RESUMO
The low aqueous solubility of colchicine site antimitotic agents, of which the trimethoxyphenyl (A ring) is a heavy contributor, is a serious drawback in their clinical development. We have designed new A ring analogs with chameleonic masked polar amino groups able to increase aqueous solubility and also behave as non-polar through intramolecular hydrogen bonds when bound to tubulin. We have incorporated these new A rings in several scaffolds (sulfonamides, combretastatins, phenstatins, isocombretastatins), synthesized, and assayed 43 representatives. The amino analogs show improved aqueous solubility and some of them (8, 60Z, and 67) nanomolar anti-proliferative potencies against human cancer cell lines, with the most favorable substituent being a 3-methylamino group. The antiproliferative effect relates to tubulin inhibition as shown by in vitro tubulin polymerization inhibition, immunofluorescence microscopy, and cell cycle and apoptosis analysis by flow cytometry. The compounds arrest the cell cycle of treated cells in G2/M and later develop an apoptotic response. Docking studies suggested binding at the colchicine site of tubulin with good agreement with the DFT models of the new structural variations made. The 3-methylamino-4,5dimethoxyphenyl moiety is an example of the masked polar group incorporation (MPGI) strategy for soluble ligands binding to hydrophobic sites and a good trimethoxyphenyl ring replacement for the development of new colchicine site ligands.
Assuntos
Antineoplásicos , Colchicina , Humanos , Colchicina/química , Linhagem Celular Tumoral , Sítios de Ligação , Tubulina (Proteína)/metabolismo , Solubilidade , Relação Estrutura-Atividade , Moduladores de Tubulina/farmacologia , Moduladores de Tubulina/química , Antineoplásicos/farmacologia , Antineoplásicos/química , Proliferação de CélulasRESUMO
Searching for improved indolesulfonamides with higher polarities, 45 new analogues with modifications on the sulfonamide nitrogen, the methoxyaniline, and/or the indole 3-position were synthesised. They show submicromolar to nanomolar antiproliferative IC50 values against four human tumour cell lines and they are not P-glycoprotein substrates as their potencies against HeLa cells did not improve upon cotreatment with multidrug resistance (MDR) inhibitors. The compounds inhibit tubulin polymerisation in vitro and in cells, thus causing a mitotic arrest followed by apoptosis as shown by cell cycle distribution studies. Molecular modelling studies indicate binding at the colchicine site. Methylated sulfonamides were more potent than those with large and polar substitutions. Amide, formyl, or nitrile groups at the indole 3-position provided drug-like properties for reduced toxicity, with Polar Surface Areas (PSA) above a desirable 75 Å2. Nitriles 15 and 16 are potent polar analogues and represent an interesting class of new antimitotics.
Assuntos
Antineoplásicos/farmacologia , Colchicina/antagonistas & inibidores , Sulfonamidas/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Colchicina/química , Colchicina/metabolismo , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HeLa , Humanos , Modelos Moleculares , Estrutura Molecular , Polimerização/efeitos dos fármacos , Relação Estrutura-Atividade , Sulfonamidas/síntese química , Sulfonamidas/química , Tubulina (Proteína)/química , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/química , Células Tumorais CultivadasRESUMO
Thirty seven N-(5-methoxyphenyl)-4-methoxybenzenesulphonamide with methoxy or/and bromo substitutions (series 1-4) and with different substituents on the sulphonamide nitrogen have been synthesised. 21 showed sub-micromolar cytotoxicity against HeLa and HT-29 human tumour cell lines, and were particularly effective against MCF7. The most potent series has 2,5-dimethoxyanilines, especially the 4-brominated compounds 23-25. The active compounds inhibit microtubular protein polymerisation at micromolar concentrations, thus pointing at tubulin as the target. Co-treatment with the MDR inhibitor verapamil suggests that they are not MDR substrates. Compound 25 showed nanomolar antiproliferative potency. It severely disrupts the microtubule network in cells and arrests cells at the G2/M cell-cycle phase, thus confirming tubulin targeting. 25 triggered apoptotic cell death, and induced autophagy. Docking studies suggest binding in a distinct way to the colchicine site. These compounds are promising new antitumor agents acting on tubulin.
Assuntos
Adenocarcinoma/tratamento farmacológico , Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Sulfonamidas/uso terapêutico , Adenocarcinoma/patologia , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Células MCF-7RESUMO
Pan-Gyn cancers entail 1 in 5 cancer cases worldwide, breast cancer being the most commonly diagnosed and responsible for most cancer deaths in women. The high incidence and mortality of these malignancies, together with the handicaps of taxanes-first-line treatments-turn the development of alternative therapeutics into an urgency. Taxanes exhibit low water solubility that require formulations that involve side effects. These drugs are often associated with dose-limiting toxicities and with the appearance of multi-drug resistance (MDR). Here, we propose targeting tubulin with compounds directed to the colchicine site, as their smaller size offer pharmacokinetic advantages and make them less prone to MDR efflux. We have prepared 52 new Microtubule Destabilizing Sulfonamides (MDS) that mostly avoid MDR-mediated resistance and with improved aqueous solubility. The most potent compounds, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methylaminobenzenesulfonamide 38, N-methyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 42, and N-benzyl-N-(3,4,5-trimethoxyphenyl-4-methoxy-3-aminobenzenesulfonamide 45 show nanomolar antiproliferative potencies against ovarian, breast, and cervix carcinoma cells, similar or even better than paclitaxel. Compounds behave as tubulin-binding agents, causing an evident disruption of the microtubule network, in vitro Tubulin Polymerization Inhibition (TPI), and mitotic catastrophe followed by apoptosis. Our results suggest that these novel MDS may be promising alternatives to taxane-based chemotherapy in chemoresistant Pan-Gyn cancers.
Assuntos
Antineoplásicos/farmacologia , Sulfonamidas/farmacologia , Taxoides/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Feminino , Células HT29 , Células HeLa , Humanos , Células MCF-7 , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Polimerização/efeitos dos fármacos , Sulfonamidas/química , Sulfonamidas/uso terapêutico , Taxoides/uso terapêutico , Moduladores de Tubulina/química , Moduladores de Tubulina/uso terapêuticoRESUMO
Colchicine site antimitotic agents typically suffer from low aqueous solubilities and are formulated as phosphate prodrugs of phenolic groups. These hydroxyl groups are the aim of metabolic transformations leading to resistance. There is an urgent need for more intrinsically soluble analogues lacking these hydroxyl groups. The 3,4,5-trimethoxyphenyl ring of combretastatin A-4 is a liability in terms of solubility but it is considered essential for high cytotoxic and tubulin polymerization inhibitory (TPI) activity. We have synthesized 36 new analogues of combretastatin A-4 replacing the trimethoxyphenyl moiety with more polar pyridine based moieties, measured their aqueous solubility, and studied their anti-proliferative effects against 3 human cancer cell lines. We show here that pyridine rings can be successful replacements for the trimethoxyphenyl ring, resulting in potent and more soluble analogues. The more straightforward replacement, a 2,6-dimethoxypyridine ring led to inactive analogues, but a 2-methoxy-6-methylsulfanylpyridine moiety led to active analogues when combined with different B rings. This replacement led to potent cytotoxic activity against sensitive human cancer cell lines due to tubulin inhibition, as shown by cell cycle analysis, confocal microscopy, and tubulin polymerization inhibitory activity studies. Cell cycle analysis also showed apoptotic responses following treatment. Docking studies suggested binding at the colchicine site of tubulin and provided a good agreement with the observed SAR. A 2-methoxy-6-methylsulfanylpyridine moiety is a good trimethoxyphenyl ring replacement for the development of new colchicine site ligands.
Assuntos
Antineoplásicos/farmacologia , Colchicina/farmacologia , Piridinas/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Colchicina/síntese química , Colchicina/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Ligantes , Estrutura Molecular , Polimerização/efeitos dos fármacos , Piridinas/química , Solubilidade , Relação Estrutura-Atividade , Tubulina (Proteína)/metabolismo , Células Tumorais CultivadasRESUMO
Tubulin, the microtubules and their dynamic behavior are amongst the most successful antitumor, antifungal, antiparasitic, and herbicidal drug targets. Sulfonamides are exemplary drugs with applications in the clinic, in veterinary and in the agrochemical industry. This review summarizes the actual state and recent progress of both fields looking from the double point of view of the target and its drugs, with special focus onto the structural aspects. The article starts with a brief description of tubulin structure and its dynamic assembly and disassembly into microtubules and other polymers. Posttranslational modifications and the many cellular means of regulating and modulating tubulin's biology are briefly presented in the tubulin code. Next, the structurally characterized drug binding sites, their occupying drugs and the effects they induce are described, emphasizing on the structural requirements for high potency, selectivity, and low toxicity. The second part starts with a summary of the favorable and highly tunable combination of physical-chemical and biological properties that render sulfonamides a prototypical example of privileged scaffolds with representatives in many therapeutic areas. A complete description of tubulin-binding sulfonamides is provided, covering the different species and drug sites. Some of the antimitotic sulfonamides have met with very successful applications and others less so, thus illustrating the advances, limitations, and future perspectives of the field. All of them combine in a mechanism of action and a clinical outcome that conform efficient drugs.
Assuntos
Sulfonamidas/farmacologia , Moduladores de Tubulina/farmacologia , Sequência de Aminoácidos , Animais , Ensaios Clínicos como Assunto , Humanos , Sulfonamidas/química , Alicerces Teciduais/química , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/químicaRESUMO
Colchicine site ligands suffer from low aqueous solubility due to the highly hydrophobic nature of the binding site. A new strategy for increasing molecular polarity without exposing polar groups-termed masked polar group incorporation (MPGI)-was devised and applied to nitrogenated combretastatin analogues. Bulky ortho substituents to the pyridine nitrogen hinder it from the hydrophobic pocket while increasing molecular polarity. The resulting analogues show improved aqueous solubilities and highly potent antiproliferative activity against several cancer cell lines of different origin. The more potent compounds showed moderate tubulin polymerization inhibitory activity, arrested the cell cycle of treated cells at the G2/M phase, and subsequently caused apoptotic cell death represented by the cells gathered at the subG0/G1 population after 48 h of treatment. Annexin V/Propidium Iodide (PI) double-positive cells observed after 72 h confirmed the induction of apoptosis. Docking studies suggest binding at the colchicine site of tubulin in a similar way as combretastatin A4, with the polar groups masked by the vicinal substituents. These results validate the proposed strategy for the design of colchicine site ligands and open a new road to increasing the aqueous solubility of ligands binding in apolar environments.
Assuntos
Bibenzilas/química , Nitrogênio/química , Moduladores de Tubulina/química , Tubulina (Proteína)/metabolismo , Apoptose/efeitos dos fármacos , Sítios de Ligação , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células , Colchicina/química , Desenho de Fármacos , Células HT29 , Células HeLa , Humanos , Ligantes , Células MCF-7 , Simulação de Acoplamento Molecular , Piridinas/química , Solubilidade/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
The structures of a new family of macrocyclic analogues of combretastatins B combining oxygenated substituents on the phenyl rings and indole rings are described. The effects of the stereochemistry, of the length of the spacer linking both aryl groups, and of the decoration of the macrocycles on the kinematics of the system have been studied by means of NMR studies at several temperatures and in different solvents combined with theoretical studies including Monte Carlo conformational searches and molecular dynamics simulations at different temperatures. The new indole macrocycles provide a more rigid view of this kind of macrocycles than that previously held. The tubulin polymerization activity of this new class of macrocycles has been assayed and analyzed.
Assuntos
Antimitóticos/química , Antimitóticos/farmacologia , Bibenzilas/química , Bibenzilas/farmacologia , Colchicina/química , Compostos Macrocíclicos/química , Compostos Macrocíclicos/farmacologia , Estilbenos/química , Estilbenos/farmacologia , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologia , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Conformação Molecular , PolimerizaçãoRESUMO
The synthesis of a new family of methoxy-substituted [2.7]- and [2.8]paracyclophanes linked by 3-oxapentamethylene-1,5-dioxy and hexamethylene-1,6-dioxy bridges has been carried out by using the McMurry methodology. Related indole compounds were also synthesised. Olefin-to-diol ratios depended on the bridge length, the structure of the aromatic ring and the reaction conditions. Macrocyclisation, the methoxy substituents and the presence of a rigid indole moiety restricted the conformational equilibria, as observed by NMR spectroscopy and according to theoretical calculations. The synthesised compounds display micromolar tubulin polymerisation inhibitory activity. The conformational implications on the tubulin polymerisation inhibitory activity derived from the macrocyclisation when compared with combretastatins, closely related stilbenes, are also discussed.
Assuntos
Estilbenos/química , Estilbenos/síntese química , Moduladores de Tubulina/química , Contraindicações , Espectroscopia de Ressonância Magnética , Conformação Molecular , Estrutura Molecular , Polimerização , Relação Estrutura-AtividadeRESUMO
New drugs against visceral leishmaniasis with mechanisms of action differing from existing treatments and with adequate cost, stability, and properties are urgently needed. No antitubulin drug is currently in the clinic against Leishmania infantum, the causative agent of visceral leishmaniasis in the Mediterranean area. We have designed and synthesized a focused library of 350 compounds against the Leishmania tubulin based on the structure-activity relationship (SAR) and sequence differences between host and parasite. The compounds synthesized are accessible, stable, and appropriately soluble in water. We assayed the library against Leishmania promastigotes, axenic, and intracellular amastigotes and found 0, 8, and 16 active compounds, respectively, with a high success rate against intracellular amastigotes of over 10%, not including the cytotoxic compounds. Five compounds have a similar or better potency than the clinically used miltefosine. 14 compounds showed a host-dependent mechanism of action that might be advantageous as it may render them less susceptible to the development of drug resistance. The active compounds cluster in five chemical classes that provide structure-activity relationships for further hit improvement and facilitate series development. Molecular docking is consistent with the proposed mechanism of action, supported by the observed structure-activity relationships, and suggests a potential extension to other Leishmania species due to sequence similarities. A new family of diarylsulfonamides designed against the parasite tubulins is active against Leishmania infantum and represents a new class of potential drugs with favorable cost, stability, and aqueous solubility for the treatment of visceral leishmaniasis (VL). These results could be extended to other clinically relevant species of Leishmania spp.
Assuntos
Antiprotozoários , Leishmania infantum , Leishmaniose Visceral , Antiprotozoários/farmacologia , Antiprotozoários/uso terapêutico , Resistência a Medicamentos , Humanos , Leishmaniose Visceral/tratamento farmacológico , Simulação de Acoplamento MolecularRESUMO
Isocombretastatins are the not isomerizable 1,1-diarylethene isomers of combretastatins. Both families of antimitotics are poorly soluble and new analogs with improved water solubility are needed. The ubiquitous 3,4,5-trimethoxyphenyl ring and most of its replacements contribute to the solubility problem. 39 new compounds belonging to two series of isocombretastatin analogs with 2-chloro-6-methylsulfanyl-4-pyridinyl or 2,6-bis(methylsulfanyl)-4-pyridinyl moieties replacing the 3,4,5-trimethoxyphenyl have been synthesized and their antimitotic activity and aqueous solubility have been studied. We show here that 2-chloro-6-methylsulfanylpyridines are more successful replacements than 2,6-bis(methylsulfanyl)pyridines, giving highly potent tubulin inhibitors and cytotoxic compounds with improved water solubilities. The optimal combination is with indole rings carrying polar substitutions at the three position. The resulting diheteroaryl isocombretastatin analogs showed potent cytotoxic activity against human cancer cell lines caused by tubulin inhibition, as shown by in vitro tubulin polymerization inhibitory assays, cell cycle analysis, and confocal microscopy studies. Cell cycle analysis also showed apoptotic responses following G2/M arrest after treatment. Conformational analysis and docking studies were applied to propose binding modes of the compounds at the colchicine site of tubulin and were in good agreement with the observed SAR. 2-Chloro-6-methylsulfanylpyridines represent a new and successful trimethoxyphenyl ring substitution for the development of improved colchicine site ligands.
Assuntos
Proliferação de Células/efeitos dos fármacos , Piridinas/química , Estilbenos/farmacologia , Divisão Celular/efeitos dos fármacos , Colchicina/metabolismo , Fase G2/efeitos dos fármacos , Humanos , Solubilidade , Estilbenos/química , Tubulina (Proteína)/metabolismoRESUMO
Isocombretastatins A are 1,1-diarylethene isomers of combretastatins A. We have synthesized the isomers of combretastatin A-4, deoxycombretastatin A-4, 3-amino-deoxycombretastatin A-4 (AVE-8063), naphthylcombretastatin and the N-methyl- and N-ethyl-5-indolyl analogues of combretastatin A-4. Analogues with a 2,3,4-trimethoxyphenyl ring instead of the 3,4,5-trimethoxyphenyl ring have also been prepared. The isocombretastatins A strongly inhibit tubulin polymerization and are potent cytotoxic compounds, some of them with IC(50)s in the nanomolar range. This new family of tubulin inhibitors shows higher or comparable potency when compared to phenstatin or combretastatin analogues. These results suggest that one carbon bridges with a geminal diaryl substitution can successfully replace the two carbon bridge of combretastatins and that the carbonyl group of phenstatins is not essential for high potency.
Assuntos
Bibenzilas/química , Moduladores de Tubulina/química , Tubulina (Proteína)/química , Bibenzilas/síntese química , Bibenzilas/toxicidade , Sítios de Ligação , Linhagem Celular Tumoral , Simulação por Computador , Humanos , Isomerismo , Relação Estrutura-Atividade , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/toxicidadeRESUMO
A new family of naphthalenic analogues of phenstatins with modifications on the ketone-bridge has been synthesised. The synthesised compounds have been assayed for tubulin polymerisation inhibitory activity as well as for cytotoxic activity against cancer cell lines. The naphthalene has been confirmed as a good surrogate for the isovanillin moiety (3-hydroxy-4-methoxyphenyl) of phenstatin, when combined with the 3,4,5-trimethoxyphenyl ring, but not when combines with the 2,3,4-trimethoxyphenyl ring. Binding models for the synthesised compounds have been generated and analysed in terms of a pharmacophore proposed for colchicine site ligands. The ketone is the optimal bridge substitution but E-acetyloximes or acetylhydrazones are also tolerated. Significant differences with indole substituted phenstatins are observed and discussed.
Assuntos
Antineoplásicos/farmacologia , Naftalenos/farmacologia , Tubulina (Proteína)/química , Algoritmos , Antineoplásicos/síntese química , Benzaldeídos/química , Sítios de Ligação , Linhagem Celular Tumoral , Colchicina/química , Ensaios de Seleção de Medicamentos Antitumorais , Células HT29 , Células HeLa , Humanos , Hidrazonas/química , Concentração Inibidora 50 , Ligantes , Naftalenos/síntese química , Oximas/química , Relação Estrutura-Atividade , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/farmacologiaRESUMO
We describe the synthesis and biological evaluation of a series of diarylmethyloxime and diarylmethylhydrazone analogues that contain an indole ring and different modifications on the nitrogen of the bridge. Several compounds showed potent tubulin polymerization inhibitory action as well as cytotoxic activity against cancer cell lines. The N-methyl-5-indolyl substituted analogues are more potent than ethyl substituted ones. The most potent inhibitors of tubulin polymerization are the diarylketones and the diaryloximes. The cytotoxicity against several cancer cell lines is lower for the oximes than for the ketones. Other substitutions on the imine nitrogen greatly reduce the tubulin inhibitory and/or cytotoxic potencies.
Assuntos
Hidrazonas/síntese química , Indóis/síntese química , Oximas/síntese química , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/toxicidade , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/toxicidade , Benzofenonas/química , Bibenzilas/química , Células HL-60 , Células HT29 , Células HeLa , Humanos , Hidrazonas/toxicidade , Indóis/toxicidade , Organofosfatos/química , Oximas/toxicidade , EstereoisomerismoRESUMO
Resistance to combretastatin A-4 is mediated by metabolic modification of the phenolic hydroxyl and ether groups of the 3-hydroxy-4-methoxyphenyl (B ring). Replacement of the B ring of combretastatin A-4 by a N-methyl-5-indolyl reduces tubulin polymerization inhibition (TPI) and cytotoxicity against human cancer cell lines but cyano, methoxycarbonyl, formyl, and hydroxyiminomethyl substitutions at the indole 3-position restores potent TPI and cytotoxicity against sensitive human cancer cell lines. These highly potent substituted derivatives displayed low nanomolar cytotoxicity against several human cancer cell lines due to tubulin inhibition, as shown by cell cycle analysis, confocal microscopy, and tubulin polymerization inhibitory activity studies, and promoted cell killing mediated by caspase-3 activation. Binding at the colchicine site was suggested by molecular modeling studies. Substituted combretastatins displayed higher potencies than the isomeric isocombretastatins and the highest potencies were achieved for the hydroxyiminomethyl (21) and cyano (23) groups, with TPI values in the submicromolar range and cytotoxicities in the nanomolar and subnanomolar range. Dose-response and time-course studies showed that drug concentrations as low as 1â¯nM (23) or 10â¯nM (21) led to a complete G2/M cell cycle arrest after 15â¯h treatment followed by a high apoptosis-like cell response after 48-72â¯h treatment. The P-glycoprotein antagonist verapamil increased 21 and 23 cytotoxicity to IC50 values of 10-10â¯M, and highly potentiated the cytotoxic activity in 100-fold of the CHO derivative (17), in A-549 human non-small cell lung cancer cells. The cyano substituted indolecombretastatin 23 is by itself highly potent against rather resistant HT-29 and A-549â¯cell lines. A 3,4,5-trimethoxyphenyl ring always afforded more potent derivatives than a 2,3,4-trimethoxyphenyl ring.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Bibenzilas/química , Bibenzilas/farmacologia , Indóis/química , Indóis/farmacologia , Caspase 3/metabolismo , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Humanos , Modelos Moleculares , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologiaRESUMO
To pharmacologically interrupt bile acid enterohepatic circulation, two compounds named BAPA-3 and BAPA-6, with a steroid structure and 1 or 2 positive charges, were obtained by conjugation of N-(3-aminopropyl)-1,3-propanediamine with one or two moieties of glycocholic acid (GC). Both BAPA-3 and BAPA-6 inhibited Na+-dependent taurocholate (TC) uptake by Xenopus laevis oocytes expressing rat Asbt, with Ki values of 28 and 16 microM, respectively. BAPA-3 reduced Vmax without affecting Km. In contrast, BAPA-6 increased Km, with no effect on Vmax. Uptake of [14C]-GC by the last 10 cm of the rat ileum, perfused in situ over 60 min, was inhibited to a similar extent by unlabeled GC, BAPA-3 and BAPA-6. However, the intestinal absorption of these compounds was lower (BAPA-6) or much lower (BAPA-3) than that of GC. When administered orally to mice, both compounds (BAPA-3>BAPA-6) reduced the bile acid pool size, which was accompanied by up-regulation of hepatic Cyp7a1 and Hmgcr and intestinal Ostalpha/Ostbeta. A tendency towards a decreased expression of hepatic Ntcp and an enhanced expression of intestinal Asbt was also observed. Serum biochemical parameters were not affected by treatment with these compounds, except for a moderate increase in serum triglyceride concentrations. In sum, our results suggest that these compounds, in particular BAPA-3, are potentially useful tools for inhibiting the intestinal absorption of bile acids in a non-competitive manner.
Assuntos
Ácidos e Sais Biliares/metabolismo , Absorção Intestinal/efeitos dos fármacos , Esteróis/farmacologia , Animais , Íleo/metabolismo , Masculino , Camundongos , Transportadores de Ânions Orgânicos Dependentes de Sódio/fisiologia , Ratos , Ratos Wistar , Simportadores/fisiologia , Xenopus laevisRESUMO
Drug targeting may contribute to overcoming resistance to chemotherapy and to reducing side effects. Here, by conjugating a nitrogenated base (NB) to the side chain of a bile acid (BA) moiety, we have synthesized and evaluated six novel compounds, designated BANB-1 to -6, with potential cytostatic activity and vectoriality toward enterohepatic tumors. These compounds were purified by liquid chromatography and their purity was checked by TLC and HPLC before being chemically characterized using IR, (1)H/(13)C NMR and FAB-MS. Using several cell lines - HepG2 (human hepatoblastoma), LS 174T and Caco-2 (human colon adenocarcinoma), Hepa 1-6 (mouse hepatoma), McA-RH7777 (rat hepatoma), CCRF S-180 II (mouse sarcoma) and CHO (Chinese hamster ovary) - their effect on cell viability was measured with the formazan test after drug exposure for 6h (cytotoxic effect) or 72h (cytostatic effect). A weak cytostatic effect of BANB-1, BANB-2 and BANB-3 was detected even in CHO cells stably transfected with rat bile acid transporters (Ntcp and Oatp1/1a1). In contrast, BANB-4, BANB-5 and BANB-6, similarly to cisplatin, showed strong cytostatic effects, together with mild non-specific toxicity. BANB-6 was effective even against Hepa 1-6/R cells, which were partly resistant to cisplatin. Treatment with BANB-6, but not cisplatin, was able to prolong the life span of Nude mice bearing tumors formed by Hepa 1-6/R cells orthotopically implanted in the liver. In conclusion, our results support the hypothesis that cytostatic bile acid derivatives such as BANB-6 may offer a useful pharmacological strategy for the treatment of tumors of the enterohepatic circuit.
Assuntos
Ácidos e Sais Biliares/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Hepáticas Experimentais/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Ácidos e Sais Biliares/síntese química , Ácidos e Sais Biliares/química , Ácidos e Sais Biliares/uso terapêutico , Carcinoma Hepatocelular , Sobrevivência Celular/fisiologia , Modelos Animais de Doenças , Sistemas de Liberação de Medicamentos , Humanos , Camundongos , Camundongos Nus , Transplante de Neoplasias , Ratos , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The reactivity of 6-(nitrophenyl or trimethoxyphenyl)-4-tert-butyldimethyl- siloxy-1,2,3,6-tetrahydropyridine derivatives with hydrazines under acid conditions is described. The structure of the products isolated - hydrazones, pyrazolines or pyridazinones - depended on the conditions used. In addition, a systematic study of the reaction outcomes was carried out by introducing variations on the substituents of the tetrahydropyridine ring.
Assuntos
Hidrazinas/química , Piridinas/química , Siloxanas/química , Isótopos de Carbono , Espectroscopia de Ressonância Magnética , PrótonsRESUMO
By synthesis and biological studies of new naphthalene analogues of combretastatins, we have found that the naphthalene is a good surrogate for the isovanillin moiety (3-hydroxy-4-methoxyphenyl) of combretastatin A-4, always generating highly cytotoxic analogues when combined with the 3,4,5-trimethoxyphenyl or related systems. On the other hand, when the naphthalene replaces the 3,4,5-trimethoxyphenyl moiety, the cytotoxic activity is largely decreased. The most cytotoxic naphthalene analogues of combretastatins, which also produce inhibition of tubulin polymerization, exerted their antimitotic effects through microtubule network disruption and subsequent G(2)/M arrest of the cell cycle in human cancer cells.
Assuntos
Compostos de Anilina/síntese química , Antineoplásicos/síntese química , Naftalenos/síntese química , Estilbenos/síntese química , Compostos de Anilina/química , Compostos de Anilina/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Biopolímeros , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Microtúbulos/efeitos dos fármacos , Microtúbulos/ultraestrutura , Naftalenos/química , Naftalenos/farmacologia , Estereoisomerismo , Estilbenos/química , Estilbenos/farmacologia , Relação Estrutura-Atividade , Tubulina (Proteína)/químicaRESUMO
We have synthesized and assayed dimethylaminophenyl, pyrrolidin-1-ylphenyl and carbazole containing phenstatins and isocombretastatins as analogues of the highly potent indoleisocombretastatins with extended or reduced ring sizes. This is an attempt to explore beyond the structural constraints of the X-ray crystal structures the zone of the colchicine site where the tropolone ring of colchicine binds to tubulin (zone 1). The isocombretastatins display up to 30 fold increased water solubility when compared with combretastatin A-4, potent inhibition of tubulin polymerization, and nanomolar cytotoxicities against several human cancer cell lines irrespective of the size of the B ring. On the other hand, substitutions ortho to the nitrogen cause an important reduction in potency. We have also shown that representative compounds inhibit autophagy. These results show that zone 1 can adapt to systems of different size as far as they stay in a common plane, but does not tolerate substituents protruding above or below it. These results can help in the understanding of the binding modes of structures with similar systems and in the design of new colchicine site ligands.