51
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Gao Y, Luo J, Yao ZJ, Guo R, Zou H, Kelley J, Voigt JH, Yang D, Burke TR. Inhibition of Grb2 SH2 domain binding by non-phosphate-containing ligands. 2. 4-(2-Malonyl)phenylalanine as a potent phosphotyrosyl mimetic. J Med Chem 2000; 43:911-20. [PMID: 10715157 DOI: 10.1021/jm9904248] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nonhydrolyzable phosphotyrosyl (pTyr) mimetics serve as important components of many competitive Grb2 SH2 domain inhibitors. To date, the most potent of these inhibitors have relied on phosphonate-based structures to replace the 4-phosphoryl group of the parent pTyr residue. Reported herein is the design and evaluation of a new pTyr mimetic, p-malonylphenylalanine (Pmf), which does not contain phosphorus yet, in Grb2 SH2 domain binding systems, approaches the potency of phosphonate-based pTyr mimetics. When incorporated into high affinity Grb2 SH2 domain-directed platforms, Pmf is 15-20 times more potent than the closely related previously reported pTyr mimetic, O-malonyltyrosine (OMT). Pmf-containing inhibitors show inhibition constants as low as 8 nM in extracellular Grb2 binding assays and in whole cell systems, effective blockade of both endogenous Grb2 binding to cognate erbB-2, and downstream MAP kinase activation. Evidence is provided that use of an N(alpha)()-oxalyl auxiliary enhances effectiveness of Pmf and other inhibitors in both extracellular and intracellular contexts. As one of the most potent Grb2 SH2 domain-directed pTyr mimetics yet disclosed, Pmf may potentially have utility in the design of new chemotherapeutics for the treatment of various proliferative diseases, including breast cancer.
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Affiliation(s)
- Y Gao
- Laboratory of Medicinal Chemistry, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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52
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Watanabe T, Suzuki T, Umezawa Y, Takeuchi T, Otsuka M, Umezawa K. Structure–Activity Relationship and Rational Design of 3,4-Dephostatin Derivatives as Protein Tyrosine Phosphatase Inhibitors. Tetrahedron 2000. [DOI: 10.1016/s0040-4020(99)01058-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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53
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Sinha S, Corey SJ. Implications for Src kinases in hematopoiesis: signal transduction therapeutics. JOURNAL OF HEMATOTHERAPY & STEM CELL RESEARCH 1999; 8:465-80. [PMID: 10791898 DOI: 10.1089/152581699319920] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Signal transduction therapeutics is now the dominant theme of drug discovery, and its most immediate impact will be in cancer therapeutics. Blood cell proliferation, differentiation, and activation are controlled by cytokines, whose receptors contain tyrosine kinase catalytic domains or recruit cytosolic tyrosine kinases. Among the most important cytosolic protein tyrosine kinases are the Src and Jak families. Receptor or cytosolic protein tyrosine kinases activate a similar set of intracellular signaling molecules. In blood cells, excessive tyrosine kinase activity is associated with either cancer or autoreactive diseases. Therefore, tyrosine kinases and their substrates serve as excellent candidates for drug intervention. Herceptin has been approved for use in breast cancer. Other agents, such as SU101 and CGP 57418B, are well into phase I-III trials. Newer, more selective tyrosine kinase inhibitors are being evaluated for future use in the treatment of hematologic and solid tumors as well as a wide range of inflammatory or autoimmune diseases.
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Affiliation(s)
- S Sinha
- Department of Pediatrics (Hematology-Oncology), Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, PA 15213, USA
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54
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Beaulieu PL, Cameron DR, Ferland JM, Gauthier J, Ghiro E, Gillard J, Gorys V, Poirier M, Rancourt J, Wernic D, Llinas-Brunet M, Betageri R, Cardozo M, Hickey ER, Ingraham R, Jakes S, Kabcenell A, Kirrane T, Lukas S, Patel U, Proudfoot J, Sharma R, Tong L, Moss N. Ligands for the tyrosine kinase p56lck SH2 domain: discovery of potent dipeptide derivatives with monocharged, nonhydrolyzable phosphate replacements. J Med Chem 1999; 42:1757-66. [PMID: 10346928 DOI: 10.1021/jm980676t] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
p56lck is a member of the src family of tyrosine kinases. Through modular binding units called SH2 domains, p56lck promotes phosphotyrosine-dependent protein-protein interactions and plays a critical role in signal transduction events that lead to T-cell activation. Starting from the phosphorylated dipeptide (2), a high-affinity ligand for the p56lck SH2 domain, we have designed novel dipeptides that contain monocharged, nonhydrolyzable phosphate group replacements and bind to the protein with KD's in the low micromolar range. Replacement of the phosphate group in phosphotyrosine-containing sequences by a (R/S)-hydroxyacetic (compound 8) or an oxamic acid (compound 10) moiety leads to hydrolytically stable, monocharged ligands, with 83- and 233-fold decreases in potency, respectively. This loss in binding affinity can be partially compensated for by incorporating large lipophilic groups at the inhibitor N-terminus. These groups provide up to 13-fold increases in potency depending on the nature of the phosphate replacement. The discovery of potent (2-3 microM), hydrolytically stable dipeptide derivatives, bearing only two charges at physiological pH, represents a significant step toward the discovery of compounds with cellular activity and the development of novel therapeutics for conditions associated with undesired T-cell proliferation.
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Affiliation(s)
- P L Beaulieu
- Boehringer Ingelheim Pharmaceuticals Inc., 175 Briar Ridge Road, Ridgefield, Connecticut 06877, USA
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55
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Abstract
A one-step enzymatic synthesis of the conformationally restrained tyrosine analog (2S,3R)-beta-methyltyrosine is reported. This synthesis extends the preparative chemistry associated with tyrosine phenol-lyase. This beta-methyltyrosine derivative was shown to be an efficient protein tyrosine kinase substrate, suggesting that conformational restraint may ultimately be used to enhance tyrosine kinase recognition of substrates.
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Affiliation(s)
- K Kim
- Laboratory of Bioorganic Chemistry, Rockefeller University, New York, NY 10021, USA
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56
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Yao ZJ, Gao Y, Voigt JH, Ford H, Burke TR. Synthesis of Fmoc-protected 4-carboxydifluoromethyl-L-phenylalanine: A phosphotyrosyl mimetic of potential use for signal transduction studies. Tetrahedron 1999. [DOI: 10.1016/s0040-4020(99)00076-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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57
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Yokomatsu T, Murano T, Umesue I, Soeda S, Shimeno H, Shibuya S. Synthesis and biological evaluation of alpha,alpha-difluorobenzylphosphonic acid derivatives as small molecular inhibitors of protein-tyrosine phosphatase 1B. Bioorg Med Chem Lett 1999; 9:529-32. [PMID: 10098656 DOI: 10.1016/s0960-894x(99)00027-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A series of alpha,alpha-difluorobenzylphosphonic acids having a hydrophobic functional group were prepared via the Stille coupling reaction from halogenated alpha,alpha-difluorobenzylphosphonates. Evaluation of inhibitory activity toward protein tyrosine phosphatase (PTP 1B) revealed that the ethynyl, phenylethynyl and (E)-styryl groups on the benzene nuclei increased the inhibitory activity of alpha,alpha-difluorobenzylphosphonic acid. Inhibitory activities significantly increased upon introducing both (E)-styryl and bis-methylsulfonamide functional groups onto the benzene nuclei of alpha,alpha-difluorobenzylphosphonic acid.
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Affiliation(s)
- T Yokomatsu
- School of Pharmacy, Tokyo University of Pharmacy & Life Science, Horinouchi, Hachioji, Japan
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58
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Burke TR, Luo J, Yao ZJ, Gao Y, Zhao H, Milne GW, Guo R, Voigt JH, King CR, Yang D. Monocarboxylic-based phosphotyrosyl mimetics in the design of GRB2 SH2 domain inhibitors. Bioorg Med Chem Lett 1999; 9:347-52. [PMID: 10091682 DOI: 10.1016/s0960-894x(98)00740-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Three monocarboxylic-containing analogues, O-carboxymethyltyrosine (cmT, 5), 4-(carboxymethyl)phenylalanine (cmF, 6), and 4-(carboxydifluoromethyl)phenylalanine (F2cmF, 7) were utilized as phosphotyrosyl (pTyr) replacements in a high affinity B-bend mimicking platform, where they exhibited IC50 values of 2.5 microM, 65 microM and 28 microM, respectively, in a Grb2 SH2 domain Biacore binding assay. When a terminal N(alpha)-oxalyl axillary was utilized to enhance ligand interactions with a critical SH2 domain Arg67 residue (alphaA-helix), binding potencies increased from 4- to 10-fold, resulting in submicromolar affinity for cmF (IC50 = 0.6 microM) and low micromolar affinity for F2cmF (IC50 = 2 microM). Cell lysate binding studies also showed inhibition of cognate Grb2 binding to the p185erbB-2 phosphoprotein in the same rank order of potency as observed in the Biacore assay. These results indicate the potential value of cmF and F2cmF residues as pTyr mimetics for the study of Grb2 SH2 domains and suggest new strategies for improvements in inhibitor design.
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Affiliation(s)
- T R Burke
- Laboratory of Medicinal Chemistry, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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59
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Yao ZJ, King CR, Cao T, Kelley J, Milne GW, Voigt JH, Burke TR. Potent inhibition of Grb2 SH2 domain binding by non-phosphate-containing ligands. J Med Chem 1999; 42:25-35. [PMID: 9888830 DOI: 10.1021/jm980388x] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Development of Grb2 Src homology 2 (SH2) domain binding inhibitors has important implications for treatment of a variety of diseases, including several cancers. In cellular studies, inhibitors of Grb2 SH2 domain binding have to date been large, highly charged peptides which relied on special transport devices for cell membrane penetration. Work presented in the current study examines a variety of pTyr mimetics in the context of a high-affinity Grb2 binding platform. Among the analogues studied are new non-phosphorus-containing pTyr mimetics 23a and 23b which, when incorporated into tripeptide structures 18f and 20f, are able to inhibit Grb2 SH2 domain binding with affinities among the best yet reported for non-phosphorus-containing SH2 domain inhibitors (IC50 values of 6.7 and 1.3 microM, respectively). The present study has also demonstrated the usefulness of the Nalpha-oxalyl group as an auxiliary which enhances the binding potency of both phosphorus- and non-phosphorus-containing pTyr mimetics. When combined with the (phosphonomethyl)phenylalanine (Pmp) residue to give analogues such as L-20d, potent inhibition of Grb2 SH2 domain binding can be achieved both in extracellular assays using isolated Grb2 SH2 domain protein and in intracellular systems measuring the association of endogenous Grb2 with its cognate p185erbB-2 ligand. These latter effects can be achieved at micromolar to submicromolar concentrations without prodrug derivatization. The oxalyl-containing pTyr mimetics presented in this study should be of general usefulness for the development of other Grb2 SH2 domain antagonists, independent of the beta-bend-mimicking platform utilized for their display.
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Affiliation(s)
- Z J Yao
- Laboratory of Medicinal Chemistry, Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
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60
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Combinatorial synthesis of peptidomimetics. ACTA ACUST UNITED AC 1999. [DOI: 10.1016/s1874-5113(99)80003-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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61
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Kotoris CC, Chen MJ, Taylor SD. Novel phosphate mimetics for the design of non-peptidyl inhibitors of protein tyrosine phosphatases. Bioorg Med Chem Lett 1998; 8:3275-80. [PMID: 9873717 DOI: 10.1016/s0960-894x(98)00598-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Benzylic alpha,alpha-difluorosulfonates, alpha,alpha-difluorotetrazoles, and alpha,alpha-difluorocarboxylates of type 5 and 6 were synthesized and examined as potential phosphate biosteres for PTP1B inhibition. The alpha,alpha-difluorosulfonates and alpha,alpha-difluorotetrazoles were found to be more effective inhibitors than the analogous compounds bearing the fluoromalonyl group, a phosphate biostere currently being used for PTP inhibition.
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Affiliation(s)
- C C Kotoris
- Department of Chemistry, University of Toronto, Mississauga, Ontario, Canada
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62
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Li Z, Yeo SL, Pallen CJ, Ganesan A. Solid-phase synthesis of potential protein tyrosine phosphatase inhibitors via the Ugi four-component condensation. Bioorg Med Chem Lett 1998; 8:2443-6. [PMID: 9873558 DOI: 10.1016/s0960-894x(98)00408-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A library of 108 alpha,alpha-difluoromethylenephosphonic acids was prepared by Ugi four-component condensation using Rink-NH2 resin, 4-[(diethoxyphosphinyl) difluoromethyl]benzoic acid, and a set of 18 aldehydes and 6 isonitriles. Following resin cleavage, the diethylphosphonate esters were hydrolyzed with trimethylsilyl bromide to yield the free acids which were assayed for inhibition of PTP alpha, PTP beta and PTP epsilon.
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Affiliation(s)
- Z Li
- Institute of Molecular and Cell Biology, National University of Singapore
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63
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Roller PP, Wu L, Zhang ZY, Burke TR. Potent inhibition of protein-tyrosine phosphatase-1B using the phosphotyrosyl mimetic fluoro-O-malonyl tyrosine (FOMT). Bioorg Med Chem Lett 1998; 8:2149-50. [PMID: 9873503 DOI: 10.1016/s0960-894x(98)00376-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To enhance PTP binding interactions, both inside and outside the pTyr binding pocket, a thioether-cyclized peptide has been designed based on the EGF receptor autophosphorylation sequence (EGFR988-993) "Asp-Ala-Asp-Glu-pTyr-Leu", in which the pTyr resiude has been replaced by the nonphosphorus-containing pTyr mimetic fluoro-O-malonyltyrosine (FOMT, 2). The resulting peptide 4 exhibits a Ki value of 170 nM, making it one of the most potent inhibitors of PTP1B yet reported.
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Affiliation(s)
- P P Roller
- Laboratory of Medicinal Chemistry, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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64
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Burke TR, Yao ZJ, Zhao H, Milne GW, Wu L, Zhang ZY, Voigt JH. Enantioselective synthesis of nonphosphorus-containing phosphotyrosyl mimetics and their use in the preparation of tyrosine phosphatase inhibitory peptides. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)00590-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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65
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Yokomatsu T, Minowa T, Murano T, Shibuya S. Enzymatic desymmetrization of prochiral 2-benzyl-1,3-propanediol derivatives: A practical chemoenzymatic synthesis of novel phosphorylated tyrosine analogues. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)00586-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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66
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Iorga B, Eymery F, Savignac P. A highly selective synthesis of α-monofluoro- and α-monochloro- benzylphosphonates using electrophilic halogenation of benzylphosphonates carbanions. Tetrahedron Lett 1998. [DOI: 10.1016/s0040-4039(98)00648-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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67
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O-(Carboxydifluoromethyl)-L-tyrosine: Design and synthesis of a novel non phosphorous-containing phosphotyrosine isostere. Tetrahedron 1998. [DOI: 10.1016/s0040-4020(98)00192-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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68
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Lauer JL, Fields GB. Design and Use of Synthetic Peptides as Biological Models. Proteins 1998. [DOI: 10.1016/b978-012058785-8/50005-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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69
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Abstract
Proteins with SH2 or phosphotyrosine binding (PTB) domains bind activated tyrosine kinase receptors and their substrates to propagate signals into cells. Both of the domains recognize phosphotyrosine. Selectivity in these interactions is conferred by short flanking peptide motifs. Therefore, potential exists for modulating tyrosine kinase signaling pathways by the discovery of compounds that selectively bind SH2 and PTB domains. Recent advances with small peptides and nonpeptide compounds suggest that this opportunity can be realized.
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Affiliation(s)
- S E Shoelson
- Department of Medicine, Harvard Medical School and Joslin Diabetes Center, 1 Joslin Place, Boston, MA 02215, USA.
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70
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Qabar MN, Urban J, Kahn M. A facile solution and solid phase synthesis of phosphotyrosine mimetic l-4-[diethylphosphono(difluoromethyl)]-phenylalanine (F2Pmp(EtO)2) derivatives. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00374-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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71
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Giorgetti-Peraldi S, Ottinger E, Wolf G, Ye B, Burke TR, Shoelson SE. Cellular effects of phosphotyrosine-binding domain inhibitors on insulin receptor signaling and trafficking. Mol Cell Biol 1997; 17:1180-8. [PMID: 9032245 PMCID: PMC231843 DOI: 10.1128/mcb.17.3.1180] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shc and insulin receptor substrate 1 (IRS-1) are cytoplasmic substrates of tyrosine kinase receptors that engage, localize, and activate downstream SH2 enzymes. Each contains a phosphotyrosine-binding (PTB) domain that is structurally unrelated to SH2 domains. We have designed high-affinity, cellular inhibitors of the Shc PTB domain by incorporating nonnatural, phosphatase-resistant amino acids into short peptides. None of the inhibitors bind the IRS-1 PTB domain, consistent with distinct specificities for domains. The best inhibitor of the Shc domain was introduced by electroporation into Rat1 fibroblasts that express human insulin receptors. Insulin-stimulated phosphorylation of Shc was inhibited, with no effect on IRS-1, and downstream effects on mitogen-activated protein kinase and DNA synthesis were both inhibited. The PTB domain inhibitor had less influence on epidermal growth factor-induced effects and essentially no impact on serum- or phorbol ester-induced effects. The inhibitor did not affect insulin internalization and its degradation. We conclude that the PTB domain of Shc is critical for its phosphorylation by the insulin receptor, that Shc is an important mediator of insulin's mitogenic effects, and that Shc is not central to insulin receptor cycling in these cells. PTB domains can be inhibited selectively in cells and represent potential targets for drug discovery.
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Affiliation(s)
- S Giorgetti-Peraldi
- Joslin Diabetes Center and Department of Medicine, Harvard Medical School, Boston, Massachusetts 02215, USA
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72
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Shah A, Font JL, Miller MJ, Ream JE, Walker MC, Sikorski JA. New aromatic inhibitors of EPSP synthase incorporating hydroxymalonates as novel 3-phosphate replacements. Bioorg Med Chem 1997; 5:323-34. [PMID: 9061197 DOI: 10.1016/s0968-0896(96)00239-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A new, aromatic analogue of the EPSP synthase enzyme reaction intermediate 1 has been identified, which contains a 3-hydroxymalonate moiety in place of the usual 3-phosphate group. This simplified inhibitor was readily prepared in five steps from ethyl 3,4-dihydroxybenzoate. The resulting tetrahedral intermediate mimic 9 is an effective, competitive inhibitor versus S3P with an apparent Ki of 0.57 +/- 0.06 microM. This result demonstrates that 3-hydroxymalonates exhibit potencies comparable to aromatic inhibitors containing the previously identified 3-malonate ether replacements and can thus function as suitable 3-phosphate mimics in this system. These new compounds provide another example in which a simple benzene ring can be used effectively in place of the more complex shikimate ring in the design of EPSP synthase inhibitors. Furthermore, the greater potency of 9 versus the glycolate derivative 10 and the 5-deoxy-analog 11, again confirms the requirement for multiple anionic charges at the dihydroxybenzoate 5-position in order to attain effective inhibition of this enzyme.
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Affiliation(s)
- A Shah
- Ceregen Corporate Research, Unit of Monsanto Company, St. Louis, MO 63198, USA
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73
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Peptidomimetic ligands for src Homology-2 Domains. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1874-5113(97)80007-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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74
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Akamatsu M, Roller PP, Chen L, Zhang ZY, Ye B, Burke TR. Potent inhibition of protein-tyrosine phosphatase by phosphotyrosine-mimic containing cyclic peptides. Bioorg Med Chem 1997; 5:157-63. [PMID: 9043667 DOI: 10.1016/s0968-0896(96)00195-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In an effort to derive potent and bioavailable protein-tyrosine phosphatase inhibitors, we have previously reported hexameric peptides based on the epidermal growth factor receptor sequence EGFR988-993 (Asp-Ala-Asp-Glu-Xxx-Leu, where Xxx = Tyr), in which the tyrosyl residue has been replaced by the non-hydrolyzable phosphotyrosyl mimics phosphonomethylphenylalanine (Pmp), difluorophosphonomethylphenylalanine (F2Pmp) and O-malonyltyrosine (OMT). Inhibitory potencies (IC50 values) of these peptides against the tyrosine phosphatase PTP IB were 200, 0.2 and 10 microM, respectively. Since cellular penetration of peptides containing highly charged phosphonate residues is compromised, and good bioreversible protection strategies for the F2Pmp residue have not yet been reported, the OMT residue is of particular interest in that it affords potential new prodrug approaches. In the current study we have prepared cyclized versions of the OMT-containing EGFR988-993 peptide in order to increase its proteolytic stability and restrain conformational flexibility. Three different cyclic analogues were synthesized. Two of these were cyclized through the peptide backbone ('head to tail') using in one case a single glycine spacer (heptamer peptide) and in the second instance, two glycines (octamer peptide). In a PTPI-based assay the cyclic heptamer experienced a two-fold loss of potency (Ki = 25.2 +/- 3.9 microM) relative to the linear hexamer parent (Ki = 13 +/- 0.9 microM), while the cyclic octamer demonstrated a live-fold increase in potency (Ki = 2.60 +/- 0.11 microM). The third peptide was cyclized by means of a sulfide bridge between the side chain of a C-terminally added cysteine residue and the beta-carbon of a N-terminal acetyl residue. Although the overall size of this ring was identical to that exhibited by the preceding backbone-cyclized octamer, it displayed a three-fold enhancement in potency (Ki = 0.73 +/- 0.03 microM). The structural basis for the observed results are discussed. Conformation restrictions induced by cyclization could aid in defining geometries for peptidomimetic design. Finally, it can be speculated that cyclization of other liner PTP-inhibitory peptides, such as the F2Pmp-containing hexamer, may also increase their potency.
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Affiliation(s)
- M Akamatsu
- Division of Basic Sciences, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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75
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Synthesis of novel L-phenylalanine derivatives substituted with a keto ylide as stable precursor of a vicinal tricarbonyl moiety. Tetrahedron Lett 1996. [DOI: 10.1016/0040-4039(96)01978-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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76
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Yokomatsu T, Yamagishi T, Matsumoto K, Shibuya S. Stereocontrolled synthesis of hydroxymethylene phosphonate analogues of phosphorylated tyrosine and their conversion to monofluoromethylene phosphonate analogues. Tetrahedron 1996. [DOI: 10.1016/0040-4020(96)00671-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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