RESUMEN
RuII(arene) complexes have been shown to be promising anticancer agents, capable of overcoming major drawbacks of currently used chemotherapeutics. We have synthesized RuII(η6-arene) compounds carrying bioactive flavonol ligands with the aim to obtain multitargeted anticancer agents. To validate this concept, studies on the mode of action of the complexes were conducted which indicated that they form covalent bonds to DNA, have only minor impact on the cell cycle, but inhibit CDK2 and topoisomerase IIα in vitro. The cytotoxic activity was determined in human cancer cell lines, resulting in very low IC50 values as compared to other RuII(arene) complexes and showing a structure-activity relationship dependent on the substitution pattern of the flavonol ligand. Furthermore, the inhibition of cell growth correlates well with the topoisomerase inhibitory activity. Compared to the flavonol ligands, the RuII(η6-p-cymene) complexes are more potent antiproliferative agents, which can be explained by potential multitargeted properties.
Asunto(s)
Antineoplásicos/química , Antineoplásicos/farmacología , Flavonoles/química , Compuestos de Rutenio/química , Compuestos de Rutenio/farmacología , Línea Celular Tumoral , Quinasa 2 Dependiente de la Ciclina/antagonistas & inhibidores , ADN-Topoisomerasas de Tipo II/efectos de los fármacos , Ensayos de Selección de Medicamentos Antitumorales , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Humanos , Ligandos , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Espectrometría de Masa por Ionización de Electrospray , Relación Estructura-ActividadRESUMEN
Ru(II)(arene)-flavonoids with high in vitro antitumour activity were synthesised. These compounds are capable of inhibiting human topoisomerase IIα and binding covalently to DNA.
Asunto(s)
Antígenos de Neoplasias/metabolismo , ADN-Topoisomerasas de Tipo II/metabolismo , Proteínas de Unión al ADN/metabolismo , ADN/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/química , Complejos de Coordinación/farmacología , Proteínas de Unión al ADN/antagonistas & inhibidores , Flavonoides/química , Humanos , Conformación Molecular , Unión Proteica , Rutenio/químicaRESUMEN
In the present study, we addressed the question whether cyanidin-3-glucoside (C3G) or complex C3G-rich blackberry extracts affect human topoisomerases with special emphasis on the contribution of the potential degradation products phloroglucinol aldehyde (PGA) and protocatechuic acid (PCA). In HT29 colon carcinoma cells a C3G-rich blackberry extract suppressed camptothecin- (CPT-) or doxorubicin- (DOX-) induced stabilization of the covalent DNA-topoisomerase intermediate, thus antagonizing the effects of these classical topoisomerase poisons on DNA integrity. As a single compound, C3G (100 µM) decreased the DNA-damaging effects of CPT as well, but did not significantly affect those induced by DOX. At the highest applied concentration (100 µM), cyanidin protected DNA from CPT- and DOX-induced damage. Earlier reports on DNA-damaging properties of cyanidin were found to result most likely from the formation of hydrogen peroxide as an artifact in the cell culture medium when the incubation was performed in the absence of catalase. The suppression of hydrogen peroxide accumulation, achieved by the addition of catalase, demonstrated that cyanidin does not exhibit DNA-damaging properties in HT29 cells (up to 100 µM). The observed effects on topoisomerase interference and DNA protection against CPT or DOX were clearly limited to the parent compound and were not observed for the potential cyanidin degradation products PGA and PCA.