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Schistosomiasis, caused by a parasitic blood fluke of the genus Schistosoma, is a global health problem for which new chemotherapeutic options are needed. We explored the scaffold of gallinamide A, a natural peptidic metabolite of marine cyanobacteria that has previously been shown to inhibit cathepsin L-type proteases. We screened a library of 19 synthetic gallinamide A analogs and identified nanomolar inhibitors of the cathepsin B-type protease SmCB1, which is a drug target for the treatment of schistosomiasis mansoni. Against cultured S. mansoni schistosomula and adult worms, many of the gallinamides generated a range of deleterious phenotypic responses. Imaging with a fluorescent-activity-based probe derived from gallinamide A demonstrated that SmCB1 is the primary target for gallinamides in the parasite. Furthermore, we solved the high-resolution crystal structures of SmCB1 in complex with gallinamide A and its two analogs and describe the acrylamide covalent warhead and binding mode in the active site. Quantum chemical calculations evaluated the contribution of individual positions in the peptidomimetic scaffold to the inhibition of the target and demonstrated the importance of the P1' and P2 positions. Our study introduces gallinamides as a powerful chemotype that can be exploited for the development of novel antischistosomal chemotherapeutics.
Assuntos
Catepsina B , Schistosoma mansoni , Catepsina B/antagonistas & inibidores , Catepsina B/metabolismo , Animais , Schistosoma mansoni/enzimologia , Schistosoma mansoni/efeitos dos fármacos , Cristalografia por Raios X , Esquistossomicidas/farmacologia , Esquistossomicidas/química , Ligação Proteica , Modelos MolecularesRESUMO
Protecting groups (PGs) in peptide synthesis have inspired advanced design principles that incorporate "orthogonality" for selective C- and N-terminus and side-chain deprotections. The conventionally acid-stable 9-fluorenylmethoxycarbonyl (Fmoc) group is one of the most widely used N-protection groups in solid- and solution-phase synthesis. Despite the versatility of Fmoc, deprotection by the removal of the Fmoc group to unmask primary amines requires the use of a basic secondary amine nucleophile, but this stratagem poses challenges in sensitive molecules that bear reactive electrophilic groups. An expansion of PG versatility, a tunable orthogonality, in the late-stage synthesis of peptides would add flexibility to the synthetic design and implementation. Here, we report a novel Fmoc deprotection method using hydrogenolysis under mildly acidic conditions for the synthesis of Z-Arg-Lys-acyloxymethyl ketone (Z-R-K-AOMK). This new method is not only valuable for Fmoc deprotection in the synthesis of complex peptides that contain highly reactive electrophiles, or other similar sensitive functional groups, that are incompatible with traditional Fmoc deprotection conditions but also tolerant of N-Boc groups present in the substrate.
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The Plasmodium proteasome is a promising antimalarial drug target due to its essential role in all parasite lifecycle stages. Furthermore, proteasome inhibitors have synergistic effects when combined with current first-line artemisinin and related analogues. Linear peptides that covalently inhibit the proteasome are effective at killing parasites and have a low propensity for inducing resistance. However, these scaffolds generally suffer from poor pharmacokinetics and bioavailability. Here we describe the development of covalent, irreversible, macrocyclic inhibitors of the Plasmodium falciparum proteasome. We identified compounds with excellent potency and low cytotoxicity; however, the first generation suffered from poor microsomal stability. Further optimization of an existing macrocyclic scaffold resulted in an irreversible covalent inhibitor carrying a vinyl sulfone electrophile that retained high potency and low cytotoxicity and had acceptable metabolic stability. Importantly, unlike the parent reversible inhibitor that selected for multiple mutations in the proteasome, with one resulting in a 5,000-fold loss of potency, the irreversible analogue only showed a 5-fold loss in potency for any single point mutation. Furthermore, an epoxyketone analogue of the same scaffold retained potency against a panel of known proteasome mutants. These results confirm that macrocycles are optimal scaffolds to target the malarial proteasome and that the use of a covalent electrophile can greatly reduce the ability of the parasite to generate drug resistance mutations.
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Metabolomics is an analytical approach that involves profiling and comparing the metabolites present in biological samples. This scoping review article offers an overview of current metabolomics approaches and their utilization in evaluating metabolic changes in biological fluids that occur in response to viral infections. Here, we provide an overview of metabolomics methods including high-throughput analytical chemistry and multivariate data analysis to identify the specific metabolites associated with viral infections. This review also focuses on data interpretation and applications designed to improve our understanding of the pathogenesis of these viral diseases.
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Proteasomes are essential for protein homeostasis in mammalian cells1-4 and in protozoan parasites such as Trichomonas vaginalis (Tv).5 Tv and other protozoan 20S proteasomes have been validated as druggable targets.6-8 However, in the case of Tv 20S proteasome (Tv20S), biochemical and structural studies were impeded by low yields and purity of the native proteasome. We successfully made recombinant Tv20S by expressing all seven α and seven ß subunits together with the Ump-1 chaperone in insect cells. We isolated recombinant proteasome and showed that it was biochemically indistinguishable from the native enzyme. We confirmed that the recombinant Tv20S is inhibited by the natural product marizomib (MZB)9 and the recently developed peptide inhibitor carmaphycin-17 (CP-17)8,10. Specifically, MZB binds to the ß1, ß2 and ß5 subunits, while CP-17 binds the ß2 and ß5 subunits. Next, we obtained cryo-EM structures of Tv20S in complex with these covalent inhibitors at 2.8Å resolution. The structures revealed the overall fold of the Tv20S and the binding mode of MZB and CP-17. Our work explains the low specificity of MZB and higher specificity of CP-17 towards Tv20S as compared to human proteasome and provides the platform for the development of Tv20S inhibitors for treatment of trichomoniasis.
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Commiphora gileadensis L. is an important endangered medicinal plant that belongs to the family Burseraceae. In this study, C. gileadensis callus culture was established successfully using mature leaves as explants cultured on Murashige and Skoog (MS) media supplemented with 24.50 µM of indole butyric acid (IBA) and 2.22 µM 6-Benzylaminopurine (BAP) (callus induction media). The obtained callus was maintained on MS medium supplemented with 16.11 µM naphthalene acetic acid (NAA) in combination with 6.66 µM BAP, which resulted in a substantial increase in callus fresh and dry weights. The cell suspension culture was established successfully using liquid callus induction media supplemented with 3.0 mg·L-1 proline. Thereafter, the chemical constituents of different C. gileadensis methanolic extracts (callus, cell suspension, leaves, and seeds) were profiled, and their cytotoxic and antimicrobial properties were investigated. The LC-MS GNPS analyses were applied for chemical profiling of the methanolic plant extracts, and several natural products were identified, including flavonols, flavanones, and flavonoids glycosides, with two unusual families that included puromycin, 10-hydroxycamptothecin, and justicidin B. The methanolic extracts have shown selective antimicrobial and cytotoxic properties against different microbes and cancer cell lines. For instance, leaf extract showed the highest zone of inhibition for Staphylococcus aureus, while cell suspension culture was effective against Staphylococcus epidermidis and Staphylococcus aureus. All extracts showed selective activity against A549 cell lines for the cytotoxicity assay, while the leaf extract had a broad cytotoxic effect against all tested cell lines. This study revealed that C. gileadensis callus and cell suspension cultures can be employed to increase the in vitro formation of biologically active compounds that may have cytotoxicity and antibacterial action against different cancer cell lines and bacterial species. Further studies are required to isolate and identify such constituents that corroborate the observed activities.
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The protozoan parasite, Trichomonas vaginalis (Tv) causes trichomoniasis, the most common, non-viral, sexually transmitted infection in the world. Only two closely related drugs are approved for its treatment. The accelerating emergence of resistance to these drugs and lack of alternative treatment options poses an increasing threat to public health. There is an urgent need for novel effective anti-parasitic compounds. The proteasome is a critical enzyme for T. vaginalis survival and was validated as a drug target to treat trichomoniasis. However, to develop potent inhibitors of the T. vaginalis proteasome, it is essential that we understand which subunits should be targeted. Previously, we identified two fluorogenic substrates that were cleaved by T. vaginalis proteasome, however after isolating the enzyme complex and performing an in-depth substrate specificity study, we have now designed three fluorogenic reporter substrates that are each specific for one catalytic subunit. We screened a library of peptide epoxyketone inhibitors against the live parasite and evaluated which subunits are targeted by the top hits. Together we show that targeting of the ß5 subunit of T. vaginalis is sufficient to kill the parasite, however, targeting of ß5 plus either ß1 or ß2 results in improved potency.
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The Plasmodium falciparum proteasome constitutes a promising antimalarial target, with multiple chemotypes potently and selectively inhibiting parasite proliferation and synergizing with the first-line artemisinin drugs, including against artemisinin-resistant parasites. We compared resistance profiles of vinyl sulfone, epoxyketone, macrocyclic peptide, and asparagine ethylenediamine inhibitors and report that the vinyl sulfones were potent even against mutant parasites resistant to other proteasome inhibitors and did not readily select for resistance, particularly WLL that displays covalent and irreversible binding to the catalytic ß2 and ß5 proteasome subunits. We also observed instances of collateral hypersensitivity, whereby resistance to one inhibitor could sensitize parasites to distinct chemotypes. Proteasome selectivity was confirmed using CRISPR/Cas9-edited mutant and conditional knockdown parasites. Molecular modeling of proteasome mutations suggested spatial contraction of the ß5 P1 binding pocket, compromising compound binding. Dual targeting of P. falciparum proteasome subunits using covalent inhibitors provides a potential strategy for restoring artemisinin activity and combating the spread of drug-resistant malaria.
Assuntos
Antimaláricos , Artemisininas , Malária Falciparum , Plasmodium , Humanos , Antimaláricos/farmacologia , Antimaláricos/química , Complexo de Endopeptidases do Proteassoma/metabolismo , Plasmodium/metabolismo , Artemisininas/química , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Inibidores de Proteassoma/farmacologia , Inibidores de Proteassoma/químicaRESUMO
Here, we present remarkable epoxyketone-based proteasome inhibitors with low nanomolar inâ vitro potency for blood-stage Plasmodium falciparum and low cytotoxicity for human cells. Our best compound has more than 2,000-fold greater selectivity for erythrocytic-stage P.â falciparum over HepG2 and H460 cells, which is largely driven by the accommodation of the parasite proteasome for a D-amino acid in the P3 position and the preference for a difluorobenzyl group in the P1 position. We isolated the proteasome from P.â falciparum cell extracts and determined that the best compound is 171-fold more potent at inhibiting the ß5 subunit of P.â falciparum proteasome when compared to the same subunit of the human constitutive proteasome. These compounds also significantly reduce parasitemia in a P. berghei mouse infection model and prolong survival of animals by an average of 6â days. The current epoxyketone inhibitors are ideal starting compounds for orally bioavailable anti-malarial drugs.
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Antimaláricos , Plasmodium , Camundongos , Animais , Humanos , Inibidores de Proteassoma/química , Complexo de Endopeptidases do Proteassoma/química , Plasmodium falciparum , Antimaláricos/farmacologiaRESUMO
Obesity is the most common nutritional disorder in the developed world and is associated with important comorbidities. Pancreatic lipase (PL) inhibitors play a key role in the metabolism of human fat. A series of novel epoxyketones peptide derivatives were investigated for their pancreatic lipase inhibitory activity. The epoxyketone moiety is a well-known reactive electrophile group that has been used as part of proteasome inhibitors in cancer therapy, and it is widely believed that these are very selective for targeting the proteasome active site. Here we investigated various peptide derivatives with an epoxide warhead for their anti-lipase activity. The assessment of these novel epoxyketones was performed by an in-house method that we developed for rapid screening and identification of lipase inhibitors using GC-FID. Herein, we present a novel anti-lipase pharmacophore based on epoxyketone peptide derivatives that showed potent anti-lipase activity. Many of these derivatives had comparable or more potent activity than the clinically used lipase inhibitors such as orlistat. In addition, the lipase appears to be inhibited by a wide range of epoxyketone analogues regardless of the configuration of the epoxide in the epoxyketone moiety. The presented data in this study shows the first example of the use of epoxyketone peptides as novel lipase inhibitors.
Assuntos
Peptídeos , Inibidores de Proteassoma , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Compostos de Epóxi/farmacologia , Humanos , Lipase , Peptídeos/química , Peptídeos/farmacologia , Complexo de Endopeptidases do Proteassoma/química , Inibidores de Proteassoma/químicaRESUMO
Three new compounds, portobelamides A and B (1 and 2), 3-amino-2-methyl-7-octynoic acid (AMOYA) and hydroxyisovaleric acid (Hiva) containing cyclic depsipeptides, and one long chain lipopeptide caciqueamide (3), were isolated from a field-collection of a Caldora sp. marine cyanobacterium obtained from Panama as part of the Panama International Cooperative Biodiversity Group Program. Their planar structures were elucidated through analysis of 2D NMR and MS data, especially high resolution (HR) MS2/MS3 fragmentation methods. The absolute configurations of compounds 1 and 2 were deduced by traditional hydrolysis, derivative formation, and chromatographic analyses compared with standards. Portobelamide A (1) showed good cytotoxicity against H-460 human lung cancer cells (33% survival at 0.9 µM).
Assuntos
Antineoplásicos/farmacologia , Cianobactérias/química , Depsipeptídeos/química , Antineoplásicos/química , Organismos Aquáticos/química , Produtos Biológicos/química , Produtos Biológicos/farmacologia , Linhagem Celular Tumoral , Depsipeptídeos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , PanamáRESUMO
The tropical marine cyanobacterium Moorena bouillonii occupies a large geographic range across the Indian and Western Tropical Pacific Oceans and is a prolific producer of structurally unique and biologically active natural products. An ensemble of computational approaches, including the creation of the ORCA (Objective Relational Comparative Analysis) pipeline for flexible MS1 feature detection and multivariate analyses, were used to analyze various M. bouillonii samples. The observed chemogeographic patterns suggested the production of regionally specific natural products by M. bouillonii. Analyzing the drivers of these chemogeographic patterns allowed for the identification, targeted isolation, and structure elucidation of a regionally specific natural product, doscadenamide A (1). Analyses of MS2 fragmentation patterns further revealed this natural product to be part of an extensive family of herein annotated, proposed natural structural analogs (doscadenamides B-J, 2-10); the ensemble of structures reflect a combinatorial biosynthesis using nonribosomal peptide synthetase (NRPS) and polyketide synthase (PKS) components. Compound 1 displayed synergistic in vitro cancer cell cytotoxicity when administered with lipopolysaccharide (LPS). These discoveries illustrate the utility in leveraging chemogeographic patterns for prioritizing natural product discovery efforts.
Assuntos
Amidas/química , Amidas/farmacologia , Organismos Aquáticos/química , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Técnicas de Química Analítica/métodos , Química Computacional/métodos , Cianobactérias/química , Citotoxinas/química , Citotoxinas/isolamento & purificação , Descoberta de Drogas/métodos , Pirróis , Amidas/isolamento & purificação , Animais , Produtos Biológicos/farmacologia , Linhagem Celular Tumoral , Cromatografia Líquida , Citotoxinas/farmacologia , Sinergismo Farmacológico , Humanos , Lipopolissacarídeos/farmacologia , Espectrometria de Massas , Redes e Vias Metabólicas , Camundongos , Pirróis/química , Pirróis/farmacologiaRESUMO
Marine cyanobacteria (blue-green algae) have been shown to possess an enormous capacity to produce structurally diverse natural products that exhibit a broad spectrum of potent biological activities, including cytotoxic, antifungal, antiparasitic, antiviral, and antibacterial activities. Using mass-spectrometry-guided fractionation together with molecular networking, cyanobacterial field collections from American Samoa and Palmyra Atoll yielded three new cyclic peptides, tutuilamides A-C. Their structures were established by spectroscopic techniques including 1D and 2D NMR, HR-MS, and chemical derivatization. Structure elucidation was facilitated by employing advanced NMR techniques including nonuniform sampling in combination with the 1,1-ADEQUATE experiment. These cyclic peptides are characterized by the presence of several unusual residues including 3-amino-6-hydroxy-2-piperidone and 2-amino-2-butenoic acid, together with a novel vinyl chloride-containing residue. Tutuilamides A-C show potent elastase inhibitory activity together with moderate potency in H-460 lung cancer cell cytotoxicity assays. The binding mode to elastase was analyzed by X-ray crystallography revealing a reversible binding mode similar to the natural product lyngbyastatin 7. The presence of an additional hydrogen bond with the amino acid backbone of the flexible side chain of tutuilamide A, compared to lyngbyastatin 7, facilitates its stabilization in the elastase binding pocket and possibly explains its enhanced inhibitory potency.
Assuntos
Antineoplásicos/isolamento & purificação , Cianobactérias/química , Depsipeptídeos/isolamento & purificação , Inibidores Enzimáticos/isolamento & purificação , Neoplasias Pulmonares/tratamento farmacológico , Elastase Pancreática/antagonistas & inibidores , Peptídeos Cíclicos/isolamento & purificação , Aminoácidos/química , Aminobutiratos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão , Depsipeptídeos/química , Depsipeptídeos/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/farmacologia , Humanos , Modelos Moleculares , Estrutura Molecular , Peptídeos Cíclicos/farmacologia , Piperidonas/química , Ligação Proteica , Espectrometria de Massas em Tandem , Cloreto de Vinil/químicaRESUMO
BACKGROUND: Flt3 is an oncogenic kinase involved in different leukemias. It is most prominently associated with acute myeloid leukemia (AML). Flt3-specific inhibitors have shown promising results in interfering with AML. METHODS: The crystallographic structures of two inhibitors complexed within Flt3, namely, quizartinib and F6M, were used to guide the synthesis of new sulfonamide-based Flt3 inhibitors. RESULTS: One of the prepared compounds showed low micromolar anti-Flt3 bioactivity, and interestingly, low micromolar bioactivity against the related oncogenic kinase VEGFR2. CONCLUSION: Sulfonamides were successfully used as privileged scaffolds for the synthesis of novel Flt3 inhibitors of micromolar potencies.
Assuntos
Antineoplásicos/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Sulfonamidas/farmacologia , Tirosina Quinase 3 Semelhante a fms/antagonistas & inibidores , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Linhagem Celular Tumoral , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Simulação de Acoplamento Molecular , Ligação Proteica , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/metabolismo , Sulfonamidas/síntese química , Sulfonamidas/metabolismo , Tirosina Quinase 3 Semelhante a fms/metabolismoRESUMO
In our daily lives, we consume foods that have been transported, stored, prepared, cooked, or otherwise processed by ourselves or others. Food storage and preparation have drastic effects on the chemical composition of foods. Untargeted mass spectrometry analysis of food samples has the potential to increase our chemical understanding of these processes by detecting a broad spectrum of chemicals. We performed a time-based analysis of the chemical changes in foods during common preparations, such as fermentation, brewing, and ripening, using untargeted mass spectrometry and molecular networking. The data analysis workflow presented implements an approach to study changes in food chemistry that can reveal global alterations in chemical profiles, identify changes in abundance, as well as identify specific chemicals and their transformation products. The data generated in this study are publicly available, enabling the replication and re-analysis of these data in isolation, and serve as a baseline dataset for future investigations.
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Bebidas/análise , Análise de Alimentos , Manipulação de Alimentos , Espectrometria de Massas , Metabolômica , Fermentação , Fluxo de TrabalhoRESUMO
Gallinamide A, originally isolated with a modest antimalarial activity, was subsequently reisolated and characterized as a potent, selective, and irreversible inhibitor of the human cysteine protease cathepsin L. Molecular docking identified potential modifications to improve binding, which were synthesized as a suite of analogs. Resultingly, this current study produced the most potent gallinamide analog yet tested against cathepsin L (10, Ki = 0.0937 ± 0.01 nM and kinact/Ki = 8â¯730â¯000). From a protein structure and substrate preference perspective, cruzain, an essential Trypanosoma cruzi cysteine protease, is highly homologous. Our investigations revealed that gallinamide and its analogs potently inhibit cruzain and are exquisitely toxic toward T. cruzi in the intracellular amastigote stage. The most active compound, 5, had an IC50 = 5.1 ± 1.4 nM, but was relatively inactive to both the epimastigote (insect stage) and the host cell, and thus represents a new candidate for the treatment of Chagas disease.
Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Catepsina L/antagonistas & inibidores , Inibidores de Cisteína Proteinase/química , Inibidores de Cisteína Proteinase/farmacologia , Desenho de Fármacos , Proteínas de Protozoários/antagonistas & inibidores , Trypanosoma cruzi/enzimologia , Cisteína Endopeptidases , Humanos , Cinética , Simulação de Acoplamento MolecularRESUMO
Trichomoniasis is a sexually transmitted disease with hundreds of millions of annual cases worldwide. Approved treatment options are limited to two related nitro-heterocyclic compounds, yet resistance to these drugs is an increasing concern. New antimicrobials against the causative agent, Trichomonas vaginalis, are urgently needed. We show here that clinically approved anticancer drugs that inhibit the proteasome, a large protease complex with a critical role in degrading intracellular proteins in eukaryotes, have submicromolar activity against the parasite in vitro and on-target activity against the enriched T. vaginalis proteasome in cell-free assays. Proteomic analysis confirmed that the parasite has all seven α and seven ß subunits of the eukaryotic proteasome although they have only modest sequence identities, ranging from 28 to 52%, relative to the respective human proteasome subunits. A screen of proteasome inhibitors derived from a marine natural product, carmaphycin, revealed one derivative, carmaphycin-17, with greater activity against T. vaginalis than the reference drug metronidazole, the ability to overcome metronidazole resistance, and reduced human cytotoxicity compared to that of the anticancer proteasome inhibitors. The increased selectivity of carmaphycin-17 for T. vaginalis was related to its >5-fold greater potency against the ß1 and ß5 catalytic subunits of the T. vaginalis proteasome than against the human proteasome subunits. In a murine model of vaginal trichomonad infection, proteasome inhibitors eliminated or significantly reduced parasite burden upon topical treatment without any apparent adverse effects. Together, these findings validate the proteasome of T. vaginalis as a therapeutic target for development of a novel class of trichomonacidal agents.
Assuntos
Antitricômonas/farmacologia , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Complexo de Endopeptidases do Proteassoma/genética , Vaginite por Trichomonas/tratamento farmacológico , Trichomonas vaginalis/efeitos dos fármacos , Trichomonas vaginalis/genética , Sequência de Aminoácidos , Animais , Anti-Infecciosos/farmacologia , Citoplasma/parasitologia , Resistência a Medicamentos/efeitos dos fármacos , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Parasitária/métodos , Proteômica/métodos , Infecções Sexualmente Transmissíveis/tratamento farmacológico , Infecções Sexualmente Transmissíveis/parasitologia , Tricomoníase/tratamento farmacológico , Tricomoníase/parasitologia , Vaginite por Trichomonas/parasitologiaRESUMO
Proteases are fundamental to successful parasitism, including that of the schistosome flatworm parasite, which causes the disease schistosomiasis in 200 million people worldwide. The proteasome is receiving attention as a potential drug target for treatment of a variety of infectious parasitic diseases, but it has been understudied in the schistosome. Adult Schistosoma mansoni were incubated with 1 µM concentrations of the proteasome inhibitors bortezomib, carfilzomib, and MG132. After 24 h, bortezomib and carfilzomib decreased worm motility by more than 85% and endogenous proteasome activity by >75%, and after 72 h, they increased caspase activity by >4.5-fold. The association between the engagement of the proteasome target and the phenotypic and biochemical effects recorded encouraged the chromatographic enrichment of the S. mansoni proteasome (Sm20S). Activity assays with fluorogenic proteasome substrates revealed that Sm20S contains caspase-type (ß1), trypsin-type (ß2), and chymotrypsin-type (ß5) activities. Sm20S was screened with 11 peptide epoxyketone inhibitors derived from the marine natural product carmaphycin B. Analogue 17 was 27.4-fold less cytotoxic to HepG2 cells than carmaphycin B and showed equal potency for the ß5 subunits of Sm20S, human constitutive proteasome, and human immunoproteasome. However, this analogue was 13.2-fold more potent at targeting Sm20S ß2 than it was at targeting the equivalent subunits of the human enzymes. Furthermore, 1 µM 17 decreased both worm motility and endogenous Sm20S activity by more than 90% after 24 h. We provide direct evidence of the proteasome's importance to schistosome viability and identify a lead for which future studies will aim to improve the potency, selectivity, and safety.
Assuntos
Sistemas de Liberação de Medicamentos/métodos , Complexo de Endopeptidases do Proteassoma/efeitos dos fármacos , Inibidores de Proteassoma/farmacologia , Schistosoma mansoni/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Bortezomib/farmacologia , Caspases/metabolismo , Inibidores de Cisteína Proteinase/farmacologia , Células Hep G2 , Humanos , Leupeptinas , Oligopeptídeos/farmacologiaRESUMO
Antibody-drug conjugates (ADCs) represent a new dimension of anticancer chemotherapeutics, with warheads to date generally involving either antitubulin or DNA-directed agents to achieve low-to sub-nanomolar potency. However, other potent cytotoxins working by different pharmacological mechanisms are under investigation, such as α,ß-epoxyketone based proteasome inhibitors. These proteasome active agents are an emerging class of anticancer drug that possesses ultra-potent cytotoxicity to some cancer cell lines. The carmaphycins are representatives of this latter class that we isolated and characterized from a marine cyanobacterium, and these as well as several synthetic analogues exhibit this level of potency. In the current work, we investigated the use of these highly potent cytotoxic compounds as warheads in the design of novel ADCs. We designed and synthesized a library of carmaphycin B analogues that contain amine handles, enabling their attachment to an antibody linker. The basicity of these incorporated amine handles was shown to strongly affect their cytotoxic properties. Linear amines resulted in the greatest reduction in cytotoxicity whereas less basic aromatic amines retained potent activity as demonstrated by a 4-sulfonylaniline derivative. These investigations resulted in identifying the P2 residue in the carmaphycins as the most suitable site for linker attachment point, and hence, we synthesized a highly potent analogue of carmaphycin B that contained a 4-sulfonylaniline handle as an attachment point for the linker antibody.