RESUMEN
Arylalkylamine N-acetyltransferase (AANAT) catalyzes the rate-limiting step in melatonin synthesis and is a potential target for disorders involving melatonin overproduction, such as seasonal affective disorder. Previously described AANAT inhibitor bromoacetyltryptamine (BAT) and benzothiophenes analogs were reported to react with CoASH to form potent bisubstrate inhibitors through AANAT's alkyltransferase function, which is secondary to its role as an acetyltransferase. We replaced the bromoacetyl group in BAT with various Michael acceptors to mitigate possible off-target activity of its bromoacetyl group. Additionally, we modified the length of the carbon linker between the Michael acceptor and indole bicycle of tryptamine to determine its effect on potency. An AANAT enzymatic assay showed a two-carbon linker present in BAT was optimal, while none of the new warheads had activity. Kinetic analysis indicated that these Michael acceptors reacted with CoASH much slower than BAT and not within the timeframe of our enzymatic assay. Additionally, we confirmed earlier reports that the acetyltransferase function of AANAT follows an ordered bi bi mechanism in which AcCoA binds before serotonin. In contrast, BAT's alkyltransferase kinetics revealed a bi uni mechanism in which BAT binds to AANAT before CoASH. Our model combines both functions of AANAT into one kinetic mechanism.
Asunto(s)
N-Acetiltransferasa de Arilalquilamina , Triptaminas , Triptaminas/química , Triptaminas/metabolismo , Triptaminas/síntesis química , Cinética , N-Acetiltransferasa de Arilalquilamina/metabolismo , N-Acetiltransferasa de Arilalquilamina/química , Humanos , Relación Estructura-Actividad , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Inhibidores Enzimáticos/síntesis química , Estructura Molecular , Relación Dosis-Respuesta a DrogaRESUMEN
The human L-type amino acid transporter 1 (LAT1; SLC7A5) is a membrane transporter of amino acids, thyroid hormones, and drugs such as the Parkinson's disease drug levodopa (L-Dopa). LAT1 is found in the blood-brain barrier, testis, bone marrow, and placenta, and its dysregulation has been associated with various neurological diseases, such as autism and epilepsy, as well as cancer. In this study, we combine metainference molecular dynamics simulations, molecular docking, and experimental testing, to characterize LAT1-inhibitor interactions. We first conducted a series of molecular docking experiments to identify the most relevant interactions between LAT1's substrate-binding site and ligands, including both inhibitors and substrates. We then performed metainference molecular dynamics simulations using cryoelectron microscopy structures in different conformations of LAT1 with the electron density map as a spatial restraint, to explore the inherent heterogeneity in the structures. We analyzed the LAT1 substrate-binding site to map important LAT1-ligand interactions as well as newly described druggable pockets. Finally, this analysis guided the discovery of previously unknown LAT1 ligands using virtual screening and cellular uptake experiments. Our results improve our understanding of LAT1-inhibitor recognition, providing a framework for rational design of future lead compounds targeting this key drug target.
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Sistemas de Transporte de Aminoácidos , Humanos , Simulación del Acoplamiento Molecular , Microscopía por CrioelectrónRESUMEN
A series of 1,2,3-triazole analogs of the amino acids l-histidine and l-tryptophan were modeled, synthesized and tested for l-type amino acid transporter 1 (LAT1; SLC7A5) activity to guide the design of amino acid-drug conjugates (prodrugs). These triazoles were conveniently prepared by the highly convergent Huisgen 1,3-dipolar cycloaddition (Click Chemistry). Despite comparable predicted binding modes, triazoles generally demonstrated reduced cell uptake and LAT1 binding potency relative to their natural amino acid counterparts. The structure-activity relationship (SAR) data for these triazoles has important ramifications for treating cancer and brain disorders using amino acid prodrugs or LAT1 inhibitors.
Asunto(s)
Antineoplásicos/farmacología , Histidina/farmacología , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Neoplasias/tratamiento farmacológico , Profármacos/farmacología , Triazoles/farmacología , Triptófano/farmacología , Antineoplásicos/síntesis química , Antineoplásicos/química , Encefalopatías/tratamiento farmacológico , Encefalopatías/metabolismo , Química Clic , Relación Dosis-Respuesta a Droga , Histidina/química , Humanos , Estructura Molecular , Neoplasias/metabolismo , Profármacos/síntesis química , Profármacos/química , Relación Estructura-Actividad , Triazoles/síntesis química , Triazoles/química , Triptófano/químicaRESUMEN
Previous research suggests that the endocrine disrupting chemical tolylfluanid (TF) may promote metabolic dysfunction and insulin resistance in humans. The potential impact of TF on skeletal muscle metabolism has yet to be fully investigated. The purpose of this study was to determine whether TF can promote insulin resistance and metabolic dysfunction in mammalian skeletal muscle cells. C2C12 murine skeletal myotubes were exposed to 1â¯ppmâ¯TF for 24â¯h. To examine the potential effect of cellular fatty acid levels on TF-dependent regulation of mitochondrial metabolism and insulin signaling, we treated skeletal myotubes with 0.25â¯mM or 1.0â¯mM oleic acid (OA) during TF exposure trials. Tolylfluanid (1-10â¯ppm) reduced lipid accumulation by approximately 20% in 0.25 and 1.0â¯mM OA treated cells. The addition of 0.25â¯mM OA completely inhibited the TF-dependent reduction in maximal mitochondrial oxygen consumption rate (OCR) while 1.0â¯mM OA exacerbated the TF-dependent reduction in mitochondrial OCR. Exposing skeletal myotubes to 1â¯ppmâ¯TF promoted an 80% reduction in mitochondrial membrane potential, which was completely inhibited by 0.25â¯mM OA and partially inhibited by1.0â¯mM OA. The addition of 0.25â¯mM OA promoted a TF-dependent increase in insulin-dependent P-Akt (Ser473). In contrast, the addition of 1.0â¯mM OA promoted a significant reduction in insulin-dependent P-Akt (Ser473). Further, the addition of 1â¯ppmâ¯TF significantly reduced insulin-dependent mTORC1 activity regardless of OA concentration. Finally, TF significantly reduced insulin-dependent protein synthesis in the 1â¯mM OA treated cells only. Our results demonstrate that the effect of 1â¯ppmâ¯TF on mitochondrial function and insulin-dependent protein synthesis in skeletal myotubes was largely dependent upon cellular fatty acid levels.
Asunto(s)
Ácidos Grasos/farmacología , Resistencia a la Insulina , Enfermedades Mitocondriales/inducido químicamente , Fibras Musculares Esqueléticas/patología , Sulfonamidas/farmacología , Toluidinas/farmacología , Animales , Línea Celular , Disruptores Endocrinos/farmacología , Insulina/farmacología , Potencial de la Membrana Mitocondrial/efectos de los fármacos , Ratones , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/citología , Ácido Oléico/farmacología , Inhibidores de la Síntesis de la ProteínaRESUMEN
The transporter protein Large-neutral Amino Acid Transporter 1 (LAT-1, SLC7A5) is responsible for transporting amino acids such as tyrosine and phenylalanine as well as thyroid hormones, and it has been exploited as a drug delivery mechanism. Recently its role in cancer has become increasingly appreciated, as it has been found to be up-regulated in many different tumor types, and its expression levels have been correlated with prognosis. Substitution at the meta position of aromatic amino acids has been reported to increase affinity for LAT-1; however, the SAR for this position has not previously been explored. Guided by newly refined computational models of the binding site, we hypothesized that groups capable of filling a hydrophobic pocket would increase binding to LAT-1, resulting in improved substrates relative to parent amino acid. Tyrosine and phenylalanine analogs substituted at the meta position with halogens, alkyl and aryl groups were synthesized and tested in cis-inhibition and trans-stimulation cell assays to determine activity. Contrary to our initial hypothesis we found that lipophilicity was correlated with diminished substrate activity and increased inhibition of the transporter. The synthesis and SAR of meta-substituted phenylalanine and tyrosine analogs is described.
Asunto(s)
Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Fenilalanina/farmacología , Tirosina/farmacología , Relación Dosis-Respuesta a Droga , Humanos , Modelos Moleculares , Estructura Molecular , Fenilalanina/síntesis química , Fenilalanina/química , Relación Estructura-Actividad , Tirosina/análogos & derivados , Tirosina/químicaRESUMEN
Large neutral amino acid transporter 1 (LAT1) is a solute carrier protein located primarily in the blood-brain barrier (BBB) that offers the potential to deliver drugs to the brain. It is also up-regulated in cancer cells, as part of a tumor's increased metabolic demands. Previously, amino acid prodrugs have been shown to be transported by LAT1. Carboxylic acid bioisosteres may afford prodrugs with an altered physicochemical and pharmacokinetic profile than those derived from natural amino acids, allowing for higher brain or tumor levels of drug and/or lower toxicity. The effect of replacing phenylalanine's carboxylic acid with a tetrazole, acylsulfonamide and hydroxamic acid (HA) bioisostere was examined. Compounds were tested for their ability to be LAT1 substrates using both cis-inhibition and trans-stimulation cell assays. As HA-Phe demonstrated weak substrate activity, its structure-activity relationship (SAR) was further explored by synthesis and testing of HA derivatives of other LAT1 amino acid substrates (i.e., Tyr, Leu, Ile, and Met). The potential for a false positive in the trans-stimulation assay caused by parent amino acid was evaluated by conducting compound stability experiments for both HA-Leu and the corresponding methyl ester derivative. We concluded that HA's are transported by LAT1. In addition, our results lend support to a recent account that amino acid esters are LAT1 substrates, and that hydrogen bonding may be as important as charge for interaction with the transporter binding site.
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Ácidos Carboxílicos/metabolismo , Ácidos Hidroxámicos/metabolismo , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Barrera Hematoencefálica , Ácidos Carboxílicos/química , Cromatografía Líquida de Alta Presión , Células HEK293 , Humanos , Ácidos Hidroxámicos/química , Espectroscopía de Resonancia Magnética , Relación Estructura-ActividadRESUMEN
Application of safety lead optimization screening strategies during the early stage of drug discovery led to the identification of a series of CNS-active small molecule inhibitors with opioid off-target effects, as evidenced by potent agonistic activity in functional cell-based assays for mu (MOP), kappa (KOP) and delta (DOP) opioid receptors. The translation of these effects was confirmed in vivo with the following observations: hypoactivity and decreased fecal production in rats (characteristic of MOP agonism); increased urine production in rats (characteristic of KOP agonism); and decreased intestinal transit time in mice, which was partially blocked by the MOP antagonist naloxone, demonstrating that the in vivo effects were specific for MOP. Based on the confirmation of in vitro-in vivo translatability, an in vitro screening strategy was implemented that resulted in the identification of an optimized backup molecule, devoid of in vivo off-target opioid effects. In addition, in silico modeling by docking of the various molecules to the opioid receptors allowed the identification of the structural drivers of these off-target effects, which can be applied to future chemical-design criteria. Thus, implementation of the safety lead optimization strategy described in this article demonstrates the utility and impact of such approaches on risk mitigation and identification of lead small molecules with improved safety profiles.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Diseño de Fármacos , Inhibidores de Proteasas/farmacología , Receptores Opioides/agonistas , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Sitios de Unión , Células CHO , Cricetulus , Defecación/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Femenino , Tránsito Gastrointestinal/efectos de los fármacos , Cobayas , Íleon/efectos de los fármacos , Íleon/metabolismo , Técnicas In Vitro , Ratones , Simulación del Acoplamiento Molecular , Antagonistas de Narcóticos/farmacología , Inhibidores de Proteasas/química , Inhibidores de Proteasas/metabolismo , Inhibidores de Proteasas/toxicidad , Unión Proteica , Conformación Proteica , Ratas Sprague-Dawley , Receptores Opioides/genética , Receptores Opioides/metabolismo , Relación Estructura-Actividad , Factores de Tiempo , Transfección , Micción/efectos de los fármacosRESUMEN
The development of 1,3,4,4a,5,10a-hexahydropyrano[3,4-b]chromene analogs as BACE1 inhibitors is described. Introduction of the spirocyclic pyranochromene scaffold yielded several advantages over previous generation cores, including increased potency, reduced efflux, and reduced CYP2D6 inhibition. Compound 13 (BACE1 IC50=110 nM) demonstrated a reduction in CSF Aß in wild type rats after a single dose.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Benzopiranos/farmacología , Oxazoles/farmacología , Inhibidores de Proteasas/farmacología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/líquido cefalorraquídeo , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Benzopiranos/síntesis química , Benzopiranos/química , Relación Dosis-Respuesta a Droga , Humanos , Microsomas Hepáticos/enzimología , Conformación Molecular , Oxazoles/síntesis química , Oxazoles/química , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/química , Ratas , Relación Estructura-Actividad , PorcinosRESUMEN
The discovery and optimization of a series of tetrahydropyridopyrimidine based extracellular signal-regulated kinase (Erks) inhibitors discovered via HTS and structure based drug design is reported. The compounds demonstrate potent and selective inhibition of Erk2 and knockdown of phospho-RSK levels in HepG2 cells and tumor xenografts.
Asunto(s)
Descubrimiento de Drogas , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Piridinas/síntesis química , Piridinas/farmacología , Pirimidinas/síntesis química , Pirimidinas/farmacología , Línea Celular Tumoral , Técnicas Químicas Combinatorias , Cristalografía por Rayos X , Activación Enzimática/efectos de los fármacos , Células Hep G2 , Humanos , Concentración 50 Inhibidora , Estructura Molecular , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Piridinas/química , Pirimidinas/química , Bibliotecas de Moléculas Pequeñas , Relación Estructura-ActividadRESUMEN
BACKGROUND: The conventional sequence when using supraglottic airway devices is insertion, cuff inflation and fixation. Our hypothesis was that a tighter fit of the cuff and tip could be achieved with a consequently lower incidence of air leak, better separation of gastrointestinal and respiratory tracts and less airway morbidity if the device were first affixed and the cuff then inflated. METHODS: Our clinical review board approved the study (public registry number DRKS00003174). An LMA Supreme® was inserted into 184 patients undergoing lower limb arthroscopy in propofol-remifentanil anaesthesia who were randomly assigned to either the control (inflation then fixation; n = 92) or study group (fixation then inflation; n = 92). The cuff was inflated to 60 cmH2O. The patients' lungs were ventilated in pressure-controlled mode with 5 cmH2O PEEP, Pmax to give 6 ml kg-1 tidal volume, and respiratory rate adjusted to end-tidal CO2 of 4.8 and 5.6 kPa. Correct cuff and tip position were determined by leak detection, capnometry trace, oropharyngeal leak pressure, suprasternal notch test, and lube-tube test. Bowl and cuff position and the presence of glottic narrowing were assessed by fiberscopic examination. Postoperative dysphagia, hoarseness and sore throat were assessed with a questionnaire. Ventilatory impairment was defined as a tidal volume < 6 ml kg-1 with Pmax at oropharyngeal leak pressure, glottic narrowing was defined as an angle between the vocal cords under 16 degrees. RESULTS: The incidence of incorrect device position (18% vs. 21%), failed ventilation (10% vs. 9%), leak pressure (24.8 vs. 25.2 cmH2O, p = 0.63), failed lube-tube test (16.3% vs. 17.6%) and glottic narrowing (19.3% vs. 14.1%, p = 0.35) was similar in both groups (control vs. study, resp.). When glottic narrowing occurred, it was more frequently associated with ventilatory impairment in the control group (77% vs. 39%; p = 0.04). Airway morbidity was more common in the control group (33% vs. 19%; p < 0.05). CONCLUSIONS: Altering the sequence of cuff inflation and device fixation does not affect device position, oropharyngeal leak pressures or separation of gastrointestinal and respiratory tracts. It reduces the incidence of glottic narrowing with impaired ventilation and also perioperative airway morbidity.
Asunto(s)
Anestesia General/métodos , Máscaras Laríngeas , Laringoscopios , Laringoscopía/métodos , Ventilación Pulmonar/fisiología , Adulto , Anestesia General/instrumentación , Diseño de Equipo/instrumentación , Diseño de Equipo/normas , Femenino , Glotis/anatomía & histología , Glotis/fisiología , Humanos , Máscaras Laríngeas/normas , Laringoscopios/normas , Laringoscopía/instrumentación , Masculino , Persona de Mediana Edad , Estudios ProspectivosRESUMEN
Transforaminal lumbar interbody fusions (TLIFs) are performed for various lumbar spine pathologies. Posterior migration of an interbody cage is a complication that may result in neurologic injury and require reoperation. Sparse information exists regarding the safety and efficacy of a transdural approach for cage retrieval. We describe a surgical technique, in which centrally retropulsed cages were safely retrieved transdurally. A patient with prior L3-S1 posterior lumbar fusion and L4-S1 TLIFs presented with radiculopathy and weakness in dorsiflexion. Imaging revealed posterior central migration of TLIF cages causing compression of the traversing L5 nerve root. Cages were removed transdurally; the correction was performed with an all-posterior T10-pelvis fusion. Aside from temporary weakness in right-sided dorsiflexion, the patient experienced complete resolution in their radiculopathy and strength returned to its presurgical state by 3 months. The transdural approach for interbody removal can be safely performed and should be a tool in the spine surgeon's armamentarium.
RESUMEN
Circadian rhythm (CR) dysregulation negatively impacts health and contributes to mental disorders. The role of melatonin, a hormone intricately linked to CR, is still a subject of active study. The enzyme arylalkylamine N-acetyltransferase (AANAT) is responsible for melatonin synthesis, and it is a potential target for disorders that involve abnormally high melatonin levels, such as seasonal affective disorder (SAD). Current AANAT inhibitors suffer from poor cell permeability, selectivity, and/or potency. To address the latter, we have employed an X-ray crystal-based model to guide the modification of a previously described AANAT inhibitor, containing a rhodanine-indolinone core. We made various structural modifications to the core structure, including testing the importance of a carboxylic acid group thought to bind in the CoA site, and we evaluated these changes using MD simulations in conjunction with enzymatic assay data. Additionally, we tested three AANAT inhibitors in a zebrafish locomotion model to determine their effects inâ vivo. Key discoveries were that potency could be modestly improved by replacing a 5-carbon alkyl chain with rings and that the central rhodanine ring could be replaced by other heterocycles and maintain potency.
Asunto(s)
Melatonina , Rodanina , Animales , Humanos , Melatonina/metabolismo , Acetiltransferasas , Rodanina/farmacología , Pez Cebra , N-Acetiltransferasa de Arilalquilamina/metabolismoRESUMEN
This study was conducted to determine the pharmacokinetics (PK) and pharmacodynamics (PD) of two novel inhibitors of ß-site amyloid precursor protein (APP)-cleaving enzyme (BACE1), GNE-629 [(4S,4a'S,10a'S)-2-amino-8'-(2-fluoropyridin-3-yl)-1-methyl-3',4',4a',10a'-tetrahydro-1'H-spiro[imidazole-4,10'-pyrano[4,3-b]chromen]-5(1H)-one] and GNE-892 [(R)-2-amino-1,3',3'-trimethyl-7'-(pyrimidin-5-yl)-3',4'-dihydro-2'H-spiro[imidazole-4,1'-naphthalen]-5(1H)-one], and to develop a PK-PD model to predict in vivo effects based solely on in vitro activity and PK. GNE-629 and GNE-892 concentrations and PD biomarkers including amyloid ß (Aß) in the plasma and cerebrospinal fluid (CSF), and secreted APPß (sAPPß) and secreted APPα (sAPPα) in the CSF were measured after a single oral administration of GNE-629 (100 mg/kg) or GNE-892 (30 or 100 mg/kg) in cynomolgus monkeys. A mechanistic PK-PD model was developed to simultaneously characterize the plasma Aß and CSF Aß, sAPPα, and sAPPß using GNE-629 in vivo data. This model was used to predict the in vivo effects of GNE-892 after adjustments based on differences in in vitro cellular activity and PK. The PK-PD model estimated GNE-629 CSF and free plasma IC50 of 0.0033 µM and 0.065 µM, respectively. These differences in CSF and free plasma IC50 suggest that different mechanisms are involved in Aß formation in these two compartments. The predicted in vivo effects for GNE-892 using the PK-PD model were consistent with the observed data. In conclusion, a PK-PD model was developed to mechanistically describe the effects of BACE1 inhibition on Aß, sAPPß, and sAPPα in the CSF, and Aß in the plasma. This model can be used to prospectively predict in vivo effects of new BACE1 inhibitors using just their in vitro activity and PK data.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Precursor de Proteína beta-Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Imidazoles/farmacología , Compuestos de Espiro/farmacología , Secuencia de Aminoácidos , Animales , Cromatografía Liquida , Perros , Células HEK293 , Humanos , Macaca fascicularis , Modelos Biológicos , Datos de Secuencia Molecular , Pirimidinas/farmacología , Espectrometría de Masas en Tándem , Tiazinas/farmacologíaRESUMEN
We report the synthesis and cytotoxicity in MCF-7 and MDA-MB-231 breast cancer cells of novel 1,2,3- and 1,2,4-triazolyl analogs of ribavirin. We modified ribavirin's carboxamide moiety to test the effects of lipophilic groups. 1-ß-D-Ribofuranosyl-1H-1,2,3-triazoles were prepared using Click Chemistry, whereas an unprecedented application of a prior 1,2,4-triazole ring synthesis was used for 1-ß-D-ribofuranosyl-1H-1,2,4-triazole analogs. Though cytotoxicity was mediocre and there was no correlation with lipophilicity, we discovered that a structurally similar concentrative nucleoside transporter 2 (CNT2) inhibitor was modestly cytotoxic (MCF-7 IC50 of 42 µM). These syntheses could be used to efficiently investigate variation in the nucleobase.
Asunto(s)
Antineoplásicos , Neoplasias de la Mama , Humanos , Femenino , Ribavirina , Células MCF-7 , Amidas , Antineoplásicos/farmacología , Triazoles , Relación Estructura-ActividadRESUMEN
Thermophysical properties of organic compounds are used in countless scientific, engineering, and industrial settings in developing theories, designing new systems and devices, analyzing costs and risks, and improving existing infrastructure. Often, due to costs, safety, prior interest, or procedural difficulties, experimental values for desired properties are not available and must be predicted. The literature is filled with prediction techniques, but even the best traditional methods have significant errors compared to what is possible considering experimental uncertainty. Recently, machine learning and artificial intelligence techniques have been applied to the property prediction problem, but the examples to date do not extrapolate well outside the data set used for training the model. This work demonstrates a solution to this problem by combining chemistry and physics when training the model and builds upon prior traditional and machine learning methods. Two case studies are presented. The first is for parachor which is used for surface tension prediction. Surface tensions are needed to design distillation columns, adsorption processes, gas-liquid reactors, liquid-liquid extractors, improve oil reservoir recovery, and undertake environmental impact studies or remediation actions. A set of 277 compounds is divided into training, validation, and test sets, and a multilayered physics-informed neural network (PINN) is developed. The results demonstrate that better extrapolation by deep learning models can be developed by adding in physics-based constraints. Second, a set of 1600 compounds is utilized for training, validating, and testing a PINN to improve normal boiling point predictions based on group contribution methods and physics-based constraints. The results show that the PINN performs better than any other method with a normal boiling point mean absolute error of 6.95 °C on training and 11.2 °C on test data. Key observations are that (1) a balanced split by compound type is important to have representative compound families in each of the train, validation, and test sets and (2) constraining group contributions being positive improves predictions on the test set. While this work demonstrates improvements for only surface tension and normal boiling point, the results offer significant hope that PINNs can improve prediction of other relevant thermophysical properties over existing approaches.
RESUMEN
The l-type amino acid transporter 1 (LAT1, SLC7A5) imports dietary amino acids and amino acid drugs (e. g., l-DOPA) into the brain, and plays a role in cancer metabolism. Though there have been numerous reports of LAT1-targeted amino acid-drug conjugates (prodrugs), identifying the structural determinants to enhance substrate activity has been challenging. In this work, we investigated the position and orientation of a carbonyl group in linking hydrophobic moieties including the anti-inflammatory drug ketoprofen to l-tyrosine and l-phenylalanine. We found that esters of meta-carboxyl l-phenylalanine had better LAT1 transport rates than the corresponding acylated l-tyrosine analogues. However, as the size of the hydrophobic moiety increased, we observed a decrease in LAT1 transport rate with a concomitant increase in potency of inhibition. Our results have important implications for designing amino acid prodrugs that target LAT1 at the blood-brain barrier or on cancer cells.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Encéfalo/efectos de los fármacos , Cetoprofeno/farmacología , Transportador de Aminoácidos Neutros Grandes 1/metabolismo , Profármacos/farmacología , Antiinflamatorios no Esteroideos/química , Encéfalo/metabolismo , Relación Dosis-Respuesta a Droga , Humanos , Cetoprofeno/química , Estructura Molecular , Tamaño de la Partícula , Profármacos/química , Relación Estructura-ActividadRESUMEN
Inhibition of the thiamine-utilizing enzyme transketolase (TK) has been linked with diminished tumor cell proliferation. Most thiamine antagonists have a permanent positive charge on the B-ring, and it has been suggested that this charge is required for diphosphorylation by thiamine pyrophosphokinase (TPPK) and binding to TK. We sought to make neutral thiazolium replacements that would be substrates for TPPK, while not necessarily needing thiamine transporters (ThTr1 and ThTr2) for cell penetration. The synthesis, SAR, and structure-based rationale for highly potent non-thiazolium TK antagonists are presented.
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Inhibidores Enzimáticos/farmacología , Tiamina/análogos & derivados , Transcetolasa/antagonistas & inhibidores , Animales , Catálisis , Línea Celular , Cristalografía por Rayos X , Inhibidores Enzimáticos/química , Humanos , Ratones , Conformación Proteica , Relación Estructura-Actividad , Tiamina/química , Tiamina/farmacologíaRESUMEN
Transketolase, a key enzyme in the pentose phosphate pathway, has been suggested as a target for inhibition in the treatment of cancer. Compound 5a ('N3'-pyridyl thiamine'; 3-(6-methyl-2-amino-pyridin-3-ylmethyl)-5-(2-hydroxy-ethyl)-4-methyl-thiazol-3-ium chloride hydrochloride), an analog of the transketolase cofactor thiamine, is a potent transketolase inhibitor but suffers from poor pharmacokinetics due to high clearance and C(max) linked toxicity. An efficient way of improving the pharmacokinetic profile of 5a is to prepare oxidized prodrugs which are slowly reduced in vivo yielding longer, sustained blood levels of the drug. The synthesis of such prodrugs and their evaluation in rodent models is reported.
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Inhibidores Enzimáticos/farmacología , Profármacos/farmacología , Tiamina/análogos & derivados , Transcetolasa/antagonistas & inhibidores , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacocinética , Estructura Molecular , Profármacos/química , Profármacos/farmacocinética , Tiamina/química , Tiamina/farmacocinética , Tiamina/farmacologíaRESUMEN
Tumor cells extensively utilize the pentose phosphate pathway for the synthesis of ribose. Transketolase is a key enzyme in this pathway and has been suggested as a target for inhibition in the treatment of cancer. In a pharmacodynamic study, nude mice with xenografted HCT-116 tumors were dosed with 1 ('N3'-pyridyl thiamine'; 3-(6-methyl-2-amino-pyridin-3-ylmethyl)-5-(2-hydroxy-ethyl)-4-methyl-thiazol-3-ium chloride hydrochloride), an analog of thiamine, the co-factor of transketolase. Transketolase activity was almost completely suppressed in blood, spleen, and tumor cells, but there was little effect on the activity of the other thiamine-utilizing enzymes alpha-ketoglutarate dehydrogenase or glucose-6-phosphate dehydrogenase. Synthesis and SAR of transketolase inhibitors is described.
Asunto(s)
Neoplasias del Colon/tratamiento farmacológico , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , Tiamina/análogos & derivados , Tiamina/antagonistas & inhibidores , Transcetolasa/antagonistas & inhibidores , Animales , Neoplasias del Colon/enzimología , Cristalografía por Rayos X , Glucosafosfato Deshidrogenasa/metabolismo , Humanos , Técnicas In Vitro , Complejo Cetoglutarato Deshidrogenasa/metabolismo , Espectroscopía de Resonancia Magnética , Ratones , Ratones Desnudos , Estructura Molecular , Oxitiamina/antagonistas & inhibidores , Fosforilación/efectos de los fármacos , Bazo/efectos de los fármacos , Bazo/enzimología , Relación Estructura-Actividad , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
The L-type amino acid transporter 1 (LAT1, SLC7A5) transports essential amino acids across the blood-brain barrier (BBB) and into cancer cells. To utilize LAT1 for drug delivery, potent amino acid promoieties are desired, as prodrugs must compete with millimolar concentrations of endogenous amino acids. To better understand ligand-transporter interactions that could improve potency, we developed structural LAT1 models to guide the design of substituted analogues of phenylalanine and histidine. Furthermore, we evaluated the structure-activity relationship (SAR) for both enantiomers of naturally occurring LAT1 substrates. Analogues were tested in cis-inhibition and trans-stimulation cell assays to determine potency and uptake rate. Surprisingly, LAT1 can transport amino acid-like substrates with wide-ranging polarities including those containing ionizable substituents. Additionally, the rate of LAT1 transport was generally nonstereoselective even though enantiomers likely exhibit different binding modes. Our findings have broad implications to the development of new treatments for brain disorders and cancer.