Étude théorique des interactions entre dérivés du cisplatine et composés soufrés d'intérêt biologique

The study of the reactions between thiolates and derivatives of cisplatin are key to improving the understanding of the behaviour of this anticancer drug. These reactions, namely thiolations (replacement of a ligand by a thiolate) or bidentations (replacement of another ligand by a second group of the considered thiolate), are involved in the mechanisms which give rise to the destruction of cancer cells. They are also involved in the development of resistance mechanisms towards the treatment. We have used quantum chemistry methods (Møller-Plesset perturbation theory at degree 2 (MP2) completed by large basis functions set) to build a robust theoretical study of the reactions between cisplatin (and its main hydrolyzed products) and some thiolates of biological interest, such as cysteine and glutathione. Kinetic and thermodynamic data obtained for both thiolations and bidentations shed light on the nature of the preferred chemical pathways. Our Raman spectroscopy measurements show that only two thiolations actually occur, possibly due to bidentation reactions eventually taking place after each thiolation. In addition, the S,N bidentation is shown to be preferred with respect to the S,O bidentation. Also, the lability scale of the ligands was found to be almost systematically H2O > Cl– ≈ NH3(trans) > NH3(cis) > OH–, the difference between ammine ligands being induced by a significant trans-labilization by thiolates, due to the trans effect inherent in the planar square structure of platinum (II) complexes.L’étude des réactions entre thiolates et dérivés du cisplatine est une étape essentielle pour améliorer la compréhension du comportement de ce médicament anti-cancéreux en milieu biologique. Ces réactions, qu’il s'agisse de thiolations (remplacement d'un ligand par un thiolate) ou de bidentations (remplacement d'un autre ligand par un second groupement du thiolate considéré), sont en effet impliquées à la fois dans les mécanismes de destruction des cellules cancéreuses et dans le développement de mécanismes de résistance vis-à-vis du traitement.À l’aide de simulations de chimie quantique à un niveau de théorie élevé (méthode de perturbationMøller-Plesset au degré 2 (MP2) et des jeux de fonctions de base très complets), nous avons mené une étude robuste et complète des réactions entre le cisplatine (et ses dérivés d’hydrolyse principaux) et des thiolates d’intérêt biologique comme la cystéine et le glutathion.Les caractéristiques cinétiques et thermodynamiques obtenues pour les thiolations et les bidentations permettent de mettre en lumière les chemins de réactions les plus probables. Nos résultats de spectroscopie Raman montrent également que deux thiolations au maximum peuvent avoir lieu, probablement en raison de bidentations après chaque thiolation. En outre, les bidentations S,N semblent favorisées par rapport aux bidentations S,O. Nous avons également observé de manière presque systématique l'échelle de labilité des ligands suivante : H2O > Cl– ≈ NH3(trans) > NH3(cis) > OH–. La différence entre les ammines vient d'une forte translabilisation par les thiolates, due à l’effet trans inhérent aux structures carrée plane des sels de platine (II)

Theoretical Study of the interactions between cisplatin derivatives and biological sulfur-based chemical compounds

L’étude des réactions entre thiolates et dérivés du cisplatine est une étape essentielle pour améliorer la compréhension du comportement de ce médicament anti-cancéreux en milieu biologique. Ces réactions, qu’il s'agisse de thiolations (remplacement d'un ligand par un thiolate) ou de bidentations (remplacement d'un autre ligand par un second groupement du thiolate considéré), sont en effet impliquées à la fois dans les mécanismes de destruction des cellules cancéreuses et dans le développement de mécanismes de résistance vis-à-vis du traitement.À l’aide de simulations de chimie quantique à un niveau de théorie élevé (méthode de perturbationMøller-Plesset au degré 2 (MP2) et des jeux de fonctions de base très complets), nous avons mené une étude robuste et complète des réactions entre le cisplatine (et ses dérivés d’hydrolyse principaux) et des thiolates d’intérêt biologique comme la cystéine et le glutathion.Les caractéristiques cinétiques et thermodynamiques obtenues pour les thiolations et les bidentations permettent de mettre en lumière les chemins de réactions les plus probables. Nos résultats de spectroscopie Raman montrent également que deux thiolations au maximum peuvent avoir lieu, probablement en raison de bidentations après chaque thiolation. En outre, les bidentations S,N semblent favorisées par rapport aux bidentations S,O. Nous avons également observé de manière presque systématique l'échelle de labilité des ligands suivante : H2O > Cl– ≈ NH3(trans) > NH3(cis) > OH–. La différence entre les ammines vient d'une forte translabilisation par les thiolates, due à l’effet trans inhérent aux structures carrée plane des sels de platine (II).The study of the reactions between thiolates and derivatives of cisplatin are key to improving the understanding of the behaviour of this anticancer drug. These reactions, namely thiolations (replacement of a ligand by a thiolate) or bidentations (replacement of another ligand by a second group of the considered thiolate), are involved in the mechanisms which give rise to the destruction of cancer cells. They are also involved in the development of resistance mechanisms towards the treatment. We have used quantum chemistry methods (Møller-Plesset perturbation theory at degree 2 (MP2) completed by large basis functions set) to build a robust theoretical study of the reactions between cisplatin (and its main hydrolyzed products) and some thiolates of biological interest, such as cysteine and glutathione. Kinetic and thermodynamic data obtained for both thiolations and bidentations shed light on the nature of the preferred chemical pathways. Our Raman spectroscopy measurements show that only two thiolations actually occur, possibly due to bidentation reactions eventually taking place after each thiolation. In addition, the S,N bidentation is shown to be preferred with respect to the S,O bidentation. Also, the lability scale of the ligands was found to be almost systematically H2O > Cl– ≈ NH3(trans) > NH3(cis) > OH–, the difference between ammine ligands being induced by a significant trans-labilization by thiolates, due to the trans effect inherent in the planar square structure of platinum (II) complexes

C. CALVO RIGUAL / L. MINERVINI / A. THIBAULT (éds.), « Section 11 : Linguistique de contact », dans É. Buchi / J.-P. Chauveau / J.-M. Pierrel (éds.), Actes du XXVIIe Congrès international de linguistique et de philologie romanes (Nancy, 15-20 juillet 2013), Strasbourg, Éditions de Linguistique et de Philologie, 2016, vol. 2, pp. 1183-1268.

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Fate of cisplatin and its main hydrolysed forms in the presence of thiolates: a comprehensive computational and experimental study

International audienceAbstract Interaction of platinum-based drugs with proteins containing sulphur amino acids is usually argued as one of the major reasons for the observed resistance to these drugs, mainly due to the deactivation of the native compounds by very efficient thiolation processes in the organism. In this work, we have investigated the detailed thermodynamics and kinetics of reaction between cisplatin cis-[PtCl2(NH3)2] and its major hydrolysed forms (monohydroxocisplatin cis-[PtCl(OH)(NH3)2] and monoaquacisplatin cis-[PtCl(H2O)(NH3)2]+) with various thiolates (methanethiolate, cysteine and glutathione) and methionine. We have used a demanding quantum chemistry approach at the MP2 and DFT levels of theory to determine the Gibbs free energies and the barrier of reactions of the most possible reaction paths. The substitution of the four ligands of the complexes studied here (Cl−, OH−, H2O and NH3) can either proceed by direct thiolations or bidentations. Our Raman spectroscopy measurements show that only two thiolations actually occur, although four are possible in principle. The reason could lie in the bidentation reactions eventually taking place after each thiolation, which is backed up by our computational results. The observed lability scale of the ligands under thiolate exposure was found to be in the following order H2O > Cl− ≈ NH3(trans) > NH3(cis) > OH−, the difference between ammine ligands being induced by a significant trans-labilization by thiolates. Finally, the S,N bidentation is shown to be preferred with respect to the S,O one

Lipoproteins LDL versus HDL as nanocarriers to target either cancer cells or macrophages

International audienceIn this work, we have explored natural unmodified low- and high-density lipoproteins (LDL and HDL) as selective delivery vectors in colorectal cancer therapy. We show in vitro in cultured cells and in vivo (NanoSPECT/CT) in the CT-26 mice colorectal cancer model that LDLs are mainly taken up by cancer cells, while HDLs are preferentially taken up by macrophages. We loaded LDLs with cisplatin and HDLs with the heat shock protein-70 inhibitor AC1LINNC, turning them into a pair of “Trojan horses” delivering drugs selectively to their target cells as demonstrated in vitro in human colorectal cancer cells and macrophages, and in vivo. Coupling of the drugs to lipoproteins and stability was assessed by mass and raman spectrometry analysis. Cisplatin vectorized in LDLs led to better tumor growth suppression with strongly reduced adverse effects such as a renal or liver toxicity. AC1LINNC vectorized into HDLs induced a strong oxidative burst in macrophages and innate anti-cancer immune response. Cumulative anti-tumor effect was observed for both drug-loaded lipoproteins. Altogether, our data show that lipoproteins from patient’s blood can be used as natural nanocarriers allowing cell specific targeting, paving the way toward more efficient, safer and personalized use of chemo-and immunotherapeutic drugs in cance