151
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Xu LW, Ju YD, Li L, Qiu HY, Jiang JX, Lai GQ. Homogeneous silicone modified primary amine-Brønsted acid salt catalyzed aldol reaction: unexpected synergistic effect of polysiloxane with remarkable improvement of efficiency and stereoselectivity. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.09.145] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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152
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The Tubulin Binding Mode of MT Stabilizing and Destabilizing Agents Studied by NMR. Top Curr Chem (Cham) 2008; 286:151-208. [DOI: 10.1007/128_2008_22] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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153
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Paterson I, Gardner NM, Guzmán E, Wright AE. Total synthesis and biological evaluation of novel C2-C6 region analogues of dictyostatin. Bioorg Med Chem 2008; 17:2282-9. [PMID: 19022679 DOI: 10.1016/j.bmc.2008.10.084] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 06/12/2008] [Accepted: 10/31/2008] [Indexed: 11/26/2022]
Abstract
By exploiting a Still-Gennari HWE coupling with a common C11-C26 aldehyde, a series of C2-C6 modified analogues of the microtubule-stabilising marine natural product dictyostatin were synthesised and evaluated in vitro for growth inhibition against a range of human cancer cell lines, including the (P-glycoprotein efflux-mediated) Taxol-resistant NCI/ADR cell line. Removal of the C6 methyl substituent in dictyostatin was found to be well tolerated and led to the retention of antiproliferative activity in the low nanomolar range (IC(50)=43 nM in the NCI/ADR cell line), while partial and full saturation of the (2Z,4E)-dienoate region led to a progressive reduction in biological potency. The lactone ring size was found to be critical, as C21 to C19 translactonisation to afford 20-membered isodictyostatin analogues led to a significant loss of cytotoxicity. In a series of incubatory experiments performed on the PANC-1 cell line, all three of the 22-membered macrolide analogues acted in an analogous fashion to dictyostatin, through a mechanism of microtubule stabilization, causing both an accumulation of cells at the G2/M phase and formation of characteristic dense intracellular microtubule bundles.
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Affiliation(s)
- Ian Paterson
- University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
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154
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Mulzer J, Altmann KH, Höfle G, Müller R, Prantz K. Epothilones – A fascinating family of microtubule stabilizing antitumor agents. CR CHIM 2008. [DOI: 10.1016/j.crci.2008.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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155
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The Tubulin Binding Mode of Microtubule Stabilizing Agents Studied by Electron Crystallography. Top Curr Chem (Cham) 2008; 286:209-57. [DOI: 10.1007/128_2008_24] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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156
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Lehotzky A, Tőkési N, Gonzalez-Alvarez I, Merino V, Bermejo M, Orosz F, Lau P, Kovacs G, Ovádi J. Progress in the development of early diagnosis and a drug with unique pharmacology to improve cancer therapy. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2008; 366:3599-3617. [PMID: 18644768 PMCID: PMC2696110 DOI: 10.1098/rsta.2008.0106] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Cancer continues to be one of the major health and socio-economic problems worldwide, despite considerable efforts to improve its early diagnosis and treatment. The identification of new constituents as biomarkers for early diagnosis of neoplastic cells and the discovery of new type of drugs with their mechanistic actions are crucial to improve cancer therapy. New drugs have entered the market, thanks to industrial and legislative efforts ensuring continuity of pharmaceutical development. New targets have been identified, but cancer therapy and the anti-cancer drug market still partly depend on anti-mitotic agents. The objective of this paper is to show the effects of KAR-2, a potent anti-mitotic compound, and TPPP/p25, a new unstructured protein, on the structural and functional characteristics of the microtubule system. Understanding the actions of these two potential effectors on the microtubule system could be the clue for early diagnosis and improvement of cancer therapy.
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Affiliation(s)
- A. Lehotzky
- Institute of Enzymology, Biological Research Centre, Hungarian Academy of SciencesKarolina út 29, 1113 Budapest, Hungary
| | - N. Tőkési
- Institute of Enzymology, Biological Research Centre, Hungarian Academy of SciencesKarolina út 29, 1113 Budapest, Hungary
| | - I. Gonzalez-Alvarez
- Department of Pharmaceutics and Pharmaceutical Technology, University of Valencia46010 Valencia, Spain
| | - V. Merino
- Department of Pharmaceutics and Pharmaceutical Technology, University of Valencia46010 Valencia, Spain
| | - M. Bermejo
- Department of Pharmaceutics and Pharmaceutical Technology, University of Valencia46010 Valencia, Spain
| | - F. Orosz
- Institute of Enzymology, Biological Research Centre, Hungarian Academy of SciencesKarolina út 29, 1113 Budapest, Hungary
| | - P. Lau
- Section of Developmental Genetics, National Institute of Neurological Disorders and Stroke, National Institutes of HealthBethesda, MD 20892, USA
| | - G.G. Kovacs
- Institute of Neurology, Medical University of Vienna1097 Vienna, Austria
| | - J. Ovádi
- Institute of Enzymology, Biological Research Centre, Hungarian Academy of SciencesKarolina út 29, 1113 Budapest, Hungary
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157
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Paterson I, Gardner NM, Guzmán E, Wright AE. Total synthesis and biological evaluation of potent analogues of dictyostatin: modification of the C2-C6 dienoate region. Bioorg Med Chem Lett 2008; 18:6268-72. [PMID: 18951787 DOI: 10.1016/j.bmcl.2008.09.109] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 09/22/2008] [Indexed: 11/30/2022]
Abstract
By exploiting a Still-Gennari olefination of a common C11-C26 aldehyde with a C4-C10 or C1-C10 beta-ketophosphonate, three modified C2-C6 region analogues of the 22-membered macrolide dictyostatin were synthesised and evaluated in vitro for growth inhibition against a range of human cancer cell lines, including the Taxol-resistant NCI/ADR-Res cell line. 6-Desmethyldictyostatin and 2,3-dihydrodictyostatin displayed potent (low nanomolar) antiproliferative activity, intermediate between dictyostatin and discodermolide, while 2,3,4,5-tetrahydrodictyostatin showed activity comparable to discodermolide. As with dictyostatin, these simplified analogues act through a mechanism of microtubule stabilisation, G2/M arrest and apoptosis.
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Affiliation(s)
- Ian Paterson
- University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW, UK.
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158
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Ishiguro K, Ando T, Watanabe O, Goto H. Specific reaction of alpha,beta-unsaturated carbonyl compounds such as 6-shogaol with sulfhydryl groups in tubulin leading to microtubule damage. FEBS Lett 2008; 582:3531-6. [PMID: 18805415 DOI: 10.1016/j.febslet.2008.09.027] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 09/10/2008] [Indexed: 12/20/2022]
Abstract
6-Shogaol and 6-gingerol are ginger components with similar chemical structures. However, while 6-shogaol damages microtubules, 6-gingerol does not. We have investigated the molecular mechanism of 6-shogaol-induced microtubule damage and found that the action of 6-shogaol results from the structure of alpha,beta-unsaturated carbonyl compounds. alpha,beta-Unsaturated carbonyl compounds such as 6-shogaol react with sulfhydryl groups of cysteine residues in tubulin, and impair tubulin polymerization. The reaction with sulfhydryl groups depends on the chain length of alpha,beta-unsaturated carbonyl compounds. In addition, alpha,beta-unsaturated carbonyl compounds are more reactive with sulfhydryl groups in tubulin than in 2-mercaptoethanol, dithiothreitol, glutathione and papain, a cysteine protease.
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Affiliation(s)
- Kazuhiro Ishiguro
- Molecular Biology and Pathogenesis of Gastroenterology, Nagoya University School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Aichi 466-8550, Japan.
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159
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Paterson I, Naylor GJ, Wright AE. Total synthesis of a potent hybrid of the anticancer natural products dictyostatin and discodermolide. Chem Commun (Camb) 2008:4628-30. [PMID: 18815706 DOI: 10.1039/b811575c] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A potent dictyostatin-discodermolide hybrid was designed and synthesised; it showed enhanced cell growth inhibitory activity relative to discodermolide in four human cancer cell lines including the Taxol-resistant NCI/ADR-Res cell line.
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Affiliation(s)
- Ian Paterson
- University Chemical Laboratory, Lensfield Road, Cambridge, UKCB2 1EW.
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160
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Bolognesi ML, Calonghi N, Mangano C, Masotti L, Melchiorre C. Parallel Synthesis and Cytotoxicity Evaluation of a Polyamine−Quinone Conjugates Library. J Med Chem 2008; 51:5463-7. [DOI: 10.1021/jm800637b] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Maria Laura Bolognesi
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy, Department of Biochemistry “G. Moruzzi”, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Natalia Calonghi
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy, Department of Biochemistry “G. Moruzzi”, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Chiara Mangano
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy, Department of Biochemistry “G. Moruzzi”, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Lanfranco Masotti
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy, Department of Biochemistry “G. Moruzzi”, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Carlo Melchiorre
- Department of Pharmaceutical Sciences, Alma Mater Studiorum, University of Bologna, Via Belmeloro 6, 40126 Bologna, Italy, Department of Biochemistry “G. Moruzzi”, Alma Mater Studiorum, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
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161
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Feyen F, Jantsch A, Hauenstein K, Pfeiffer B, Altmann KH. Synthesis of 12-aza analogs of epothilones and (E)-9,10-dehydroepothilones. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.06.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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162
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Altmann KH, Memmert K. Epothilones as lead structures for new anticancer drugs--pharmacology, fermentation, and structure-activity-relationships. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2008; 66:273, 275-334. [PMID: 18416309 DOI: 10.1007/978-3-7643-8595-8_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epothilones (Epo's) A and B are naturally occurring microtubule-stabilizers, which inhibit the growth of human cancer cells in vitro at low nM or sub-nM concentrations. In contrast to taxol (paclitaxel, Taxol) epothilones are also active against different types of multidrug-resistant cancer cell lines in vitro and against multidrug-resistant tumors in vivo. Their attractive preclinical profile has made epothilones important lead structures in the search for improved cytotoxic anticancer drugs and Epo B (EPO906, patupilone) is currently undergoing Phase III clinical trials. Numerous synthetic and semisynthetic analogs have been prepared since the absolute stereochemistry of epothilones was first disclosed in mid-1996 and their in vitro biological activity has been determined. Apart from generating a wealth of SAR information, these efforts have led to the identification of at least six compounds (in addition to Epo B), which are currently at various stages of clinical evaluation in humans. The most advanced of these compounds, Epo B lactam BMS-247550 (ixabepilone), has recently obtained FDA approval for the treatment of metastatic and advanced breast cancer. This chapter will first provide a summary of the basic features of the biological profile of Epo B in vitro and in vivo. This will be followed by a review of the processes that have been developed for the fermentative production of Epo B. The main part of the chapter will focus on the most relevant aspects of the epothilone SAR with regard to effects on tubulin polymerization, in vitro antiproliferative activity, and in vivo antitumor activity. Particular emphasis will be placed on work conducted in the authors' own laboratories, but data from other groups will also be included. In a final section, the current status of those epothilone analogs undergoing clinical development will be briefly discussed.
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Affiliation(s)
- Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology (ETH) Zürich, Switzerland.
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163
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Carlson RO. New tubulin targeting agents currently in clinical development. Expert Opin Investig Drugs 2008; 17:707-22. [PMID: 18447597 DOI: 10.1517/13543784.17.5.707] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The first tubulin targeting agents were approved as cancer chemotherapeutics over 40 years ago and tubulin as an antitumor target continues to attract significant drug discovery and development attention. Mechanism of action as defined by tubulin binding sites and effect on microtubules distinguishes these agents, but the end result is equivalent in that microtubule disruption leads to cell cycle arrest at G2/M phase of the cell cycle and subsequent apoptotic cell death. OBJECTIVES The goal of this review is to describe the state of clinical development of tubulin targeting agents as of early 2008, with descriptions of clinical experience slanted toward the most advanced trials for each agent. METHOD Objective information in this review was obtained exclusively from public sources that included journals, scientific meeting abstracts, posters and oral presentations, websites and public presentations from companies. Opinions expressed in this review are exclusively from the author. RESULTS/CONCLUSIONS A large number of tubulin targeting agents are currently in clinical development, including microtubule stabilizing and destabilizing compounds acting through all three of the characterized tubulin binding sites. With the approval of ixabepilone for refractory breast cancer, the epothilones appear best positioned to make an impact among the new microtubule stabilizing compounds. There are 17 microtubule destabilizing agents under clinical assessment, with many only in Phase I and results to date include at best modest efficacy signals with no obvious indication trend.
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Affiliation(s)
- Robert O Carlson
- Discovery Biology, Myriad Pharmaceuticals, Inc., 320 Wakara Way, Salt Lake City, UT 84103, USA.
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164
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Bräuer L, Brandt W, Schulze D, Zakharova S, Wessjohann L. A structural model of the membrane-bound aromatic prenyltransferase UbiA from E. coli. Chembiochem 2008; 9:982-92. [PMID: 18338424 DOI: 10.1002/cbic.200700575] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The membrane-bound enzyme 4-hydroxybenzoic acid oligoprenyltransferase (ubiA) from E. coli is crucial for the production of ubiquinone, the essential electron carrier in prokaryotic and eukaryotic organisms. On the basis of previous modeling analyses, amino acids identified as important in two putative active sites (1 and 2) were selectively mutated. All mutants but one lost their ability to form geranylated hydroxybenzoate, irrespective of their being from active site 1 or 2. This suggests either that the two active sites are interrelated or that they are in fact only one site. With the aid of the experimental results and a new structure-based classification of prenylating enzymes, a relevant 3D model could be developed by threading. The new model explains the substrate specificities and is in complete agreement with the results of site-directed mutagenesis. The high similarity of the active fold of UbiA-transferase to that of 5-epi-aristolochene synthase (Nicotiana tabacum), despite a low homology, allows a hypothesis on a convergent evolution of these enzymes to be formed.
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Affiliation(s)
- Lars Bräuer
- Leibniz-Institute of Plant Biochemistry, Department of Bioorganic Chemistry, Weinberg 3, 06120 Halle/Saale, Germany
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165
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Enomoto T, Morimoto T, Ueno M, Matsukubo T, Shimada Y, Tsutsumi K, Shirai R, Kakiuchi K. A novel route for the construction of Taxol ABC-ring framework: skeletal rearrangement approach to AB-ring and intramolecular aldol approach to C-ring. Tetrahedron 2008. [DOI: 10.1016/j.tet.2008.02.039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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166
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Paterson I, Ashton K, Britton R, Cecere G, Chouraqui G, Florence GJ, Knust H, Stafford J. Total synthesis of (-)-reidispongiolide A, an actin-targeting macrolide isolated from the marine sponge Reidispongia coerulea. Chem Asian J 2008; 3:367-87. [PMID: 18181126 DOI: 10.1002/asia.200700357] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A stereocontrolled total synthesis of the microfilament-destabilizing cytotoxic macrolide (-)-reidispongiolide A, isolated from the New Caledonian marine sponge Reidispongia coerulea, is described. This synthesis utilizes a convergent aldol-based strategy to construct the 26-membered macrolactone, followed by the late-stage coupling of a derived aldehyde with an N-vinylformamide-containing ketone subunit to install the full side chain. Two alternative routes were examined for the introduction of the 2E,4E-dienoate region, and a complex Mukaiyama aldol coupling was used to connect the northern and southern hemispheres to install the C13 stereocenter. This constitutes the first chemical synthesis of any member of the reidispongiolide/sphinxolide family of marine macrolides and unequivocally establishes the relative and absolute configuration.
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Affiliation(s)
- Ian Paterson
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK.
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167
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Paterson I, Gardner NM, Poullennec KG, Wright AE. Synthesis and biological evaluation of 10,11-dihydrodictyostatin, a potent analogue of the marine anticancer agent dictyostatin. JOURNAL OF NATURAL PRODUCTS 2008; 71:364-369. [PMID: 18081257 DOI: 10.1021/np070547s] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
By employing a diverted total synthesis strategy with late-stage intermediates, 10,11-dihydrodictyostatin ( 5) was prepared and evaluated in vitro for growth inhibition against a range of human cancer cell lines, including the NCI/ADR Taxol-resistant cell line. This novel dictyostatin analogue was found to retain potent antimitotic activity, with a comparable profile to discodermolide and Taxol, functioning by microtubule stabilization and G2/M arrest. These SAR studies provide further insight into the interaction between dictyostatin ( 1) and its tubulin target.
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168
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Florence GJ, Gardner NM, Paterson I. Development of practical syntheses of the marine anticancer agents discodermolide and dictyostatin. Nat Prod Rep 2008; 25:342-75. [PMID: 18389141 DOI: 10.1039/b705661n] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Initially isolated in trace quantities from deep-sea sponges, the structurally related polyketides discodermolide and dictyostatin share the same microtubule-stabilizing antimitotic mechanism as Taxol. Discodermolide has been the focus of intense research activity in order to develop a practical supply route, and these efforts ultimately allowed its large-scale synthesis and the initiation of clinical trials as a novel anticancer drug. Similarly, the re-isolation and synthesis of dictyostatin continues to stimulate the biological and chemical communities in their quest for the development of new chemotherapeutic agents. This comprehensive review chronicles the synthetic endeavours undertaken over the last 15 years towards the development and realization of practical chemical syntheses of discodermolide and, more recently, dictyostatin, focusing on the methods and strategies employed for achieving overall stereocontrol and key fragment unions, as well as the design and synthesis of novel hybrid structures.
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Affiliation(s)
- Gordon J Florence
- School of Chemistry and Centre for Biomolecular Sciences, University of St Andrews, North Haugh, St Andrews KY16 9 ST, United Kingdom.
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169
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Abstract
Throughout history, natural products have afforded a rich source of compounds that have found many applications in the fields of medicine, pharmacy and biology. Within the sphere of cancer, a number of important new commercialised drugs have been obtained from natural sources, by structural modification of natural compounds, or by the synthesis of new compounds, designed following a natural compound as model. The search for improved cytotoxic agents continues to be an important line in the discovery of modern anticancer drugs. The huge structural diversity of natural compounds and their bioactivity potential have meant that several products isolated from plants, marine flora and microorganisms can serve as "lead" compounds for improvement of their therapeutic potential by molecular modification. Additionally, semisynthesis processes of new compounds, obtained by molecular modification of the functional groups of lead compounds, are able to generate structural analogues with greater pharmacological activity and with fewer side effects. These processes, complemented with high-throughput screening protocols, combinatorial chemistry, computational chemistry and bioinformatics are able to afford compounds that are far more efficient than those currently used in clinical practice. Combinatorial biosynthesis is also applied for the modification of natural microbial products. Likewise, advances in genomics and the advent of biotechnology have improved both the discovery and production of new natural compounds.
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170
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Paterson I, Florence GJ. The Chemical Synthesis of Discodermolide. Top Curr Chem (Cham) 2008; 286:73-119. [DOI: 10.1007/128_2008_7] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
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171
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Feyen F, Cachoux F, Gertsch J, Wartmann M, Altmann KH. Epothilones as lead structures for the synthesis-based discovery of new chemotypes for microtubule stabilization. Acc Chem Res 2008; 41:21-31. [PMID: 18159935 DOI: 10.1021/ar700157x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Epothilones are macrocyclic bacterial natural products with potent microtubule-stabilizing and antiproliferative activity. They have served as successful lead structures for the development of several clinical candidates for anticancer therapy. However, the structural diversity of this group of clinical compounds is rather limited, as their structures show little divergence from the original natural product leads. Our own research has explored the question of whether epothilones can serve as a basis for the development of new structural scaffolds, or chemotypes, for microtubule stabilization that might serve as a basis for the discovery of new generations of anticancer drugs. We have elaborated a series of epothilone-derived macrolactones whose overall structural features significantly deviate from those of the natural epothilone scaffold and thus define new structural families of microtubule-stabilizing agents. Key elements of our hypermodification strategy are the change of the natural epoxide geometry from cis to trans, the incorporation of a conformationally constrained side chain, the removal of the C3-hydroxyl group, and the replacement of C12 with nitrogen. So far, this approach has yielded analogs 30 and 40 that are the most advanced, the most rigorously modified, structures, both of which are potent antiproliferative agents with low nanomolar activity against several human cancer cell lines in vitro. The synthesis was achieved through a macrolactone-based strategy or a high-yielding RCM reaction. The 12-aza-epothilone ("azathilone" 40) may be considered a "non-natural" natural product that still retains most of the overall structural characteristics of a true natural product but is structurally unique, because it lies outside of the general scope of Nature's biosynthetic machinery for polyketide synthesis. Like natural epothilones, both 30 and 40 promote tubulin polymerization in vitro and at the cellular level induce cell cycle arrest in mitosis. These facts indicate that cancer cell growth inhibition by these compounds is based on the same mechanistic underpinnings as those for natural epothilones. Interestingly, the 9,10-dehydro analog of 40 is significantly less active than the saturated parent compound, which is contrary to observations for natural epothilones B or D. This may point to differences in the bioactive conformations of N-acyl-12-aza-epothilones like 40 and natural epothilones. In light of their distinct structural features, combined with an epothilone-like (and taxol-like) in vitro biological profile, 30 and 40 can be considered as representative examples of new chemotypes for microtubule stabilization. As such, they may offer the same potential for pharmacological differentiation from the original epothilone leads as various newly discovered microtubule-stabilizing natural products with macrolactone structures, such as laulimalide, peloruside, or dictyostatin.
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Affiliation(s)
- Fabian Feyen
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zürich, HCI H405, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Frédéric Cachoux
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zürich, HCI H405, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Jürg Gertsch
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zürich, HCI H405, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Markus Wartmann
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zürich, HCI H405, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Karl-Heinz Altmann
- Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology (ETH) Zürich, HCI H405, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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172
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Tripathi A, Fornabaio M, Kellogg GE, Gupton JT, Gewirtz DA, Yeudall WA, Vega NE, Mooberry SL. Docking and hydropathic scoring of polysubstituted pyrrole compounds with antitubulin activity. Bioorg Med Chem 2007; 16:2235-42. [PMID: 18083520 DOI: 10.1016/j.bmc.2007.11.076] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 11/26/2007] [Accepted: 11/28/2007] [Indexed: 11/29/2022]
Abstract
Compounds that bind at the colchicine site of tubulin have drawn considerable attention with studies indicating that these agents suppress microtubule dynamics and inhibit tubulin polymerization. Data for 18 polysubstituted pyrrole compounds are reported, including antiproliferative activity against human MDA-MB-435 cells and calculated free energies of binding following docking the compounds into models of alphabeta-tubulin. These docking calculations coupled with HINT interaction analyses are able to represent the complex structures and the binding modes of inhibitors such that calculated and measured free energies of binding correlate with an r(2) of 0.76. Structural analysis of the binding pocket identifies important intermolecular contacts that mediate binding. As seen experimentally, the complex with JG-03-14 (3,5-dibromo-4-(3,4-dimethoxyphenyl)-1H-pyrrole-2-carboxylic acid ethyl ester) is the most stable. These results illuminate the binding process and should be valuable in the design of new pyrrole-based colchicine site inhibitors as these compounds have very accessible syntheses.
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Affiliation(s)
- Ashutosh Tripathi
- Department of Medicinal Chemistry & Institute for Structural Biology and Drug Discovery, Virginia Commonwealth University, Richmond, VA 23298-0540, USA
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Dixon N, Wong LS, Geerlings TH, Micklefield J. Cellular targets of natural products. Nat Prod Rep 2007; 24:1288-310. [DOI: 10.1039/b616808f] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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