RESUMO
BACKGROUND: In recent years, much progress has been made in the treatment of multiple myeloma. However, a major limitation of existing chemotherapeutic drugs is the eventual emergence of resistance; hence, the development of novel agents with new mechanisms of action is pertinent. Here, we describe the activity and mechanism of action of pyrrolo-1,5-benzoxazepine-15 (PBOX-15), a novel microtubule-targeting agent, in multiple myeloma cells. METHODS: The anti-myeloma activity of PBOX-15 was assessed using NCI-H929, KMS11, RPMI8226, and U266 cell lines, and primary myeloma cells. Cell cycle distribution, apoptosis, cytochrome c release, and mitochondrial inner membrane depolarisation were analysed by flow cytometry; gene expression analysis was carried out using TaqMan Low Density Arrays; and expression of caspase-8 and Bcl-2 family of proteins was assessed by western blot analysis. RESULTS: Pyrrolo-1,5-benzoxazepine-15 induced apoptosis in ex vivo myeloma cells and in myeloma cell lines. Death receptor genes were upregulated in both NCI-H929 and U266 cell lines, which displayed the highest and lowest apoptotic responses, respectively, following treatment with PBOX-15. The largest increase was detected for the death receptor 5 (DR5) gene, and cotreatment of both cell lines with tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), the DR5 ligand, potentiated the apoptotic response. In NCI-H929 cells, PBOX-15-induced apoptosis was shown to be caspase-8 dependent, with independent activation of extrinsic and intrinsic apoptotic pathways. A caspase-8-dependent decrease in expression of Bim(EL) preceded downregulation of other Bcl-2 proteins (Bid, Bcl-2, Mcl-1) in PBOX-15-treated NCI-H929 cells. CONCLUSION: PBOX-15 induces apoptosis and potentiates TRAIL-induced cell death in multiple myeloma cells. Thus, PBOX-15 represents a promising agent, with a distinct mechanism of action, for the treatment of this malignancy.
Assuntos
Apoptose/efeitos dos fármacos , Microtúbulos/efeitos dos fármacos , Mieloma Múltiplo/patologia , Oxazepinas/farmacologia , Pirróis/farmacologia , Receptores de Morte Celular/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/fisiologia , Regulação para Cima/efeitos dos fármacos , Linhagem Celular Tumoral , Regulação para Baixo/efeitos dos fármacos , Humanos , Microscopia de FluorescênciaRESUMO
BACKGROUND: Imatinib is a direct and potent inhibitor of the constitutively active tyrosine kinase, breakpoint cluster region-Abelson (Bcr-Abl), which is central to the pathogenesis of chronic myeloid leukaemia (CML) patients. As such, imatinib has become the front-line treatment for CML patients. However, the recent emergence of imatinib resistance, commonly associated with point mutations within the kinase domain, has led to the search for alternative drug treatments and combination therapies for CML. METHODS: In this report, we analyse the effects of representative members of the novel pro-apoptotic microtubule depolymerising pyrrolo-1,5-benzoxazepines or PBOX compounds on chemotherapy-refractory CML cells using a series of Bcr-Abl mutant cell lines, clinical ex vivo patient samples and an in vivo mouse model. RESULTS: The PBOX compounds potently reduce cell viability in cells expressing the E225K and H396P mutants as well as the highly resistant T315I mutant. The PBOX compounds also induce apoptosis in primary CML samples including those resistant to imatinib. We also show for the first time, the in vivo efficacy of the pro-apoptotic PBOX compound, PBOX-6, in a CML mouse model of the T315I Bcr-Abl mutant. CONCLUSION: Results from this study highlight the potential of these novel series of PBOX compounds as an effective therapy against CML.
Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Oxazepinas/farmacologia , Pirróis/farmacologia , Adulto , Idoso , Animais , Apoptose/efeitos dos fármacos , Western Blotting , Linhagem Celular Tumoral , Separação Celular , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Feminino , Citometria de Fluxo , Genes abl/genética , Humanos , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , MutaçãoRESUMO
Clinical treatment-failures to affordable drugs encouraged new investigation for discovery and development of new prophylactic and therapeutic interventions against malaria. The Drug Discovery Cluster (DDcl) of the Italian Malaria Network gathers several highly integrated and complementary laboratories from different Italian Institutions to identify, synthesise, screen in vitro and in vivo new antimalarial molecules directed against the intraerythrocytic stage of P. falciparum parasites and/or with transmission blocking activity to select lead compounds for further development. Complementary research activities, both in vitro and in the clinics, aim at investigating the pathogenetic mechanisms of severe malaria anaemia and the different manifestations of the disease in malaria-HIV co-infected patients to identify new therapies and improve survival.
Assuntos
Antimaláricos/farmacologia , Inseticidas/farmacologia , Sociedades Científicas/organização & administração , Animais , Anopheles/efeitos dos fármacos , Anopheles/metabolismo , Anopheles/parasitologia , Antimaláricos/uso terapêutico , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Sistemas de Liberação de Medicamentos , Desenho de Fármacos , Avaliação Pré-Clínica de Medicamentos , Resistência a Medicamentos , Humanos , Insetos Vetores/efeitos dos fármacos , Insetos Vetores/metabolismo , Insetos Vetores/parasitologia , Inseticidas/uso terapêutico , Itália , Cinurenina/metabolismo , Malária Falciparum/tratamento farmacológico , Malária Falciparum/parasitologia , Malária Falciparum/transmissão , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Parasitária , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Plasmodium falciparum/efeitos dos fármacosRESUMO
Microtubules are currently ranked one of the most validated targets for chemotherapy; with clinical use of microtubule targeting agents (MTAs) extending beyond half a century. Recent research has focused on the development of novel MTAs to combat drug resistance and drug associated toxicities. Of particular interest are compounds structurally different to those currently used within the clinic. The pyrrolo-1, 5-benzoxazepines (PBOXs) are a structurally distinct novel group of anti-cancer agents, some of which target tubulin. Herein, we review the chemistry, mechanism of action, preclinical development of the PBOXs and comparisons with clinically relevant chemotherapeutics. The PBOXs induce a range of cellular responses including; cell cycle arrest, apoptosis, autophagy, anti-vascular and anti-angiogenic effects. The apoptotic potential of the PBOXs extends across a wide spectrum of cancer-derived cell lines, by targeting tubulin and multiple molecular pathways frequently deregulated in human cancers. Extensive experimental data suggest that combining the PBOXs with established chemotherapeutics or radiation is therapeutically advantageous. Pre-clinical highlights of the PBOXs include; cancer specificity and improved therapeutic efficacy as compared to some current first line therapeutics.
RESUMO
Most neurological diseases have a multifactorial nature and the number of molecular mechanisms discovered as underpinning these diseases is continuously evolving. The old concept of developing selective agents for a single target does not fit with the medical need of most neurological diseases. The development of designed multiple ligands holds great promises and appears as the next step in drug development for the treatment of these multifactorial diseases. Dopamine and its five receptor subtypes are intimately involved in numerous neurological disorders. Dopamine receptor ligands display a high degree of cross interactions with many other targets including G-protein coupled receptors, transporters, enzymes and ion channels. For brain disorders like Parkinsons disease, schizophrenia and depression the dopaminergic system, being intertwined with many other signaling systems, plays a key role in pathogenesis and therapy. The concept of designed multiple ligands and polypharmacology, which perfectly meets the therapeutic needs for these brain disorders, is herein discussed as a general ligand-based concept while focusing on dopaminergic agents and receptor subtypes in particular.
Assuntos
Dopaminérgicos/farmacologia , Polifarmacologia , Animais , Dopaminérgicos/química , Dopaminérgicos/uso terapêutico , Humanos , Receptores Dopaminérgicos/metabolismoRESUMO
A series of 26 pyrrolo[2,1-c][1,4]benzothiazines, which have been already synthesized and reported to show calcium antagonist activity in both radioligand-binding assays and functional studies, were investigated using the comparative molecular field analysis (CoMFA) paradigm. Due to the lack of experimental structural data on these derivatives, the minimum energy conformers obtained by molecular mechanics calculations were used in the subsequent study. Structures were aligned following an alignment criterion based on the pharmacophoric groups of the studied compounds. The predictive ability of the CoMFA model was evaluated using a test set consisting of three representative compounds. The best 3D-quantitative structure-activity relationship model found yields significant cross-validated, conventional, and predictive r2 values equal to 0.703, 0.970, and 0.865, respectively, the average absolute error of predictions being 0.26 log unit. The predictive capability of this model was also tested on a further test set of molecules consisting of diltiazem and nine pyrrolo[2,1-d][1,5]benzothiazepines endowed with calcium antagonist activity. The accurate results obtained also in this case revealed the robustness of the model. On the basis of the same alignment, the structural moieties of the studied calcium entry blockers which are thought to contribute to the biological activity were identified, and a possible receptor-binding site for all these compounds is presented taking into account the information derived from the analysis of the steric and electrostatic CoMFA contour maps.
Assuntos
Bloqueadores dos Canais de Cálcio/química , Diltiazem/química , Modelos Moleculares , Tiazinas/química , Animais , Bloqueadores dos Canais de Cálcio/metabolismo , Córtex Cerebral/metabolismo , Diltiazem/metabolismo , Nitrendipino/metabolismo , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
A series of 42 6-arylpyrrolo[2,1-d][1,5]benzothiazepines, which we have recently described as selective ligands of the mitochondrial benzodiazepine receptor (MBR) (Fiorini I.; et al. J. Med. Chem. 1994, 37, 1427-1438), have been investigated using the comparative molecular field analysis (CoMFA) approach. The resulting 3D-QSAR model rationalizes the steric and electronic factors which modulate affinity to the MBR with a cross-validation standard error of 0.648 pIC50 unit. A set of seven novel pyrrolobenzothiazepine congeners has successively been synthesized and tested. The CoMFA model forecasts the binding affinity values of these new compounds with a prediction standard error of 0.536.
Assuntos
Mitocôndrias/metabolismo , Modelos Moleculares , Pirróis/metabolismo , Receptores de GABA-A/metabolismo , Tiazepinas/metabolismo , Animais , Isoquinolinas/metabolismo , Ligantes , Masculino , Conformação Molecular , Ratos , Ratos Sprague-Dawley , Análise de Regressão , Relação Estrutura-AtividadeRESUMO
The 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives have been recently proposed as a new class of ligands specific for the mitochondrial benzodiazepine receptor (Fiorini et al. J. Med. Chem. 1994, 37, 1427-1438) (Greco et al. J. Med. Chem. 1994, 37, 4100-4108). In this paper we report the X-ray crystallographic structures of three potent (1-3) and two inactive (4 and 5) previously described benzothiazepines, as well as binding affinity constants for two newly assayed analogs in which the acyloxy side chain was replaced by a methoxy group (6) or removed (7). Structure-affinity relationships and molecular mechanics calculations performed using crystal structures as references have led to a revised 3D pharmacophore model accounting for all the data available up until now. Interestingly, the hypothetical receptor-bound conformations of 1-3 display a considerable degree of similarity with their crystal geometries. Additional calculations have confirmed that the poor affinities of benzothiazepines bearing an aroyloxy group (4 and 5) should be ascribed to the steric and/or electronic features of the side chain aryl moieties rather than to unfavorable conformational properties.
Assuntos
Mitocôndrias/metabolismo , Modelos Moleculares , Pirróis/química , Pirróis/metabolismo , Receptores de GABA-A/metabolismo , Tiazepinas/química , Tiazepinas/metabolismo , Difração de Raios X , Animais , Encéfalo/ultraestrutura , Simulação por Computador , Cristalização , Masculino , Conformação Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
Two novel classes of pyrrolobenzothiazepinones and pyrrolobenzoxazepinones were investigated as potential anti-AIDS drugs. These compounds were found to inhibit HIV-1 reverse transcriptase (RT) enzyme in vitro and to prevent HIV-1 cytopathogenicity in T4 lymphocytes, without appreciable activity on HIV-2 cytopathic effects, and against HBV as well as calfthymus DNA alpha-polymerase. Their potency is influenced by substituents at position 6 and on the fused aromatic ring. Specifically, small lipophilic substituents at C-6 were preferred, whereas substitutions on the benzo-fused ring were found to be detrimental to activity, with respect to the unsubstituted compounds. Modification of the pie-system at C-6 is well tolerated, although the replacement of the benzo-fused with a [2,3]naphtho-fused ring leads to a less active compound. Maximum potency and specificity is achieved with a phenyl and an ethyl group at position 6 of the pyrrolobenzoxazepinone system. In the enzymatic assay the oxazepinone derivative (+/-)-6-ethyl-6-phenylpyrrolo[2,1-d][1,5] benzoxazepin-7(6H)-one 16e (IC50 = 0.25 microM) was found to be more potent than nevirapine (IC50 = 0.5 microM), tested in the same experimental conditions using rC.dG as a template-primer. In cell culture assay benzoxazepine 16e was active against HIV-1, both wild type and AZT-sensitive, and HIV-1 (IIIB) strains, but not against HIV-2. In enzyme assay although 16e inhibited HIV-1 RT, it was inactive against the nevirapine-resistant recombinant RT Y181C at 50 microM. Molecular modeling studies suggest that these derivatives present a 3D pharmacophoric arrangement similar to that of other non-nucleoside inhibitors such as nevirapine.
Assuntos
Antivirais/farmacologia , HIV-1/efeitos dos fármacos , Oxazepinas/farmacologia , DNA Polimerase Dirigida por RNA/efeitos dos fármacos , Inibidores da Transcriptase Reversa/farmacologia , Antivirais/síntese química , Linhagem Celular , Transcriptase Reversa do HIV , Humanos , Modelos Moleculares , Estrutura Molecular , Oxazepinas/síntese química , DNA Polimerase Dirigida por RNA/metabolismo , Inibidores da Transcriptase Reversa/síntese química , Relação Estrutura-Atividade , Tiazepinas/síntese química , Tiazepinas/farmacologiaRESUMO
A novel class of ligands specific for MBR receptors has been identified: 6-arylpyrrolo[2,1-d][1,5]benzothiazepine derivatives. The majority of newly synthesized esters 37-64 as well as some intermediate ketones showed micro- or nanomolar affinity for [3H]PK 11195 binding inhibition. A SAR study on 42 compounds and a molecular modeling approach led to a preliminary structural selectivity profile: the 6,7-double bond, the carbamoyloxy, alcanoyloxy, and mesyloxy side chains at the 7-position, and the prospective chloro substitution at the 4-position seemed to be the most important structural features improving affinity. Therefore, 7-[(dimethylcarbamoyl)oxy]- and 7-acetoxy-4-chloro-6-phenylpyrrolo[2,1-d][1,5]benzothiazepine (43 and 57) were synthesized. With 7-[(dimethylcarbamoyl)oxy]-6-(p-methoxyphenyl)pyrrolo[2,1- d][1,5]benzothiazepine (65), these were the most promising compounds with IC50s of respectively 9, 8, and 9 nM, under conditions where PK 11195 had an IC50 of 2 nM.
Assuntos
Mitocôndrias/metabolismo , Receptores de GABA-A/metabolismo , Tiazepinas/síntese química , Tiazepinas/metabolismo , Analgésicos/síntese química , Analgésicos/farmacologia , Animais , Ligação Competitiva , Córtex Cerebral/metabolismo , Técnicas In Vitro , Ligantes , Masculino , Camundongos , Modelos Moleculares , Conformação Molecular , Pirróis/síntese química , Pirróis/metabolismo , Ensaio Radioligante , Ratos , Relação Estrutura-Atividade , Tiazepinas/química , Tiazepinas/farmacologiaRESUMO
The synthesis and pharmacological evaluation of a series of pyrrolo[1,4]benzothiazine derivatives are described. These compounds, related to diltiazem, have been shown to be representative of a novel series of calcium channel antagonists. The IC50S for inhibition of [3H]nitrendipine binding calculated by radioreceptor assay on rat cortex and rat heart homogenates showed that some of the described compounds possess an affinity equal to or higher than those of the reference calcium antagonists verapamil and cis-(+)-diltiazem. Furthermore, the alteration of the benzothiazepinone system of diltiazem to the pyrrolo[1,4]benzothiazine system of the title compounds resulted in a clear-cut selectivity for cardiac over vascular tissue, as shown in functional studies. In fact comparison of calcium antagonist activity on guinea pig aorta strips with the negative inotropic activity, determined by using an isolated guinea pig left atrium, revealed that the compounds examined displayed higher selectivity than the reference standard, within a wide variation of data. A number of structure-activity relationship trends have been identified, and possible explanation is advanced in order to account for the observed differences in selectivity. Prerequisite for in vitro calcium channel-blocking activity is the presence of two pharmacophores, namely, the substitution at C-4 and the substitution on the pyrrole ring. Two of the tested compounds, 8b and 28a, were identified as potent calcium antagonists selective for cardiac over vascular tissue.
Assuntos
Bloqueadores dos Canais de Cálcio/síntese química , Coração/efeitos dos fármacos , Tiazinas/síntese química , Animais , Ligação Competitiva , Encéfalo/efeitos dos fármacos , Bloqueadores dos Canais de Cálcio/química , Bloqueadores dos Canais de Cálcio/farmacologia , Gráficos por Computador , Diltiazem/farmacologia , Feminino , Cobaias , Técnicas In Vitro , Masculino , Modelos Moleculares , Contração Miocárdica/efeitos dos fármacos , Nitrendipino/antagonistas & inibidores , Nitrendipino/metabolismo , Nitrendipino/farmacologia , Pirróis/síntese química , Pirróis/metabolismo , Pirróis/farmacologia , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Tiazinas/metabolismo , Tiazinas/farmacologia , Verapamil/farmacologiaRESUMO
The synthesis and the biological evaluation of a series of novel pyrroloquinoxaline derivatives are described. In binding studies several compounds proved to be potent and selective 5-HT3 receptor ligands. The most active pyrroloquinoxalines, 11d and 11e, showed a subnanomolar affinity for 5-HT3 receptor and were able to functionally discriminate the central and peripheral 5-HT3 receptor, being agonists and antagonists, respectively. In functional studies ([14C]-guanidinium accumulation test in NG 108-15 cells, in vitro) most of the synthesized compounds showed clear-cut 5-HT3 agonist properties. In in vivo studies on the von Bezold-Jarisch reflex test (a peripheral interaction model) the behavior of the tested compounds ranged from agonist to antagonist, while clear agonist properties were obtained with 12a on cortical acetylcholine release in freely moving rats. Pharmacokinetic studies with 11e and 12c indicate that the compounds easily cross the blood-brain barrier (BBB) after systemic administration with a brain/plasma ratio of 17.5 and 37.5, respectively. Thus compounds 11e and 12c represent the most potent central 5-HT3 agonists identified to date that are able to cross the blood-brain barrier.
Assuntos
Quinoxalinas/farmacologia , Receptores de Serotonina/efeitos dos fármacos , Agonistas do Receptor de Serotonina/farmacologia , Animais , Barreira Hematoencefálica , Linhagem Celular , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Células Híbridas , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Quinoxalinas/química , Quinoxalinas/farmacocinética , Ratos , Ratos Sprague-Dawley , Receptores 5-HT3 de Serotonina , Reflexo/efeitos dos fármacos , Agonistas do Receptor de Serotonina/química , Agonistas do Receptor de Serotonina/farmacocinética , Espectrofotometria Infravermelho , Relação Estrutura-AtividadeRESUMO
The synthesis, pharmacological evaluation, and structure-activity relationships (SARs) of a series of novel pyrroloquinoxalines and heteroaromatic-related derivatives are described. The new pyrroloquinoxaline-related ligands were tested in rat cortex, a tissue expressing high density of 5-HT(3) receptors, and on NG108-15 cells and exhibited IC(50) values in the low nanomolar or subnanomolar range, as measured by the inhibition of [(3)H]zacopride binding. The SAR studies detailed herein delineated a number of structural features required for improving affinity. Some of the ligands were employed as "molecular yardsticks" to probe the spatial dimensions of the lipophilic pockets L1, L2, and L3 in the 5-HT(3) receptor cleft, while the 7-OH pyrroloquinoxaline analogue was designed to investigate hydrogen bonding with a putative receptor site H1 possibly interacting with the serotonin hydroxy group. The most active pyrroloquinoxaline derivatives showed subnanomolar affinity for the 5-HT(3) receptor. In functional studies ([(14)C]guanidinium accumulation test in NG108-15 hybrid cells, in vitro) most of the tested compounds showed clear-cut 5-HT(3) agonist properties, while some others were found to be partial agonists. Several heteroaromatic systems, bearing N-substituted piperazine moieties, have been explored with respect to 5-HT(3) affinity, and novel structural leads for the development of potent and selective central 5-HT(3) receptor agonists have been identified. Preliminary pharmacokinetic studies indicate that these compounds easily cross the blood-brain barrier (BBB) after systemic administration with a brain/plasma ratio between 2 and 20, unless they bear a highly hydrophilic group on the piperazine ring. None of the tested compounds showed in vivo anxiolytic-like activity, but potential analgesic-like properties have been possibly disclosed for this new class of 5-HT(3) receptor agonists.
Assuntos
Pirróis/síntese química , Quinoxalinas/síntese química , Receptores de Serotonina/efeitos dos fármacos , Agonistas do Receptor de Serotonina/síntese química , Animais , Ansiolíticos/síntese química , Ansiolíticos/química , Ansiolíticos/farmacocinética , Ansiolíticos/farmacologia , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacocinética , Anti-Inflamatórios não Esteroides/farmacologia , Barreira Hematoencefálica , Encéfalo/metabolismo , Guanidina/metabolismo , Cobaias , Células Híbridas , Técnicas In Vitro , Ligantes , Masculino , Pirróis/química , Pirróis/farmacocinética , Pirróis/farmacologia , Quinoxalinas/química , Quinoxalinas/farmacocinética , Quinoxalinas/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores 5-HT3 de Serotonina , Antagonistas da Serotonina/síntese química , Antagonistas da Serotonina/química , Antagonistas da Serotonina/farmacocinética , Antagonistas da Serotonina/farmacologia , Agonistas do Receptor de Serotonina/química , Agonistas do Receptor de Serotonina/farmacocinética , Agonistas do Receptor de Serotonina/farmacologia , Relação Estrutura-AtividadeRESUMO
A series of thiazolothiazepines were prepared and tested against purified human immunodeficiency virus type-1 integrase (HIV-1 IN) and viral replication. Structure-activity studies reveal that the compounds possessing the pentatomic moiety SC(O)CNC(O) with two carbonyl groups are in general more potent against purified IN than those containing only one carbonyl group. Substitution with electron-donating or -withdrawing groups did not enhance nor abolish potency against purified IN. By contrast, compounds with a naphthalene ring system showed enhanced potency, suggesting that a hydrophobic pocket in the IN active site might accommodate an aromatic system rather than a halogen. The position of sulfur in the thiazole ring appears important for potency against IN, as its replacement with an oxygen or carbon abolished activity. Further extension of the thiazole ring diminished potency. Compounds 1, 19, and 20 showed antiviral activity and inhibited IN within similar concentrations. These compounds inhibited IN when Mn(2+) or Mg(2+) was used as cofactor. None of these compounds showed detectable activities against HIV-1 reverse transcriptase, protease, virus attachment, or nucleocapsid protein zinc fingers. Therefore, thiazolothiazepines are potentially important lead compounds for development as inhibitors of IN and HIV replication.
Assuntos
Inibidores de Integrase de HIV/síntese química , HIV-1 , Tiazepinas/síntese química , Tiazóis/síntese química , Tiazolidinedionas , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Inibidores de Integrase de HIV/química , Inibidores de Integrase de HIV/farmacologia , Inibidores da Protease de HIV/síntese química , Inibidores da Protease de HIV/química , Inibidores da Protease de HIV/farmacologia , Magnésio/química , Manganês/química , Proteínas do Nucleocapsídeo/química , Inibidores da Transcriptase Reversa/síntese química , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/farmacologia , Relação Estrutura-Atividade , Tiazepinas/química , Tiazepinas/farmacologia , Tiazóis/química , Tiazóis/farmacologia , Replicação Viral/efeitos dos fármacos , Dedos de Zinco/efeitos dos fármacosRESUMO
The development of a synthetic approach to the novel pyrrolo[2, 1-b][1,3]benzothiazepine and its derivatives and their biological evaluation as potential antipsychotic drugs are described. In binding studies these compounds proved to be potent 5-HT2, D2, and D3 receptor ligands. The more potent benzothiazepine (+/-)-3b was resolved into its enantiomers by using HPLC techniques. In vitro testing confirmed that (-)-3b is a more potent D2 receptor ligand, maintaining high affinity for 5-HT2 receptors. In contrast, the (+)-3b enantiomer presents a 35 times higher affinity for 5-HT2 than for dopamine D2 receptors with a similar dopamine D1 receptor affinity to that of (-)-3b. Overall, (+)-3b shows an "atypical" neuroleptic binding profile, while (-)-3b has a more "classical" profile. Furthermore pharmacological and biochemical testing displayed that the novel benzothiazepine (+/-)-3b is able to increase the extracellular levels of dopamine in the rat striatum and causes a dose-related suppression of apomorphine-induced locomotor activity. At low doses (+/-)-3b does not induce catalepsy, showing atypical antipsychotic properties similar to those of olanzapine. These heterocyclic compouds represent new leads for the development of novel antipsychotic drugs with atypical properties.
Assuntos
Antipsicóticos/síntese química , Antagonistas de Dopamina/síntese química , Pirróis/síntese química , Antagonistas da Serotonina/síntese química , Tiazepinas/síntese química , Ácido 3,4-Di-Hidroxifenilacético/metabolismo , Animais , Antipsicóticos/química , Antipsicóticos/metabolismo , Antipsicóticos/farmacologia , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Catalepsia/induzido quimicamente , Dopamina/metabolismo , Antagonistas de Dopamina/química , Antagonistas de Dopamina/metabolismo , Antagonistas de Dopamina/farmacologia , Relação Dose-Resposta a Droga , Masculino , Atividade Motora/efeitos dos fármacos , Pirróis/química , Pirróis/metabolismo , Pirróis/farmacologia , Ratos , Receptores de Dopamina D1/metabolismo , Receptores de Dopamina D2/metabolismo , Receptores de Dopamina D3 , Receptores de Serotonina/metabolismo , Antagonistas da Serotonina/química , Antagonistas da Serotonina/metabolismo , Antagonistas da Serotonina/farmacologia , Estereoisomerismo , Relação Estrutura-Atividade , Tiazepinas/química , Tiazepinas/metabolismo , Tiazepinas/farmacologiaRESUMO
Quinoxalinylethylpyridylthioureas (QXPTs) represent a new class of human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase (RT) inhibitors (NNRTIs) whose prototype is 6-FQXPT (6). Docking studies based on the three-dimensional structure of RT prompted the synthesis of novel heteroarylethylpyridylthioureas which were tested as anti-HIV agents. Several compounds proved to be potent broad-spectrum enzyme inhibitors and significantly inhibited HIV-1 replication in vitro. Their potency depends on the substituents and the nature of the heterocyclic skeleton linked to the ethyl spacer, and structure-activity relationships are discussed in terms of the possible interaction with the RT binding site. Although the new QXPTs analogues show potent antiviral activity, none of the compounds tested overcome the pharmacokinetic disadvantages inherent to ethylpyridylthioureidic antiviral agents, which in general have very low oral bioavailability. Through an integrated effort involving synthesis, docking studies, and biological and pharmacokinetic evaluation, we investigated the structural dependence of the poor bioavailability and rapid clearance within the thioureidic series of antivirals. Replacing the ethylthioureidic moiety with a hydrazine linker led to a new antiviral lead, offering promising pharmacological and pharmacokinetic properties in terms of antiviral activity and oral bioavailability.
Assuntos
Fármacos Anti-HIV/síntese química , Transcriptase Reversa do HIV/antagonistas & inibidores , Piridinas/síntese química , Quinoxalinas/síntese química , Inibidores da Transcriptase Reversa/síntese química , Tioureia/análogos & derivados , Tioureia/síntese química , Animais , Fármacos Anti-HIV/química , Fármacos Anti-HIV/farmacologia , Disponibilidade Biológica , Linhagem Celular , Didanosina/farmacologia , Sinergismo Farmacológico , HIV-1/efeitos dos fármacos , Humanos , Camundongos , Modelos Moleculares , Piridinas/química , Piridinas/farmacologia , Quinoxalinas/química , Quinoxalinas/farmacologia , Inibidores da Transcriptase Reversa/química , Inibidores da Transcriptase Reversa/farmacologia , Estereoisomerismo , Relação Estrutura-Atividade , Tioureia/química , Tioureia/farmacologia , Zidovudina/farmacologiaRESUMO
(S)-CPW399 (2b) is a novel, potent, and subtype-selective AMPA receptor full agonist that, unlike (S)-willardiine and related compounds, in mouse cerebellar granule cells, stimulated an increase in [Ca(2+)](i), and induced neuronal cell death in a time- and concentration-dependent manner. Compound 2b appears to be a weakly desensitizing, full agonist at AMPA receptors and therefore represents a new pharmacological tool to investigate the role of AMPA receptors in excitotoxicity and their molecular mechanisms of desensitization.
Assuntos
Alanina/síntese química , Agonistas de Aminoácidos Excitatórios/síntese química , Pirimidinas/síntese química , Pirimidinonas/síntese química , Receptores de AMPA/agonistas , Alanina/análogos & derivados , Alanina/farmacologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Morte Celular/efeitos dos fármacos , Linhagem Celular , Eletrofisiologia , Agonistas de Aminoácidos Excitatórios/farmacologia , Técnicas In Vitro , Ligantes , Camundongos , Modelos Moleculares , Neurônios/citologia , Neurônios/efeitos dos fármacos , Oócitos/metabolismo , Pirimidinas/farmacologia , Pirimidinonas/farmacologia , Ensaio Radioligante , Ratos , Receptores de AMPA/metabolismo , Receptores de AMPA/fisiologia , Proteínas Recombinantes/metabolismo , Estereoisomerismo , Xenopus laevisRESUMO
The "peripheral-type" benzodiazepine receptor (PBR) has been reported to play a role in many biological processes. We have synthesized and tested a novel series of PBR ligands based on a pyrrolobenzoxazepine skeleton, in order to provide new receptor ligands. Several of these new compounds proved to be high affinity and selective ligands for PBR, and benzoxazepines 17f and 17j were found to be the most potent ligands for this receptor to have been identified to date. The SAR and the molecular modeling studies detailed herein delineated a number of structural features required for improving affinity. Some of the ligands were employed as "molecular yardsticks" to probe the spatial dimensions of the lipophilic pockets L1 and L3 in the PBR cleft and to determine the effect of occupation of L1 and L3 with respect to affinity, while other C-7 modified analogues provided information specifically on the hydrogen bonding with a putative receptor site H1. The new pyrrolobenzoxazepines were tested in rat cortex, a tissue expressing high density of mitochondrial PBR, and exhibited IC50 and Ki values in the low nanomolar or subnanomolar range, as measured by the displacement of [3H]PK 11195 binding. A subset of the highest affinity ligands was also found to have high affinities for [3H]PK 11195 and [3H]Ro 5-4864 binding in rat adrenal mitochondria. All the ligands in this subset are stimulators of steroidogenesis having similar potency and extent of stimulation as PK 11195 and Ro 5-4864 of steroidogenesis in the mouse Y-1 adrenocortical cell line.
Assuntos
Receptores de GABA-A/metabolismo , Animais , Benzodiazepinonas/metabolismo , Sítios de Ligação , Córtex Cerebral/metabolismo , Isoquinolinas/metabolismo , Ligantes , Camundongos , Ratos , Ratos Wistar , Relação Estrutura-AtividadeRESUMO
The synthesis and cardiovascular characterization of a series of novel pyrrolo[2,1-d][1,5]-benzothiazepine derivatives (54-68) are described. Selective peripheral-type benzodiazepine receptor (PBR) ligands, such as PK 11195 and Ro 5-4864, have recently been found to possess low but significant inhibitory activity of L-type calcium channels, and this property is implicated in the cardiovascular effects observed with these compounds. In functional studies both PK 11195 (1-(2-chlorophenyl)-N-methyl-N-(1-methylpropyl)-3-isoquinolinecarboxa mide) and Ro 5-4864 (4'-chlorodiazepam) did not display selectivity between cardiac and vascular tissue. Therefore, several 7-(acyloxy)-6-arylpyrrolo[2,1-d][1,5]benzothiazepines, potent and selective peripheral-type benzodiazepine receptor ligands recently developed by us (3, 7-20), were subjected to calcium channel receptor binding assay. Some of these compounds showed an unexpected potency in displacing the binding of [3H]nitrendipine from L-type calcium channels, much higher than that reported for PK 11195 and Ro 5-4864 and equal to or higher than that of reference calcium antagonists such as verapamil and (+)-cis-diltiazem. Specifically, in rat cortex homogenate, our prototypic PBR ligand 7-acetoxy-6-(p-methoxyphenyl)pyrrolo[2,1-d][1,5]benzothiazepine (3) showed an IC50 equal to 0.13 nM for inhibition of [3H]nitrendipine binding. Furthermore, in functional studies this compound displayed a clear-cut selectivity for cardiac over vascular tissue. Comparison of calcium antagonist activity on guinea pig aorta strips with the negative inotropic activity, determined by using isolated guinea pig left atria, revealed that 3 displayed higher selectivity than the reference (+)-cis-diltiazem. Thus, the pyrrolobenzothiazepine 3 might represent a new tool for characterizing the relationship between the PBR and cardiac function. Furthermore, we have also investigated the structural dependence of binding to PBR and L-type calcium channels, and this study allowed us to identify a new class of potent calcium channel blockers selective for cardiac over vascular tissue, with no affinity for PBR. A number of structure-activity relationship trends have been identified, and a possible explanation is advanced in order to account for the observed differences in selectivity. Three structural features, namely, (i) the saturation of the C(6)-C(7) double bond, with a consequent higher molecular flexibility, (ii) the presence of a substituent in the benzofused ring, and (iii) a basic side chain at C-10 of the pyrrolobenzothiazepine ring system, were found to be responsible for potent L-type calcium channel antagonism and clear-cut selectivity for cardiac over vascular tissue. Among the synthesized compounds the pyrrolobenzothiazepine 62 was found to be the most promising selective calcium channel blocker. Additionally, the molecular structure determination of the key intermediate 48 by X-ray diffraction, molecular modeling, and NMR analysis is reported.
Assuntos
Bloqueadores dos Canais de Cálcio/síntese química , Canais de Cálcio/metabolismo , Sistema Cardiovascular/efeitos dos fármacos , Pirróis/síntese química , Receptores de GABA-A/metabolismo , Tiazepinas/síntese química , Animais , Função Atrial , Ligação Competitiva , Bloqueadores dos Canais de Cálcio/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Córtex Cerebral/metabolismo , Depressão Química , Feminino , Cobaias , Frequência Cardíaca/efeitos dos fármacos , Masculino , Modelos Moleculares , Contração Miocárdica/efeitos dos fármacos , Miocárdio/metabolismo , Pirróis/metabolismo , Pirróis/farmacologia , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Tiazepinas/metabolismo , Tiazepinas/farmacologiaRESUMO
Pyrrolobenzoxazepinone (PBO) derivatives represent a new class of human immunodeficiency virus type 1 (HIV-1) non-nucleoside reverse transcriptase (RT) inhibitors (NNRTs) whose prototype is (+/-)-6-ethyl-6-phenylpyrrolo[2,1-d][1,5]benzoxazepin-7(6H)- one (6). Docking studies based on the three-dimensional structure of RT prompted the synthesis and biological evaluation of novel derivatives and analogues of 6 featuring a meta-substituted phenyl or a 2-thienyl ring at C-6 and a pyridine system in place of the fused-benzene ring to yield pyrrolopyridooxazepinones (PPOs). Compared with the lead 6 and nevirapine, several of the synthesized compounds (PBOs 13a-d and PPOs 13i-k) displayed higher inhibitory activity against wild-type RT and clinically relevant mutant RTs containing the single amino acid substitutions L100I, K103N, V106A, Y181I, and Y188L. The most potent inhibitors were further evaluated for in vitro antiviral activity on lymphocytes and monocyte-macrophages, for cytotoxicity on a panel of cell lines, and for potential synergistic antiviral activity with AZT. Pharmacokinetic studies performed on 13b, 13c, and 13i showed that these compounds achieve high concentrations in the brain. The results of the biological and pharmacokinetic experiments suggest a potential clinical utility of analogues such as 13b-d, 13i, and 13j, in combination with nucleoside RT inhibitors, against strains of HIV-1 bearing those mutations that confer resistance to known NNRTI.