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.

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.

Computational and experimental exploration of the structure-activity relationships of flavonoids as potent glyoxalase-I inhibitors.

Hit, Lead & Candidate Discovery Glyoxalase-I (Glo-I) enzyme has emerged as a potential target for cancer treatment. Several classes of natural products including coumarins and flavonoids have shown remarkable Glo-I inhibitory activity. In the present study, computational and experimental approaches were used to explore the structure-activity relationships of a panel of 24 flavonoids as inhibitors of the Glo-1 enzyme. Scutellarein with an IC50 value of 2.04 µM was identified as the most potent inhibitor among the series studied. Di- or tri-hydroxylation of the benzene rings A and B accompanied with a C2/C3 double bond in ring C were identified as essential structural features for enzyme inhibition. Moreover, the ketol system showed a minor role in the inhibitory power of these compounds. The structure-activity relationships revealed in this study had deepened our understanding of the Glo-I inhibitory activities of flavonoids and opened the door for further exploration of this promising compound class.

Identification of the First "Two Digit Nano-molar" Inhibitors of the Human Glyoxalase-I Enzyme as Potential Anticancer Agents.

BACKGROUND: Glyoxalase-I (Glo-I) enzyme is recognized as an indispensable druggable target in cancer treatment. Its inhibition will lead to the accumulation of toxic aldehyde metabolites and cell death. Paramount efforts were spent to discover potential competitive inhibitors with the aim to eradicate cancer. OBJECTIVE: Based on our previous work on this target for discovering potent inhibitors of this enzyme, herein, we address the discovery of the most potent Glo-I inhibitors reported in the literature with two digits nano-molar activity. METHODS: Molecular docking and in vitro assay were performed to discover these inhibitors and explore the binding pattern within the active site. A detailed SAR scheme was generated, which identifies the major functionalities responsible for the observed activity. RESULTS: Compound 1 with an IC50 of 16.5 nM exhibited the highest activity, which possess catechol moiety as an essential zinc chelating functionality. It has been shown by using molecular modeling techniques that the catechol moiety is responsible for chelation zinc atom at the active site; an essential feature for enzyme inhibition. CONCLUSION: Catechol derivatives are successful zinc chelators in Glo-I enzyme while showing exceptional activity against the enzyme to nanomolar level.

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.

Mortality incidence and its determinants after fragility hip fractures: a prospective cohort study from an Egyptian level one trauma center.

BACKGROUND: Fragility hip fracture is a common condition with serious consequences. Most outcomes data come from Western and Asian populations. There are few data from African and Middle Eastern countries. OBJECTIVE: The primary objective was to describe mortality rates after fragility hip fracture in a Level-1 trauma centre in Egypt. The secondary objective was to study the causes of re-admissions, complications, and mortality. METHODS: A prospective cohort study of 301 patients, aged > 65 years, with fragility hip fractures. Data collected included sociodemographic, co-morbidities, timing of admission, and intraoperative,ostoperative, and post-discharge data as mortality, complications, hospital stay, reoperation, and re-admission. Cox regression analysis was conducted to investigate factors associated with 1-year mortality. RESULTS: In-hospital mortality was 8.3% (25 patients) which increased to 52.8% (159 patients) after one year; 58.5% of the deaths occurred in the first 3-months. One-year mortality was independently associated with increasing age, ASA 3-4, cardiac or hepatic co-morbidities, trochanteric fractures, total hospital stay, and postoperative ifection and metal failure. CONCLUSION: Our in-hospital mortality rate resembles developed countries reports, reflecting good initial geriatric healthcare. However, our 3- and 12-months mortality rates are unexpectedly high. The implementation of orthogeriatric care after discharge is mandatory to decrease mortality rates.

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.

Combination of pharmacophore modeling and 3D-QSAR analysis of potential glyoxalase-I inhibitors as anticancer agents.

Glyoxalase system is an ubiquitous system in human cells which has been examined thoroughly for its role in different diseases. It comprises two enzymes; Glyoxalase I (Glo-I) and Glyoxalase II (Glo-II) which perform detoxifying endogenous harmful metabolites, mainly methylglyoxal (MG) into non-toxic bystanders. In silico computer Aided Drug Design approaches were used and ninety two diverse pharmacophore models were generated from eighteen Glyoxalase I crystallographic complexes. Subsequent QSAR modeling followed by ROC evaluation identified a single pharmacophore model which was able to predict the expected Glyoxalase I inhibition. Screening of the National Cancer Institute (NCI) database using the optimal pharmacophore Hypo(3VW9) identified several promising hits. Thirty eight hits were successfully predicted then ordered and evaluated in vitro. Seven hits out of the thirty eight tested compounds showed more than 50% inhibition with low micromolar IC50.

Recent Advances in Glyoxalase-I Inhibition.

Glyoxalase system is a ubiquitous system in human cells which has been examined thoroughly for its role in different disease conditions. It is composed of Glyoxalase-I (Glo-I) and Glyoxalase- II which perform an essential metabolic process inside the cell by detoxifying endogenous harmful metabolites, mainly methylglyoxal (MG) into non-toxic D-lactic acid. Tumor cells are well-known for their high metabolic rate which results in elevated levels of toxic metabolites. The over-expression of Glo-I in tumor cells makes this enzyme a pivotal target for anticancer drug development. Glo-I is metalloenzyme with two polypeptide chains and encompasses two active sites with an integral zinc atoms at their center. This review aims to highlight the important role of Glo-I in different pathogenic conditions, and more importantly, it provides a thorough discussion of all known human Glo-I inhibitors since its discovery, a hundred years ago, up to date. It embraces the different classes they belong to, their design and chemical structures. We believe this review will help guide the design of novel and potent human Glo-I inhibitors by providing a handy reference for interested researchers in this target.

Predictive Value of Thompson-Score for Long-Term Neurological and Cognitive Outcome in Term Newborns with Perinatal Asphyxia and Hypoxic-Ischemic Encephalopathy Undergoing Controlled Hypothermia Treatment.

BACKGROUND: The so-called Thompson-score (TS) for newborns with hypoxic-ischemic encephalopathy (HIE) was developed before the introduction of controlled hypothermia as clinical routine. Information on the predictive value of TS in newborns undergoing therapeutic hypothermia to estimate long-term outcome is limited. OBJECTIVES: To determine the predictive value of TS to estimate long-term cognitive and neurological outcome in newborns with perinatal asphyxia treated with controlled hypothermia. METHODS: Thirty-six term newborns with HIE undergoing controlled hypothermia were followed using Wechsler Preschool and Primary Scale of intelligence III test and standardized neurological examination. The primary outcome was survival without cognitive impairment, defined as an IQ ≥85. Secondary outcomes were motor outcomes, survival without relevant neurological impairment, death and epilepsy. RESULTS: Follow-up was done in 33 out of 36 (91.6%) infants at 53 ± 12 months (mean ± SD). For all investigated parameters, a statistically significant relationship with peak TS was demonstrated. A one-point increase in peak TS indicated an OR (95% CI) of 1.5 (1.1-2.0, p = 0.006) for death or cognitive impairment, an OR (95% CI) of 2.2 (1.3-3.8, p = 0.004) for death or relevant neurologic impairment, an OR (95% CI) of 2.1 (1.3-3.5, p = 0.005) for death or epilepsy and an OR (95% CI) of 1.5 (1.1-2.1, p = 0.02) for death. Although the TS for newborns with adverse outcome (death or cognitive impairment) compared to normal outcome tended to be higher (13 [4-16] vs. 9 [0-13], d1; 15 [5-19] vs. 9 [1-14], d2; 14 [5-21] vs. 8 [2-15], d3; median [range]), there was a considerable overlap during the first 3 days of life between both groups. CONCLUSIONS: The TS seems to be a prognostic tool for predicting the long-term outcome in asphyxiated term newborns undergoing controlled hypothermia after the third day of life. A higher score appears to be significantly associated with an adverse outcome.

Tidal Volume Delivery and Endotracheal Tube Leak during Cardiopulmonary Resuscitation in Intubated Newborn Piglets with Hypoxic Cardiac Arrest Exposed to Different Modes of Ventilatory Support.

BACKGROUND: There are few data available on the interaction of inflations, chest compressions (CC), and delivery of tidal volumes in newborn infants undergoing resuscitation in the presence of endotracheal tube (ET) leaks. OBJECTIVES: To determine the effects of different respiratory support strategies along with CC on changes in tidal volume and ET leaks in hypoxic newborn piglets with cardiac arrest. METHODS: Asphyxiated newborn piglets, intubated with weight-adapted uncuffed ET, were randomized into three groups and resuscitated according to ILCOR 2010 guidelines: (1) T-piece resuscitator (TPR) group = peak inspiratory pressure (PIP)/positive end-expiratory pressure (PEEP) 25/5 cm H2O, rate 30/min, inflations interposed between CC (3:1 ratio); (2) self- inflating bag (SIB) group = PIP 25 cm H2O without PEEP, rate 30/min, inflations interposed between CC (3:1 ratio), and (3) ventilator group = PIP/PEEP of 25/5 cm H2O, rate 30/min. CC were applied with a rate of 120/min without synchrony to inflations. RESULTS: We observed a significant increase of leak (average increase 11.4%) when CC was added to respiratory support (p = 0.0001). Expired tidal volume was larger in the SIB group than in the two other modes which both applied PEEP. However, tidal volumes caused by CC only were larger in the two groups with PEEP than in the SIB group (without PEEP). CONCLUSIONS: There is interaction between lung inflations and CC affecting leak and delivery of tidal volume, which may be influenced by the mode/device used for respiratory support. Leak is larger in the presence of PEEP. However, CC cause additional tidal volume which is larger in the presence of PEEP.

Effect of Different Respiratory Modes on Return of Spontaneous Circulation in a Newborn Piglet Model of Hypoxic Cardiac Arrest.

BACKGROUND: There are no clear evidence-based recommendations on the use of different techniques of respiratory support and chest compressions (CC) during neonatal cardiopulmonary resuscitation (CPR). OBJECTIVES: To determine the effects of different respiratory support strategies along with CC representing clinical practice on the return of spontaneous circulation (ROSC) in hypoxic newborn piglets with cardiac arrest. We hypothesized that use of a T-piece resuscitator (TPR) providing positive end-expiratory pressure (PEEP) reduces time to ROSC as compared to a self-inflating bag (SIB) without PEEP. Furthermore, we explored the effects of a ventilator providing inflations without synchrony to CC. METHODS: Thirty-three newborn piglets were exposed to hypoxia until asystole occurred and randomized into three groups and resuscitated according to ILCOR guidelines: group 1 = TPR [peak inspiratory pressure (PIP)/PEEP of 25/5 cm H2O, rate 30/min], inflations interposed between CC (3:1 ratio); group 2 = SIB (PIP of 25 cm H2O without PEEP, rate 30/min), inflations interposed between CC (3:1 ratio), and group 3 = ventilator (PIP/PEEP of 25/5 cm H2O, rate 30/min), CC were applied with a rate of 120/min without synchrony to inflations. Animals were supported for 120 min after ROSC. Primary outcome was time to ROSC. RESULTS: All animals achieved ROSC. We found no significant difference in time to ROSC between groups [median (IQR); TPR: 150 s (150-210); SIB: 150 s (120-180); ventilator: 180 s (150-345)]. There was no difference in use of epinephrine, in blood gases or hemodynamic parameters during the 120-min observation time after ROSC. CONCLUSIONS: We found no significant effect of different respiratory support strategies during CPR on ROSC.

Novel glyoxalase-I inhibitors possessing a "zinc-binding feature" as potential anticancer agents.

BACKGROUND: The glyoxalase system including two thiol-dependent enzymes, glyoxalase I (Glo-I) and glyoxalase II, plays an important role in a ubiquitous metabolic pathway involved in cellular detoxification of cytotoxic 2-oxoaldehydes. Tumor cells have high glycolytic activity, leading to increased cellular levels of these toxic metabolites. The increased activity of the detoxification system in cancerous cells makes this pathway a viable target for developing novel anticancer agents. In this study, we examined the potential utility of non-glutathione-based inhibitors of the Glo-I enzyme as novel anticancer drugs. METHODS: Computer-aided drug design techniques, such as customized pharmacophoric features, virtual screening, and flexible docking, were used to achieve the project goals. Retrieved hits were extensively filtered and subsequently docked into the active site of the enzyme. The biological activities of retrieved hits were assessed using an in vitro assay against Glo-I. RESULTS: Since Glo-I is a zinc metalloenzyme, a customized Zn-binding pharmacophoric feature was used to search for selective inhibitors via virtual screening of a small-molecule database. Seven hits were selected, purchased, and biologically evaluated. Three of the seven hits inhibited Glo-I activity, the most effective of which exerted 76.4% inhibition at a concentration of 25 µM. CONCLUSION: We successfully identified a potential Glo-I inhibitor that can serve as a lead compound for further optimization. Moreover, our in silico and experimental results were highly correlated. Hence, the docking protocol adopted in this study may be efficiently employed in future optimization steps.

Different Techniques of Respiratory Support Do Not Significantly Affect Gas Exchange during Cardiopulmonary Resuscitation in a Newborn Piglet Model.

BACKGROUND: There are no evidence-based recommendations on the use of different techniques of respiratory support and chest compressions (CC) during neonatal cardiopulmonary resuscitation (CPR). OBJECTIVES: We studied the short-term effects of different ventilatory support strategies along with CC representing clinical practice on gas exchange [arterial oxygen saturation (SaO2), arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2)], hemodynamics and cerebral oxygenation. We hypothesized that in newborn piglets with cardiac arrest, use of a T-piece resuscitator (TPR) providing positive end-expiratory pressure (PEEP) improves gas exchange as measured by SaO2 during CPR as compared to using a self-inflating bag (SIB) without PEEP. Furthermore, we explored the effects of a mechanical ventilator without synchrony to CC. METHODS: Thirty newborn piglets with asystole were randomized into three groups and resuscitated for 20 min [fraction of inspired oxygen (FiO2) = 0.21 for 10 min and 1.0 thereafter]. Group 1 received ventilation using a TPR [peak inspiratory pressure (PIP)/PEEP of 20/5 cm H2O, rate 30/min] with inflations interposed between CC (3:1 ratio). Group 2 received ventilation using a SIB (PIP of 20 cm H2O without PEEP, rate 30/min) with inflations interposed between CC (3:1 ratio). Group 3 received ventilation using a mechanical ventilator (PIP/PEEP of 20/5 cm H2O, rate 30/min). CC were applied with a rate of 120/min without synchrony to inflations. RESULTS: We found no significant differences in SaO2 between the three groups. However, there was a trend toward a higher SaO2 [TPR: 28.0% (22.3-40.0); SIB: 23.7% (13.4-52.3); ventilator: 44.1% (39.2-54.3); median (interquartile range)] and a lower PaCO2 [TPR: 95.6 mm Hg (82.1-113.6); SIB: 100.8 mm Hg (83.0-108.0); ventilator: 74.1 mm Hg (68.5-83.1); median (interquartile range)] in the mechanical ventilator group. CONCLUSIONS: We found no significant effect on gas exchange using different respiratory support strategies during CPR.

Novel N-substituted aminobenzamide scaffold derivatives targeting the dipeptidyl peptidase-IV enzyme.

BACKGROUND: The dipeptidyl peptidase-IV (DPP-IV) enzyme is considered a pivotal target for controlling normal blood sugar levels in the body. Incretins secreted in response to ingestion of meals enhance insulin release to the blood, and DPP-IV inactivates these incretins within a short period and stops their action. Inhibition of this enzyme escalates the action of incretins and induces more insulin to achieve better glucose control in diabetic patients. Thus, inhibition of this enzyme will lead to better control of blood sugar levels. METHODS: In this study, computer-aided drug design was used to help establish a novel N-substituted aminobenzamide scaffold as a potential inhibitor of DPP-IV. CDOCKER software available from Discovery Studio 3.5 was used to evaluate a series of designed compounds and assess their mode of binding to the active site of the DPP-IV enzyme. The designed compounds were synthesized and tested against a DPP-IV enzyme kit provided by Enzo Life Sciences. The synthesized compounds were characterized using proton and carbon nuclear magnetic resonance, mass spectrometry, infrared spectroscopy, and determination of melting point. RESULTS: Sixty-nine novel compounds having an N-aminobenzamide scaffold were prepared, with full characterization. Ten of these compounds showed more in vitro activity against DPP-IV than the reference compounds, with the most active compounds scoring 38% activity at 100 µM concentration. CONCLUSION: The N-aminobenzamide scaffold was shown in this study to be a valid scaffold for inhibiting the DPP-IV enzyme. Continuing work could unravel more active compounds possessing the same scaffold.

Methoxyphenylcipro induces antitumor activity in human cancer cells.

To examine the antitumor activity of a new derivative of ciprofloxacin called methoxyphenylcipro (CMPP). Cell viability was assessed using the MTT assay and apoptotic cells and reactive oxygen species were evaluated using flow cytometry. Results revealed that CMPP induces antiproliferative activity against breast cancer cells and melanoma and to a lesser extent against colorectal cancer cells. Interestingly, compared to ciprofloxacin, CMPP-induced a selective cytotoxicity against human cancer cells but not human normal fibroblasts. The potential of CMPP to inhibit cellular growth in MD-MB-486 breast cancer cells and MV3 melanoma cells was largely due to induction of caspase-dependent apoptosis, as confirmed by caspase-3 activation and cleavage of its substrate PARP. In addition, results indicated that CMPP-induced apoptosis is mediated by generation of reactive oxygen species. These findings revealed that CMPP has a selective antitumor activity against cancer cells and warrants further clinical evaluation.

Virtual lead identification of farnesyltransferase inhibitors based on ligand and structure-based pharmacophore techniques.

Farnesyltransferase enzyme (FTase) is considered an essential enzyme in the Ras signaling pathway associated with cancer. Thus, designing inhibitors for this enzyme might lead to the discovery of compounds with effective anticancer activity. In an attempt to obtain effective FTase inhibitors, pharmacophore hypotheses were generated using structure-based and ligand-based approaches built in Discovery Studio v3.1. Knowing the presence of the zinc feature is essential for inhibitor's binding to the active site of FTase enzyme; further customization was applied to include this feature in the generated pharmacophore hypotheses. These pharmacophore hypotheses were thoroughly validated using various procedures such as ROC analysis and ligand pharmacophore mapping. The validated pharmacophore hypotheses were used to screen 3D databases to identify possible hits. Those which were both high ranked and showed sufficient ability to bind the zinc feature in active site, were further refined by applying drug-like criteria such as Lipiniski's "rule of five" and ADMET filters. Finally, the two candidate compounds (ZINC39323901 and ZINC01034774) were allowed to dock using CDOCKER and GOLD in the active site of FTase enzyme to optimize hit selection.

Synthesis and anticandidal activity of azole-containing sulfonamides.

Twenty five benzenesulfonamides containing one imidazole or triazole ring, or two imidazole or triazole rings have been synthesized and evaluated as anticandidal agents. The most active compounds were 5c, 6b, 6c, 6e, and 17b, which exhibited MIC values of 4.55-24.39 mM depending on the clinical isolate. Comparing imidazole to triazole derivatives did not show a clear effect on activity. Compounds containing a N-benzyl group also showed no clear evidence on activity given the fact that they have an extra aromatic ring. Secondary sulfonamides, 5l, 5m, and 5n showed activities that were proportional to their lipophilicity. The activities of N-aryl-substituted derivatives 5j, 5k, 5l, 5m, 5n, and 6j were also proportional to their lipophilicity. Halogenation enhanced the activity as a result of improvement of lipophilicity. The presence of two imidazole or triazole rings in the same compound did not show a clear enhancement of activity.