Interaction of 4-arylcoumarin analogues of combretastatins with microtubule network of HBL100 cells and binding to tubulin.
The synthesis of different 4-arylcoumarin analogues of combretastatin A-4 led to the identification of two new compounds (1 and 2) with potent cytotoxic activity on a CEM leukemia cell line and a third one completely inactive (compound 3). It was suggested that the cytotoxicity of compounds 1 and 2 may be related to their interaction with microtubules and tubulin, since these compounds inhibit microtubule formation from purified tubulin in vitro [Bailly et al. (2003) J. Med. Chem. 46 (25), 5437-5444]. In the present study, tubulin was identified as the main target of these molecules. We studied structure-activity relationships of these compounds using biological experiments specific for tubulin binding. The modification of cell cycle progression induced by compounds 1 and 2 was characterized by an apoptotic induction on human breast cells (HBL100). In addition, these two molecules disturbed cell survival by depolymerizing the microtubule network, leading to a mitotic block. We then determined the thermodynamic parameters of their interaction with purified tubulin by fluorescence spectroscopy and isothermal microcalorimetry. These results, together with a superimposition of the molecule on colchicine in the X-ray-determined three-dimensional structure model of tubulin-colchicine complex, allowed us to identify the pharmacophore of the combretastatin A-4 analogues responsible for their biological activity.
Rappl
Catherine
C
FRE-CNRS 2737, Universités Aix-Marseille 1 et 2, Cytosquelette et Intégration des Signaux du Micro-Environnement Tumoral, 27 boulevard Jean Moulin, 13385 Marseille Cedex 5, France.
Barbier
Pascale
P
Bourgarel-Rey
Véronique
V
Grégoire
Catherine
C
Gilli
Robert
R
Carre
Manon
M
Combes
Sébastien
S
Finet
Jean-Pierre
JP
Peyrot
Vincent
V
D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000378:metabolism*; D017209:Apoptosis; D002151:Calorimetry; D002453:Cell Cycle; D045744:Cell Line, Tumor; D003374:Coumarins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008870:Microtubules / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013267:Stilbenes / Q000737:chemistry / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D014404:Tubulin / Q000737:chemistry / Q000378:metabolism*
D000972:Antineoplastic Agents, Phytogenic; D003374:Coumarins; D013267:Stilbenes; D014404:Tubulin; C030123:coumarin; C058728:fosbretabulin