RESUMO
Colibactin is a genotoxic metabolite produced by commensal-pathogenic members of the human microbiome that possess the clb (aka pks) biosynthetic gene cluster. clb+ bacteria induce tumorigenesis in models of intestinal inflammation and have been causally linked to oncogenesis in humans. While colibactin is believed underlie these effects, it has not been possible to study the molecule directly due to its instability. Herein, we report the synthesis and biological studies of colibactin 742 (4), a stable colibactin derivative. We show that colibactin 742 (4) induces DNA interstrand-cross-links, activation of the Fanconi Anemia DNA repair pathway, and G2/M arrest in a manner similar to clb+E. coli. The linear precursor 9, which mimics the biosynthetic precursor to colibactin, also recapitulates the bacterial phenotype. In the course of this work, we discovered a novel cyclization pathway that was previously undetected in MS-based studies of colibactin, suggesting a refinement to the natural product structure and its mode of DNA binding. Colibactin 742 (4) and its precursor 9 will allow researchers to study colibactin's genotoxic effects independent of the producing organism for the first time.
Assuntos
Proteínas de Escherichia coli/síntese química , Peptídeos/síntese química , Policetídeos/síntese química , DNA/química , Escherichia coli/genética , Humanos , Microbiota/genética , Conformação Molecular , Família Multigênica , Mutagênicos/metabolismo , Mutação , Oxirredução , Fenótipo , Ligação Proteica , Relação Estrutura-AtividadeRESUMO
Plocabulin, a marine natural polyketide isolated from the sponge Lithoplocamia lithistoides, is a novel and potent microtubule-destabilizing agent. Guided by the reported binding mode, several new analogs of plocabulin have been designed through removing the right aliphatic chain and further modifying on the carbamate group and the enamide unit. The preliminary results indicate that the right aliphatic chain in plocabulin is allowed to remove with a little loss of activity, the carbamate group plays a role in the activity, and particularly, the enamide unit has an important effect on the activity. This new finding will aid the design of novel potent tubulin-binding agents based on plocabulin.
Assuntos
Antineoplásicos/farmacologia , Policetídeos/farmacologia , Pironas/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Policetídeos/síntese química , Policetídeos/química , Pironas/síntese química , Pironas/química , Relação Estrutura-Atividade , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/químicaRESUMO
Covering: 2015 to 2020 The field of natural products is dominated by a discovery paradigm that follows the sequence: isolation, structure elucidation, chemical synthesis, and then elucidation of mechanism of action and structure-activity relationships. Although this discovery paradigm has proven successful in the past, researchers have amassed enough evidence to conclude that the vast majority of nature's secondary metabolites - biosynthetic "dark matter" - cannot be identified and studied by this approach. Many biosynthetic gene clusters (BGCs) are expressed at low levels, or not at all, and in some instances a molecule's instability to fermentation or isolation prevents detection entirely. Here, we discuss an alternative approach to natural product identification that addresses these challenges by enlisting synthetic chemistry to prepare putative natural product fragments and structures as guided by biosynthetic insight. We demonstrate the utility of this approach through our structure elucidation of colibactin, an unisolable genotoxin produced by pathogenic bacteria in the human gut.
Assuntos
Peptídeos/síntese química , Peptídeos/farmacologia , Policetídeos/síntese química , Policetídeos/farmacologia , Artefatos , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Proteínas de Escherichia coli/genética , Humanos , Estrutura Molecular , Mutação , Peptídeo Hidrolases/genética , Peptídeos/química , Peptídeos/genética , Policetídeos/química , Piridonas/química , Relação Estrutura-AtividadeRESUMO
Overcoming the global health threat of HIV infection requires continuous pipelines of novel drug candidates. We identified the γ-pyrone polyketides Aureothin/Neoaureothin as potent hits by anti-HIV screening of an extensive natural compound collection. Total synthesis of a structurally diverse group of Aureothin-derivatives successfully identified a lead compound (#7) superior to Aureothin that combines strong anti-HIV activity (IC90<45 nM), photostability and improved cell safety. Compound #7 inhibited de novo virus production from integrated proviruses by blocking the accumulation of HIV RNAs that encode the structural components of virions and include viral genomic RNAs. Thus, the mode-of-action displayed by compound #7 is different from those of all current clinical drugs. Proteomic analysis indicated that compound #7 does not affect global protein expression in primary blood cells and may modulate cellular pathways linked to HIV infection. Compound #7 inhibited multiple HIV genotypes, including HIV-type 1 and 2 and synergistically inhibited HIV in combination with clinical reverse transcriptase and integrase inhibitors. We conclude that compound #7 represents a promising new class of HIV inhibitors that will facilitate the identification of new virus-host interactions exploitable for antiviral attack and holds promise for further drug development.
Assuntos
Antivirais/farmacologia , Infecções por HIV/virologia , HIV/efeitos dos fármacos , HIV/fisiologia , Policetídeos/farmacologia , Replicação Viral/efeitos dos fármacos , Antivirais/síntese química , Antivirais/química , Cromonas/farmacologia , Desenho de Fármacos , Sinergismo Farmacológico , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Policetídeos/síntese química , Policetídeos/química , Cultura Primária de CélulasRESUMO
Sorbicillinoids are fungal polyketides characterized by highly complex and diverse molecular structures, with considerable stereochemical intricacy combined with a high degree of oxygenation. Many sorbicillinoids possess promising biological activities. An interesting member of this natural product family is sorbicatecholâ A, which is reported to have antiviral activity, particularly against influenzaâ A virus (H1N1). Through a straightforward, one-pot chemoenzymatic approach with recently developed oxidoreductase SorbC, the characteristic bicyclo[2.2.2]octane core of sorbicatechol is structurally diversified by variation of its natural 2-methoxyphenol substituent. This facilitates the preparation of a focused library of structural analogues bearing substituted aromatic systems, alkanes, heterocycles, and ethers. Fast access to this structural diversity provides an opportunity to explore the antiviral potential of the sorbicatechol family.
Assuntos
Antivirais/química , Antivirais/síntese química , Policetídeos , Antivirais/farmacologia , HIV/efeitos dos fármacos , Alphainfluenzavirus/efeitos dos fármacos , Estrutura Molecular , Policetídeos/síntese química , Policetídeos/químicaRESUMO
Covering: 2014 to 2019Nonribosomal peptide synthetases (NRPSs) and polyketide synthases (PKSs) have been the subject of engineering efforts for multiple decades. Their modular assembly line architecture potentially allows unlocking vast chemical space for biosynthesis. However, attempts thus far are often met with mixed success, due to limited molecular compatibility of the parts used for engineering. Now, new engineering strategies, increases in genomic data, and improved computational tools provide more opportunities for major progress. In this review we highlight some of the challenges and progressive strategies for the re-design of NRPSs & type I PKSs and survey useful computational tools and approaches to attain the ultimate goal of semi-automated and design-based engineering of novel peptide and polyketide products.
Assuntos
Desenho Assistido por Computador , Engenharia Metabólica/métodos , Biossíntese Peptídica , Policetídeos/síntese química , Peptídeos/metabolismo , Policetídeos/metabolismoRESUMO
The tumor microenvironment is considered as one of the important targets for anticancer drug discovery. In particular, nutrient deficiency may be observed in tumor microenvironment; biakamides A-D (1-4) isolated from marine sponge Petrosaspongia sp. as growth inhibitors against cancer cells adapted to glucose-deprived conditions have potential as new drugs and tools for elucidating adaptation mechanisms to these conditions. In this paper, we investigated structure-activity relationship (SAR) of biakamide to create easily accessible analog and gain insights about participation of the substructures to growth-inhibitory activity toward development of anticancer drug. This work revealed that 14,15-dinor-biakamide C (5), which is easily accessible, has similar activity to natural biakamide C (3). In addition, detailed SAR study showed the terminal acyl chain is important for interacting with target molecule and amide part including thiazole ring has acceptability to convert structures without losing activity.
Assuntos
Antineoplásicos/química , Policetídeos/química , Poríferos/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Policetídeos/síntese química , Policetídeos/farmacologia , Poríferos/metabolismo , Estereoisomerismo , Relação Estrutura-Atividade , Tiazóis/químicaRESUMO
Fatty acid synthases (FASs) and polyketide synthases (PKSs) condense acyl compounds to fatty acids and polyketides, respectively. Both, FASs and PKSs, harbor acyltransferases (ATs), which select substrates for condensation by ß-ketoacyl synthases (KSs). Here, we present the structural and functional characterization of the polyspecific malonyl/acetyltransferase (MAT) of murine FAS. We assign kinetic constants for the transacylation of the native substrates, acetyl- and malonyl-CoA, and demonstrate the promiscuity of FAS to accept structurally and chemically diverse CoA-esters. X-ray structural data of the KS-MAT didomain in a malonyl-loaded state suggests a MAT-specific role of an active site arginine in transacylation. Owing to its enzymatic properties and its accessibility as a separate domain, MAT of murine FAS may serve as versatile tool for engineering PKSs to provide custom-tailored access to new polyketides that can be applied in antibiotic and antineoplastic therapy.
Assuntos
Descoberta de Drogas , Ácido Graxo Sintase Tipo I , Policetídeo Sintases/metabolismo , Engenharia de Proteínas/métodos , Transferases , Acilação , Aciltransferases/química , Animais , Malonil Coenzima A , Camundongos , Policetídeos/síntese químicaRESUMO
Structurally complex polyketide natural products, isolated from a variety of marine and terrestrial sources, continue to provide a valuable source of rewarding targets for the synthetic chemist to tackle. In this account, we provide an overview of the total synthesis of several structurally fascinating polyketides with promising anticancer activity completed in our group based on our versatile asymmetric aldol methodology-spirastrellolide A methyl ester, leiodermatolide, rhizopodin and chivosazole F-and highlight the unanticipated challenges and discoveries encountered.
Assuntos
Produtos Biológicos/síntese química , Produtos Biológicos/farmacologia , Descoberta de Drogas , Policetídeos/síntese química , Animais , Antibióticos Antineoplásicos/síntese química , Antibióticos Antineoplásicos/farmacologia , Humanos , Policetídeo Sintases , Policetídeos/farmacologiaRESUMO
Since the discovery of penicillin, Penicillium has become one of the most attractive fungal genera for the production of bioactive molecules. Marine-derived Penicillium has provided numerous excellent pharmaceutical leads over the past decades. In this review, we focused on the cytotoxic metabolites * (* Cytotoxic potency was referred to five different levels in this review, extraordinary (IC50/LD50: <1 µM or 0.5 µg/mL); significant (IC50/LD50: 1~10 µM or 0.5~5 µg/mL); moderate (IC50/LD50: 10~30 µM or 5~15 µg/mL); mild (IC50/LD50: 30~50 µM or 15~25 µg/mL); weak (IC50/LD50: 50~100 µM or 25~50 µg/mL). The comparative potencies of positive controls were referred when they were available). produced by marine-derived Penicillium species, and on their cytotoxicity mechanisms, biosyntheses, and chemical syntheses.
Assuntos
Antineoplásicos/farmacologia , Organismos Aquáticos/metabolismo , Produtos Biológicos/farmacologia , Neoplasias/tratamento farmacológico , Penicillium/metabolismo , Alcaloides/síntese química , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Alcaloides/uso terapêutico , Antineoplásicos/síntese química , Antineoplásicos/isolamento & purificação , Antineoplásicos/uso terapêutico , Produtos Biológicos/síntese química , Produtos Biológicos/isolamento & purificação , Produtos Biológicos/uso terapêutico , Biotecnologia/métodos , Humanos , Concentração Inibidora 50 , Lipopeptídeos/síntese química , Lipopeptídeos/isolamento & purificação , Lipopeptídeos/farmacologia , Lipopeptídeos/uso terapêutico , Oceanos e Mares , Policetídeos/síntese química , Policetídeos/isolamento & purificação , Policetídeos/farmacologia , Policetídeos/uso terapêutico , Terpenos/síntese química , Terpenos/isolamento & purificação , Terpenos/farmacologia , Terpenos/uso terapêuticoRESUMO
The first total synthesis and absolute configuration assignment of protulactone A (1) has been achieved. Four stereoisomers, 1a, ent-1a, 1b, and ent-1b, of this natural polyketide were prepared by chiral pool synthesis starting from l- and d-arabinose, respectively. The absolute and relative configurations of all isomers were assigned by single-crystal X-ray analysis. Target compounds were screened for their in vitro cytotoxicity toward certain human tumor cells (NCI60 cancer cell line panel).
Assuntos
Policetídeos/síntese química , Linhagem Celular Tumoral , Cristalografia por Raios X , Humanos , Estrutura Molecular , Policetídeos/química , Policetídeos/farmacologia , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Biakamides A-D, novel unusually unique polyketides, were isolated from an Indonesian marine sponge (Petrosaspongia sp.) with a constructed bioassay using PANC-1 human pancreatic cancer cells. Through detailed analyses of the one- and two-dimensional NMR spectra of biakamides, planar chemical structures possessing a terminal thiazole, two N-methyl amides, a chloromethylene, and a substituted butyryl moiety were obtained. After elucidation of the configuration of the secondary alcohol moiety in biakamides A and B, the absolute stereostructures of the two secondary methyl groups in biakamides A-D were determined by the asymmetric total syntheses of all possible stereoisomers from the optically pure monoprotected 2,4-dimethyl-1,5-diol. Biakamides A-D showed selective antiproliferative activities against PANC-1 cells cultured under glucose-deficient conditions in a concentration-dependent manner. The primary mode of action of biakamides was found to be inhibition of complex I in the mitochondrial electron transport chain.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Pancreáticas/tratamento farmacológico , Policetídeos/farmacologia , Poríferos/química , Inanição/tratamento farmacológico , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Conformação Molecular , Neoplasias Pancreáticas/patologia , Policetídeos/síntese química , Policetídeos/química , Inanição/patologia , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Goniodenin is a lipophilic polyketide originating from plant sources and which possesses a potent cytotoxic activity against cancer cell lines. The first total synthesis of (+)-goniodenin has been achieved in 23 steps from (R)-glycidol. The synthetic sequence featured a cross metathesis for the formation of the C8-C9 bond and installation of the terminal γ-butenolactone ring unit by the alkylation of α-phenylthio-γ-butyrolactone with the corresponding C3-O-triflate. The stereogenic center at C18 carbon was created by Hiyama-Fujita reduction of the corresponding ketone with high diastereoselectivity.
Assuntos
Acetogeninas/síntese química , Policetídeos/síntese química , 4-Butirolactona/química , Alquilação , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Ciclização , Policetídeos/química , Policetídeos/farmacologia , Espectroscopia de Prótons por Ressonância Magnética , Espectrometria de Massas de Bombardeamento Rápido de Átomos , EstereoisomerismoRESUMO
Precolibactins and colibactins represent a family of natural products that are encoded by the clb gene cluster and are produced by certain commensal, extraintestinal, and probiotic E. coli. clb+ E. coli induce megalocytosis and DNA double-strand breaks in eukaryotic cells, but paradoxically, this gene cluster is found in the probiotic Nissle 1917. Evidence suggests precolibactins are converted to genotoxic colibactins by colibactin peptidase (ClbP)-mediated cleavage of an N-acyl-d-Asn side chain, and all isolation efforts have employed ΔclbP strains to facilitate accumulation of precolibactins. It was hypothesized that colibactins form unsaturated imines that alkylate DNA by cyclopropane ring opening (2 â 3). However, as no colibactins have been isolated, this hypothesis has not been tested experimentally. Additionally, precolibactins A-C (7-9) contain a pyridone that cannot generate the unsaturated imines that form the basis of this hypothesis. To resolve this, we prepared 13 synthetic colibactin derivatives and evaluated their DNA binding and alkylation activity. We show that unsaturated imines, but not the corresponding pyridone derivatives, potently alkylate DNA. The imine, unsaturated lactam, and cyclopropane are essential for efficient DNA alkylation. A cationic residue enhances activity. These studies suggest that precolibactins containing a pyridone are not responsible for the genotoxicity of the clb cluster. Instead, we propose that these are off-pathway fermentation products produced by a facile double cyclodehydration route that manifests in the absence of viable ClbP. The results presented herein provide a foundation to begin to connect metabolite structure with the disparate phenotypes associated with clb+ E. coli.
Assuntos
Produtos Biológicos/toxicidade , Escherichia coli/química , Mutagênicos/toxicidade , Peptídeos/toxicidade , Policetídeos/toxicidade , Produtos Biológicos/síntese química , Produtos Biológicos/química , Clivagem do DNA/efeitos dos fármacos , Escherichia coli/genética , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Estrutura Molecular , Família Multigênica/genética , Mutagênicos/síntese química , Mutagênicos/química , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Peptídeos/síntese química , Peptídeos/química , Peptídeos/genética , Fenótipo , Policetídeos/síntese química , Policetídeos/químicaRESUMO
Odoamide is a novel cyclic depsipeptide with highly potent cytotoxic activity isolated from the Okinawan marine cyanobacterium Okeania sp. It contains a 26-membered macrocycle composed of a fatty acid moiety, a peptide segment and isoleucic acid. Four possible stereoisomers of the odoamide polyketide substructure were synthesised using a chiral pool approach. The first total synthesis of odoamide was also successfully achieved. The structure of synthetic odoamide was verified by comparing its NMR spectra with those of the natural product.
Assuntos
Antineoplásicos/síntese química , Cianobactérias/química , Depsipeptídeos/síntese química , Policetídeos/síntese química , Células A549 , Antineoplásicos/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Depsipeptídeos/química , Depsipeptídeos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Neoplasias/tratamento farmacológico , Policetídeos/química , Policetídeos/farmacologia , EstereoisomerismoRESUMO
Covering: up to early 2016Marine sponges are widely known as a rich source of natural products, especially of polyketide origin, with a wealth of chemical diversity. Within this vast collection, peroxide and peroxide-derived secondary metabolites have attracted significant interest in the fields of natural product isolation and chemical synthesis for their structural distinction and promising in vitro antimicrobial and anticancer properties. In this review, peroxide and peroxide-derived polyketide metabolites isolated from marine sponges in the past 35 years are summarised. Efforts toward their synthesis are detailed with a focus on methods that utilise or attempt to elucidate the complex biosynthetic interrelationships of these compounds beyond enzymatic polyketide synthesis. Recent isolations, advances in synthetic methodology and theories of biogenesis are highlighted and critically evaluated.
Assuntos
Produtos Biológicos/síntese química , Peróxidos/síntese química , Policetídeo Sintases/metabolismo , Policetídeos/síntese química , Poríferos/química , Animais , Anti-Infecciosos , Produtos Biológicos/química , Biologia Marinha , Estrutura Molecular , Peróxidos/química , Policetídeos/químicaRESUMO
The colibactins are hybrid polyketide-nonribosomal peptide natural products produced by certain strains of commensal and extraintestinal pathogenic Escherichia coli. The metabolites are encoded by the clb gene cluster as prodrugs termed precolibactins. clb(+) E. coli induce DNA double-strand breaks in mammalian cells in vitro and in vivo and are found in 55-67% of colorectal cancer patients, suggesting that mature colibactins could initiate tumorigenesis. However, elucidation of their structures has been an arduous task as the metabolites are obtained in vanishingly small quantities (µg/L) from bacterial cultures and are believed to be unstable. Herein we describe a flexible and convergent synthetic route to prepare advanced precolibactins and derivatives. The synthesis proceeds by late-stage union of two complex precursors (e.g., 28 + 17 â 29a, 90%) followed by a base-induced double dehydrative cascade reaction to form two rings of the targets (e.g., 29a â 30a, 79%). The sequence has provided quantities of advanced candidate precolibactins that exceed those obtained by fermentation, and is envisioned to be readily scaled. These studies have guided a structural revision of the predicted metabolite precolibactin A (from 5a or 5b to 7) and have confirmed the structures of the isolated metabolites precolibactins B (3) and C (6). Synthetic precolibactin C (6) was converted to N-myristoyl-d-asparagine and its corresponding colibactin by colibactin peptidase ClbP. The synthetic strategy outlined herein will facilitate mechanism of action and structure-function studies of these fascinating metabolites, and is envisioned to accommodate the synthesis of additional (pre)colibactins as they are isolated.
Assuntos
Peptídeos/química , Policetídeos/química , Técnicas de Química Sintética , Ciclização , Escherichia coli/metabolismo , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Peptídeos/síntese química , Policetídeos/síntese químicaRESUMO
The synthesis of five diastereomeric model compounds incorporating the C32-C46 segment of the antitumor marine natural product hemicalide has been achieved through a convergent approach relying on the 1,4-addition of an alkenyl boronate to an α,ß-unsaturated δ-lactone followed by α-hydroxylation of an enolate and a Julia-Kocienski olefination. Comparison of the (1)H and (13)C NMR data of the model compounds with those of hemicalide enabled the assignment of the relative configuration of the C36-C42 subunit.
Assuntos
Antineoplásicos/síntese química , Produtos Biológicos/síntese química , Policetídeos/química , Policetídeos/síntese química , Antineoplásicos/química , Produtos Biológicos/química , Conformação Molecular , EstereoisomerismoRESUMO
Clostrubin is a potent antibiotic against methicillin- and vancomycin-resistant bacteria that was isolated from a strictly anaerobic bacterium Clostridium beijerinckii in 2014. This polyphenol possesses a fully substituted arene moiety on its pentacyclic scaffold, which poses a considerable challenge for chemical synthesis. Here we report the first total synthesis of clostrubin in nine steps (the longest linear sequence). A desymmetrization strategy is exploited based on the inherent structural feature of the natural product. Barton-Kellogg olefination forges the two segments together to form a tetrasubstituted alkene. A photo-induced 6π electrocyclization followed by spontaneous aromatization constructs the hexasubstituted B ring at a late stage. In total, 200 mg of clostrubin are delivered through this approach.
Assuntos
Alcenos/química , Antibacterianos/síntese química , Hidrocarbonetos Policíclicos Aromáticos/síntese química , Policetídeos/síntese química , Polifenóis/síntese química , Anaerobiose , Clostridium beijerinckii/química , Clostridium beijerinckii/metabolismo , Ciclização , Luz , Processos FotoquímicosRESUMO
The relative configuration of a key subunit of hemicalide, a recently isolated, highly bioactive marine natural product having potent antiproliferative activity against a panel of human cancer cell lines, was assigned by combining stereocontrolled synthesis of model substrates with NMR, IR, and vibrational circular dichroism (VCD) spectroscopy. The assignment of the absolute configuration of asymmetric carbon center C42 in two structurally complex epimeric substructures containing six stereocenters by VCD analysis illustrates the power and reliability of combining methods.