Publicaciones > Casado et al

Mol Cancer Ther. 2008 May;7(5):1309-18. doi: 10.1158/1535-7163.MCT-07-2432. PubMed 18483318

Relevance of the Fanconi anemia pathway in the response of human cells to trabectedin.

Jose A Casado, Paula Rio, Esther Marco, Veronica Garcia-Hernandez, Alberto Domingo, Laura Perez, Juan Carlos Tercero, Juan Jose Vaquero, Beatriz Albella, Federico Gago, Juan A Bueren

Division of Hematopoiesis and Gene Therapy Program, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Avenida Complutense 22, 28040 Madrid, Spain.

Abstract

Trabectedin (Yondelis; ET-743) is a potent anticancer drug that binds to DNA by forming a covalent bond with a guanine in one strand and one or more hydrogen bonds with the opposite strand. Using a fluorescence-based melting assay, we show that one single trabectedin-DNA adduct increases the thermal stability of the double helix by >20 degrees C. As deduced from the analysis of phosphorylated H2AX and Rad51 foci, we observed that clinically relevant doses of trabectedin induce the formation of DNA double-strand breaks in human cells and activate homologous recombination repair in a manner similar to that evoked by the DNA interstrand cross-linking agent mitomycin C (MMC). Because one important characteristic of this drug is its marked cytotoxicity on cells lacking a functional Fanconi anemia (FA) pathway, we compared the response of different subtypes of FA cells to MMC and trabectedin. Our data clearly show that human cells with mutations in FANCA, FANCC, FANCF, FANCG, or FANCD1 genes are highly sensitive to both MMC and trabectedin. However, in marked contrast to MMC, trabectedin does not induce any significant accumulation of FA cells in G2-M. The critical relevance of FA proteins in the response of human cells to trabectedin reported herein, together with observations showing the role of the FA pathway in cancer suppression, strongly suggest that screening for mutations in FA genes may facilitate the identification of tumors displaying enhanced sensitivity to this novel anticancer drug.

Publicaciones > Negri et al

J Med Chem. 2007 Jul 12;50(14):3322-33. doi: 10.1021/jm070381s. PubMed 17571868

Antitumor activity, X-ray crystal structure, and DNA binding properties of thiocoraline A, a natural bisintercalating thiodepsipeptide.

Ana Negri, Esther Marco, Veronica Garcia-Hernandez, Alberto Domingo, Antonio L Llamas-Saiz, Silvia Porto-Sanda, Ricardo Riguera, William Laine, Marie-Helene David-Cordonnier, Christian Bailly, Luis F Garcia-Fernandez, Juan Jose Vaquero, Federico Gago

Departamento de Farmacologia, Universidad de AlcalA, E-28871 Madrid, Spain.

Abstract

The marine natural product thiocoraline A displayed approximately equal cytotoxic activity at nanomolar concentrations in a panel of 12 human cancer cell lines. X-ray diffraction analyses of orthorhombic crystals of this DNA-binding drug revealed arrays of docked pairs of staple-shaped molecules in which one pendent hydroxyquinoline chromophore from each cysteine-rich molecule appears intercalated between the two chromophores of a facing molecule. This arrangement is in contrast to the proposed mode of binding to DNA that shows the two drug chromophores clamping two stacked base pairs, in agreement with the nearest-neighbor exclusion principle. Proof of DNA sequence recognition was obtained from both classical DNase I footprinting experiments and determination of the melting temperatures of several custom-designed fluorescently labeled oligonucleotides. A rationale for the DNA-binding behavior was gained when models of thiocoraline clamping a central step embedded in several octanucleotides were built and studied by means of unrestrained molecular dynamics simulations in aqueous solution.

Publicaciones > Martinez et al

J Med Chem. 2004 Feb 26;47(5):1136-48. doi: 10.1021/jm0310434. PubMed 14971893

Benzo[f]azino[2,1-a]phthalazinium cations: novel DNA intercalating chromophores with antiproliferative activity.

Valentin Martinez, Carolina Burgos, Julio Alvarez-Builla, Geronimo Fernandez, Alberto Domingo, Raquel Garcia-Nieto, Federico Gago, Ignacio Manzanares, Carmen Cuevas, Juan J Vaquero

Departamento de Quimica Organica, Universidad de Alcala, 28871-Alcala de Henares, Madrid, Spain.

Abstract

New azaquinolizinium-type cations have been obtained from isochromane. The synthesis was completed over seven steps and included as the key feature an intramolecular Westphal condensation. This first example of the intramolecular process allowed the preparation of benzo[f]pyrido[2,1-a]phthalazinium and benzo[f]quino[2,1-a]phthalazinium salts, which were evaluated as DNA intercalators, DNA topoisomerase I inhibitors, and antiproliferative compounds. Both cationic systems behave as DNA intercalators and exhibit antiproliferative activity. The pentacyclic benzo[f]quino[2,1-a]phthalazinium cations also have an inhibitory effect on the catalytic activity of DNA topoisomerase I, without trapping of cleavage complexes. Structural characterization using density functional theory indicates that the fused ring systems are slightly nonplanar, and additional molecular modeling studies suggest a preferred orientation for the intercalating chromophores within a typical CpG or TpG intercalation site.