Structure-based discovery of a specific SHP2 inhibitor with enhanced blood-brain barrier penetration from PubChem database.

The thiophene [2,3-d]pyrimidine structure-like small molecules were discovered from structure-based virtual screening of 1 billion compounds. Base on enzyme activity assay results, a SHP2-specific molecule inhibitor Comp#2 with IC50 of 1.174 µM, 85-fold more selective for SHP2 than the highly related SHP1 (IC50 > 100 µM). The compound can effectively inhibit SHP2-mediated cell signaling and cancer cell proliferation, including cervix cancer, human pancreatic cancer, large cell lung cancer, and mouse glioma cell. Moreover, the in vivo assay indicated that Comp#2 could inhibit cervix cancer tumors growth in BABL/c mice. This work has shown the specific SHP2 inhibitor can inhibit glioblastoma growth in vivo.

Design, synthesis, biological evaluation and molecular dynamics simulation studies of imidazolidine-2,4-dione derivatives as novel PTP1B inhibitors.

Protein tyrosine phosphatase 1B (PTP1B) is a member of the phosphotyrosine phosphatase family and plays an important role in the signal transduction of diabetes. Inhibition of PTP1B activity can increase insulin sensitivity and reduce blood sugar levels. Therefore, it is urgent to find compounds with novel structures that can inhibit PTP1B. This study designed imidazolidine-2,4-dione derivatives through the computer-aided drug design (CADD) strategy, and the Comp#10 showed outstanding inhibitory ability. (IC50 = 2.07 µM) and selectivity. The inhibitory mechanism at molecular level of Comp#10 on PTP1B was studied by molecular dynamics simulation. The results show that the catalytic region of PTP1B protein is more stable, which makes the catalytic sites unsuitable for exposure. Interestingly, the most obvious changes in the interaction between residues in the P-loop region (such as: His214, Cys215, and Ser216). In short, this study reported for the first time that imidazolidine-2,4-dione derivatives as novel PTP1B inhibitors had good inhibitory activity and selectivity, providing new ideas for the development of small molecule PTP1B inhibitors.

Exploring the dynamic mechanism of allosteric drug SHP099 inhibiting SHP2E69K.

The E69K mutation is one of the most frequent protein tyrosine phosphatase-2 (SHP2) mutations in leukemia, and it can cause the increase in the protein activity. Recent studies have shown that the E69K mutation was fairly sensitive to the allosteric inhibitor of SHP2 (SHP099). However, the molecular mechanism of the allosteric drug SHP099 inhibiting SHP2E69K remains unclear. Thus, the molecular dynamic simulations and the post-dynamics analyses (RMSF, PCA, DCCM, RIN and the binding free energies) for SHP2WT, SHP2WT-SHP099, SHP2E69K and SHP2E69K-SHP099 were carried out, respectively. Owing to the strong binding affinity of SHP099 to residues Thr219 and Arg220, the flexibility of linker region (residues Val209-Arg231) was reduced. Moreover, the presence of SHP099 kept the autoinhibition state of the SHP2 protein through enhancing the interactions between the linker region and Q loop in PTP domain, such as Thr219/Val490, Thr219/Asn491, Arg220/Ile488 and Leu254/Asn491. In addition, it was found that the residues (Thr219, Arg220, Leu254 and Asn491) might be the key residues responsible for the conformational changes of protein. Overall, this study may provide an important basis for understanding how the SHP099 effectively inhibited the SHP2E69K activity at the molecular level.

Identification of protein tyrosine phosphatase 1B (PTP1B) inhibitors through De Novo Evoluton, synthesis, biological evaluation and molecular dynamics simulation.

Protein tyrosine phosphatase 1B (PTP1B) is a widely expressed 50 kDa enzyme and the first intracellular PTP to be purified from human placental tissue. It has been proved that protein tyrosine phosphatase 1B played a significant role in the negative regulation of insulin signaling pathway and overexpression of PTP1B could lead to the decrease of insulin resistance. Therefore PTP1B has emerged as a novel promising therapeutic target for the treatment of type-2 diabetes mellitus. Computer aided drug design (CADD), chemical synthesis and biological activity assay resulted in the identification of a novel potent PTP1B inhibitor, compound 1a, which shared an IC50 value of 4.46 µM. Finally, the analysis of molecular dynamics simulation provided the theoretical basis for favorable activity of compound 1a.

Scaffold-based selective SHP2 inhibitors design using core hopping, molecular docking, biological evaluation and molecular simulation.

PTPN11 (coding the gene of SHP2), a classic non-receptor protein tyrosine phosphatase, is implicated in multiple cell signaling pathway. Abnormal activation of SHP2 has been shown to contribute to a variety of human diseases, including Juvenile myelomonocytic leukemia (JMML), Noonan syndrome and tumors. Thus, the SHP2 inhibitors have important therapeutic value. Here, based on the compound PubChem CID 8,478,960 (IC50 = 45.01 µM), a series of thiophene [2,3-d] pyrimidine derivatives (IC50 = 0.4-37.87 µM) were discovered as novel and efficient inhibitors of SHP2 through powerful "core hopping" and CDOCKER technology. Furthermore, the SHP2-PTP phosphatase activity assay indicated that Comp#5 (IC50 = 0.4 µM) was the most active SHP2 inhibitor. Subsequently, the effects of Comp#5 on the structure and function of SHP2 were investigated through molecular dynamics (MD) simulation and post-kinetic analysis. The result indicated that Comp#5 enhanced the interaction of residues THR357, ARG362, LYS366, PRO424, CYS459, SER460, ALA461, ILE463, ARG465, THR507 and GLN510 with the surrounding residues, improving the stability of the catalytic active region and the entrance of catalytic active region. In particular, the Comp#5 conjugated with residue ARG362, elevating the efficient and selectivity of SHP2 protein. The study here may pave the way for discovering the novel SHP2 inhibitors for suffering cancer patients.

Design, synthesis and biological evaluation of pyridine derivatives as selective SHP2 inhibitors.

SHP2 is a non-receptor protein tyrosine phosphatase encoded by the PTPN11 gene, which affects the transduction of multiple signaling pathways, including RAS-ERK, PI3K-AKT and JAK-STAT. SHP2 also plays an important role in the programmed cell death pathway (PD-1/PD-L1). Studies have shown that SHP2 is associated with a variety of cancers, including breast, liver and gastric cancers. Therefore, the development of SHP2 inhibitors has attracted extensive attention. In this study, based on the known inhibitor 1 (SHP099), novel SHP2 inhibitors were designed by means of scaffold hopping, and 35 pyridine derivatives as SHP2 inhibitors were found. The in vitro enzyme activity assay was performed on these compounds, and multiple selective SHP2 inhibitors with activity potency similar to that of SHP099 were obtained. Among them, compound (2-(4-(aminomethyl)piperidin-1-yl)-5-(2,3-dichlorophenyl)pyridin-3-yl)methanol (11a) was the most potent and highly selective SHP2 inhibitor with an in vitro enzyme activity IC50 value of 1.36 µM. Fluorescence titration assay verified that 11a bound directly to SHP2 protein. Subsequently, cell assay of representative compounds showed that these compounds could effectively inhibit the proliferation of Ba/F3 cells. In addition, the pharmacokinetic characteristics of the designed compounds were analyzed by the in silico ADMET prediction. Molecular docking study provided more detailed information on the binding mode of compounds and SHP2 protein. In brief, this study reported for the first time that pyridine derivatives as novel SHP2 inhibitors had good inhibitory activity and selectivity, providing new clues for the development of small molecule SHP2 inhibitors.

Exploring the effect of inhibitor AKB-9778 on VE-PTP by molecular docking and molecular dynamics simulation.

Diabetic macular edema, also known as diabetic eye disease, is mainly caused by the overexpression of vascular endothelial protein tyrosine phosphatase (VE-PTP) at hypoxia/ischemic. AKB-9778 is a known VE-PTP inhibitor that can effectively interact with the active site of VE-PTP to inhibit the activity of VE-PTP. However, the binding pattern of VE-PTP with AKB-9778 and the dynamic implications of AKB-9778 on VE-PTP system at the molecular level are poorly understood. Through molecular docking, it was found that the AKB-9778 was docked well in the binding pocket of VE-PTP by the interactions of hydrogen bond and Van der Waals. Furthermore, after molecular dynamic simulations on VE-PTP system and VE-PTP AKB-9778 system, a series of postdynamic analyses found that the flexibility and conformation of the active site undergone an obvious transition after VE-PTP binding with AKB-9778. Moreover, by constructing the RIN, it was found that the different interactions in the active site were the detailed reasons for the conformational differences between these two systems. Thus, the finding here might provide a deeper understanding of AKB-9778 as VE-PTP Inhibitor.

Synthesis, biological evaluation and 3D-QSAR studies of 1,2,4-triazole-5-substituted carboxylic acid bioisosteres as uric acid transporter 1 (URAT1) inhibitors for the treatment of hyperuricemia associated with gout.

As a part of our ongoing research to develop novel URAT1 inhibitors, 19 compounds (1a-1s) based on carboxylic acid bioisosteres were synthesized and tested for in vitro URAT1 inhibitor activity (IC50). The structure-activity relationship (SAR) exploration led to the discovery of a highly potent novel URAT1 inhibitor 1g, which was 225-fold more potent than the parent lesinurad in vitro (IC50 = 0.032 µM for 1g against human URAT1 vs 7.20 µM for lesinurad). Besides, 3D-QSAR pharmacophore models were established based on the activity of the compounds (1a-1s) by Accelrys Discovery Studio 2.5/HypoGen. The best hypothesis, Hypo 1, was validated by three methods (cost analysis, Fisher's randomization and leave-one-out). Although compound 1g is among the most potent URAT1 inhibitors currently under development in clinical trials, the Hypo1 appears to be favorable for future lead optimization.

Structure based design of selective SHP2 inhibitors by De novo design, synthesis and biological evaluation.

SHP2 phosphatase, encoded by the PTPN11 gene, is a non-receptor PTP, which plays an important role in growth factor, cytokine, integrin, hormone signaling pathways, and regulates cellular responses, such as proliferation, differentiation, adhesion migration and apoptosis. Many studies have reported that upregulation of SHP2 expression is closely related to human cancer, such as breast cancer, liver cancer and gastric cancer. Hence, SHP2 has become a promising target for cancer immunotherapy. In this paper, we reported the identification of compound 1 as SHP2 inhibitor. Fragment-based ligand design, De novo design, ADMET and Molecular docking were performed to explore potential selective SHP2 allosteric inhibitors based on SHP836. The results of docking studies indicated that the selected compounds had higher selective SHP2 inhibition than existing inhibitors. Compound 1 was found to have a novel selectivity against SHP2 with an in vitro enzyme activity IC50 value of 9.97 µM. Fluorescence titration experiment confirmed that compound 1 directly bound to SHP2. Furthermore, the results of binding free energies demonstrated that electrostatic energy was the primary factor in elucidating the mechanism of SHP2 inhibition. Dynamic cross correlation studies also supported the results of docking and molecular dynamics simulation. This series of analyses provided important structural features for designing new selective SHP2 inhibitors as potential drugs and promising candidates for pre-clinical pharmacological investigations.

Exploring the effect of E76K mutation on SHP2 cause gain-of-function activity by a molecular dynamics study.

Juvenile myelomonocytic leukemia (JMML), an invasive myeloproliferative neoplasm, is a childhood disease with very high clinical lethality. Somatic mutation E76K in SHP2 is the most commonly identified mutation found in up to 35% of patients with JMML. To investigate the effect of gain-of-function mutation-E76K on SHP2 activity, molecular dynamic simulations on the wild-type SHP2 (SHP2-WT) system and the mutated E76K (SHP2-E76K) system were performed. The evaluation of stability of these two systems indicated that the simulated trajectories were stable after simulation for 3 nanoseconds. The root mean square fluctuation and the per-residue root mean square deviation illustrated that there were two regions (residues Tyr 81-Glu 83 and Glu 258-Leu 261) in the wild-type system and the mutated system, which had large differences. The principal component analysis, dynamic cross correlation maps analysis, as well as secondary structure analysis suggested that the mutated E76K impacted the movement of these two regions in SHP2 protein. Furthermore, residue interaction network analysis, hydrogen bond occupancy, and binding free energies analysis were used to explain how the two regions were specifically affected by the mutant. The results indicated that the primary variances between SHP2-WT and SHP2-E76K were the different interactions between Glu/Lys 76 and Arg 265, Tyr 80 and Leu 77, Leu 77 and Tyr 81, Thr 73 and Glu 258, Ala 75 and Cys 259, Phe 71 and Tyr 81, Ala 75 and Glu 258, and Tyr 73 and Glu/Lys 76. Consequently, these findings here might provide insights into the increased activity in SHP2-E76K.

Synthesis of 6-hydroxyaurone analogues and evaluation of their α-glucosidase inhibitory and glucose consumption-promoting activity: Development of highly active 5,6-disubstituted derivatives.

A series of 6-hydroxyaurones and their analogues have been synthesized and evaluated for their in vitro α-glucosidase inhibitory and glucose consumption-promoting activity. These compounds exhibited varying degrees of α-glucosidase inhibitory activity, 11 of them showing higher potency than that of the control standard acarbose (IC50=50.30µM). Surprisingly, analogues devoid of a substituent at C-2 but having an aryl group at C-5 were found to be highly active (e.g., 7f, IC50=9.88µM). Docking analysis substantiated these findings. The kinetic analysis of compound 7f, the most potent α-glucosidase inhibitor of this study, revealed that it inhibited α-glucosidase in an irreversible and mixed competitive mode. In addition, compounds 7f and 10c exhibited significant glucose consumption promoting activity at 1µM.

An Approach to Optically Pure Bridging Chiral p-tert-Butylcalix[4]arenes through a Homologous Anionic Ortho-Fries Rearrangement.

A novel efficient approach to optically pure bridging chiral calix[4]arenes through a homologous anionic ortho-Fries rearrangement of inherently chiral calix[4]arenes was presented for the first time. As a result, two pairs of N,N'-dimethylformamidyl-substituted bridging chiral p-tert-butylcalix[4]arene enantiomers were facilely obtained. Their absolute configurations were determined through ROESY analysis, ECD comparison, and X-ray crystallographic analysis.

Efficient enzymatic synthesis of L-rhamnulose and L-fuculose.

L-Rhamnulose (6-deoxy-L-arabino-2-hexulose) and L-fuculose (6-deoxy-L-lyxo-2-hexulose) were prepared from L-rhamnose and L-fucose by a two-step strategy. In the first reaction step, isomerization of L-rhamnose to L-rhamnulose, or L-fucose to L-fuculose was combined with a targeted phosphorylation reaction catalyzed by L-rhamnulose kinase (RhaB). The by-products (ATP and ADP) were selectively removed by silver nitrate precipitation method. In the second step, the phosphate group was hydrolyzed to produce L-rhamnulose or L-fuculose with purity exceeding 99% in more than 80% yield (gram scale).

Design, synthesis and docking study of novel tetracyclic oxindole derivatives as α-glucosidase inhibitors.

A series of novel tetracyclic oxindole derivatives were synthesized via tandem Suzuki coupling-Michael addition reaction catalyzed by palladium. Twenty derivatives were designed and synthesized in 6-8 steps in 8-20% overall yields. Their structures were confirmed by (1)H, (13)C NMR and LC/MS. These compounds were evaluated for α-glucosidase inhibitory activity in vitro. Compounds 7c, 7d, 7e, 7g, 7h, and 7i exhibited IC50 values of 32.3, 12.1, 15.7, 29.0, 16.0, and 4.8 µM, respectively, with potency all higher than that of the control standard acarbose (IC50=115.8 µM). Molecular docking studies revealed the existence of potential hydrogen bonding and hydrophobic interaction between the enzyme and the active compound 7i.

Synthesis, α-glucosidase inhibitory and molecular docking studies of prenylated and geranylated flavones, isoflavones and chalcones.

Three series of prenylated and/or geranylated flavonoids were synthesized and evaluated for their α-glucosidase inhibitory activity. The 3',5'-digeranylated chalcone (16) was identified as a new α-glucosidase inhibitor whose activity (IC50=0.90 µM) was 50-fold more than that of acarbose (IC50=51.32 µM). Molecular docking studies revealed the existence of strong hydrophobic interaction and H-bonding between compound 16 and α-glucosidase's active site. The inhibitory mode analysis showed that 16 exhibited a competitive inhibitory mode.

Design, synthesis, biological activity and molecular dynamics studies of specific protein tyrosine phosphatase 1B inhibitors over SHP-2.

Over expressing in PTPN1 (encoding Protein tyrosine phosphatase 1B, PTP1B), a protein tyrosine phosphatase (PTP) that plays an overall positive role in insulin signaling, is linked to the pathogenesis of diabetes and obesity. The relationship between PTP1B and human diseases exhibits PTP1B as the target to treat these diseases. In this article, small weight molecules of the imidazolidine series were screened from databases and optimized on silicon as the inhibitors of PTP1B based on the steric conformation and electronic configuration of thiazolidinedione (TZD) compounds. The top three candidates were tested using an in vitro biological assay after synthesis. Finally, we report a novel inhibitor, Compound 13, that specifically inhibits PTP1B over the closely related phosphatase Src homology 2 (SH2) domain-containing phosphatase 2 (SHP-2) at 80 µΜ. Its IC50 values are reported in this paper as well. This compound was further verified by computer analysis for its ability to combine the catalytic domains of PTP1B and SHP-2 by molecular dynamics (MD) simulations.

Exploring the mechanism of C473D mutation on CDC25B causing weak binding affinity with CDK2/CyclinA by molecular dynamics study.

CDC25B belongs to the CDC25 family, and it plays an important part in regulating the activity of CDK/CyclinA. Studies have shown that CDC25B is closely related to cancer development. When CYS473 on CDC25B is mutated into ASP, the affinity between CDC25B and CDK2/CyclinA weakens, and their dissociation speed is greatly improved. However, the mechanism by which the CDC25BC473D mutant weakens its binding to CDK2/CyclinA is unclear. In order to study the effect of CDC25BC473D mutants on CDK2/CyclinA substrates, we constructed and verified the rationality of the CDC25BWT:CDK2/CyclinA system and CDC25BC473D:CDK2/CyclinA system and conducted molecular dynamics (MD) simulation analysis. In the post-analysis, the fluctuations of residues ARG488-SER499, LYS541-TRP550 on CDC25B and residues ASP206-ASP210 on CDK2 were massive in the mutant CDC25BC473D:CDK2/CyclinA system. And the interactions between residue ARG492 and residue GLU208, residue ARG544 and residue GLU42, residue ARG544 and TRP550 were weakened in the mutant CDC25BC473D:CDK2/CyclinA system. The results showed that when CYS473 on CDC25B was mutated into ASP473, the mutant CDC25BC473D:CDK2/CyclinA system was less stable than the wild-type CDC25BWT:CDK2/CyclinA system. Finally, active site CYS473 of CDC25B was speculated to be the key residue, which had great effects on the binding between CDC25BCYS473 and CDK2 in the CDC25BC473D:CDK2/CyclinA system. Consequently, overall analyses appeared in this study ultimately provided a useful understanding of the weak interactions between CDC25BCYS473D and CDK2/CyclinA.Communicated by Ramaswamy H. Sarma.

Design, synthesis and evaluation of novel metalloproteinase inhibitors based on L-tyrosine scaffold.

A series of novel L-tyrosine derivatives were designed, synthesized and assayed for their inhibitory activities on matrix metalloproteinase 2 (MMP-2) and histone deacetylase 8 (HDAC-8). The results showed that these L-tyrosine derivatives exhibited inhibitory profiles against MMP-2 and HDAC-8. The compounds 6h (IC(50)=0.013 ± 0.001 µM) and 6j (IC(50)=0.017 ± 0.001 µM) were equal potent MMP-2 inhibitors to the positive control NNGH (IC(50)=0.014 ± 0.001 µM). As for HDAC-8 inhibition, some of the hydroxamate compounds, such as 6d (IC(50)=3.6 ± 0.2 µM) and 6c (IC(50)=5.8 ± 0.5 µM), were equal potent to the positive control SAHA (IC(50)=1.6 ± 0.1 µM). Structure-activity relationships were also briefly discussed.

1-(2-Hy-droxy-3,5-dimeth-oxy-phen-yl)ethanone.

In title compound, C(10)H(12)O(4), all of the non-H atoms lie approximately in a plane with the largest deviation being 0.061 (2) Å. An intra-molecular O-H⋯O hydrogen bond generates an S(6) ring motif. No classical inter-molecular hydrogen bonding occurs, with only van der Waals forces stabilizing the crystal structure.

Poly[[bis-(µ-4,4'-bipyridine-κ(2)N:N')copper(I)] perchlorate 0.24-hydrate].

The title copper(I) polymeric compound, {[Cu(C(10)H(8)N(2))(2)]ClO(4)·0.24H(2)O}(n), obtained by the reaction of Cu(ClO(4))(2) and 4,4'-bipyridine (4,4'-bpy) under hydro-thermal conditions, features a fourfold-inter-penetrated diamondoid coordination framework. The asymmetric unit consists of two Cu(I) atoms, three 4,4'-bpy ligands in general positions and two halves of two centrosymmetric 4,4'-bpy ligands, two ClO(4) (-) anions and water mol-ecule with a site-occupancy factor of 0.480 (17). The Cu(I) atoms are in a distorted tetra-hedral coordination environment and are bridged by 4,4'-bpy ligands, forming a diamondoid cationic polymeric framework that encloses two symmetry-independent channels along [100], which accommodate perchlorate anions and water mol-ecules.