Other search tools

About this data

The publication data currently available has been vetted by Vanderbilt faculty, staff, administrators and trainees. The data itself is retrieved directly from NCBI's PubMed and is automatically updated on a weekly basis to ensure accuracy and completeness.

If you have any questions or comments, please contact us.

Results: 1 to 10 of 604

Publication Record

Connections

Kinetic Modeling of Steady-State Situations in Cytochrome P450 Enzyme Reactions.
Guengerich FP
(2019) Drug Metab Dispos 47: 1232-1239
MeSH Terms: Computer Simulation, Cytochrome P-450 Enzyme Inhibitors, Cytochrome P-450 Enzyme System, Humans, Kinetics, Ligands
Show Abstract · Added March 3, 2020
In the course of investigations of the kinetics of individual reactions of cytochrome P450 (P450) enzymes, a number of points about the complexity of P450 enzyme kinetics have become apparent. Several of these are of particular relevance to work with P450 enzymes in the course of drug development and lead optimization, particularly with regard to estimating in vitro kinetic parameters and dealing with enzyme inhibitors. Modern simulation modeling has been applied to situations involving issues of preincubation time with moderate strength and strong inhibitors, inhibition by tightly bound ligands that have been identified in P450 enzymes, extensive substrate depletion, P450 reactions with a rate-limiting step after product formation, and the consumption of an inhibitor during a reaction by either a P450 enzyme being monitored or another one in a mixture. The results all follow from first principles, and simulations reveal the extent of their significance in various settings. The order of addition of substrate and inhibitors can change the apparent outcome (inhibition constant, ), and the effect of the order is more pronounced with a stronger inhibitor. Substrate depletion alters parameters (Michaelis constant, ) and can generate apparently sigmoidal plots. A rate-limiting step after product formation lowers the apparent and distorts Consumption of an inhibitor during a reaction affects and differs depending on which enzyme is involved. The results are relevant with P450 enzymes and other enzymes as well. SIGNIFICANCE STATEMENT: Kinetic simulations have been used to address several potential problems in enzyme kinetic analysis. Although the simulations done here are general for enzyme reactions, several problems addressed here are particularly relevant to cytochrome P450 reactions encountered in drug development work.
Copyright © 2019 by The American Society for Pharmacology and Experimental Therapeutics.
0 Communities
1 Members
0 Resources
6 MeSH Terms
The anti-parasitic agent suramin and several of its analogues are inhibitors of the DNA binding protein Mcm10.
Paulson CN, John K, Baxley RM, Kurniawan F, Orellana K, Francis R, Sobeck A, Eichman BF, Chazin WJ, Aihara H, Georg GI, Hawkinson JE, Bielinsky AK
(2019) Open Biol 9: 190117
MeSH Terms: Animals, Cell Survival, DNA Replication, DNA-Binding Proteins, Drug Discovery, Enzyme Inhibitors, Gene Expression, High-Throughput Nucleotide Sequencing, Humans, Kinetics, Minichromosome Maintenance Proteins, Molecular Structure, Protein Binding, Suramin, Xenopus
Show Abstract · Added August 26, 2019
Minichromosome maintenance protein 10 (Mcm10) is essential for DNA unwinding by the replisome during S phase. It is emerging as a promising anti-cancer target as MCM10 expression correlates with tumour progression and poor clinical outcomes. Here we used a competition-based fluorescence polarization (FP) high-throughput screening (HTS) strategy to identify compounds that inhibit Mcm10 from binding to DNA. Of the five active compounds identified, only the anti-parasitic agent suramin exhibited a dose-dependent decrease in replication products in an in vitro replication assay. Structure-activity relationship evaluation identified several suramin analogues that inhibited ssDNA binding by the human Mcm10 internal domain and full-length Xenopus Mcm10, including analogues that are selective for Mcm10 over human RPA. Binding of suramin analogues to Mcm10 was confirmed by surface plasmon resonance (SPR). SPR and FP affinity determinations were highly correlated, with a similar rank between affinity and potency for killing colon cancer cells. Suramin analogue NF157 had the highest human Mcm10 binding affinity (FP K 170 nM, SPR K 460 nM) and cell activity (IC 38 µM). Suramin and its analogues are the first identified inhibitors of Mcm10 and probably block DNA binding by mimicking the DNA sugar phosphate backbone due to their extended, polysulfated anionic structures.
0 Communities
2 Members
0 Resources
15 MeSH Terms
Human cytochrome P450 enzymes bind drugs and other substrates mainly through conformational-selection modes.
Guengerich FP, Wilkey CJ, Phan TTN
(2019) J Biol Chem 294: 10928-10941
MeSH Terms: Catalysis, Cytochrome P-450 CYP2D6, Cytochrome P-450 CYP2E1, Cytochrome P-450 CYP3A, Cytochrome P-450 Enzyme Inhibitors, Cytochrome P-450 Enzyme System, Humans, Kinetics, Lauric Acids, Ligands, Molecular Conformation, Oxidation-Reduction, Palmitic Acid, Protein Binding, Protein Conformation, Spiro Compounds, Substrate Specificity
Show Abstract · Added March 3, 2020
Cytochrome P450 (P450) enzymes are major catalysts involved in the oxidations of most drugs, steroids, carcinogens, fat-soluble vitamins, and natural products. The binding of substrates to some of the 57 human P450s and other mammalian P450s is more complex than a two-state system and has been proposed to involve mechanisms such as multiple ligand occupancy, induced-fit, and conformational-selection. Here, we used kinetic analysis of binding with multiple concentrations of substrates and computational modeling of these data to discern possible binding modes of several human P450s. We observed that P450 2D6 binds its ligand rolapitant in a mechanism involving conformational-selection. P450 4A11 bound the substrate lauric acid via conformational-selection, as did P450 2C8 with palmitic acid. Binding of the steroid progesterone to P450 21A2 was also best described by a conformational-selection model. Hexyl isonicotinate binding to P450 2E1 could be described by either a conformational-selection or an induced-fit model. Simulation of the binding of the ligands midazolam, bromocriptine, testosterone, and ketoconazole to P450 3A4 was consistent with an induced-fit or a conformational-selection model, but the concentration dependence of binding rates for varying both P450 3A4 and midazolam concentrations revealed discordance in the parameters, indicative of conformational-selection. Binding of the P450s 2C8, 2D6, 3A4, 4A11, and 21A2 was best described by conformational-selection, and P450 2E1 appeared to fit either mode. These findings highlight the complexity of human P450-substrate interactions and that conformational-selection is a dominant feature of many of these interactions.
© 2019 Guengerich et al.
0 Communities
1 Members
0 Resources
17 MeSH Terms
Displacement of WDR5 from Chromatin by a WIN Site Inhibitor with Picomolar Affinity.
Aho ER, Wang J, Gogliotti RD, Howard GC, Phan J, Acharya P, Macdonald JD, Cheng K, Lorey SL, Lu B, Wenzel S, Foshage AM, Alvarado J, Wang F, Shaw JG, Zhao B, Weissmiller AM, Thomas LR, Vakoc CR, Hall MD, Hiebert SW, Liu Q, Stauffer SR, Fesik SW, Tansey WP
(2019) Cell Rep 26: 2916-2928.e13
MeSH Terms: Binding Sites, Cell Line, Tumor, Chromatin, Enzyme Inhibitors, Female, HEK293 Cells, Humans, Intracellular Signaling Peptides and Proteins, Male, Protein Binding
Show Abstract · Added March 26, 2019
The chromatin-associated protein WDR5 is a promising target for pharmacological inhibition in cancer. Drug discovery efforts center on the blockade of the "WIN site" of WDR5, a well-defined pocket that is amenable to small molecule inhibition. Various cancer contexts have been proposed to be targets for WIN site inhibitors, but a lack of understanding of WDR5 target genes and of the primary effects of WIN site inhibitors hampers their utility. Here, by the discovery of potent WIN site inhibitors, we demonstrate that the WIN site links WDR5 to chromatin at a small cohort of loci, including a specific subset of ribosome protein genes. WIN site inhibitors rapidly displace WDR5 from chromatin and decrease the expression of associated genes, causing translational inhibition, nucleolar stress, and p53 induction. Our studies define a mode by which WDR5 engages chromatin and forecast that WIN site blockade could have utility against multiple cancer types.
Copyright © 2019 The Author(s). Published by Elsevier Inc. All rights reserved.
0 Communities
1 Members
0 Resources
10 MeSH Terms
Endogenous bradykinin and B1-B5 during angiotensin-converting enzyme inhibitor-associated angioedema.
Hubers SA, Kohm K, Wei S, Yu C, Nian H, Grabert R, Sexton DJ, Brown NJ
(2018) J Allergy Clin Immunol 142: 1636-1639.e5
MeSH Terms: Aged, Angioedema, Angiotensin-Converting Enzyme Inhibitors, Bradykinin, Enalapril, Female, Humans, Kininogen, High-Molecular-Weight, Lisinopril, Male, Middle Aged, Peptide Fragments, Quinapril
Added November 7, 2018
0 Communities
1 Members
0 Resources
13 MeSH Terms
amplification is a mechanism of acquired resistance to EGFR inhibitors identified by transposon mutagenesis and clinical genomics.
Fan PD, Narzisi G, Jayaprakash AD, Venturini E, Robine N, Smibert P, Germer S, Yu HA, Jordan EJ, Paik PK, Janjigian YY, Chaft JE, Wang L, Jungbluth AA, Middha S, Spraggon L, Qiao H, Lovly CM, Kris MG, Riely GJ, Politi K, Varmus H, Ladanyi M
(2018) Proc Natl Acad Sci U S A 115: E6030-E6038
MeSH Terms: Cell Line, Tumor, DNA Transposable Elements, Drug Resistance, Neoplasm, Enzyme Inhibitors, ErbB Receptors, Gene Amplification, Gene Expression Regulation, Neoplastic, Humans, Lung Neoplasms, Proto-Oncogene Proteins c-fyn, Proto-Oncogene Proteins c-yes, Proto-Oncogene Proteins pp60(c-src)
Show Abstract · Added September 10, 2020
In ∼30% of patients with -mutant lung adenocarcinomas whose disease progresses on EGFR inhibitors, the basis for acquired resistance remains unclear. We have integrated transposon mutagenesis screening in an -mutant cell line and clinical genomic sequencing in cases of acquired resistance to identify mechanisms of resistance to EGFR inhibitors. The most prominent candidate genes identified by insertions in or near the genes during the screen were , a gene whose amplification is known to mediate resistance to EGFR inhibitors, and the gene encoding the Src family kinase YES1. Cell clones with transposon insertions that activated expression of exhibited resistance to all three generations of EGFR inhibitors and sensitivity to pharmacologic and siRNA-mediated inhibition of Analysis of clinical genomic sequencing data from cases of acquired resistance to EGFR inhibitors revealed amplification of in five cases, four of which lacked any other known mechanisms of resistance. Preinhibitor samples, available for two of the five patients, lacked amplification. None of 136 postinhibitor samples had detectable amplification of other Src family kinases ( and ). amplification was also found in 2 of 17 samples from fusion-positive lung cancer patients who had progressed on ALK TKIs. Taken together, our findings identify acquired amplification of as a recurrent and targetable mechanism of resistance to EGFR inhibition in -mutant lung cancers and demonstrate the utility of transposon mutagenesis in discovering clinically relevant mechanisms of drug resistance.
Copyright © 2018 the Author(s). Published by PNAS.
0 Communities
1 Members
0 Resources
MeSH Terms
Excipients for the lyoprotection of MAPKAP kinase 2 inhibitory peptide nano-polyplexes.
Mukalel AJ, Evans BC, Kilchrist KV, Dailing EA, Burdette B, Cheung-Flynn J, Brophy CM, Duvall CL
(2018) J Control Release 282: 110-119
MeSH Terms: Cell Line, Drug Stability, Enzyme Inhibitors, Excipients, Freeze Drying, Humans, Intracellular Signaling Peptides and Proteins, Nanoparticles, Peptides, Protein-Serine-Threonine Kinases, Sucrose, Trehalose, Trisaccharides
Show Abstract · Added May 22, 2018
Herein, excipients are investigated to ameliorate the deleterious effects of lyophilization on peptide-polymer nano-polyplex (NP) morphology, cellular uptake, and bioactivity. The NPs are a previously-described platform technology for intracellular peptide delivery and are formulated from a cationic therapeutic peptide and the anionic, pH-responsive, endosomolytic polymer poly(propylacrylic acid) (PPAA). These NPs are effective when formulated and immediately used for delivery into cells and tissue, but they are not amenable to reconstitution following storage as a lyophilized powder due to aggregation. To develop a lyophilized NP format that facilitates longer-term storage and ease of use, MAPKAP kinase 2 inhibitory peptide-based NPs (MK2i-NPs) were prepared in the presence of a range of concentrations of the excipients sucrose, trehalose, and lactosucrose prior to lyophilization and storage. All excipients improved particle morphology post-lyophilization and significantly improved MK2i-NP uptake in human coronary artery smooth muscle cells relative to lyophilized NPs without excipient. In particular, MK2i-NPs lyophilized with 300 mM lactosucrose as an excipient demonstrated a 5.23 fold increase in cellular uptake (p < 0.001), a 2.52 fold increase in endosomal disruption (p < 0.05), and a 2.39 fold increase in ex vivo bioactivity (p < 0.01) compared to MK2i-NPs lyophilized without excipients. In sum, these data suggest that addition of excipients, particularly lactosucrose, maintains and even improves the uptake and therapeutic efficacy of peptide-polymer NPs post-lyophilization relative to freshly-made formulations. Thus, the use of excipients as lyoprotectants is a promising approach for the long-term storage of biotherapeutic NPs and poises this NP platform for clinical translation.
Copyright © 2018 Elsevier B.V. All rights reserved.
0 Communities
2 Members
0 Resources
13 MeSH Terms
Angiotensin receptor blocker vs ACE inhibitor effects on HDL functionality in patients on maintenance hemodialysis.
Kaseda R, Tsuchida Y, Gamboa JL, Zhong J, Zhang L, Yang H, Dikalova A, Bian A, Davies S, Fogo AF, Linton MF, Brown NJ, Ikizler TA, Kon V
(2018) Nutr Metab Cardiovasc Dis 28: 582-591
MeSH Terms: Adult, Angiotensin II Type 1 Receptor Blockers, Angiotensin-Converting Enzyme Inhibitors, Biomarkers, Cholesterol, HDL, Double-Blind Method, Female, Humans, Inflammation Mediators, Kidney Failure, Chronic, Male, Middle Aged, Oxidative Stress, Ramipril, Renal Dialysis, Tennessee, Time Factors, Treatment Outcome, Valsartan
Show Abstract · Added August 3, 2018
BACKGROUND AND AIMS - Angiotensin receptor blockers (ARB) and angiotensin converting enzyme inhibitors (ACEI) reduce cardiovascular events in the general population. Maintenance hemodialysis (MHD) patients are at high cardiovascular risk but few studies have directly addressed the comparative efficacy of these drugs. MHD disrupts the normally atheroprotective actions of high density lipoprotein (HDL), therefore, we compared ACEI or ARB treatment on HDL functions in MHD.
METHODS AND RESULTS - HDL was isolated at the starting point (pre) and 3-6 months later (post) in 30 MHD randomly assigned to placebo, ramipril or valsartan. Outcomes included cholesterol efflux, inflammatory cytokine response, effects on Toll-like receptors (TLR), superoxide production, methylarginine and serum amyloid A (SAA) levels. HDL from ARB- or ACEI-treated subjects was more effective in maintaining efflux than HDL of placebo. HDL from ARB- or ACEI-treated subjects but not placebo lessened cellular superoxide production. In contrast, neither ARB nor ACEI improved HDL anti-inflammatory effect. Indeed, HDL of ACEI-treated subjects potentiated the cytokine responses in association with activation of TLR but did not alter the HDL content of methylarginines or SAA.
CONCLUSION - Both ACEI and ARB stabilized HDL cholesterol acceptor function and sustained cellular anti-oxidative effects but not anti-inflammatory effects, and ACEI-treatment instead amplified the HDL inflammatory response. The findings reveal possible utility of antagonizing angiotensin actions in MDH and suggest a possible mechanism for superiority of ARB vs ACEI in the setting of advanced kidney disease.
Copyright © 2018 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.
1 Communities
3 Members
0 Resources
19 MeSH Terms
The Vasculature in Prediabetes.
Wasserman DH, Wang TJ, Brown NJ
(2018) Circ Res 122: 1135-1150
MeSH Terms: Angiotensin-Converting Enzyme Inhibitors, Animals, Blood Vessels, Cardiovascular Diseases, Combined Modality Therapy, Diabetes Mellitus, Type 2, Diet, Reducing, Disease Progression, Endothelium, Vascular, Extracellular Matrix, Fatty Acids, Nonesterified, Fibrinolysis, Glucose, Humans, Hyperglycemia, Hypoglycemic Agents, Inflammation, Insulin Resistance, Life Style, Metabolic Syndrome, Mice, MicroRNAs, Microcirculation, Muscle, Skeletal, Obesity, Prediabetic State, Risk, Weight Loss
Show Abstract · Added March 26, 2019
The frequency of prediabetes is increasing as the prevalence of obesity rises worldwide. In prediabetes, hyperglycemia, insulin resistance, and inflammation and metabolic derangements associated with concomitant obesity cause endothelial vasodilator and fibrinolytic dysfunction, leading to increased risk of cardiovascular and renal disease. Importantly, the microvasculature affects insulin sensitivity by affecting the delivery of insulin and glucose to skeletal muscle; thus, endothelial dysfunction and extracellular matrix remodeling promote the progression from prediabetes to diabetes mellitus. Weight loss is the mainstay of treatment in prediabetes, but therapies that improved endothelial function and vasodilation may not only prevent cardiovascular disease but also slow progression to diabetes mellitus.
© 2018 American Heart Association, Inc.
1 Communities
0 Members
0 Resources
28 MeSH Terms
Inhibition of the -Subunit of Phosphoinositide 3-Kinase in Heart Increases Late Sodium Current and Is Arrhythmogenic.
Yang T, Meoli DF, Moslehi J, Roden DM
(2018) J Pharmacol Exp Ther 365: 460-466
MeSH Terms: Action Potentials, Animals, Arrhythmias, Cardiac, CHO Cells, Cricetulus, Dose-Response Relationship, Drug, Electrophysiological Phenomena, Enzyme Inhibitors, Female, Heart, Mice, Mice, Inbred C57BL, Myocytes, Cardiac, Phosphoinositide-3 Kinase Inhibitors, Sodium
Show Abstract · Added April 22, 2018
Although inhibition of phosphoinositide 3-kinase (PI3K) is an emerging strategy in cancer therapy, we and others have reported that this action can also contribute to drug-induced QT prolongation and arrhythmias by increasing cardiac late sodium current (I). Previous studies in mice implicate the PI3K- isoform in arrhythmia susceptibility. Here, we have determined the effects of new anticancer drugs targeting specific PI3K isoforms on I and action potentials (APs) in mouse cardiomyocytes and Chinese hamster ovary cells (CHO). Chronic exposure (10-100 nM; 5-48 hours) to PI3K--specific subunit inhibitors BYL710 (alpelisib) and A66 and a pan-PI3K inhibitor (BKM120) increased I in -transfected CHO cells and mouse cardiomyocytes. The specific inhibitors (10-100 nM for 5 hours) markedly prolonged APs and generated triggered activity in mouse cardiomyocytes (9/12) but not in controls (0/6), and BKM120 caused similar effects (3/6). The inclusion of water-soluble PIP3, a downstream effector of the PI3K signaling pathway, in the pipette solution reversed these arrhythmogenic effects. By contrast, inhibition of PI3K-, -, and - isoforms did not alter I or APs. We conclude that inhibition of cardiac PI3K- is arrhythmogenic by increasing I and this effect is not seen with inhibition of other PI3K isoforms. These results highlight a mechanism underlying potential cardiotoxicity of PI3K- inhibitors.
Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.
0 Communities
2 Members
0 Resources
15 MeSH Terms