RESUMO
A series of combretastatin derivatives were designed and synthesised by a two-step stereoselective synthesis by use of Wittig olefination followed by Suzuki cross-coupling. Interestingly, all new compounds (2a-2i) showed potent cell-based antiproliferative activities in nanomolar concentrations. Among the compounds, 2a, 2b and 2e were the most active across three cancer cell lines. In addition, these compounds inhibited the polymerisation of tubulin in vitro more efficiently than CA-4. They caused cell cycle arrest in G2/M phase further confirming their ability to inhibit tubulin polymerisation.
Assuntos
Antineoplásicos/farmacologia , Estilbenos/farmacologia , Moduladores de Tubulina/farmacologia , Tubulina (Proteína)/metabolismo , Antineoplásicos/síntese química , Antineoplásicos/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Polimerização/efeitos dos fármacos , Estereoisomerismo , Estilbenos/síntese química , Estilbenos/química , Relação Estrutura-Atividade , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/químicaRESUMO
5,7-Dihydro-3,9,10,11-tetramethoxybenz[c,e]oxepin-4-ol 1, prepared from a dibenzyl ether precursor via Pd-catalysed intramolecular direct arylation, possesses broad-spectrum in vitro cytotoxicity towards various tumour cell lines, and induces vascular shutdown, necrosis and growth delay in tumour xenografts in mice at sub-toxic doses. The biological properties of 1 and related compounds can be attributed to their ability to inhibit microtubule assembly at the micromolar level, by binding reversibly to the same site of the tubulin αß-heterodimer as colchicine 2 and the allocolchinol, N-acetylcolchinol 4.
Assuntos
Dibenzoxepinas/metabolismo , Neoplasias/irrigação sanguínea , Tubulina (Proteína)/metabolismo , Animais , Linhagem Celular Tumoral , Dibenzoxepinas/química , Dibenzoxepinas/farmacologia , Relação Dose-Resposta a Droga , Xenoenxertos , Humanos , Camundongos , Estrutura MolecularRESUMO
A series of novel cyanocombretastatins bearing a 3,4,5-trimethoxyphenyl moiety combined with a variety of substituted phenyl rings, were synthesised and their antitumour activity was evaluated. The Z-cyanocombretastatins were synthesised in a one-step protocol in high purity and yield. Fluoro, bromo, iodo, and derivatives with boronic acid and an ethyne function at meta position of the B ring were synthesised. In vitro MTT bioassays against human chronic myelogenous leukaemia (K562) and transfected breast adenocarcinoma (MDA NQO1) cell lines, revealed promising IC(50) inhibitory values in nanomolar range (<50 nM). Introduction of a nitrile function on the olefinic bond not only increased the cytotoxicity of the less active Z-isomers but rendered the analogues as moderate to potent inhibitors of tubulin polymerisation comparable to that of CA-4 (IC(50)=2.2 µM).
Assuntos
Bibenzilas/síntese química , Nitrilas/síntese química , Moduladores de Tubulina/síntese química , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Bibenzilas/química , Bibenzilas/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Nitrilas/química , Nitrilas/farmacologia , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologiaRESUMO
Various methoxy- and hydroxy-substituted dibenz[c,e]oxepines were prepared via the copper(I)-induced coupling of ether-tethered arylstannanes or the dehydrative cyclisation of 1,1'-biphenyl-2,2'-dimethanols, assembled using the Ullmann cross-coupling of ortho-bromoaryl carbonyl compounds. The dibenzoxepines were screened for their ability to inhibit tubulin polymerisation and the in vitro growth of K562 human chronic myelogenous leukemia cells. The most active was 5,7-dihydro-3,9,10,11-tetramethoxydibenz[c,e]oxepin-4-ol, whose tubulin inhibitory and cytotoxicity (IC(50)) values were 1 µM and 40 nM, respectively.
Assuntos
Dibenzoxepinas/química , Neovascularização Patológica , Tubulina (Proteína)/química , Dibenzoxepinas/metabolismo , Dibenzoxepinas/farmacologia , Humanos , Células K562 , Modelos Moleculares , Ligação Proteica , Tubulina (Proteína)/metabolismoRESUMO
Two new series of inhibitors of tubulin polymerization based on the 2-amino-3-(3,4,5-trimethoxybenzoyl)benzo[b]thiophene molecular skeleton and its 3-amino positional isomer were synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization, and cell cycle effects. Although many more 3-amino derivatives have been synthesized so far, the most promising compound in this series was 2-amino-6-methyl-3-(3,4,5-trimethoxybenzoyl)benzo[b]thiophene, which inhibits cancer cell growth at subnanomolar concentrations and interacts strongly with tubulin by binding to the colchicine site.
Assuntos
Antimitóticos/síntese química , Tiofenos/síntese química , Animais , Antimitóticos/química , Antimitóticos/farmacologia , Sítios de Ligação , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Colchicina/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Camundongos , Ligação Proteica , Ensaio Radioligante , Relação Estrutura-Atividade , Tiofenos/química , Tiofenos/farmacologia , Tubulina (Proteína)/metabolismo , Moduladores de Tubulina/síntese química , Moduladores de Tubulina/química , Moduladores de Tubulina/farmacologiaRESUMO
A series of combretastatins substituted with epoxides, amides and small alkyl groups has been synthesised and evaluated for cytotoxicity and their ability to inhibit the assembly of tubulin. The methyl and ethyl substituted phenols 36, 44 have shown potent antimitotic effects whilst exhibiting reduced cytotoxicity.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Bibenzilas/síntese química , Bibenzilas/farmacologia , Estilbenos/síntese química , Estilbenos/farmacologia , Amidas/síntese química , Amidas/química , Amidas/farmacologia , Antineoplásicos/química , Bibenzilas/química , Ciclo Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Compostos de Epóxi/síntese química , Compostos de Epóxi/química , Compostos de Epóxi/farmacologia , Formazans/química , Humanos , Concentração Inibidora 50 , Células K562 , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Espectrofotometria Ultravioleta , Estilbenos/química , Sais de Tetrazólio/química , Tubulina (Proteína)/metabolismo , Moduladores de TubulinaRESUMO
The photoisomerization of relatively nontoxic E-combretastatins to clinically active Z-isomers is shown to occur in solution through both one- and two-photon excitations at 340 and 625 nm, respectively. The photoisomerization is also demonstrated to induce mammalian cell death by a two-photon absorption process at 625 nm. Unlike conventional photodynamic therapy (PDT), the mechanism of photoisomerization is oxygen-independent and active in hypoxic environments such as in tumors. The use of red or near-infrared (NIR) light for two-photon excitation allows greater tissue penetration than conventional UV one-photon excitation. The results provide a baseline for the development of a novel phototherapy that overcomes nondiscriminative systemic toxicity of Z-combretastatins and the limitations of PDT drugs that require the presence of oxygen to promote their activity, with the added benefits of two-photon red or NIR excitation for deeper tissue penetration.
Assuntos
Antineoplásicos/química , Bibenzilas/química , Fototerapia/métodos , Animais , Anexina A5/química , Células CHO , Morte Celular , Sobrevivência Celular , Cricetinae , Cricetulus , Ensaios de Seleção de Medicamentos Antitumorais , Hidrazinas/química , Interações Hidrofóbicas e Hidrofílicas , Microscopia Confocal , Permeabilidade , Fótons , Fármacos Fotossensibilizantes/química , Propídio/química , Isoformas de Proteínas , Espectroscopia de Luz Próxima ao InfravermelhoRESUMO
The uptake of E -combretastatins, potential prodrugs of the anticancer Z -isomers, into multicellular spheroids has been imaged by intrinsic fluorescence in three dimensions using two-photon excited fluorescence lifetime imaging with 625-nm ultrafast femtosecond laser pulses. Uptake is initially observed at the spheroid periphery but extends to the spheroid core within 30 min. Using agarose gels as a three-dimensional model, the conversion of Z(trans)âE(cis) via two-photon photoisomerization is demonstrated and the location of this photochemical process may be precisely selected within the micron scale in all three dimensions at depths up to almost 2 mm. We discuss these results for enhanced tissue penetration at longer near-infrared wavelengths for cancer therapy and up to three-photon excitation and imaging using 930-nm laser pulses with suitable combretastatin analogs.
Assuntos
Antineoplásicos/farmacocinética , Bibenzilas/farmacocinética , Imageamento Tridimensional/métodos , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Esferoides Celulares/metabolismo , Antineoplásicos/química , Bibenzilas/química , Linhagem Celular Tumoral , Corantes Fluorescentes/química , Humanos , Fótons , Células Tumorais Cultivadas/metabolismoRESUMO
To investigate within live mammalian cells the uptake and disposition of combretastatins, fluorescence lifetime imaging was used with two-photon excitation (2PE). Combretastatin A4 (CA4) and analogues are potential anticancer drugs due to their ability to inhibit angiogenesis. E(trans)-combretastatins are considerably less active than the Z(cis)-combretastatins proposed for clinical use. However the E-combretastatins exhibit stronger intrinsic fluorescence with quantum yields and lifetimes that depend markedly on solvent polarity and viscosity. It is proposed that 2PE in the red and near-infrared tissue window may allow in situ isomerization of E-combretastatins to the more active Z-isomer, offering spatial and temporal control of drug activation and constitute a novel form of photodynamic therapy. In the present work we have characterised 2PE of E-CA4 and have used fluorescence lifetime imaging with 2PE to study uptake and intracellular disposition of E-CA4 and an analogue. The results show that these molecules accumulate rapidly in cells and are located mainly in lipidic environments such as lipid droplets. Within the droplets the local concentrations may be up to two orders of magnitude higher than that of the drug in the surrounding medium.
Assuntos
Bibenzilas/farmacocinética , Microscopia de Fluorescência por Excitação Multifotônica , Estilbenos/farmacocinética , Animais , Bibenzilas/química , Células CHO , Cricetinae , Células HeLa , Humanos , Estilbenos/químicaRESUMO
A series of combretastatins possessing both a trimethoxy unit and other substituents on ring A has been synthesised and tested for cytotoxicity and their ability to interact with the protein tubulin. All previous studies have indicated that the trimethoxy unit is essential for interaction with tubulin. The studies herein show that molecules possessing functionalities other than trimethoxy can also interact with tubulin. Importantly a trimethyl substituted agent 52a has shown reduced cytotoxicity, but increased potency in its ability to inhibit the assembly of tubulin.
Assuntos
Antineoplásicos/química , Bibenzilas/química , Estilbenos/química , Tubulina (Proteína)/efeitos dos fármacos , Animais , Antineoplásicos/farmacologia , Bibenzilas/farmacologia , Linhagem Celular , Chlorocebus aethiops , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Imuno-Histoquímica , Concentração Inibidora 50 , Células K562 , Estrutura Molecular , Estilbenos/análise , Estilbenos/síntese química , Estilbenos/farmacologia , Relação Estrutura-Atividade , Células VeroRESUMO
The naturally occurring aurone 1, isolated from Uvaria hamiltonii, and a series of aurones analogues based structurally on known tubulin binding agents were prepared and evaluated for anticancer activity. Aurone 20 was the most active (IC(50) K562 50 nM) and caused significant G2/M cell-cycle arrest.
Assuntos
Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/farmacologia , Benzofuranos/síntese química , Benzofuranos/farmacologia , Flavonoides/síntese química , Flavonoides/farmacologia , Uvaria/química , Antineoplásicos Fitogênicos/isolamento & purificação , Benzofuranos/isolamento & purificação , Ciclo Celular/efeitos dos fármacos , DNA de Neoplasias/efeitos dos fármacos , Fase G2/efeitos dos fármacos , Humanos , Indicadores e Reagentes , Células K562 , Mitose/efeitos dos fármacos , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Relação Estrutura-Atividade , Sais de Tetrazólio , Tiazóis , Tubulina (Proteína)/efeitos dos fármacos , Tubulina (Proteína)/metabolismoRESUMO
Microtubules are intracellular organelles formed from the protein tubulin. These organelles have a number of essential cellular functions including chromosome segregation, the maintenance of cell shape, transport, motility, and organelle distribution. Drugs that affect the tubulin-microtubule equilibrium (taxol, vinca alkaloids) are effective anticancer drugs. This review describes the molecular target, methods used in screening, the structures of compounds known to interact with tubulin, and the clinical use of these agents. In addition the ability of these agents to destroy tumour vasculature is described. This represents an exciting new molecular target in the design of anticancer drugs.