PTP1B Inhibitors Research Articles

Protein tyrosine phosphatase 1B inhibitors from natural sources.

Since PTP1B enzyme was discovered in 1988, it has captured the research community's attention. This landmark discovery has stimulated numerous research studies on a variety of human diseases, including cancer, inflammation, and diabetes. Tremendous progress has been made in finding PTP1B inhibitors and exploring PTP1B regulatory mechanisms. This review investigates for the natural PTP1B inhibitors, and focuses on the common characteristics of the discovered structures and structure-activity relationships. To facilitate understanding, all the natural compounds are here divided into five different classes (fatty acids, phenolics, terpenoids, steroids, and alkaloids), according to their skeletons. These PTP1B inhibitors of scaffold structures could serve as a theoretical basis for new concept drug discovery and design.

Benzo[c][1,2,5]thiadiazole derivatives: A new class of potent Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) inhibitors

The Src homology-2 domain containing protein tyrosine phosphatase-2 (SHP2) is an oncogenic phosphatase linked to various kinds of cancers. Consequently, SHP2 has emerged as a promising target for novel anti-cancer agents. Using scaffold-hopping strategy, a series of benzo[c][1,2,5]thiadiazole derivatives was designed from PTP1B inhibitors with 1H-2,3-Dihydroperimidine motif, synthesized and evaluated their biological activities against PTP1B and SHP2. Among them, the representative compound 11g displayed SHP2 inhibitory activity with IC50 of 2.11 ± 0.99 μM, exhibited 2.02-fold and 25-fold selectivity for SHP2 over SHP1 and PTP1B respectively and had no visible activity against TCPTP. These preliminary results could provide a possible opportunity for the development of novel SHP2 inhibitors with optimal potency and improved pharmacological properties.

Benzyl Mono-P-Fluorophosphonate and Benzyl Penta-P-Fluorophosphate Anions Are Physiologically Stable Phosphotyrosine Mimetics and Inhibitors of Protein Tyrosine Phosphatases.

α,α-Difluoro-benzyl phosphonates are currently the most popular class of phosphotyrosine mimetics. Structurally derived from the natural substrate phosphotyrosine, they constitute classical bioisosteres and have enabled the development of potent inhibitors of protein tyrosine phosphatases (PTP) and phosphotyrosine recognition sites such as SH2 domains. Being dianions bearing two negative charges, phosphonates, however, do not permeate membranes and thus are often inactive in cells and have not been a successful starting point toward therapeutics, yet. In this work, benzyl phosphonates were modified by replacing phosphorus-bound oxygen atoms with phosphorus-bound fluorine atoms. Surprisingly, mono-P-fluorophosphonates were fully stable under physiological conditions, thus enabling the investigation of their mode of action toward PTP. Three alternative scenarios were tested and mono-P-fluorophosphonates were identified as stable reversible PTP1B inhibitors, despite of the loss of one negative charge and the replacement of one oxygen atom as an H-bond donor by fluorine. In extending this replacement strategy, α,α-difluorobenzyl penta-P-fluorophosphates were synthesized and found to be novel phosphotyrosine mimetics with improved affinity to the phosphotyrosine binding site of PTP1B.

Antidiabetic and antiplatelet aggregation study of various methanol fractions of Nymphaea stellata Willd. leaves

Summary Introduction: Nymphaea stellata Willd. (Nymphaeaceae) is traditionally used for the treatment of diabetes. Alcohol extract of N. stellata leaves has been reported for hypoglycaemic activity. Objective: The aim of this study was to further investigate the different methanol fractions of N. stellata leaves for anti-diabetic activity and anti-platelet aggregation activity. Methods: Methanol extract was fractioned in to unsaponified petroleum ether fraction of methanol extract (UPFME), chloroform fraction of methanol extract (CFME) and residual fraction of methanol extract (RFME). All fractions were evaluated for in vivo anti-diabetic activity (STZ-NAD-induced rat model), in vitro anti-diabetic activity (PTP1B inhibition study) and anti-platelet aggregation activity. Results: UPFME showed significant changes in all studied parameters, compared to the diabetic control. UPFME also showed an IC50 value of 19.30±1.1 mg/ml and 13.11±0.7 μg/ml in PTP1B inhibition study and anti-platelet aggregation study, respectively. Conclusion: The study indicates that UPFME of N. stellata leaves exhibit anti-diabetic and anti-platelet aggregation activity.

Isoprenylated phenolic compounds with PTP1B inhibition from Morus alba

Two new Diels-Alder adducts, albasins A and B (1 and 2), one new isoprenylated 2-arylbenzofuran, albasin C (3), one new isoprenylated flavone, albasin D (4), together with sixteen known phenolic compounds, were isolated from the root bark of Morus alba. Their structures were elucidated by extensive spectroscopic analysis, including NMR, MS, and ECD data. All the new compounds and most of the known ones showed significant inhibitory effects on PTP1B in vitro with IC50 values ranging from 0.57 to 7.49μM.

Identification of Anthocyanins from Four Kinds of Berries and Their Inhibition Activity to α-Glycosidase and Protein Tyrosine Phosphatase 1B by HPLC-FT-ICR MS/MS.

The polyphenolic profiles of four berries (blueberry, bilberry, mulberry, and cranberry) in China were investigated using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Thirty-nine polyphenols including 26 anthocyanins, 9 flavonoids, and 4 phenolic acids were identified accurately. Cyanidin aglycones are common in four berries, and malvidin aglycones are the main compounds found in bilberry and cranberry. The anthocyanin level in blueberry are the highest with 739.6 ± 17.14 mg/g DW and presented the strongest antioxidant capacity in DPPH, ABTS, FRAP, and ORAC assay. In α-glycosidase, the inhibition activity was in the following order: mulberry > bilberry > blueberry > cranberry. For the PTP1B inhibition assay, blueberry demonstrated the highest inhibitory effect with IC50 3.06 ± 0.02 μg/mL, followed by bilberry, mulberry, and cranberry. Molecular docking results showed that cyanidin aglycones had the highest inhibition activity to PTP1B.

PTP1B inhibitory and cytotoxic activities of triterpenoids from the aerial parts of Agrimonia pilosa

Recently, PTP1B inhibitors have become the frontier as possible targeting for anti-cancer and anti-diabetic drugs. Twelve triterpenoids from the aerial parts of Agrimonia pilosa were investigated for PTP1B inhibitory and cytotoxic activities. In the results, compounds 3 (IC50 = 0.50 μM) and 7 (IC50 = 5.88 μM) were found to possess very powerful inhibitory activity against the PTP1B enzyme, comparable to the positive control ursolic acid (IC50 = 6.60 μM). In addition, compounds 1, 2, 4, and 10‒12 showed potent inhibitory effects against PTP1B, with an IC50 range of 13.48‒14.98 μM. In the kinetic assay of the PTP1B enzyme, compounds 1 and 2 were noncompetitive, whereas 7 and 11 showed a mixed type. In the docking analysis, the results showed that different residues of PTP1B interacted with twelve triterpenoids. Furthermore, compounds 6 (IC50 = 3.65 μM) and 12 (IC50 = 1.21 μM) displayed strong cytotoxic effects against the HeLa cell line. Compounds 2 (IC50 = 16.06 μM) and 4 (IC50 = 14.73 μM) showed moderate cytotoxic activities against the HeLa cell line. Compound 2 exhibited comprehensive cytotoxicity against the HL-60 (IC50 = 45.53 μM) and MCF-7 (IC50 = 34.21 μM) cell lines. These results support the use of triterpenoids in traditional medicine for prevention and treatment of diabetes and cancer.

Punicalagin, a PTP1B inhibitor, induces M2c phenotype polarization via up-regulation of HO-1 in murine macrophages

Current data have shown that punicalagin (PUN), an ellagitannin isolated from pomegranate, possesses anti-inflammatory and anti-oxidant properties; however, its direct targets have not yet been reported. This is the first report that PTP1B serves as a direct target of PUN, with IC50 value of 1.04μM. Results from NPOI further showed that the Kon and Koff of PUN-PTP1B complex were 3.38e2M−1s−1 and 4.13e-3s−1, respectively. The active site Arg24 of PTP1B was identified as a key binding site of PUN by computation simulation and point mutation. Moreover, inhibition of PTP1B by PUN promoted an M2c-like macrophage polarization and enhanced anti-inflammatory cytokines expression, including IL-10 and M-CSF. Based on gene expression profile, we elucidated that PUN treatment significantly up-regulated 275 genes and down-regulated 1059 genes. M1-like macrophage marker genes, such as Tlr4, Irf1/2, Hmgb1, and Stat1 were down-regulated, while M2 marker genes, including Tmem171, Gpr35, Csf1, Il1rn, Cebpb, Fos, Vegfα, Slc11a1, and Bhlhe40 were up-regulated in PUN-treated macrophages. Hmox-1, a gene encoding HO-1 protein, was preferentially expressed with 16-fold change. Inhibition of HO-1 obviously restored PUN-induced M2 polarization and IL-10 secretion. In addition, phosphorylation of both Akt and STAT3 contributed to PUN-induced HO-1 expression. This study provided new insights into the mechanisms of PUN-mediated anti-inflammatory and anti-oxidant activities and provided new therapeutic strategies for inflammatory diseases.

Abstract LB-022: PTP1B directed therapeutics for HER2 positive breast cancer

Abstract PTP1B, a validated therapeutic target for diabetes and obesity, has a critical positive role in HER2 signaling in breast tumorigenesis. Efforts to develop therapeutic inhibitors of PTP1B have been frustrated by the chemical properties of the active site. We define a new mechanism of allosteric inhibition that targets the C-terminal, non-catalytic segment of PTP1B. We present what is to our knowledge the first ensemble structure of PTP1B containing this intrinsically disordered segment, within which we identified a binding site for the small-molecule inhibitor MSI-1436. We demonstrate binding to a second site close to the catalytic domain, with cooperative effects between the two sites locking PTP1B in an inactive state. MSI-1436 antagonized HER2 signaling, inhibited tumorigenesis in xenografts and abrogated metastasis in the NDL2 mouse model of breast cancer, validating inhibition of PTP1B as a therapeutic strategy in breast cancer. Currently, we are testing MSI-1436 in a Phase 1 clinical trial in HER2-positive breast cancer patients, in collaboration with the Monter Cancer Center at Northwell Health formerly NS-LIJ. Note: This abstract was not presented at the meeting. Citation Format: Nava Krishnan. PTP1B directed therapeutics for HER2 positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-022. doi:10.1158/1538-7445.AM2017-LB-022

Inhibitors of Protein Tyrosine Phosphatase 1B from Marine Natural Products.

The ocean is a capacious area with the most abundant biological resources on the earth. The particularity of the marine ecological environment (high pressure, high salt, and hypoxia) makes the marine species survival competition fiercely, forcing many marine organisms in the process of life to produce a great deal of secondary metabolites with special structures and biological activities. In this article, 118 natural products which were isolated from four kinds of marine organisms, sponges, algae, soft corals and fungus, showing PTP1B inhibitory activity were summarized from 2010 to 2016, which may become the leading compounds towards treating Diabetes mellitus (DM). What's more, we briefly summarized the structure-activity relationship of PTP1B inhibitors.

Downregulation of PTP1B and TC-PTP phosphatases potentiate dendritic cell-based immunotherapy through IL-12/IFNγ signaling

ABSTRACT PTP1B and TC-PTP are highly related protein-tyrosine phosphatases (PTPs) that regulate the JAK/STAT signaling cascade essential for cytokine-receptor activation in immune cells. Here, we describe a novel immunotherapy approach whereby monocyte-derived dendritic cell (moDC) function is enhanced by modulating the enzymatic activities of PTP1B and TC-PTP. To downregulate or delete the activity/expression of these PTPs, we generated mice with PTP-specific deletions in the dendritic cell compartment or used PTP1B and TC-PTP specific inhibitor. While total ablation of PTP1B or TC-PTP expression leads to tolerogenic DCs via STAT3 hyperactivation, downregulation of either phosphatase remarkably shifts the balance toward an immunogenic DC phenotype due to hyperactivation of STAT4, STAT1 and Src kinase. The resulting increase in IL-12 and IFNγ production subsequently amplifies the IL-12/STAT4/IFNγ/STAT1/IL-12 positive autocrine loop and enhances the therapeutic potential of mature moDCs in tumor-bearing mice. Furthermore, pharmacological inhibition of both PTPs improves the maturation of defective moDCs derived from pancreatic cancer (PaC) patients. Our study provides a new advance in the use of DC-based cancer immunotherapy that is complementary to current cancer therapeutics.

Screening for bioactive natural products from a 67-compound library of Glycyrrhiza inflata

Licorice shows a variety of pharmacological activities. This work aims to discover bioactive natural products from one botanical source of licorice, Glycyrrhiza inflata. A total of 67 free phenolics were isolated to form a compound library. Based on the bioactivities of licorice, these compounds were screened using cell- or enzyme-based bioassay methods. A total of 11 compounds exhibited potent cytotoxic activities against three human cancer cell lines (HepG2, SW480 and MCF7), while showed little toxicity on human normal cell lines LO2 and HEK293T. A number of chalcones showed remarkable anti-inflammatory activities. Among them, 2 (licochalcone B, IC50 8.78μM), 10 (licoagrochalcone C, IC50 9.35μM) and 13 (licochalcone E, IC50 9.09μM) exhibited the most potent inhibitory activities on LPS-induced NO production, whereas 1, 8, 10, 12 and 13 (IC50 13.9, 7.27, 2.44, 6.67 and 3.83μM) showed potent inhibitory activities on NF-κB transcription. Nine prenylated phenolics were found to be PTP1B inhibitors. Particularly, licoagrochalcone A (4), kanzonol C (7), 2′-hydroxyisolupalbigenin (35), gancaonin Q (45), glisoflavanone (50) and glabrol (53) showed IC50 values of 0.31–0.97μM. Compounds 24 (semilicoisoflavone B, IC50 0.25μM), 26 (allolicoisoflavone B, IC50 0.80μM) and 64 (glabridin, IC50 0.10μM) showed noticeable tyrosinase inhibitory activities. Most of the above bioactive compounds were reported for the first time.

Green Nanosynthesis and Functionalization of Gold Nanoparticles as PTP 1B Inhibitors

Nanomedicine has emerged to become a frontier area of research. The interdisciplinary nature of nanoscale research inevitably leads to nanostructure fabrication and functionalization. Herein, we addressed on the potential of high therapeutic indexed Syzygium cumini seed to biofunctionalize gold nanoparticles. The aqueous seed extract of S. cumini acted as a reducing and capping agent in the formation of gold nanoparticles. Biofabricated gold nanoparticles was characterized using UV–vis spectrophotometry, TEM, SEM, EDAX, FTIR and XRD analysis. PTP 1B inhibitory activity of bioinspired gold nanoparticles was assessed using PTP 1B inhibition assay. Newly synthesized gold nanoparticles was found to possess high PTP 1B inhibitory potential. Furthermore, the newly synthesized nanoparticles not shown any genotoxicity during chromosomal studies indicates its high biocompatibility nature.

Concise synthesis and PTP1B inhibitory activity of (R)- and (S)-dihydroresorcylide

The present study was designed to develop a concise synthetic route for macrolide, with the purpose of confirming the absolute configuration of natural dihydroresorcylide (1) and making it more easily accessible for biological evaluation. The absolute configuration of C-3 in natural 1 was revised to be R by comparison of the rotation sign of synthetic (R)- and (S)-1. The synthetic (R)-1 was found to be a novel highly specific PTP1B inhibitor with an IC50 value of 17.06 μM.

A novel PTP1b inhibitor vanadium-flavone complex: synthesis and pharmacodynamic evaluation in streptozotocin-induced diabetic mice

Protein tyrosine phosphatase 1b is a negative regulator of insulin action and is emerging as a potential drug target for type 2 diabetes mellitus. A novel protein tyrosine phosphatase 1b inhibitor vanadium-flavone complex, bis(5,6,7-trihydroxyflavone)-oxovanadium, was synthesized and characterized by mass spectrometer, inductively coupled plasma, infrared, ultraviolet, electron paramagnetic resonance, X-ray photoelectron spectroscopy and thermal gravity analysis. Bis(5,6,7-trihydroxyflavone)-oxovanadium showed good anti-diabetic effect in streptozocin -induced diabetic mice without gastrointestinal stimulation and induction of hypoglycemia in normoglycemic mice. In vitro, the protein tyrosine phosphatase 1b inhibition activity of bis(5,6,7-trihydroxyflavone)-oxovanadium was enhanced after storage, during which bis(5,6,7-trihydroxyflavone)-oxovanadium could be decomposed gradually and the concentration of VO2+ would gradually increase. In vivo, baicalein not only transports VO2+ to the target organ, but also improves the morphology and function of pancreatic islets via its anti-inflammation activity. Thus bis(5,6,7-trihydroxyflavone)-oxovanadium is a promising potential drug for the treatment of type 2 diabetes mellitus.

Y-shaped bis-arylethenesulfonic acid esters: Potential potent and membrane permeable protein tyrosine phosphatase 1B inhibitors

Known PTP1B inhibitors with bis-anionic moieties exhibit potent inhibitory activity, good selectivity, however, they are incapable of penetrating cellular membranes. Based upon our finding of a new pharmacophoric group in inhibition of PTP1B and the structural characteristics of the binding pocket of PTP1B, a series of bis-arylethenesulfonic acid ester derivatives were designed and synthesized. These novel molecules, particularly Y-shaped bis-arylethenesulfonic acid ester derivatives, exhibited high PTP1B inhibitory activity, moderate selectivity, and great potential in penetrating cellular membranes (compound 7p, CLogP=9.73, Papp=9.6×10-6cm/s; IC50=140, 1290 and 920nM on PTP1B, TCPTP and SHP2, respectively). Docking simulations suggested that these Y-shaped inhibitors might interact with multiple secondary binding sites in addition to the catalytic site of PTP1B.

Xanthones from the twigs of Garcinia oblongifolia and their antidiabetic activity

Three new xanthones, oblongixanthone F–H (1–3), along with eight known xanthones (4–11), were isolated from an EtOAc extract of the twigs of Garcinia oblongifolia. Their structures were elucidated by spectroscopic analysis including 1D- and 2D-NMR spectroscopy and mass spectrometry. The antidiabetic effects of all isolated compounds were evaluated by in vitro α-glucosidase and PTP1B inhibition assays. Compound 11 was the most active compound, and inhibited α-glucosidase and PTP1B with IC50 values of 1.7±0.5 and 14.1±3.5μM, respectively.

N-alkylated thiazolidine-2,4-dione analogs as PTP1B inhibitors: synthesis, biological activity, and docking studies

Protein tyrosine phosphatase 1B enzyme has been found to be a negative regulator of insulin and leptin signaling pathway. It has gained considerable attention to medicinal chemists as a new therapeutic target for intervention in the treatment of type2 diabetes. A series of N-substituted-5-(thiophen-2-ylmethylene)thiazolidine-2,4-dione derivatives were synthesized and screened in vitro for protein tyrosine phosphatase 1B inhibitory activity and in vivo for anti-hyperglycaemic activity. The introduction of alkyl/halo alkyl moiety onto the amidic nitrogen of thiazolidine-2,4-dione ring was intended to enhance the inhibitor-enzyme affinity and hence, good protein tyrosine phosphatase 1B inhibition. The nature of interactions which governs the binding mode of ligands inside the active site of protein tyrosine phosphatase 1B was further studied by molecular docking simulation. Compound 7 was found to be a potent protein tyrosine phosphatase 1B inhibitor with IC50 9.96 µM. The synthesized compounds have also shown significant lowering of blood glucose level.

Furanoterpenes, new types of protein tyrosine phosphatase 1B inhibitors, from two Indonesian marine sponges, Ircinia and Spongia spp.

Protein tyrosine phosphatase (PTP) 1B negatively regulates the insulin and leptin signaling pathways, and, thus, the clinical application of PTP1B inhibitors to the prevention and treatment of type 2 diabetes and obesity is expected. During our studies on PTP1B inhibitors, two furanosesterterpenes and a C21 furanoterpene were obtained as new types of PTP1B inhibitors from two Indonesian marine sponges. (7E, 12E, 20Z, 18S)-Variabilin (1) and (12E, 20Z, 18S)-8-hydroxyvariabilin (2) from Ircinia sp. and furospongin-1 (3) from Spongia sp. inhibited PTP1B activity with IC50 values of 1.5, 7.1, and 9.9μM, respectively. The inhibitory activity of compound 1 against T-cell PTP (TCPTP) was approximately 2-fold that against PTP1B, whereas the vaccinia H-1-related phosphatase (VHR) inhibitory effects of 1 were 4-fold weaker than that of its PTP1B inhibitory activity. Compounds 1–3 at 50μM did not show cytotoxicity against two human cancer cell lines, hepatoma Huh-7 and bladder carcinoma EJ-1. Compound 1 did not enhance the phosphorylation level of Akt, a key downstream effector of the cascade, in Huh-7 cells.

Optimization of Extraction Process for Antidiabetic and Antioxidant Activities of Kursi Wufarikun Ziyabit Using Response Surface Methodology and Quantitative Analysis of Main Components.

By using extraction yield, total polyphenolic content, antidiabetic activities (PTP-1B and α-glycosidase), and antioxidant activity (ABTS and DPPH) as indicated markers, the extraction conditions of the prescription Kursi Wufarikun Ziyabit (KWZ) were optimized by response surface methodology (RSM). Independent variables were ethanol concentration, extraction temperature, solid-to-solvent ratio, and extraction time. The result of RSM analysis showed that the four variables investigated have a significant effect (p < 0.05) for Y1, Y2, Y3, Y4, and Y5 with R2 value of 0.9120, 0.9793, 0.9076, 0.9125, and 0.9709, respectively. Optimal conditions for the highest extraction yield of 39.28%, PTP-1B inhibition rate of 86.21%, α-glycosidase enzymes inhibition rate of 96.56%, and ABTS inhibition rate of 77.38% were derived at ethanol concentration 50.11%, extraction temperature 72.06°C, solid-to-solvent ratio 1 : 22.73 g/mL, and extraction time 2.93 h. On the basis of total polyphenol content of 48.44% in this optimal condition, the quantitative analysis of effective part of KWZ was characterized via UPLC method, 12 main components were identified by standard compounds, and all of them have shown good regression within the test ranges and the total content of them was 11.18%.