RESUMO
Glutamine synthetase, encoded by the gene GLUL, is an enzyme that converts glutamate and ammonia to glutamine. It is expressed by endothelial cells, but surprisingly shows negligible glutamine-synthesizing activity in these cells at physiological glutamine levels. Here we show in mice that genetic deletion of Glul in endothelial cells impairs vessel sprouting during vascular development, whereas pharmacological blockade of glutamine synthetase suppresses angiogenesis in ocular and inflammatory skin disease while only minimally affecting healthy adult quiescent endothelial cells. This relies on the inhibition of endothelial cell migration but not proliferation. Mechanistically we show that in human umbilical vein endothelial cells GLUL knockdown reduces membrane localization and activation of the GTPase RHOJ while activating other Rho GTPases and Rho kinase, thereby inducing actin stress fibres and impeding endothelial cell motility. Inhibition of Rho kinase rescues the defect in endothelial cell migration that is induced by GLUL knockdown. Notably, glutamine synthetase palmitoylates itself and interacts with RHOJ to sustain RHOJ palmitoylation, membrane localization and activation. These findings reveal that, in addition to the known formation of glutamine, the enzyme glutamine synthetase shows unknown activity in endothelial cell migration during pathological angiogenesis through RHOJ palmitoylation.
Assuntos
Células Endoteliais/enzimologia , Células Endoteliais/patologia , Glutamato-Amônia Ligase/metabolismo , Glutamina/biossíntese , Neovascularização Patológica , Actinas/metabolismo , Animais , Movimento Celular , Células Endoteliais/metabolismo , Feminino , Glutamato-Amônia Ligase/deficiência , Glutamato-Amônia Ligase/genética , Glutamato-Amônia Ligase/fisiologia , Células HEK293 , Células Endoteliais da Veia Umbilical Humana/citologia , Células Endoteliais da Veia Umbilical Humana/enzimologia , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Lipoilação , Camundongos , Ácido Palmítico/metabolismo , Processamento de Proteína Pós-Traducional , Fibras de Estresse/metabolismo , Proteínas rho de Ligação ao GTP/química , Proteínas rho de Ligação ao GTP/metabolismo , Quinases Associadas a rho/metabolismoRESUMO
In this work, a series of novel 1,2,3-triazolyl-coumarin hybrid systems were designed as potential antitumour agents. The structural modification of the coumarin ring was carried out by Cu(I)-catalysed Huisgen 1,3-dipolar cycloaddition of 7-azido-4-methylcoumarin and terminal aromatic alkynes to obtain 1,4-disubstituted 1,2,3-triazolyl-coumarin conjugates 2a-g, bis(1,2,3-triazolyl-coumarin)benzenes 2h-i and coumarin-1,2,3-triazolyl-benzazole hybrids 4a-b. The newly synthesised hybrid molecules were investigated for in vitro antitumour activity against five human cancer cell lines, colon carcinoma HCT116, breast carcinoma MCF-7, lung carcinoma H 460, human T-lymphocyte cells CEM, cervix carcinoma cells HeLa, as well as human dermal microvascular endothelial cells (HMEC-1). Most of these compounds showed moderate to pronounced cytotoxic activity, especially towards MCF-7 cell lines with IC50 = 0.3-32 µM. In addition, compounds 2a-i and 4a-b were studied by UV-Vis absorption and fluorescence spectroscopy and their basic photophysical parameters were determined.
RESUMO
Seasonal or pandemic influenza virus infections are a worldwide health problem requiring antiviral therapy. Since virus resistance to the established neuraminidase inhibitors and novel polymerase inhibitors is growing, new drug targets are needed. Heat shock protein 90 (Hsp90) is associated with several aspects of the influenza virus life cycle, and is considered a relevant host cell target. We report here on a series of benzo[d]thiazole and 4,5,6,7-tetrahydrobenzo[d]thiazole derivatives with robust and selective activities against influenza A (H1N1, H3N2) and influenza B viruses. Two compounds, 1 and 4, have low micromolar EC50 values and show high binding affinities for Hsp90, which suggests that inhibition of Hsp90 is the mechanism underlying their antiviral effects. These compounds represent suitable scaffolds for designing novel Hsp90 inhibitors with favourable activities against influenza virus.
Assuntos
Antivirais/farmacologia , Benzotiazóis/farmacologia , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H3N2/efeitos dos fármacos , Vírus da Influenza B/efeitos dos fármacos , Animais , Antivirais/síntese química , Antivirais/química , Benzotiazóis/síntese química , Benzotiazóis/química , Células Cultivadas , Cães , Relação Dose-Resposta a Droga , Células Madin Darby de Rim Canino/efeitos dos fármacos , Células Madin Darby de Rim Canino/virologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Relação Estrutura-AtividadeRESUMO
Oxidative stress is the product or aetiology of various multifactorial diseases; on the other hand, the development of multifunctional compounds is a recognized strategy for the control of complex diseases. To this end, a series of benzothiazole derivatives was synthesized and evaluated for their multifunctional effectiveness as antioxidant, sunscreen (filter), antifungal and antiproliferative agents. Compounds were easily synthesized via condensation reaction between 2-aminothiophenols and different benzaldehydes. SAR study, particularly in position 2 and 6 of benzothiazoles, led to the identification of 4g and 4k as very interesting potential compounds for the design of multifunctional drugs. In particular, compound 4g is the best blocker of hERG potassium channels expressed in HEK 293 cells exhibiting 60.32% inhibition with IC50 = 4.79 µM.
Assuntos
Benzotiazóis/química , Desenho de Fármacos , Antifúngicos/farmacologia , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Células HEK293 , HumanosRESUMO
A new class of inhibitors of tubulin polymerization based on the 2-alkoxycarbonyl-3-(3',4',5'-trimethoxyanilino)indole molecular skeleton was synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization and cell cycle effects. The results presented show that the methoxy substitution and location on the indole nucleus plays an important role in inhibition of cell growth, and the most favorable position for the substituent was at C-6. In addition, a small-size ester function (methoxy/ethoxycarbonyl) at the 2-position of the indole core was desirable. Also, analogues that were alkylated with methyl, ethyl or n-propyl groups or had a benzyl moiety on the N-1 indolic nitrogen retained activity equivalent to those observed in the parent N-1H analogues. The most promising compounds of the series were 2-methoxycarbonyl-3-(3',4'.5'-trimethoxyanilino)-5-methoxyindole 3f and 1-methyl-2-methoxycarbonyl-3-(3',4'.5'-trimethoxyanilino)-6-methoxy-indole 3w, both of which target tubulin at the colchicine site with antitubulin activities comparable to that of the reference compound combretastatin A-4.
Assuntos
Indóis/química , Indóis/farmacologia , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/síntese química , Simulação de Acoplamento Molecular , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Moduladores de Tubulina/síntese químicaRESUMO
Interleukin 2 (IL-2) is critical for T cell development and homeostasis, being a key regulator of adaptive immune responses in autoimmunity, hypersensitivity reactions and cancer. Therefore, its abundance in serum and peripheral tissues needs tight control. Here, we described a new mechanism contributing to the immunobiology of IL-2. We demonstrated, both in biochemical and cell-based assays, that IL-2 is subject to proteolytic processing by neutrophil matrix metalloproteinase-9 (MMP-9). IL-2 fragments produced after cleavage by MMP-9 remained linked by a disulfide bond and displayed a reduced affinity for all IL-2 receptor subunits and a distinct pattern and timing of signal transduction. Stimulation of IL-2-dependent cells, including murine CTLL-2 and primary human regulatory T cells, with cleaved IL-2 resulted in significantly decreased proliferation. The concerted action of neutrophil proteases destroyed IL-2. Our data suggest that in neutrophil-rich inflammatory conditions in vivo, neutrophil MMP-9 may reduce the abundance of signaling-competent IL-2 and generate a fragment that competes with IL-2 for receptor binding, whereas the combined activity of granulocyte proteases has the potential to degrade and thus eliminate bioavailable IL-2.
Assuntos
Interleucina-2/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Neutrófilos/enzimologia , Transdução de Sinais , Linfócitos T Reguladores/imunologia , Animais , Linhagem Celular , Humanos , Interleucina-2/genética , Metaloproteinase 9 da Matriz/genética , CamundongosRESUMO
In this study, three groups of adamantylphthalimides, bearing different substituents at the phthalimide moiety, N-(4'-R2 )phthalimidoadamantanes (1-7), 3-[N-(4'-R2 )phthalimido]-1-adamantanols (8-10), and 3-[N-(4'-R2 )phthalimido]adamantane-1-carboxylic acids (11-15), were synthesized and screened against tumor cells and viruses. The most potent compounds are not substituted at the adamantane and bear an OH or NH2 substituent at the phthalimide (compounds 3 and 5). The antiproliferative activities of compounds 3 and 5 are in the micromolar range, much higher than the one of thalidomide. A minor antiviral activity against cytomegalovirus and varicella-zoster virus was found for compounds 3 and 5, but these compounds lacked selectivity. The results presented are important for the rational design of the next-generation compounds with anticancer and antiviral activities.
Assuntos
Adamantano/farmacologia , Antineoplásicos/farmacologia , Antivirais/farmacologia , Citomegalovirus/efeitos dos fármacos , Herpesvirus Humano 3/efeitos dos fármacos , Ftalimidas/farmacologia , Adamantano/análogos & derivados , Adamantano/química , Antineoplásicos/síntese química , Antineoplásicos/química , Antivirais/síntese química , Antivirais/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Testes de Sensibilidade Microbiana , Estrutura Molecular , Ftalimidas/síntese química , Ftalimidas/química , Relação Estrutura-AtividadeRESUMO
The synthesis, cytotoxicity and inhibition of CDK8 by thirteen analogs of cortistatin A are reported. These efforts revealed that the analogs with either a 6- or 7-isoquinoline or 5-indole side chain in the 17-position are the most promising anti-proliferative agents. These compounds showed potent cytotoxic effects in CEM, HeLa and HMEC-1 cells. All three compounds exhibited IC50 values < 10µM. The most interesting 10l analog exhibited an IC50 value of 0.59 µM towards the human dermal microvascular endothelial cell line (HMEC-1), significantly lower than the reference standard 2-methoxyestradiol. At a concentration at 50 nM the most potent 10h compound reduced the activity of CDK8 to 35%.
Assuntos
Androsterona/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Quinase 8 Dependente de Ciclina/antagonistas & inibidores , Desenho de Fármacos , Leucemia de Células T/tratamento farmacológico , Androsterona/análogos & derivados , Proliferação de Células , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Leucemia de Células T/patologia , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
In the search for scaffolds for multifunctional compounds we investigated the structure activity relationship of a class of benzimidazole derivatives bearing 5-membered ring. The newly synthesized and the already known compounds were divided into three classes that present different substituent at 5 position of the benzimidazole ring (-H, -COOH or -SO3H) and different heterocycle at position 2 (thiophene, furan or pyrrole). All the derivatives were synthesized and tested to determine their photoprotective profile against UV rays, in vitro antioxidant capacity against different radicals (DPPH and FRAP test), antifungal inhibitory activity (dermatophytes and Candida albicans), antiviral and antiproliferative activity. A Structure-Activity Relationship study indicated compound 10, bearing a pyrrole heterocycle on the benzimidazole ring, as the best multifunctional derivative of the series and as potential candidate for the development of drugs especially in case of melanoma.
Assuntos
Benzimidazóis/química , Benzimidazóis/farmacologia , Protetores contra Radiação/química , Protetores contra Radiação/farmacologia , Pele/efeitos dos fármacos , Antifúngicos/química , Antifúngicos/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Antivirais/química , Antivirais/farmacologia , Candida albicans/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/farmacologia , Humanos , Pele/efeitos da radiação , Relação Estrutura-Atividade , Raios Ultravioleta/efeitos adversosRESUMO
Two novel series of compounds based on the 4,5,6,7-tetrahydrothieno[2,3-c]pyridine and 4,5,6,7-tetrahydrobenzo[b]thiophene molecular skeleton, characterized by the presence of a 3',4',5'-trimethoxyanilino moiety and a cyano or an alkoxycarbonyl group at its 2- or 3-position, respectively, were designed, synthesized, and evaluated for antiproliferative activity on a panel of cancer cell lines and for selected highly active compounds, inhibition of tubulin polymerization, and cell cycle effects. We have identified the 2-(3',4',5'-trimethoxyanilino)-3-cyano-6-methoxycarbonyl-4,5,6,7-tetrahydrothieno[2,3-c]pyridine derivative 3a and its 6-ethoxycarbonyl homologue 3b as new antiproliferative agents that inhibit cancer cell growth with IC50 values ranging from 1.1 to 4.7 µM against a panel of three cancer cell lines. Their interaction with tubulin at micromolar levels leads to the accumulation of cells in the G2/M phase of the cell cycle and to an apoptotic cell death. The cell apoptosis study found that compounds 3a and 3b were very effective in the induction of apoptosis in a dose-dependent manner. These two derivatives did not induce cell death in normal human peripheral blood mononuclear cells, suggesting that they may be selective against cancer cells. Molecular docking studies confirmed that the inhibitory activity of these molecules on tubulin polymerization derived from binding to the colchicine site.
Assuntos
Antineoplásicos/química , Produtos Biológicos/química , Piridinas/química , Moduladores de Tubulina/química , Tubulina (Proteína)/metabolismo , Animais , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Produtos Biológicos/farmacologia , Morte Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Colchicina/química , Ensaios de Seleção de Medicamentos Antitumorais/métodos , Fase G2/efeitos dos fármacos , Células HeLa , Humanos , Células K562 , Leucócitos Mononucleares/efeitos dos fármacos , Camundongos , Simulação de Acoplamento Molecular/métodos , Piridinas/farmacologia , Relação Estrutura-AtividadeRESUMO
Nicotinic acetylcholine receptors (nAChRs) belong to the family of pentameric ligand-gated ion channels and mediate fast excitatory transmission in the central and peripheral nervous systems. Among the different existing receptor subtypes, the homomeric α7 nAChR has attracted considerable attention because of its possible implication in several neurological and psychiatric disorders, including cognitive decline associated with Alzheimer's disease or schizophrenia. Allosteric modulators of ligand-gated ion channels are of particular interest as therapeutic agents, as they modulate receptor activity without affecting normal fluctuations of synaptic neurotransmitter release. Here, we used X-ray crystallography and surface plasmon resonance spectroscopy of α7-acetylcholine-binding protein (AChBP), a humanized chimera of a snail AChBP, which has 71% sequence similarity with the extracellular ligand-binding domain of the human α7 nAChR, to investigate the structural determinants of allosteric modulation. We extended previous observations that an allosteric site located in the vestibule of the receptor offers an attractive target for receptor modulation. We introduced seven additional humanizing mutations in the vestibule-located binding site of AChBP to improve its suitability as a model for studying allosteric binding. Using a fragment-based screening approach, we uncovered an allosteric binding site located near the ß8-ß9 loop, which critically contributes to coupling ligand binding to channel opening in human α7 nAChR. This work expands our understanding of the topology of allosteric binding sites in AChBP and, by extrapolation, in the human α7 nAChR as determined by electrophysiology measurements. Our insights pave the way for drug design strategies targeting nAChRs involved in ion channel-mediated disorders.
Assuntos
Acetilcolina/metabolismo , Receptor Nicotínico de Acetilcolina alfa7/química , Receptor Nicotínico de Acetilcolina alfa7/metabolismo , Acetilcolina/química , Regulação Alostérica , Sítio Alostérico , Animais , Cristalografia por Raios X , Humanos , Modelos Moleculares , Domínios Proteicos , Receptores Nicotínicos/química , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Caramujos , Receptor Nicotínico de Acetilcolina alfa7/genéticaRESUMO
The possible resistance of influenza virus against existing antiviral drugs calls for new therapeutic concepts. One appealing strategy is to inhibit virus entry, in particular at the stage of internalization. This requires a better understanding of virus-host interactions during the entry process, including the role of receptor tyrosine kinases (RTKs). To search for cellular targets, we evaluated a panel of 276 protein kinase inhibitors in a multicycle antiviral assay in Madin-Darby canine kidney cells. The RTK inhibitor Ki8751 displayed robust anti-influenza A and B virus activity and was selected for mechanistic investigations. Ki8751 efficiently disrupted the endocytic process of influenza virus in different cell lines carrying platelet-derived growth factor receptor ß (PDGFRß), an RTK that is known to act at GM3 ganglioside-positive lipid rafts. The more efficient virus entry in CHO-K1 cells compared to the wild-type ancestor (CHO-wt) cells indicated a positive effect of GM3, which is abundant in CHO-K1 but not in CHO-wt cells. Entering virus localized to GM3-positive lipid rafts and the PDGFRß-containing endosomal compartment. PDGFRß/GM3-dependent virus internalization involved PDGFRß phosphorylation, which was potently inhibited by Ki8751, and desialylation of activated PDGFRß by the viral neuraminidase. Virus uptake coincided with strong activation of the Raf/MEK/Erk cascade, but not of PI3K/Akt or phospholipase C-γ. We conclude that influenza virus efficiently hijacks the GM3-enhanced PDGFRß signalling pathway for cell penetration, providing an opportunity for host cell-targeting antiviral intervention.
Assuntos
Gangliosídeo G(M3)/metabolismo , Influenza Humana/metabolismo , Influenza Humana/virologia , Infecções por Orthomyxoviridae/metabolismo , Orthomyxoviridae/patogenicidade , Receptor beta de Fator de Crescimento Derivado de Plaquetas/metabolismo , Transdução de Sinais/fisiologia , Animais , Células CHO , Linhagem Celular , Cricetulus , Cães , Células HEK293 , Humanos , Influenza Humana/tratamento farmacológico , Células Madin Darby de Rim Canino , Orthomyxoviridae/efeitos dos fármacos , Infecções por Orthomyxoviridae/tratamento farmacológico , Compostos de Fenilureia/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação/fisiologia , Inibidores de Proteínas Quinases/farmacologia , Quinolinas/farmacologia , Receptores Proteína Tirosina Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacosRESUMO
The CCL20/CCR6 chemokine/receptor axis has previously been shown to contribute to the initiation and progression of hepatocellular carcinoma (HCC) through the recruitment of CCR6-positive leukocytes to the tumor microenvironment. In particular, high serum levels of CCL20 are reported in patients with HCC induced by the hepatitis C virus (HCV). A potential non-immune role for the CCL20/CCR6 axis in HCC development has not yet been investigated. Microarray analysis (Benkheil et al., paper submitted for publication), revealed that CCL20 is highly upregulated in hepatoma cells infected with HCV compared with non-infected hepatoma cells. To determine the role of the CCL20/CCR6 axis in HCV-related HCC, we first explored which cell populations express CCR6 in human liver tissue with chronic disease or HCC. Immunohistochemical (IHC) analysis revealed that CCR6 is present on endothelial cells (ECs) of portal blood vessels in livers with chronic HCV infection and in HCV- and alcoholic-HCC tissue. In addition, we found CCR6 to be expressed on primary macrovascular (HUVECs) and microvascular ECs (HMVEC-ds) where it co-expressed with the endothelial marker CD31. In vitro angiogenesis experiments revealed that CCL20 is a direct pro-angiogenic molecule that induces EC invasion, sprouting and migration through CCR6. Moreover, using the angiogenesis matrigel plug assay in immunodeficient NMRI-nu mice, we clearly showed that CCL20 induces blood vessel formation, by attracting CCR6-positive ECs. Finally, we demonstrated that HCV-induced CCL20 protein expression and secretion in hepatoma cells could be abolished by antiviral treatment, indicating that CCL20 expression is dependent on HCV replication. In contrast to HCV, HBV-infection resulted in a decreased expression of CCL20, implying a virus-specific effect. Taken together, we identified HCV-induced CCL20 as a direct pro-angiogenic factor that acts on endothelial CCR6. These results suggest that the CCL20/CCR6 axis contributes to hepatic angiogenesis, promoting the hypervascular state of HCV-HCC.
Assuntos
Carcinoma Hepatocelular/genética , Quimiocina CCL20/genética , Neoplasias Hepáticas/genética , Neovascularização Patológica/genética , Receptores CCR6/genética , Animais , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/virologia , Quimiotaxia/genética , Células Endoteliais/fisiologia , Células Endoteliais/virologia , Regulação Neoplásica da Expressão Gênica , Hepacivirus/genética , Hepacivirus/patogenicidade , Células Endoteliais da Veia Umbilical Humana , Humanos , Fígado/metabolismo , Fígado/patologia , Fígado/virologia , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/virologia , Camundongos , Neovascularização Patológica/patologia , Neovascularização Patológica/virologia , Microambiente Tumoral/genéticaRESUMO
A modified DNA aptamer that binds BACE1, a therapeutic target involved in Alzheimer's disease has been developed. This ssXNA not only tightly binds to BACE1 but also inhibits its protease activity in vitro in the same range as a previously described unmodified aptamer. We report the in vitro selection of functional oligonucleotides incorporating two nucleobase modifications: 5-chlorouracil and 7-deazaadenine. The nucleoside analogue 5-chloro-2'-deoxyuridine has already been explored as a replacement for thymidine in a chemically modified genome of a bacterium. Thus, 5-chlorouracil modification is a good candidate to support genetic transfer in vivo as well as functional activity.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/metabolismo , Aptâmeros de Nucleotídeos/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/metabolismo , Adenina/análogos & derivados , Adenina/química , Aptâmeros de Nucleotídeos/química , Sequência de Bases , Humanos , Ligação Proteica , Técnica de Seleção de Aptâmeros , Uracila/análogos & derivados , Uracila/químicaRESUMO
Current treatments available for African sleeping sickness or human African trypanosomiasis (HAT) are limited, with poor efficacy and unacceptable safety profiles. Here, we report a new approach to address treatment of this disease based on the use of compounds that bind to parasite surface glycans leading to rapid killing of trypanosomes. Pradimicin and its derivatives are non-peptidic carbohydrate-binding agents that adhere to the carbohydrate moiety of the parasite surface glycoproteins inducing parasite lysis in vitro. Notably, pradimicin S has good pharmaceutical properties and enables cure of an acute form of the disease in mice. By inducing resistance in vitro we have established that the composition of the sugars attached to the variant surface glycoproteins are critical to the mode of action of pradimicins and play an important role in infectivity. The compounds identified represent a novel approach to develop drugs to treat HAT.
RESUMO
Inhibition of microtubule function using tubulin targeting agents has received growing attention in the last several decades. The indole scaffold has been recognized as an important scaffold in the design of novel compounds acting as antimitotic agents. Indole-based chalcones, in which one of the aryl rings was replaced by an indole, have been explored in the last few years for their anticancer potential in different cancer cell lines. Eighteen novel (3',4',5'-trimethoxyphenyl)-indolyl-propenone derivatives with general structure 9 were synthesized and evaluated for their antiproliferative activity against a panel of four different human cancer cell lines. The highest IC50 values were obtained against the human promyelocytic leukemia HL-60 cell line. This series of chalcone derivatives was characterized by the presence of a 2-alkoxycarbonyl indole ring as the second aryl system attached at the carbonyl of the 3-position of the 1-(3',4',5'-trimethoxyphenyl)-2-propen-1-one framework. The structure-activity relationship (SAR) of the indole-based chalcone derivatives was investigated by varying the position of the methoxy group, by the introduction of different substituents (hydrogen, methyl, ethyl or benzyl) at the N-1 position and by the activity differences between methoxycarbonyl and ethoxycarbonyl moieties at the 2-position of the indole nucleus. The antiproliferative activity data of the novel synthesized compounds revealed that generally N-substituted indole analogues exhibited considerably reduced potency as compared with their parent N-unsubstituted counterparts, demonstrating that the presence of a hydrogen on the indole nitrogen plays a decisive role in increasing antiproliferative activity. The results also revealed that the position of the methoxy group on the indole ring is a critical determinant of biological activity. Among the synthesized derivatives, compound 9e, containing the 2-methoxycarbonyl-6-methoxy-N-1H-indole moiety exhibited the highest antiproliferative activity, with IC50 values of 0.37, 0.16 and 0.17 µM against HeLa, HT29 and MCF-7 cancer cell lines, respectively, and with considerably lower activity against HL-60 cells (IC50: 18 µM). This derivative also displayed cytotoxic properties (IC50 values â¼1 µM) in the human myeloid leukemia U-937 cell line overexpressing human Bcl-2 (U-937/Bcl-2) via cell cycle progression arrest at the G2-M phase and induction of apoptosis. The results obtained also demonstrated that the antiproliferative activity of this molecule is related to inhibition of tubulin polymerisation. The presence of a methoxy group at the C5- or C6-position of the indole nucleus, as well as the absence of substituents at the N-1-indole position, contributed to the optimal activity of the indole-propenone-3',4',5'-trimethoxyphenyl scaffold.
Assuntos
Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Desenho de Fármacos , Indóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Indóis/síntese química , Indóis/química , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Polymerases have a structurally highly conserved negatively charged amino acid motif that is strictly required for Mg(2+) cation-dependent catalytic incorporation of (d)NTP nucleotides into nucleic acids. Based on these characteristics, a nucleoside monophosphonate scaffold, α-carboxy nucleoside phosphonate (α-CNP), was designed that is recognized by a variety of polymerases. Kinetic, biochemical, and crystallographic studies with HIV-1 reverse transcriptase revealed that α-CNPs mimic the dNTP binding through a carboxylate oxygen, two phosphonate oxygens, and base-pairing with the template. In particular, the carboxyl oxygen of the α-CNP acts as the potential equivalent of the α-phosphate oxygen of dNTPs and two oxygens of the phosphonate group of the α-CNP chelate Mg(2+), mimicking the chelation by the ß- and γ-phosphate oxygens of dNTPs. α-CNPs (i) do not require metabolic activation (phosphorylation), (ii) bind directly to the substrate-binding site, (iii) chelate one of the two active site Mg(2+) ions, and (iv) reversibly inhibit the polymerase catalytic activity without being incorporated into nucleic acids. In addition, α-CNPs were also found to selectively interact with regulatory (i.e., allosteric) Mg(2+)-dNTP-binding sites of nucleos(t)ide-metabolizing enzymes susceptible to metabolic regulation. α-CNPs represent an entirely novel and broad technological platform for the development of specific substrate active- or regulatory-site inhibitors with therapeutic potential.
Assuntos
Nucleosídeos/farmacologia , Nucleotídeos/farmacologia , Organofosfonatos/farmacologia , Regulação Alostérica/efeitos dos fármacos , Sequência de Bases , Biocatálise/efeitos dos fármacos , Extratos Celulares , DNA Polimerase Dirigida por DNA/metabolismo , Farmacorresistência Viral/efeitos dos fármacos , Transcriptase Reversa do HIV/antagonistas & inibidores , Transcriptase Reversa do HIV/química , Transcriptase Reversa do HIV/metabolismo , Células HeLa , Humanos , Cinética , Modelos Moleculares , Dados de Sequência Molecular , Mutação/genética , Nucleosídeos/química , Nucleotídeos/química , Organofosfonatos/química , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/farmacologia , EstereoisomerismoRESUMO
Since Judah Folkman hypothesized in 1971 that angiogenesis is required for solid tumor growth, numerous studies have been conducted to unravel the angiogenesis process, analyze its role in primary tumor growth, metastasis and angiogenic diseases, and to develop inhibitors of proangiogenic factors. These studies have led in 2004 to the approval of the first antiangiogenic agent (bevacizumab, a humanized antibody targeting vascular endothelial growth factor) for the treatment of patients with metastatic colorectal cancer. This approval launched great expectations for the use of antiangiogenic therapy for malignant diseases. However, these expectations have not been met and, as knowledge of blood vessel formation accumulates, many of the original paradigms no longer hold. Therefore, the regulators and clinical implications of angiogenesis need to be revisited. In this review, we discuss recently identified angiogenesis mediators and pathways, new concepts that have emerged over the past 10 years, tumor resistance and toxicity associated with the use of currently available antiangiogenic treatment and potentially new targets and/or approaches for malignant and nonmalignant neovascular diseases.
Assuntos
Neoplasias/irrigação sanguínea , Inibidores da Angiogênese/fisiologia , Inibidores da Angiogênese/uso terapêutico , Animais , Humanos , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologiaRESUMO
In eukaryotic cells, surface expression of most type I transmembrane proteins requires translation and simultaneous insertion of the precursor protein into the endoplasmic reticulum (ER) membrane for subsequent routing to the cell surface. This co-translational translocation pathway is initiated when a hydrophobic N-terminal signal peptide (SP) on the nascent protein emerges from the ribosome, binds the cytosolic signal recognition particle (SRP), and targets the ribosome-nascent chain complex to the Sec61 translocon, a universally conserved protein-conducting channel in the ER-membrane. Despite their common function in Sec61 targeting and ER translocation, SPs have diverse but unique primary sequences. Thus, drugs that recognise SPs could be exploited to inhibit translocation of specific proteins into the ER. Here, through flow cytometric analysis the small-molecule macrocycle cyclotriazadisulfonamide (CADA) is identified as a highly selective human CD4 (hCD4) down-modulator. We show that CADA inhibits CD4 biogenesis and that this is due to its ability to inhibit co-translational translocation of CD4 into the lumen of the ER, both in cells as in a cell-free in vitro translation/translocation system. The activity of CADA maps to the cleavable N-terminal SP of hCD4. Moreover, through surface plasmon resonance analysis we were able to show direct binding of CADA to the SP of hCD4 and identify this SP as the target of our drug. Furthermore, CADA locks the SP in the translocon during a post-targeting step, possibly in a folded state, and prevents the translocation of the associated protein into the ER lumen. Instead, the precursor protein is routed to the cytosol for degradation. These findings demonstrate that a synthetic, cell-permeable small-molecule can be developed as a SP-binding drug to selectively inhibit protein translocation and to reversibly regulate the expression of specific target proteins.
Assuntos
Biossíntese de Proteínas/efeitos dos fármacos , Sinais Direcionadores de Proteínas , Inibidores da Síntese de Proteínas/farmacologia , Sequência de Aminoácidos , Antígenos CD4/química , Antígenos CD4/metabolismo , Regulação para Baixo/efeitos dos fármacos , Humanos , Interações Hidrofóbicas e Hidrofílicas , Dados de Sequência Molecular , Conformação Proteica , Transporte Proteico/efeitos dos fármacos , Sulfonamidas/química , Sulfonamidas/farmacologiaRESUMO
The Gewald three-component reaction yielding highly substituted 2-aminothiophene heterocycles has been known for a long time and holds an extraordinary potential in the pharmaceutical industry. Herein, we describe a four-component reaction initiated by the conjugate addition of different indole derivatives to α,ß-unsaturated carbonyl compounds. This is followed by an in situ Gewald three-component reaction which results in the formation of a compound containing an indole and a 2-aminothiophene moiety separated by a methylene spacer. We also examined the impact of the use of other nucleophilic components such as pyrrole derivatives on this MG-4CR (Michael-Gewald four component reaction). All these synthesized compounds were tested for anti-proliferative activity and three of them showed activity in the nanomolar range.