The Experts below are selected from a list of 5817 Experts worldwide ranked by ideXlab platform
Daan M F Van Aalten - One of the best experts on this subject based on the ideXlab platform.
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Thio-Linked UDP–Peptide Conjugates as O‑GlcNAc Transferase Inhibitors
2018Co-Authors: Karim Rafie, Riccardo Trapannone, Andrii Gorelik, Vladimir S. Borodkin, Daan M F Van AaltenAbstract:O-GlcNAc Transferase (OGT) is an essential glycosylTransferase that installs the O-GlcNAc post-translational modification on the nucleocytoplasmic proteome. We report the development of S-linked UDP–peptide conjugates as potent bisubstrate OGT Inhibitors. These compounds were assembled in a modular fashion by photoinitiated thiol–ene conjugation of allyl-UDP and optimal acceptor peptides in which the acceptor serine was replaced with cysteine. The conjugate VTPVC(S-propyl-UDP)TA (Ki = 1.3 μM) inhibits the OGT activity in HeLa cell lysates. Linear fusions of this conjugate with cell penetrating peptides were explored as prototypes of cell-penetrant OGT Inhibitors. A crystal structure of human OGT with the inhibitor revealed mimicry of the interactions seen in the pseudo-Michaelis complex. Furthermore, a fluorophore-tagged derivative of the inhibitor works as a high affinity probe in a fluorescence polarimetry hOGT assay
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o glcnac Transferase Inhibitors current tools and future challenges
Biochemical Society Transactions, 2016Co-Authors: Riccardo Trapannone, Karim Rafie, Daan M F Van AaltenAbstract:The O-linked N-acetylglucosamine (O-GlcNAc) post-translational modification (O-GlcNAcylation) is the dynamic and reversible attachment of N-acetylglucosamine to serine and threonine residues of nucleocytoplasmic target proteins. It is abundant in metazoa, involving hundreds of proteins linked to a plethora of biological functions with implications in human diseases. The process is catalysed by two enzymes: O-GlcNAc Transferase (OGT) and O-GlcNAcase (OGA) that add and remove sugar moieties respectively. OGT knockout is embryonic lethal in a range of animal models, hampering the study of the biological role of O-GlcNAc and the dissection of catalytic compared with non-catalytic roles of OGT. Therefore, selective and potent chemical tools are necessary to inhibit OGT activity in the context of biological systems. The present review focuses on the available OGT Inhibitors and summarizes advantages, limitations and future challenges.
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bisubstrate udp peptide conjugates as human o glcnac Transferase Inhibitors
Biochemical Journal, 2014Co-Authors: Vladimir S. Borodkin, Karim Rafie, Helge C. Dorfmueller, Marianne Schimpl, Mehmet Gundogdu, David A Robinson, Daan M F Van AaltenAbstract:Inhibitors of OGT (O-GlcNAc Transferase) are valuable tools to study the cell biology of protein O-GlcNAcylation. We report OG Tb isubstrate-linked Inhibitors (goblins) in which the acceptor serine in the peptide VTPVSTA is covalently linked to UDP, eliminating the GlcNAc pyranoside ring. Goblin1 co-crystallizes with OGT, revealing an ordered C3 linker and retained substratebinding modes, and binds the enzyme with micromolar affinity, inhibiting glycosyltransfer on to protein and peptide substrates.
Michael D. Lewis - One of the best experts on this subject based on the ideXlab platform.
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synthesis of sulfur containing olefinic peptide mimetic farnesyl Transferase Inhibitors using the nozaki hiyama kishi reaction and cuprate sn2 displacements
Journal of Organic Chemistry, 1999Co-Authors: Hu Yang, Xiaoning C. Sheng, Edmund M. Harrington, Karen Ackermann, Ana Maria Garcia, Michael D. LewisAbstract:Syntheses of the potent sulfur-containing tetrapeptide mimetic farnesyl Transferase Inhibitors B956 (22) and B957 (23) are described. The two double bonds in 22 and 23 were constructed by application of iterative NHK and cuprate SN2‘ reactions. Normal syn NHK reaction and substrate-dependent syn and anti-SN2‘ diastereoselectivities accompanied by exclusive E-olefin selectivity were observed for the first NHK iteration (1 → 4). In the second iteration, unexpected epimerization and a strong preference for syn diastereoselectivity was observed for the NHK reaction (5b → 7a + 9a) while an unusual Z-olefin was observed for the SN2‘ reaction (7b → 11). Deprotection conditions were optimized to ensure high purity and yield of the final aminothiol compounds.
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Synthesis of Sulfur-Containing Olefinic Peptide Mimetic Farnesyl Transferase Inhibitors Using the Nozaki−Hiyama−Kishi Reaction and Cuprate SN2‘ Displacements
The Journal of Organic Chemistry, 1999Co-Authors: Hu Yang, Xiaoning C. Sheng, Edmund M. Harrington, Karen Ackermann, Ana Maria Garcia, Michael D. LewisAbstract:Syntheses of the potent sulfur-containing tetrapeptide mimetic farnesyl Transferase Inhibitors B956 (22) and B957 (23) are described. The two double bonds in 22 and 23 were constructed by application of iterative NHK and cuprate SN2‘ reactions. Normal syn NHK reaction and substrate-dependent syn and anti-SN2‘ diastereoselectivities accompanied by exclusive E-olefin selectivity were observed for the first NHK iteration (1 → 4). In the second iteration, unexpected epimerization and a strong preference for syn diastereoselectivity was observed for the NHK reaction (5b → 7a + 9a) while an unusual Z-olefin was observed for the SN2‘ reaction (7b → 11). Deprotection conditions were optimized to ensure high purity and yield of the final aminothiol compounds.
Jean-pierre Hénichart - One of the best experts on this subject based on the ideXlab platform.
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Potent and selective farnesyl Transferase Inhibitors.
Journal of medicinal chemistry, 2004Co-Authors: Régis Millet, Juozas Domarkas, Raymond Houssin, Pauline Gilleron, Jean-françois Goossens, Philippe Chavatte, Cédric Logé, Nicole Pommery, Jean Pommery, Jean-pierre HénichartAbstract:We recently described a novel series of CA1A2X peptidomimetics as farnesyl Transferase Inhibitors (FTIs). These compounds possess an N-(4-piperidinyl)benzamide scaffold mimicking A1A2 residue. Extensive exploration of structure−activity relationships revealed that replacement of cysteine by substituted benzylimidazoles provided nanomolar FTIs with in vitro activities (18e, IC50 = 4.60 nM on isolated enzyme, EC50 = 20.0 nM for growth inhibition on a tumor cell line). The molecular docking of 18e and 19e in the active site of the enzyme provided details of key interactions with the protein and showed that the methionine or phenylalanine residue fits into the aryl binding site.
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Design, Synthesis, and Pharmacological Evaluation of New Farnesyl Protein Transferase Inhibitors
Journal of medicinal chemistry, 2001Co-Authors: Raymond Houssin, Jean-françois Goossens, Philippe Chavatte, Jean Pommery, Marie-catherine Salaün, Sophie Deweer, Jean-pierre HénichartAbstract:New CA1A2X peptidomimetics are described as Ras farnesyl Transferase Inhibitors (FTIs). They include cysteine and methionine as mimetics of the C-terminus sequence of farnesylated proteins. Furthermore, cysteine was replaced by heterocycles, taking into account the role of zinc and the metabolic instability of amino acids. The molecular docking of 8 in the active site of the enzyme and the pharmacological evaluation of the compounds are illustrative of a new class of FTIs.
Roger S. Goody - One of the best experts on this subject based on the ideXlab platform.
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Design, synthesis, and characterization of peptide-based rab geranylgeranyl Transferase Inhibitors.
Journal of medicinal chemistry, 2009Co-Authors: Kui-thong Tan, Ester Guiu-rozas, Robin S. Bon, Zhong Guo, Christine Delon, Stefan Wetzel, Sabine Arndt, Kirill Alexandrov, Herbert Waldmann, Roger S. GoodyAbstract:Rab geranylgeranyl Transferase (RabGGTase) catalyzes the attachment of geranylgeranyl isoprenoids to Rab guanine triphosphatases, which are key regulators in vesicular transport. Because geranylgeranylation is required for proper function and overexpression of Rabs has been observed in various cancers, RabGGTase may be a target for novel therapeutics. The development of selective Inhibitors is, however, difficult because two related enzymes involved in other cellular processes exist in eukaryotes and because RabGGTase recognizes protein substrates indirectly, resulting in relaxed specificity. We report the synthesis of a peptidic library based on the farnesyl Transferase inhibitor pepticinnamin E. Of 469 compounds investigated, several were identified as selective for RabGGTase with low micromolar IC50 values. The compounds were not generally cytotoxic and inhibited Rab isoprenylation in COS-7 cells. Crystal structure analysis revealed that selective Inhibitors interact with a tunnel unique to RabGGTase, implying that this structural motif is an attractive target for improved RabGGTase Inhibitors.
Jan H.m. Schellens - One of the best experts on this subject based on the ideXlab platform.
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Quantification of farnesylmethylcysteine in lysates of peripheral blood mononuclear cells using liquid chromatography coupled with electrospray tandem mass spectrometry: pharmacodynamic assay for farnesyl Transferase Inhibitors.
Analytical chemistry, 2006Co-Authors: Natalie M. G. M. Appels, Jan H.m. Schellens, Hilde Rosing, Trevor C. Stephens, Jos H. BeijnenAbstract:Biological effectiveness is an important parameter in determining optimal dosages of molecular targeted drugs, such as farnesyl Transferase Inhibitors. To determine concentration−effect relationships, robust and quantitative biological assays are a prerequisite. Here, we present a novel assay for protein farnesylation that is based on generation of the biomarker farnesylmethylcysteine (FmC). Quantification was performed with liquid chromatography coupled to tandem mass spectrometry. The assay has been validated based on the most recent FDA guidelines for bioanalytical validation, and all results were within requirements. FmC is formed under the action of an endogenous protease that is activated upon cell lysis. The biomarker could be detected in A549 human lung cancer cells as well as in human peripheral blood mononuclear cells. Incubation of A549 cells with AZD3409, a novel prenyl Transferase inhibitor, resulted in a significant decrease of the FmC concentration in the lysates. These findings provide a v...
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A rapid and simple HPLC-UV method for the determination of inhibition characteristics of farnesyl Transferase Inhibitors.
Biomedical chromatography : BMC, 2006Co-Authors: Natalie M. G. M. Appels, Jan H.m. Schellens, Kien-on Tung, Hilde Rosing, Jos H. BeijnenAbstract:Ras proteins play an important role in the development of cancer. Farnesyl Transferase Inhibitors (FTIs) block the first obligatory post-translational step for activation, prenylation, of Ras proteins. To find new potent FTIs, rapid enzyme activity assays are required to reduce FTI development time. Most assays to date are based on radioactive labelled substrates. We developed a new, in vitro, farnesyl Transferase assay based on gradient chromatography coupled to UV detection. Unfarnesylated and farnesylated H-Ras proteins were resolved on a C18 wide-pore HPLC column and their concentrations were determined with use of a calibration curve of unfarnesylated H-Ras. The assay was used to investigate inhibition characteristics of FTIs. The IC50 values of the FTIs L778,123 and SCH66336 were 4.2 nm and 78 µm, respectively. This assay could support the screening and development of FTIs to obtain rapid insights into their inhibitory properties. Copyright © 2005 John Wiley & Sons, Ltd.
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Development of Farnesyl Transferase Inhibitors: A Review
The oncologist, 2005Co-Authors: Natalie M. G. M. Appels, Jos H. Beijnen, Jan H.m. SchellensAbstract:Farnesyl Transferase Inhibitors are a new class of biologically active anticancer drugs. The exact mechanism of action of this class of agents is, however, currently unknown. The drugs inhibit farnesylation of a wide range of target proteins, including Ras. It is thought that these agents block Ras activation through inhibition of the enzyme farnesyl Transferase, ultimately resulting in cell growth arrest. In preclinical models, the farnesyl Transferase Inhibitors showed great potency against tumor cells; yet in clinical studies, their activity was far less than anticipated. Reasons for this disappointing clinical outcome might be found in the drug-development process. In this paper, we outline an algorithm that is potentially useful for the development of biologically active anticancer drugs. The development of farnesyl Transferase Inhibitors, from discovery to clinical trials, is reviewed on the basis of this algorithm. We found that two important steps of this algorithm were underestimated. First, understanding of the molecular biology of the defective pathway has mainly been focused on H-Ras activation, whereas activation of K-Ras or other farnesylated proteins is probably more important in tumorigenesis. Inhibition of farnesylation is possibly not sufficient, because geranylgeranylation might activate K-Ras and suppress the effect of farnesyl Transferase Inhibitors. Furthermore, a well-defined proof of concept in preclinical and clinical studies has not been achieved. Integrating the proposed algorithm in future studies of newly developed biologically active anti-cancer drugs might increase the rate of success of these compounds in patients.
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Ras biochemistry and farnesyl Transferase Inhibitors: a literature survey.
Anti-cancer drugs, 2001Co-Authors: M. Crul, Jos H. Beijnen, G. J. De Klerk, Jan H.m. SchellensAbstract:Over the last decades, knowledge on the genetic defects involved in tumor formation and growth has increased rapidly. This has launched the development of novel anticancer agents, interfering with the proteins encoded by the identified mutated genes. One gene of particular interest is ras, which is found mutated at high frequency in a number of malignancies. The Ras protein is involved in signal transduction: it passes on stimuli from extracellular factors to the cell nucleus, thereby changing the expression of a number of growth regulating genes. Mutated Ras proteins remain longer in their active form than normal Ras proteins, resulting in an overstimulation of the proliferative pathway. In order to function, Ras proteins must undergo a series of post-translational modifications, the most important of which is farnesylation. Inhibition of Ras can be accomplished through inhibition of farnesyl Transferase, the enzyme responsible for this modification. With this aim, a number of agents, designated farnesyl Transferase Inhibitors (FTIs), have been developed that possess antineoplastic activity. Several of them have recently entered clinical trials. Even though clinical testing is still at an early stage, antitumor activity has been observed. At the same time, knowledge on the biochemical mechanisms through which these drugs exert their activity is expanding. Apart from Ras, they also target other cellular proteins that require farnesylation to become activated, e.g. RhoB. Inhibition of the farnesylation of RhoB results in growth blockade of the exposed tumor cells as well as an increase in the rate of apoptosis. In conclusion, FTIs present a promising class of anticancer agents, acting through biochemical modulation of the tumor cells.