RESUMO
Extracellular ATP mediates proinflammatory and antiproliferative effects via activation of P2 nucleotide receptors. In contrast, its metabolite, the nucleoside adenosine, is strongly immunosuppressive and enhances tumor proliferation and metastasis. The conversion of ATP to adenosine is catalyzed by ectonucleotidases, which are expressed on immune cells and typically upregulated on tumor cells. In the present study, we identified sulfopolysaccharides from brown and red sea algae to act as potent dual inhibitors of the main ATP-hydrolyzing ectoenzymes, ectonucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) and ecto-nucleoside triphosphate diphosphohydrolase-1 (NTPDase1, CD39), showing nano- to picomolar potency and displaying a non-competitive mechanism of inhibition. We showed that one of the sulfopolysaccharides tested as a representative example reduced adenosine formation at the surface of the human glioblastoma cell line U87 in a concentration-dependent manner. These natural products represent the most potent inhibitors of extracellular ATP hydrolysis known to date and have potential as novel therapeutics for the immunotherapy of cancer.
Assuntos
Trifosfato de Adenosina/antagonistas & inibidores , Apirase/antagonistas & inibidores , Polissacarídeos/fisiologia , Pirofosfatases/antagonistas & inibidores , Alga Marinha , Ésteres do Ácido Sulfúrico/farmacologia , Trifosfato de Adenosina/metabolismo , Apirase/metabolismo , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Humanos , Hidrólise/efeitos dos fármacos , Diester Fosfórico Hidrolases/metabolismo , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Pirofosfatases/metabolismo , Alga Marinha/química , Alga Marinha/isolamento & purificação , Ésteres do Ácido Sulfúrico/química , Ésteres do Ácido Sulfúrico/isolamento & purificaçãoRESUMO
Overproduction of extracellular diphosphate due to hydrolysis of ATP by NPP1 leads to pathological calcium diphosphate (pyrophosphate) dihydrate deposition (CPPD) in cartilage, resulting in a degenerative joint disease that today lacks a cure. Here, we targeted the identification of novel NPP1 inhibitors as potential therapeutic agents for CPPD deposition disease. Specifically, we synthesized novel analogs of AMP (NPP1 reaction product) and ADP (NPP1 inhibitor). These derivatives incorporate several chemical modifications of the natural nucleotides including (1) a methylene group replacing the Pα,ß-bridging oxygen atom to provide metabolic resistance, (2) sulfonate group(s) replacing phosphonate(s) to improve binding to NPP1's catalytic zinc ions, (3) an acyclic nucleotide analog to allow flexible binding in the NPP1 catalytic site, and (4) a benzimidazole base replacing adenine. Among the investigated compounds, adenine-N9-(methoxy)ethyl-ß-bisphosphonate, 10, was identified as an NPP1 inhibitor (Ki 16.3 µM vs. the artificial substrate p-nitrophenyl thymidine-5'-monophosphate (p-Nph-5'-TMP), and 9.60 µM vs. the natural substrate, ATP). Compound 10 was selective for NPP1 vs. human NPP3, human CD39, and tissue non-specific alkaline phosphatase (TNAP), but also inhibited human CD73 (Ki 12.6 µM). Thus, 10 is a dual NPP1/CD73 inhibitor, which could not only be of interest for treating CPPD deposition disease and calcific aortic valve disease but may also be considered for the immunotherapy of cancer. Compound 10 proved to be a promising inhibitor, which almost completely reduces NPPase activity in human osteoarthritic chondrocytes at a concentration of 100 µM.
Assuntos
Difosfato de Adenosina/análogos & derivados , Trifosfato de Adenosina/análogos & derivados , Inibidores Enzimáticos/farmacologia , Pirofosfatases/antagonistas & inibidores , Condrocalcinose , Condrócitos/efeitos dos fármacos , Humanos , Osteoartrite , Diester Fosfórico HidrolasesRESUMO
Nucleotide pyrophosphatase/phosphodiesterase-1 (NPP1) inhibitors have been suggested as a potential treatment for calcium pyrophosphate dihydrate (CPPD) deposition disease. Here, we targeted the development of improved NPP1 inhibitors based on acyclic mimics of Pα,α-phosphorodithioate-substituted adenine nucleotides, 7-10. The latter were obtained in a facile two-step synthesis from adenine-(methoxy)ethanol. Among analogs 7-10, adenine-(methoxy)ethoxy-Pα,α-dithio-triphosphate, 8, was the most potent NPP1 inhibitor both with purified enzyme (IC50 0.645 µM) and in osteoarthritic human chondrocytes (IC50 0.033 µM). Furthermore, it efficaciously (10-fold vs. control) inhibited ATP-induced CPPD in human articular chondrocytes. Importantly, 8 was a highly selective NPP1 inhibitor which showed only minor inhibition of NPP3, CD39 and CD73, and did not inhibit TNAP (tissue nonspecific alkaline phosphatase) activity in human chondrocytes. Furthermore, 8 did not activate P2Y1,2,6 receptors. Analog 8 was not toxic to cultured chondrocytes at 100 µM. Therefore, 8 may be suitable for further development as a drug candidate for the treatment of CPPD arthritis and other NPP1-related diseases.
Assuntos
Adenina/farmacologia , Pirofosfato de Cálcio/antagonistas & inibidores , Condrócitos/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Osteoartrite do Joelho/tratamento farmacológico , Polifosfatos/farmacologia , Pirofosfatases/antagonistas & inibidores , Compostos de Sulfidrila/farmacologia , Adenina/síntese química , Adenina/química , Pirofosfato de Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Condrócitos/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Estrutura Molecular , Osteoartrite do Joelho/metabolismo , Osteoartrite do Joelho/patologia , Diester Fosfórico Hidrolases/metabolismo , Polifosfatos/química , Pirofosfatases/metabolismo , Relação Estrutura-Atividade , Compostos de Sulfidrila/químicaRESUMO
Introduction: Heparins, naturally occurring glycosaminoglycans, are widely used for thrombosis prevention. Upon application as anticoagulants in cancer patients, heparins were found to possess additional antitumor activities. Ectonucleotidases have recently been proposed as novel targets for cancer immunotherapy. Methods and results: In the present study, we discovered that heparin and its derivatives act as potent, selective, allosteric inhibitors of the poorly investigated ectonucleotidase NPP1 (nucleotide pyrophosphatase/phosphodiesterase-1, CD203a). Structure-activity relationships indicated that NPP1 inhibition could be separated from the compounds' antithrombotic effect. Moreover, unfractionated heparin (UFH) and different low molecular weight heparins (LMWHs) inhibited extracellular adenosine production by the NPP1-expressing glioma cell line U87 at therapeutically relevant concentrations. As a consequence, heparins inhibited the ability of U87 cell supernatants to induce CD4+ T cell differentiation into immunosuppressive Treg cells. Discussion: NPP1 inhibition likely contributes to the anti-cancer effects of heparins, and their specific optimization may lead to improved therapeutics for the immunotherapy of cancer.
Assuntos
Glioma , Heparina , Humanos , Heparina/farmacologia , Imunoterapia , Anticoagulantes , Heparina de Baixo Peso Molecular/farmacologia , Heparina de Baixo Peso Molecular/uso terapêuticoRESUMO
BACKGROUND: Immunosuppressive extracellular adenosine is generated by the enzymatic activity of CD73. In preclinical models, antibodies (Abs) targeting different epitopes on CD73 exert anticancer activity through distinct mechanisms such as inhibition of enzymatic activity, engagement of Fc receptors, and spatial redistribution of CD73. METHODS: Using controlled Fab arm exchange, we generated biparatopic bispecific antibodies (bsAbs) from parental anti-CD73 Abs with distinct anticancer activities. The resulting anticancer activity was evaluated using in vitro and in vivo models. RESULTS: We demonstrate that different anticancer activities can be combined in a biparatopic bsAb. Remarkably, the bsAb significantly improved the enzyme inhibitory activity compared with the parental Abs, which led to neutralization of adenosine-mediated T-cell suppression as demonstrated by proliferation and interferon gamma (IFN-γ) production and prolonged survival of tumor-bearing mice. Additionally, the bsAb caused more efficient internalization of cell surface CD73 and stimulated potent Fc-mediated engagement of human immune effector cells in vitro and in vivo. CONCLUSIONS: Our data collectively demonstrate that complementary anticancer mechanisms of action of distinct anti-CD73 Abs can be combined and enhanced in a biparatopic bsAb. The multiple mechanisms of action and superior activity compared with the monospecific parental Abs make the bsAb a promising candidate for therapeutic targeting of CD73 in cancer. This concept may greatly improve future Ab design.
Assuntos
Anticorpos Biespecíficos , Neoplasias , Adenosina , Animais , Anticorpos Biespecíficos/farmacologia , Anticorpos Biespecíficos/uso terapêutico , Epitopos , Humanos , CamundongosRESUMO
CD73 inhibitors are promising drugs for the (immuno)therapy of cancer. Here, we present the synthesis, structure-activity relationships, and cocrystal structures of novel derivatives of the competitive CD73 inhibitor α,ß-methylene-ADP (AOPCP) substituted in the 2-position. Small polar or lipophilic residues increased potency, 2-iodo- and 2-chloro-adenosine-5'-O-[(phosphonomethyl)phosphonic acid] (15, 16) being the most potent inhibitors with Ki values toward human CD73 of 3-6 nM. Subject to the size and nature of the 2-substituent, variable binding modes were observed by X-ray crystallography. Depending on the binding mode, large species differences were found, e.g., 2-piperazinyl-AOPCP (21) was >12-fold less potent against rat CD73 compared to human CD73. This study shows that high CD73 inhibitory potency can be achieved by simply introducing a small substituent into the 2-position of AOPCP without the necessity of additional bulky N6-substituents. Moreover, it provides valuable insights into the binding modes of competitive CD73 inhibitors, representing an excellent basis for drug development.
Assuntos
5'-Nucleotidase/antagonistas & inibidores , Difosfato de Adenosina/análogos & derivados , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , 5'-Nucleotidase/química , 5'-Nucleotidase/metabolismo , Difosfato de Adenosina/química , Difosfato de Adenosina/farmacologia , Animais , Cristalografia por Raios X , Proteínas Ligadas por GPI/antagonistas & inibidores , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/metabolismo , Humanos , Simulação de Acoplamento Molecular , Ligação Proteica , Ratos , Relação Estrutura-AtividadeRESUMO
Ecto-5'-nucleotidase (CD73) catalyzes the hydrolysis of AMP to anti-inflammatory, immunosuppressive adenosine. It is expressed on vascular endothelial, epithelial, and also numerous cancer cells where it strongly contributes to an immunosuppressive microenvironment. In the present study we designed and synthesized fluorescent-labeled CD73 inhibitors with low nanomolar affinity and high selectivity based on N 6 -benzyl-α,ß-methylene-ADP (PSB-12379) as a lead structure. Fluorescein was attached to the benzyl residue via different linkers resulting in PSB-19416 (14b, K i 12.6 nM) and PSB-18332 (14a, K i 2.98 nM) as fluorescent high-affinity probes for CD73. These compounds are anticipated to become useful tools for biological studies, drug screening, and diagnostic applications.
RESUMO
Cluster of differentiation 73 (CD73) converts adenosine 5'-monophosphate to immunosuppressive adenosine, and its inhibition was proposed as a new strategy for cancer treatment. We synthesized 5'- O-[(phosphonomethyl)phosphonic acid] derivatives of purine and pyrimidine nucleosides, which represent nucleoside diphosphate analogues, and compared their CD73 inhibitory potencies. In the adenine series, most ribose modifications and 1-deaza and 3-deaza were detrimental, but 7-deaza was tolerated. Uracil substitution with N3-methyl, but not larger groups, or 2-thio, was tolerated. 1,2-Diphosphono-ethyl modifications were not tolerated. N4-(Aryl)alkyloxy-cytosine derivatives, especially with bulky benzyloxy substituents, showed increased potency. Among the most potent inhibitors were the 5'- O-[(phosphonomethyl)phosphonic acid] derivatives of 5-fluorouridine (4l), N4-benzoyl-cytidine (7f), N4-[ O-(4-benzyloxy)]-cytidine (9h), and N4-[ O-(4-naphth-2-ylmethyloxy)]-cytidine (9e) ( Ki values 5-10 nM at human CD73). Selected compounds tested at the two uridine diphosphate-activated P2Y receptor subtypes showed high CD73 selectivity, especially those with large nucleobase substituents. These nucleotide analogues are among the most potent CD73 inhibitors reported and may be considered for development as parenteral drugs.
Assuntos
5'-Nucleotidase/antagonistas & inibidores , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Nucleotídeos de Purina/química , Nucleotídeos de Purina/farmacologia , Nucleotídeos de Pirimidina/química , Nucleotídeos de Pirimidina/farmacologia , Animais , Proteínas Ligadas por GPI/antagonistas & inibidores , Humanos , Ratos , Relação Estrutura-AtividadeRESUMO
Reversible protein kinase inhibitors that bind in the ATP cleft can be classified as typeâ I or typeâ II binders. Of these, typeâ I inhibitors address the active form, whereas typeâ II inhibitors typically lock the kinase in an inactive form. At the molecular level, the conformation of the flexible activation loop holding the key DFG motif controls access to the ATP site, thereby determining an active or inactive kinase state. Accordingly, typeâ I and typeâ II kinase inhibitors bind to so-called DFG-in or DFG-out conformations, respectively. Based on our former study on highly selective platelet-derived growth factor receptorâ ß (PDGFRß) pyrazin-2-one typeâ I inhibitors, we expanded this scaffold toward the deep pocket, yielding the highly potent and effective typeâ II inhibitor 5 (4-[(4-methylpiperazin-1-yl)methyl]-N-[3-[[6-oxo-5-(3,4,5-trimethoxyphenyl)-1H-pyrazin-3-yl]methyl]phenyl]benzamide). Inâ vitro characterization, including selectivity panel data from activity-based assays (300 kinases) and affinity-based assays (97 kinases) of these PDGFRß typeâ I (1; 5-(4-hydroxy-3-methoxy-phenyl)-3-(3,4,5-trimethoxyphenyl)-1H-pyrazin-2-one) and II (5) inhibitors showing the same pyrazin-2-one chemotype are compared. Implications are discussed regarding the data for selectivity and efficacy of typeâ I and typeâ II ligands.
Assuntos
Desenho de Fármacos , Pirazinas/síntese química , Pirazinas/farmacologia , Receptor beta de Fator de Crescimento Derivado de Plaquetas/antagonistas & inibidores , Sítios de Ligação , Western Blotting , Mesilato de Imatinib/química , Mesilato de Imatinib/farmacologia , Estrutura Molecular , Ligação Proteica/efeitos dos fármacos , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Pirazinas/químicaRESUMO
Imatinib is the first protein kinase inhibitor approved for clinical use and is a seminal drug for the concept of targeted therapy. Herein we report on the design, synthesis, photokinetic properties, and in vitro enzymatic evaluation of a photoactivatable caged prodrug of imatinib. This approach allows spatial and temporal control over the activation of imatinib triggered by ultraviolet light. The successful application of the photoactivation concept to this significant kinase inhibitor provides further evidence for the caging technique as a feasible approach in the kinase field. The presented photoactivatable imatinib prodrug will be highly useful as a pharmacological tool to study the impact of imatinib toward biological systems in greater detail.
Assuntos
Desenho de Fármacos , Mesilato de Imatinib/química , Pró-Fármacos/química , Inibidores de Proteínas Quinases/síntese química , Sítios de Ligação , Domínio Catalítico , Mesilato de Imatinib/síntese química , Simulação de Acoplamento Molecular , Pró-Fármacos/síntese química , Inibidores de Proteínas Quinases/química , Receptor beta de Fator de Crescimento Derivado de Plaquetas/química , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Raios UltravioletaRESUMO
We recently reported that CMPD1, originally developed as an inhibitor of MK2 activation, primarily inhibits tubulin polymerisation and induces apoptosis in glioblastoma cells. In the present study we provide detailed pharmacological investigation of CMPD1 analogues with improved molecular properties. We determined their anti-cancer efficacy in glioblastoma cells with enhanced EGFR signalling, as deregulated EGFR often leads to chemoresistance. Eight analogues of CMPD1 with varying lipophilicity and basicity were synthesised and tested for efficacy in the cell viability assay using established glioblastoma cell lines and patient-derived primary glioblastoma cells. The mechanism of action for the most potent analogue 15 was determined using MK2 activation and tubulin polymerisation assays, together with the immunofluorescence analysis of the mitotic spindle formation. Apoptosis was analysed by Annexin V staining, immunoblotting analysis of bcl-2 proteins and PARP cleavage. The apoptotic activity of CMPD1 and analogue 15 was comparable across glioblastoma cell lines regardless of the EGFR status. Primary glioblastoma cells of the classical subtype that are characterized by enhanced EGFR activity were most sensitive to the treatment with CMPD1 and 15. In summary, we present mechanism of action for a novel small molecule tubulin inhibitor, compound 15 that inhibits tubulin polymerisation and mitotic spindle formation, induces degradation of anti-apoptotic bcl-2 proteins and leads to apoptosis of glioblastoma cells. We also demonstrate that the enhanced EGFR activity does not decrease the efficacy of tubulin inhibitors developed in this study.