Potent Protein Tyrosine Phosphatase 1B Research Articles

Stearic Acid Serves as a Potent Inhibitor of Protein Tyrosine Phosphatase 1B

Background/Aims: Free fatty acids (FFAs) are implicated in diverse signal transduction pathways. The present study investigated the effects of the saturated FFA stearic acid on protein tyrosine phosphatase 1B (PTP1B) activity, Akt activity, and glucose uptake into cells relevant to insulin signal. Methods: PTP1B activity was assayed under the cell-free conditions. Phosphorylation of insulin receptor and Akt and glucose uptake into cells were monitored in differentiated 3T3-L1-GLUT4myc adipocytes. Results: In the cell-free PTP1B assay, stearic acid suppressed PTP1B activity in a concentration (1-30 µM)-dependent manner. For 3T3-L1-GLUT4myc adipocytes insulin phosphorylated insulin receptor at Tyr1185 and Akt at Thr308 and Ser473 in a concentration (100 fM-100 nM)-dependent manner and stimulated glucose uptake into cells in a concentration (0.1-100 nM)-dependent manner. Stearic acid (30 µM) significantly increased insulin-induced phosphorylation of insulin receptor at Tyr1185, but insulin-induced phosphorylation of Akt was not significantly enhanced. Stearic acid (30 µM) by itself promoted glucose uptake into adipocytes. Conclusion: The results of the present study indicate that stearic acid serves as a potent PTP1B inhibitor, possibly causing an enhancement in the insulin receptor signaling to stimulate glucose uptake into adipocytes.

QSAR Studies of PTP1B Inhibitors: Recent Advances and Perspectives

Diabetes mellitus, a chronic condition caused by defects in insulin secretion, or action, or both, is a group of metabolic disorders, complications of which can contribute significantly to ill health, disability, poor quality of life and premature death. From the three main types of diabetes, Type 2 is by far the most common, accounting for about 90% of cases worldwide. Studies on the role of protein tyrosine phosphatase 1B (PTP1B) have clearly shown that it serves as a key negative regulator of insulin signaling and is involved in the insulin resistance associated with Type 2 diabetes. The present work aims to survey information related to PTP1B research published in the last decade. Emphasis is laid particularly on Quantitative Structure-Activity Relationships (QSAR) based studies that supported so far the design of new, potent and selective PTP1B inhibitors. Finally, the challenges and perspectives of QSAR studies in this field are discussed to show how these method can be used to design new chemical entities with enhanced PTP1B inhibition activity.

Molecular modeling and synthesis of ZINC02765569 derivatives as protein tyrosine phosphatase 1B inhibitors: lead optimization study

This article describes design, synthesis, and molecular modeling studies of the ZINC02765569 derivatives as potent protein tyrosine phosphatase 1B (PTP1B) inhibitors, which was previously reported as a vHTS hit (ZINC02765569) by our laboratory. Ten compounds were synthesized and characterized by IR, MASS, and NMR followed by in vitro screening for PTP1B inhibition and glucose uptake in skeletal muscle L6 myotubes. The most potent compound 3j shows 66.4 % in vitro PTP1B inhibition and 39.6 % increase in glucose uptake. Glide was used to study the nature of interactions governing binding of designed molecules with active site of the PTP1B enzyme.

Synthesis, Structure–Activity Relationship and Docking Studies of Substituted Aryl Thiazolyl Phenylsulfonamides as Potential Protein Tyrosine Phosphatase 1B Inhibitors

Synthesis, Structure–Activity Relationship and Docking Studies of Substituted Aryl Thiazolyl Phenylsulfonamides as Potential Protein Tyrosine Phosphatase 1B Inhibitors

Synthesis and Biological Evaluation of Heterocyclic Ring-substituted Chalcone Derivatives as Novel Inhibitors of Protein Tyrosine Phosphatase 1B

Protein tyrosine phosphatase 1B (PTP1B) is a key factor in negative regulation of the insulin pathway, and is a promising target for the treatment of type-II diabetes, obesity and cancer. Herein, compound () was first observed to have moderate inhibitory activity against PTP1B with an value of . To obtain more potent PTP1B inhibitors, we synthesized a series of chalcone derivatives using compound () as the lead compound. Compound () was 4.4-fold more potent than the lead compound (), and more potent than the positive control, ursolic acid (). These results may help to provide suitable drug-like lead compounds for the design of inhibitors of PTP1B as well as other PTPs.

Identification of ZINC02765569: a potent inhibitor of PTP1B by vHTS

The present study describes identification of a novel lead molecule ZINC02765569 for inhibition of protein tyrosine phosphatase 1B (PTP1B) enzyme by a high-throughput virtual screening of Zinc database against catalytic domain of PTP1B employing docking algorithm Glide. The identified hit molecule ZINC02765569 was synthesized and evaluated for in vitro PTP1B enzyme inhibition, in vitro cellular glucose uptake assay, and animal models of hyperglycemia. ZINC02765569 shows promising inhibition of PTP1B enzyme at 10 μm assay, positively up-regulate the cellular glucose uptake in skeletal cell muscle myotubes and SLM/STZ hyperglycemic animal experiments. The novel hit reported here should provide a platform for the further development of its analogs as potential PTP1B enzyme inhibitors.

Design, Synthesis, and Biological Evaluation of Bromophenol Derivatives as Protein Tyrosine Phosphatase 1B Inhibitors

3-Bromo-4,5-bis(2,3-dibromo-4,5-dihydroxybenzyl)-1,2-benzenediol (BDB) is a bromophenol purified from the marine red alga Rhodomela confervoides and exhibits potent protein tyrosine phosphatase 1B (PTP1B) inhibition (IC(50) = 1.7 µmol/L). In an effort to improve the PTP1B inhibitory activity, a series of derivatives were designed, synthesized, and evaluated in vitro. The preliminary structure-activity relationship indicated that the tricyclic scaffold and multi-bromine atoms (four to five) attached to the aryl rings are important for PTP1B inhibition. Among these, compound 26 exhibited remarkable inhibitory activity against PTP1B with an IC(50) of 0.89 µmol/L, which was approximately two-fold more potent than the initial lead compound BDB.

Protein Tyrosine Phosphatase 1B and α-Glucosidase Inhibitory Phlorotannins from Edible Brown Algae,Ecklonia stoloniferaandEisenia bicyclis

The present work investigates protein tyrosine phosphatase 1B (PTP1B) and the α-glucosidase inhibitory activities of two edible brown algae, Ecklonia stolonifera and Eisenia bicyclis, as well as in their isolated phlorotannins. Since the individual extracts and fractions showed significant inhibitory activities, column chromatography was performed to isolate six phlorotannins, phloroglucinol (1), dioxinodehydroeckol (2), eckol (3), phlorofurofucoeckol-A (4), dieckol (5), and 7-phloroeckol (6). Phlorotannins 3-6 were potent and noncompetitive PTP1B inhibitors with IC(50) values ranging from 0.56 to 2.64 µM; 4-6 exhibited the most potent α-glucosidase inhibition with IC(50) values ranging from 1.37 to 6.13 µM. Interestingly, 4 and 6 were noncompetitive, while 5 exhibited competitive inhibition in an α-glucosidase assay. E. stolonifera and E. bicyclis as well as their isolated phlorotannins therefore possessed marked PTP1B and α-glucosidase inhibitory activities; this could lead to opportunities in the development of therapeutic agents to control the postprandial blood glucose level and thereby prevent diabetic complications.

Pyrrolo[2,3-c]azepine derivatives: A new class of potent protein tyrosine phosphatase 1B inhibitors

A series of pyrrolo[2,3-c]azepine derivatives was designed, synthesized, and evaluated as a new class of inhibitors against protein tyrosine phosphatase 1B (PTP1B) in vitro. The results demonstrated that compounds bearing a biphenyl moiety were proved to markedly influence the potency of these inhibitors. Particularly, compounds 29, 35 and 36 showed interesting inhibition with IC(50) value of 16.36, 14.93 and 13.92μM, respectively.

Discovery of Orally Active, Potent, and Selective Benzotriazole‐Based PTP1B Inhibitors

Discovery of Orally Active, Potent, and Selective Benzotriazole‐Based PTP1B Inhibitors

2-D QSAR studies of steroidal natural products oleanic acid and their semisynthetic derivatives as potent protein tyrosine phosphatase 1B inhibitors

QSAR study was carried out for a series of steroidal natural products including Oleanic acid derivatives exhibiting protein tyrosine phosphatase 1B inhibitory activity using different physiochemical descriptors to find out the structural features which are crucial for the biological activity. The QSAR study was carried out on V-life Molecular Design Suite software and the derived best QSAR model was derived by partial least square (forward) regression method. The whole dataset was divided into training set (34 compounds) and test set (19 compounds). The statistically significant model with high correlation coefficient (r2 = 0.8215) was selected for further study. The model was further validated by means of crossed squared correlation coefficient (q2 = 0.7685 and pred_r2 = 0.6156) which shows model has good predictive ability. Higher value of F statics (50.6217) also validates significance of model. The optimum QSAR model showed that the parameters chi4pathCluster and SssssCE-index contributed highly positive, while SssNHE-index contributed negatively for protein tyrosine phosphatase 1B inhibitory activity under given statically conditions.

Chemical Constituents from Sambucus adnata and Their Protein-Tyrosine Phosphatase 1B Inhibitory Activities

The MeOH extract from the whole plants of Sambucus adnata has shown significant protein-tyrosine phosphatase 1B (PTP1B) inhibitory activity. Chemical study on the extract resulted in the isolation of thirteen compounds, including a novel triterpene (1). The structure of 1 was determined to be 1α,3β-dihydroxy-urs-12-en-11-one-3-yl palmitate on the basis of extensive spectroscopic analyses. Among the isolated compounds, ursolic acid, oleanolic acid and (±)-boehmenan showed the most potent PTP1B inhibitory activity in vitro with the IC(50) values of 4.1, 14.4 and 43.5 µm, respectively. The kinetic analysis indicated that (±)-boehmenan inhibits PTP1B activity in a competitive manner.

Preparation of triazole-linked glycosylated α-ketocarboxylic acid derivatives as new PTP1B inhibitors

The synthesis of triazole-linked glycosyl acetophenone, benzoic acid, and α-ketocarboxylic acid derivatives was readily achieved via Cu(I)-catalyzed azide–alkyne cycloaddition (‘click’ reaction) in excellent yields of 93–97%. Among the synthesized glycoconjugates, the triazolyl α-ketocarboxylic acids were identified as the most potent protein tyrosine phosphatase 1B (PTP1B) inhibitors with micromole-ranged IC 50 values and moderate-to-good selectivity over a panel of homologous PTPs including TCPTP (4.6-fold), LAR (>30-fold), SHP-1 (>30-fold) and SHP-2 (>30-fold). Moreover, a docking simulation was conducted to propose a plausible binding mode of the glucosyl α-ketocarboxylic acid triazole with the enzymatic target.

Chimeric design, synthesis, and biological assays of a new nonpeptide insulin-mimetic vanadium compound to inhibit protein tyrosine phosphatase 1B

Prior to its total synthesis, a new vanadium coordination compound, called TSAG0101, was computationally designed to inhibit the enzyme protein tyrosine phosphatase 1B (PTP1B). The PTP1B acts as a negative regulator of insulin signaling by blocking the active site where phosphate hydrolysis of the insulin receptor takes place. TSAG001, [V(V)O(2)(OH)(picolinamide)], was characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy; IR: ν/cm(-1) 3,570 (NH), 1,627 (C=O, coordinated), 1,417 (C-N), 970/842 (O=V=O), 727 δ̣ (pyridine ring); (13)C NMR: 5 bands between 122 and 151 ppm and carbonyl C shifted to 180 ppm; and (1)H NMR: 4 broad bands from 7.6 to 8.2 ppm and NH(2) shifted to 8.8 ppm. In aqueous solution, in presence or absence of sodium citrate as a biologically relevant and ubiquitous chelator, TSAG0101 undergoes neither ligand exchange nor reduction of its central vanadium atom during 24 hours. TSAG0101 shows blood glucose lowering effects in rats but it produced no alteration of basal- or glucose-induced insulin secretion on β cells during in vitro tests, all of which excludes a direct mechanism evidencing the extrapancreatic nature of its activity. The lethal dose (LD(50)) of TSAG0101 was determined in Wistar mice yielding a value of 412 mg/kg. This value is one of the highest among vanadium compounds and classifies it as a mild toxicity agent when compared with literature data. Due to its nonsubstituted, small-sized scaffold design, its remarkable complex stability, and low toxicity; TSAG0101 should be considered as an innovative insulin-mimetic principle with promising properties and, therefore, could become a new lead compound for potential nonpeptide PTP1B inhibitors in antidiabetic drug research. In view of the present work, the inhibitory concentration (IC(50)) and extended solution stability will be tested.

Pharmacophore Modeling and Virtual Screening Studies to Design Potential Protein Tyrosine Phosphatase 1B Inhibitors as New Leads

Protein Tyrosine Phosphatase 1B (PTP-1B) is one of the important targets in the treatment of diabetes and obesity. They play a very important role in cellular signaling within and between cells. The best pharmacophore hypothesis (Hypo 1), consisting of four features, namely, one hydrogen- bond acceptor (HBA), one hydrophobic point (HY), and two ring aromatics (RA), has a correlation coefficient of 0.961, a root mean square deviation (RMSD) of 0.885, and a cost difference of 62.436, suggesting that a highly predictive pharmacophore model was successfully obtained. A chemical feature based pharmacophore model has been generated from known PTP-1B inhibitors (25 training set compounds) by HypoGen module implemented in CATALYST software. The top ranked hypothesis (Hypo1) contained four chemical feature types such as hydrogen-bond acceptor (HA), hydrophobic aromatic (HY), and two ring aromatic (RA) features. Hypo1 was further validated by 125 test set molecules giving a correlation coefficient of 0.905 between experimental and estimated activity. This was also validated using CatScramble method. Thus, the Hypo1 was exploited for searching new lead compounds over chemical compounds in Medichem database and then the selected compounds were screened based on restriction estimated activity. Finally, we obtained 30 new lead candidates and the one best highly active compound structure was selected as a lead compound. The results demonstrate that hypothesis derived in this study could be considered to be a useful and reliable tool in identifying structurally diverse compounds with desired biological activity.

Prodrug delivery of novel PTP1B inhibitors to enhance insulin signalling

A growing percentage of the population is resistant to two key hormones - insulin and leptin - as a result of increased obesity, often leading to significant health consequences such as type 2 diabetes. Protein tyrosine phosphatase 1B (PTP1B) is a key negative regulator of signalling by both of these hormones, so that inhibitors of this enzyme may provide promise for correcting endocrine abnormalities in both diabetes and obesity. As with other tyrosine phosphatases, identification of viable drug candidates targeting PTP1B has been elusive because of the nature of its active site. Beginning with novel phosphotyrosine mimetics, we have designed some of the most potent PTP1B inhibitors. However, their highly acidic structures limit intrinsic permeability and pharmacokinetics. Ester prodrugs of these inhibitors improve their drug-like properties with the goal of delivering these nanomolar inhibitors to the cytoplasm of cells within target tissues. In addition to identifying prodrugs that is able to deliver active drugs into cells to inhibit PTP1B and increase insulin signalling, these compounds were further modified to gain a variety of cleavage properties for targeting activity in vivo. One such prodrug candidate improved insulin sensitivity in ob/ob mice, with lowered fasting blood glucose levels seen in the context of lowered fasting insulin levels following 4 days of intraperitoneal dosing. The results presented in this study highlight the potential for design of orally active drug candidates targeting PTP1B, while also delineating the considerable challenges remaining.

Protein tyrosine phosphatase 1B inhibitory by dammaranes from Vietnamese Giao-Co-Lam tea

Ethnopharmacological relevance Gynostemma pentaphyllum (Thunb.) tea was used in Vietnamese folk medicine as anti-diabetic agent. Aim of the study This study was aimed to investigate the inhibitory activities of fractions and constituents isolated from Gynostemma pentaphyllum on protein tyrosine phosphatase 1B (PTP1B) since it has been proposed as a treatment therapy for type 2 diabetes and obesity. Materials and methods The 70% EtOH extract, CHCl 3 fraction, EtOAc fraction, BuOH fraction, and seven isolated dammarane triterpenes were evaluated for their inhibitory activity in protein phosphatase enzymes (PTP1B and VHR). Results CHCl 3-soluble fraction showed a dose-dependent inhibitory activity of the PTP1B enzyme with the IC 50 value of 30.5 μg/mL. Among seven tested compounds, compounds 6 showed the most potent PTP1B inhibitory activity with IC 50 value of 5.3 ± 0.4 μM compared to a range 15.7–28.5 μM for the other six compounds. The inhibition mode of 6 was competitive toward p-NPP with a K i value of 2.8 μM. Conclusion These study results suggested that the PTP1B inhibitory activity of these dammaranes may enable this plant to play an important role in the treatment of diabetes.

QSAR Study on a Series of Protein Tyrosine Phosphatase 1B Inhibitors

As a therapeutic target, protein tyrosine phosphatase 1B (PTP1B) has received considerable attention for the treatment of diabetes mellitus. A QSAR study using substituted monocyclic and polycyclic thiophene derivatives, recently reported as potent PTP1B inhibitors, was carried out. More than 60 physicochemical descriptors were calculated which underwent rational selection before their use in derivation of QSAR models. Statistically significant equations were generated using multiple linear regression analysis. External validation of the derived models with test set compounds proved good predictability of the models. Interpretation of the results revealed lipophilicity as a key regulatory feature which affects PTP1B inhibition along with several electronic and steric parameters. The study provides an important platform upon which novel rationally designed molecules can be synthesized with cautious optimism.

Total synthesis of bis-(2,3-dibromo-4,5-dihydroxyphenyl)-methane as potent PTP1B inhibitor

Protein tyrosine phosphatase 1B (PTP1B) plays an important role as a negative regulator and has been proved to be an effective target for the treatment of type 2 diabetes mellitus. Bis-(2,3-dibromo-4,5-dihydroxyphenyl)-methane 7 was first reported as a natural bromophenol with significant inhibition against PTP1B which was isolated from red algae Rhodomela confervoides. Intrigued by its astonishing activity (IC 50 = 2.4 μmol/L), compound 7 was synthesized with the overall yield of 24% and evaluated for its PTP1B inhibitory activity compared with natural compound.

Studies of the Mechanism of Selectivity of Protein Tyrosine Phosphatase 1B (PTP1B) Bidentate Inhibitors Using Molecular Dynamics Simulations and Free Energy Calculations

Bidentate inhibitors of protein tyrosine phosphatase 1B (PTP1B) are considered as a group of ideal inhibitors with high binding potential and high selectivity in treating type II diabetes. In this paper, the binding models of five bidentate inhibitors to PTP1B, TCPTP, and SHP-2 were investigated and compared by using molecular dynamics (MD) simulations and free energy calculations. The binding free energies were computed using the Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) methodology. The calculation results show that the predicted free energies of the complexes are well consistent with the experimental data. The Molecular Mechanics/Generalized Born Surface Area (MM/GBSA) free energy decomposition analysis indicates that the residues ARG24, ARG254, and GLN262 in the second binding site of PTP1B are essential for the high selectivity of inhibitors. Furthermore, the residue PHE182 close to the active site is also important for the selectivity and the binding affinity of the inhibitors. According to our analysis, it can be concluded that in most cases the polarity of the portion of the inhibitor that binds to the second binding site of the protein is positive to the affinity of the inhibitors while negative to the selectivity of the inhibitors. We expect that the information we obtained here can help to develop potential PTP1B inhibitors with more promising specificity.