RESUMO
N-heterocyclic compounds are important molecular scaffolds in the search for new drugs, since most drugs contain heterocyclic moieties in their molecular structure, and some of these classes of heterocycles are able to provide ligands for two or more biological targets. Ketene dithioacetals are important building blocks in organic synthesis and are widely used in the synthesis of N-heterocyclic compounds. In this work, we used double vinylic substitution reactions on ketene dithioacetals to synthesize a small library of heterocyclic derivatives and evaluated their cytotoxic activity in breast and ovarian cancer cells, identifying two benzoxazoles with good potency and selectivity. In silico predictions indicate that the two most active derivatives exhibit physicochemical properties within the range of drug-like compounds and showed potential to interact with HDAC8 and ERK1 cancer-related targets.
Assuntos
Antineoplásicos , Etilenos , Compostos Heterocíclicos , Cetonas , Humanos , Linhagem Celular Tumoral , Etilenos/química , Etilenos/farmacologia , Compostos Heterocíclicos/química , Compostos Heterocíclicos/farmacologia , Compostos Heterocíclicos/síntese química , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Cetonas/química , Cetonas/farmacologia , Cetonas/síntese química , Relação Estrutura-Atividade , Histona Desacetilases/metabolismo , Simulação de Acoplamento Molecular , Ensaios de Seleção de Medicamentos Antitumorais , Acetais/química , Acetais/farmacologia , Acetais/síntese química , Proteínas RepressorasRESUMO
Cardiotonic steroids (CTS) are agents traditionally known for their capacity to bind to the Na,K-ATPase (NKA), affecting the ion transport and the contraction of the heart. Natural CTS have been shown to also have effects on cell signaling pathways. With the goal of developing a new CTS derivative, we synthesized a new digoxin derivative, 21-benzylidene digoxin (21-BD). Previously, we have shown that this compound binds to NKA and has cytotoxic actions on cancer, but not on normal cells. Here, we further studied the mechanisms of actions of 21-BD. Working with HeLa cells, we found that 21-BD decreases the basal, as well as the insulin stimulated proliferation. 21-BD reduces phosphorylation of the epidermal growth factor receptor (EGFR) and extracellular-regulated kinase (ERK), which are involved in pathways that stimulate cell proliferation. In addition, 21-BD promotes apoptosis, which is mediated by the translocation of Bax from the cytosol to mitochondria and the release of mitochondrial cytochrome c to the cytosol. 21-BD also activated caspases-8, -9 and -3, and induced the cleavage of poly (ADP-ribose) polymerase-1 (PARP-1). Altogether, these results show that the new compound that we have synthesized exerts cytotoxic actions on HeLa cells by inhibition of cell proliferation and the activation of both the extrinsic and intrinsic apoptotic pathways. These results support the relevance of the cardiotonic steroid scaffold as modulators of cell signaling pathways and potential agents for their use in cancer.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Digoxina/análogos & derivados , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Digoxina/química , Digoxina/farmacologia , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Receptores ErbB/antagonistas & inibidores , Receptores ErbB/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Células HeLa , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Conformação Molecular , Inibidores de Proteínas Quinases/química , Transdução de Sinais/efeitos dos fármacos , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Bufadienolide compounds have been used for growth inhibition and apoptosis induction in tumor cells. Those families of cardiotonic steroids can bind the Na,K-ATPase, causing its inhibition. The use of bufadienolides is widely described in the literature as an anticancer function. The aim of this study was to evaluate the effects of bufadienolides and alkaloid isolated from venom samples from R. marina on tumor cells. We performed cytotoxicity assay in MDA-MB-231 and TOV-21G cells and evaluated the activity of Caspases (3 and 9), Na, K-ATPase, PMCA and SERCA. Four compounds were extrated from the venom of R. marina. The compound 1 showed higher cytotoxicity in MDA-MB-231cells. Compound 1 also showed activation of Caspase 3 and 9. This compound caused an inhibition of the activity and expression of Na, K-ATPase, and also showed activation of both caspase-9 and caspase-3 in MDA-MB-231 cells. We also observed that Compound 1 had a direct effect on some ATPases, such as Na, K-ATPase, PMCA and SERCA. Compound 1 was able to inhibit the activity of the purified Na, K-ATPase enzyme from the concentration of 5⯵M. It also caused inhibition of PMCA at all concentrations tested (1â¯nM-30⯵M). However, the compound 1 led to an increase of the activity of purified SERCA between the concentrations of 7.5-30⯵M. Thus, we present a Na, K-ATPase and PMCA inhibitor, which may lead to the activation of caspases 3 and 9, causing the cells to enter into apoptosis. Our study suggests that compound 1 may be an interesting molecule as an anticancer agent.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Bufanolídeos/farmacologia , Inibidores Enzimáticos/farmacologia , Neoplasias Ovarianas/tratamento farmacológico , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Bufanolídeos/química , Bufanolídeos/isolamento & purificação , Bufo marinus , Caspase 3/metabolismo , Caspase 9/metabolismo , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/química , Inibidores Enzimáticos/isolamento & purificação , Feminino , Humanos , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , ATPase Trocadora de Sódio-Potássio/metabolismo , Relação Estrutura-AtividadeRESUMO
BACKGROUND: A series of symmetrical 1,4-disubstituted bis-1,2,3-triazoles was prepared by double copper catalyzed Azide-alkyne Cycloaddition (CuAAC) from aliphatic bis-azides and a tetraethylene glycol bis-azide derivative. The eighteen novel compounds were evaluated in vitro for their cytotoxic activity against two human tumor cell lines: Human breast adenocarcinoma (MDA-MB 231) and ovarian adenocarcinoma (TOV-21G). RESULTS AND CONCLUSION: The results of colorimetric MTT assays showed that compounds 4j and 4q exhibited a better selectivity index and cell viability comparable with the standard drug doxorubicin. These compounds induced apoptosis in both tested cell lines, as assessed by BrdU assay. The results suggest that these structurally simple compounds may be promising prototypes for antitumoral agents.
Assuntos
Alcinos/química , Antineoplásicos Fitogênicos/farmacologia , Azidas/química , Cobre/química , Triazóis/farmacologia , Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/química , Catálise , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Reação de Cicloadição , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/química , Células Tumorais CultivadasRESUMO
Hypervalent organotellurium compounds (organotelluranes) have shown several promising applications, including their use as potent and selective cysteine protease inhibitors and antiprotozoal agents. Here, we report the antimalarial activities of three organotellurane derivatives (RF05, RF07 and RF19) in two Plasmodium falciparum strains (CQS 3D7 and CQR W2), which demonstrated significant decreases in parasitemia in vitro. The inhibition of intracellular P. falciparum proteases by RF05, RF07 and RF19 was determined and the IC50 values were 3.7±1.0µM, 1.1±0.2µM and 0.2±0.01µM, respectively. Using an assay performed in the presence of the ER Ca(2+)-ATPase inhibitor we showed that the main enzymatic targets were cysteine proteases stimulated by calcium (calpains). None of the compounds tested caused haemolysis or a significant decrease in endothelial cell viability in the concentration range used for the inhibition assay. Taken together, the results suggest promising compounds for the development of antimalarial drugs.
Assuntos
Antimaláricos/farmacologia , Calpaína/antagonistas & inibidores , Inibidores de Cisteína Proteinase/farmacologia , Compostos Organometálicos/farmacologia , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/enzimologia , Telúrio/farmacologia , Antimaláricos/toxicidade , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Inibidores de Cisteína Proteinase/toxicidade , Descoberta de Drogas , Eritrócitos/efeitos dos fármacos , Eritrócitos/parasitologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/parasitologia , Humanos , Concentração Inibidora 50 , Malária Falciparum/tratamento farmacológico , Compostos Organometálicos/toxicidade , Telúrio/toxicidadeRESUMO
Cardiotonic steroids (CS), natural compounds with traditional use in cardiology, have been recently suggested to exert potent anticancer effects. However, the repertoire of molecules with Na,K-ATPase activity and anticancer properties is limited. This paper describes the synthesis of 6 new digoxin derivatives substituted (on the C17-butenolide) with γ-benzylidene group and their cytotoxic effect on human fibroblast (WI-26 VA4) and cancer (HeLa and RKO) cell lines as well as their effect on Na,K-ATPase activity and expression. As digoxin, compound BD-4 was almost 100-fold more potent than the other derivatives for cytotoxicity with the three types of cells used and was also the only one able to fully inhibit the Na,K-ATPase of HeLa cells after 24h treatment. No change in the Na,K-ATPase α1 isoform protein expression was detected. On the other hand it was 30-40 fold less potent for direct Na,K-ATPase inhibition, when compared to the most potent derivatives, BD-1 and BD-3, and digoxin. The data presented here demonstrated that the anticancer effect of digoxin derivatives substituted with γ-benzylidene were not related with their inhibition of Na,K-ATPase activity or alteration of its expression, suggesting that this classical molecular mechanism of CS is not involved in the cytotoxic effect of our derivatives.
Assuntos
Antineoplásicos/síntese química , Compostos de Benzilideno/química , Digoxina/análogos & derivados , ATPase Trocadora de Sódio-Potássio/antagonistas & inibidores , Animais , Antineoplásicos/química , Antineoplásicos/toxicidade , Sítios de Ligação , Encéfalo/enzimologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Digoxina/síntese química , Digoxina/toxicidade , Células HeLa , Humanos , Rim/enzimologia , Simulação de Acoplamento Molecular , Estrutura Terciária de Proteína , Ratos , ATPase Trocadora de Sódio-Potássio/metabolismoRESUMO
Cardiotonic steroids are used to treat heart failure and arrhythmia and have promising anticancer effects. The prototypic cardiotonic steroid ouabain may also be a hormone that modulates epithelial cell adhesion. Cardiotonic steroids consist of a steroid nucleus and a lactone ring, and their biological effects depend on the binding to their receptor, Na,K-ATPase, through which, they inhibit Na+ and K+ ion transport and activate of several intracellular signaling pathways. In this study, we added a styrene group to the lactone ring of the cardiotonic steroid digoxin, to obtain 21-benzylidene digoxin (21-BD), and investigated the effects of this synthetic cardiotonic steroid in different cell models. Molecular modeling indicates that 21-BD binds to its target Na,K-ATPase with low affinity, adopting a different pharmacophoric conformation when bound to its receptor than digoxin. Accordingly, 21-DB, at relatively high µM amounts inhibits the activity of Na,K-ATPase α1, but not α2 and α3 isoforms. In addition, 21-BD targets other proteins outside the Na,K-ATPase, inhibiting the multidrug exporter Pdr5p. When used on whole cells at low µM concentrations, 21-BD produces several effects, including: 1) up-regulation of Na,K-ATPase expression and activity in HeLa and RKO cancer cells, which is not found for digoxin, 2) cell specific changes in cell viability, reducing it in HeLa and RKO cancer cells, but increasing it in normal epithelial MDCK cells, which is different from the response to digoxin, and 3) changes in cell-cell interaction, altering the molecular composition of tight junctions and elevating transepithelial electrical resistance of MDCK monolayers, an effect previously found for ouabain. These results indicate that modification of the lactone ring of digoxin provides new properties to the compound, and shows that the structural change introduced could be used for the design of cardiotonic steroid with novel functions.
Assuntos
Apoptose/efeitos dos fármacos , Digoxina/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , ATPase Trocadora de Sódio-Potássio/metabolismo , Junções Íntimas/efeitos dos fármacos , Animais , Cardenolídeos/metabolismo , Cardenolídeos/farmacologia , Linhagem Celular Tumoral , Digoxina/análogos & derivados , Digoxina/química , Ativação Enzimática/efeitos dos fármacos , Humanos , Camundongos , Modelos Moleculares , Conformação Molecular , Neoplasias/genética , Neoplasias/metabolismo , Ratos , ATPase Trocadora de Sódio-Potássio/química , ATPase Trocadora de Sódio-Potássio/genéticaRESUMO
A series of new chalcones substituted with azide/triazole groups were designed and synthesized, and their cytotoxic activity was evaluated in vitro against the HeLa cell line. O-Alkylation, Claisen-Schmidt condensation and Cu(I)-catalyzed cycloaddition of azides with terminal alkynes were applied in key steps. Fifteen compounds were tested against HeLa cells. Compound 8c was the most active molecule, with an IC50 value of 13.03 µM, similar to the value of cisplatin (7.37 µM).
Assuntos
Azidas/química , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Chalconas/síntese química , Chalconas/farmacologia , Triazóis/química , Alquilação/efeitos dos fármacos , Catálise , Linhagem Celular Tumoral , Chalconas/química , Reação de Cicloadição , Desenho de Fármacos , Feminino , Células HeLa , Humanos , Concentração Inibidora 50 , Estrutura MolecularRESUMO
Malaria remains one of the most serious world health problem and the major cause of mortality and morbidity in the endemic regions. Brazil is among the 30 high-burden countries and most of the cases occur in the Legal Amazonian Region. New chemotherapeutical agents are needed for the treatment of malaria. Many plant species are used in traditional medicines of malarious countries and a relatively few number of these have been investigated for evaluation of their antimalarial effect. Still lower is the number of those that have had the active natural compounds isolated and the toxicity determined. This area is, then, of great research interest. discovery project of antimalarial natural products from plants traditionally used to treat malaria must include in vitro and in vivo assays as well as bioguided isolation of active compounds. The final products would be antimalarial chemical entities, potential new drugs or templates for new drugs development, and/or standardized antimalarial extracts which are required for pre-clinical and clinical studies when the aim is the development of effective and safe phythomedicines. This review discusses these two approaches, presents briefly the screening methodologies for evaluation of antimalarial activity and focuses the activity of alkaloids belonging to different structural classes as well as its importance as new antimalarial drugs or leads and chemical markers for phytomedicines.
A malária ainda é um dos mais sérios problemas de saúde pública e a principal causa de mortalidade e morbidade nas regiões endêmicas. O Brasil está entre os 30 países com maior incidência de malária e a maior parte dos casos ocorre na Amazônia Legal. Novos agentes terapêuticos são necessários para o tratamento da malária. Muitas espécies vegetais são utilizadas na medicina tradicional de vários países endêmicos mas é relativamente reduzido o número daquelas que já foram investigadas quanto à sua atividade antimalárica. Menor ainda é o número de espécies das quais foram isoladas substâncias ativas e tiveram sua toxidade determinada. Esta área de pesquisa é, portanto, de alta relevância. Um projeto de descoberta de produtos naturais antimaláricos a partir de plantas de uso tradicional deve incluir ensaios in vitro e in vivo bem como o isolamento biomonitorado de substâncias ativas. Os produtos finais serão substâncias naturais antimaláricas, potenciais fármacos ou protótipos para o desenvolvimento de novos fármacos, e/ou extratos padronizados, com atividade antimalárica, os quais são necessários para estudos pré-clínicos e clínicos quando o objetivo é o desenvolvimento de fitoterápicos (fitomedicamentos) eficazes e seguros. A presente revisão discute estas duas abordagens, apresenta resumidamente as metodologias de bioensaios para avaliação de atividade antimalárica e focaliza a atividade de alcalóides pertencentes a diferentes classes estruturais bem como sua importância como fármacos ou protótipos e como marcadores químicos de fitoterápicos.
Assuntos
Animais , Humanos , Alcaloides , Antimaláricos , Plantas Medicinais/química , Alcaloides/química , Alcaloides/isolamento & purificação , Alcaloides/farmacologia , Antimaláricos/química , Antimaláricos/isolamento & purificação , Antimaláricos/farmacologia , Desenho de Fármacos , FitoterapiaRESUMO
The antimalarial acitivity of hydroxyethylamines, synthesized from the reaction of intermediated hydroxyethypiperazines with benzenesulfonyl chlorides or benzoyl chlorides, has been evaluated in vitro against a W2 Plasmodium falciparum clone. Some of the nineteen tested derivatives showed a significant activity in vitro, thus turning into a promising new class of antimalarials. In addition, a molecular modeling study of the most active derivative (5l) was performed and its most probable binding modes within plasmepsin II enzyme were identified.