Combined High Throughput Screening with QSAR Analysis Unravelling Potential Glyoxalase-I Inhibitors.

AIMS: Discovery of new Glo-I inhibitors as potential anticancer agents. BACKGROUND: Glyoxalase system is ubiquitous system in human cells which has been examined thoroughly for its role in cancerous diseases. It performs detoxifying endogenous harmful metabolites, mainly methylglyoxal (MG) into non-toxic bystanders. OBJECTIVE: Structure based model Hypo(2ZA0_2_02) combined with 3D-QSAR modeling were applied to predict glyoxalase I inhibition and to explain their activity. METHODS: Currently, high throughput screening approach was used to investigate the activity of inhouse database composed of 205 compounds. RESULTS: 15 compounds were found active as glyoxalase I inhibitors. The 15 candidates showed more than 50% inhibition with low micromolar IC50 ranges between 5.0 to 42.0 µM. CONCLUSION: They have been successfully mapped and fitted the Hypo(2ZA0_2_02) model which explain the presence of anti-glyoxalase I activity. This model could be used in future for further development of new and novel glyoxylase I inhibitors.

Multiscale Process Modelling in Translational Systems Biology of Leishmania major: A Holistic view.

Present work aims to utilize systems biology and molecular modelling approach to understand the inhibition kinetics of Leishmania major GLO I and identifying potential hit followed by their validation through in vitro and animal studies. Simulation of GLO I inhibition has shown to affect reaction fluxes of almost all reactions in the model that led to increased production of various AGEs and free radicals. Further, in vitro testing of C1 and C2, selected through molecular modelling revealed remarkable morphological alterations like size reduction, membrane blebbing and loss in motility of the parasite, however, only C1 showed better antileishmanial activity. Additionally, C1 showed apoptosis mediated leishmanicidal activity (apoptosis-like cell death) along with cell-cycle arrest at sub-G0/G1 phase and exhibited potent anti-leishmanial effect against intracellular amastigotes. Furthermore, decrease in parasite load was also observed in C1 treated BALB/c female mice. Our results indicate that C1 has healing effect in infected mice and effectively reduced the parasitic burden. Hence, we suggest C1 as a lead molecule which on further modification, may be used to develop novel therapeutics against Leishmaniasis.

Recent advances in the discovery and development of glyoxalase I inhibitors.

Glyoxalase I (GLO1) is a homodimeric Zn2+-metalloenzyme that catalyses the transformation of methylglyoxal (MG) to d-lacate through the intermediate S-d-lactoylglutathione. Growing evidence indicates that GLO1 has been identified as a potential target for the treatment cancer and other diseases. Various inhibitors of GLO1 have been discovered or developed over the past several decades including natural or natural product-based inhibitors, GSH-based inhibitors, non-GSH-based inhibitors, etc. The aim of this review is to summarize recent achievements of concerning discovery, design strategies, as well as pharmacological aspects of GLO1 inhibitors with the target of promoting their development toward clinical application.

Imaging Tumorous Methylglyoxal by an Activatable Near-Infrared Fluorescent Probe for Monitoring Glyoxalase 1 Activity.

The accurate detection of tumorous methylglyoxal (MGO) and its detoxifier glyoxalase 1 (GLO1) in living systems is critical for understanding their roles in tumor initiation and progression. To date, the in situ fluorescence detection of endogenous MGO and GLO1 in tumor has not been reported. Herein we developed a near-infrared (NIR) fluorescent probe MEBTD to specifically detect tumorous MGO. Compared with previously reported MGO fluorescent probes, MEBTD exhibits several distinct advantages, including NIR emission, high selectivity with an MGO detection limit of 18 nM, and a 131-fold off-on ratio. The probe could sense GLO1 activity and monitor the therapeutic effect of GLO1 inhibitors by imaging tumorous MGO in a both a real-time and in situ manner, demonstrating that the biological effect of GLO1 inhibitors is dependent on the GLO1 activity. Furthermore, MEBTD enables the visualization of tumorous MGO induced by GLO1 inhibitors in vivo. To the best of our knowledge, MEBTD is the first NIR fluorescent probe for specifically imaging tumorous MGO in living animals, indicating the promising potential for tumor diagnosis and therapeutic evaluation.

Discovery of a nanomolar inhibitor of the human glyoxalase-I enzyme using structure-based poly-pharmacophore modelling and molecular docking.

The glyoxalase-I (GLO-I) enzyme, which is the initial enzyme of the glyoxalase system that is responsible for the detoxification of cytotoxic α-ketoaldehydes, such as methylglyoxal, has been approved as a valid target in cancer therapy. Overexpression of GLO-I has been observed in several types of carcinomas, including breast, colorectal, prostate, and bladder cancer. In this work we aimed to identify potential GLO-I inhibitors via employing different structure-based drug design techniques including structure-based poly-pharmacophore modelling, virtual screening, and molecular docking. Poly-pharmacophore modelling was applied in this study in order to thoroughly explore the binding site of the target enzyme, thereby, revealing hits that could bind in a nonconventional way which can pave the way for designing more potent and selective ligands with novel chemotypes. The modelling phase has resulted in the selection of 31 compounds that were biologically evaluated against human GLO-I enzyme. Among the tested set, seven compounds showed excellent inhibitory activities with IC50 values ranging from 0.34 to 30.57 µM. The most active compound (ST018515) showed an IC50 of 0.34 ± 0.03 µM, which, compared to reported GLO-I inhibitors, can be considered a potent inhibitor, making it a good candidate for further optimization towards designing more potent GLO-I inhibitors.

Pentagamavunon-1 (PGV-1) inhibits ROS metabolic enzymes and suppresses tumor cell growth by inducing M phase (prometaphase) arrest and cell senescence.

We previously showed that curcumin, a phytopolyphenol found in turmeric (Curcuma longa), targets a series of enzymes in the ROS metabolic pathway, induces irreversible growth arrest, and causes apoptosis. In this study, we tested Pentagamavunon-1 (PGV-1), a molecule related to curcumin, for its inhibitory activity on tumor cells in vitro and in vivo. PGV-1 exhibited 60 times lower GI50 compared to that of curcumin in K562 cells, and inhibited the proliferation of cell lines derived from leukemia, breast adenocarcinoma, cervical cancer, uterine cancer, and pancreatic cancer. The inhibition of growth by PGV-1 remained after its removal from the medium, which suggests that PGV-1 irreversibly prevents proliferation. PGV-1 specifically induced prometaphase arrest in the M phase of the cell cycle, and efficiently induced cell senescence and cell death by increasing intracellular ROS levels through inhibition of ROS-metabolic enzymes. In a xenograft mouse model, PGV-1 had marked anti-tumor activity with little side effects by oral administration, whereas curcumin rarely inhibited tumor formation by this administration. Therefore, PGV-1 is a potential therapeutic to induce tumor cell apoptosis with few side effects and low risk of relapse.

Multi-Armed 1,2,3-Selenadiazole and 1,2,3-Thiadiazole Benzene Derivatives as Novel Glyoxalase-I Inhibitors.

Glyoxalase-I (Glo-I) enzyme was established to be a valid target for anticancer drug design. It performs the essential detoxification step of harmful byproducts, especially methylglyoxal. A robust computer-aided drug design approach was used to design and validate a series of compounds with selenium or sulfur based heterorings. A series of in-house multi-armed 1,2,3-selenadiazole and 1,2,3-thiadiazole benzene derivatives were tested for their Glo-I inhibitory activity. Results showed that these compounds bind Glo-I active sites competitively with strong potential to inhibit this enzyme with IC50 values in micro-molar concentration. Docking poses revealed that these compounds interact with the zinc atom at the bottom of the active site, which plays an essential role in its viability.

Indole-4-carboxaldehyde Isolated from Seaweed, Sargassum thunbergii, Attenuates Methylglyoxal-Induced Hepatic Inflammation.

Glucose degradation is aberrantly increased in hyperglycemia, which causes various harmful effects on the liver. Glyoxalase-1 (Glo-1) is a ubiquitous cellular enzyme that participates in the detoxification of methylglyoxal (MGO), a cytotoxic byproduct of glycolysis that induces protein modification (advanced glycation end-products, AGEs) and inflammation. Here, we investigated the anti-inflammatory effect of indole-4-carboxaldehyde (ST-I4C), which was isolated from the edible seaweed Sargassum thunbergii, on MGO-induced inflammation in HepG2 cells, a human hepatocyte cell line. ST-I4C attenuated the MGO-induced expression of inflammatory-related genes, such as tumor necrosis factor (TNF)-α and IFN-γ by activating nuclear factor-kappa B (NF-κB) without toxicity in HepG2 cells. In addition, ST-I4C reduced the MGO-induced AGE formation and the expression of the receptor for AGE (RAGE). Interestingly, both the mRNA and protein expression levels of Glo-1 increased following ST-I4C treatment, and the decrease in Glo-1 mRNA expression caused by MGO exposure was rescued by ST-I4C pretreatment. These results suggest that ST-I4C shows anti-inflammatory activity against MGO-induced inflammation in human hepatocytes by preventing an increase in the pro-inflammatory gene expression and AGE formation. Therefore, it represents a potential therapeutic agent for the prevention of hepatic steatosis.