Relevance of copper and organic cation transporters in the activity and transport mechanisms of an anticancer cyclometallated gold(III) compound in comparison to cisplatin

The molecular mechanisms of toxicity and cellular transport of anticancer metallodrugs, including platinum-based agents, have not yet been fully elucidated. The aim of our study was to investigate the relevance of copper transporters (CTR1 and ATP7A/B), organic cation transporters (OCT2) and the multidrug and toxin extrusion proteins (MATE) in the intracellular accumulation of a novel organometallic cytotoxic Au(III) compound in cancer cells in comparison to cisplatin. Specifically, the synthesis and characterization of the gold complex [Au(py(b)-H)(PPh2Ar)Cl]PF6 (PPh2Ar = 3-[4-(diphenylphosphino)pheny]7-methoxy-2H-chromen-2-one] (1), featuring a coumarin ligand endowed with "smart" fluorescence properties, have been achieved. Initially, the cytotoxic effects of both cisplatin and 1 were studied in a small panel of human cancer cells, and against a non-tumorigenic cell line in vitro. Thus, the human ovarian cancer cell line A2780 and its cisplatin resistant variant A2780cisR, were selected, being most sensitive to the treatment of the gold complex. Co-incubation of the metallodrugs with CuCl2 (a CTR1 substrate) increased the cytotoxic effects of both the Au(III) complex and cisplatin; while co-incubation with cimetidine (inhibitor of OCT2 and MATE) showed some effect only after 72 h incubation. ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis of the cell extracts showed that co-incubation with CuCl2 increases Au and Cu accumulation in both cancer cell lines, in accordance with the enhanced antiproliferative effects. Conversely, for cisplatin, no increase in Pt content could be observed in both cell lines after co-incubation with either CuCl2 or cimetidine, excluding the involvement of CTR1, OCT2, and MATE in drug accumulation and overall anticancer effects. This result, together with the evidence for increased Cu content in A2780 cells after cisplatin co-treatment with CuCl2, suggests that copper accumulation is the reason for the observed enhanced anticancer effects in this cell line. Moreover, metal uptake studies in the same cell lines indicate that both 1 and cisplatin are not transported intracellularly by CTR1 and OCT2. Finally, preliminary fluorescence microscopy studies enabled the visualization of the sub-cellular distribution of the gold compound in A2780 cells, suggesting accumulation in specific cytosolic components/organelles

Relevance of Copper and Organic Cation Transporters in the Activity and Transport Mechanisms of an Anticancer Cyclometallated Gold(III) Compound in Comparison to Cisplatin

The molecular mechanisms of toxicity and cellular transport of anticancer metallodrugs, including platinum-based agents, have not yet been fully elucidated. The aim of our study was to investigate the relevance of copper transporters (CTR1 and ATP7A/B), organic cation transporters (OCT2) and the multidrug and toxin extrusion proteins (MATE) in the intracellular accumulation of a novel organometallic cytotoxic Au(III) compound in cancer cells in comparison to cisplatin. Specifically, the synthesis and characterization of the gold complex [Au(pyb-H)(PPh2Ar)Cl]PF6 (PPh2Ar = 3-[4-(diphenylphosphino)phenyl]-7-methoxy-2H-chromen-2-one] (1), featuring a coumarin ligand endowed with “smart” fluorescence properties, have been achieved. Initially, the cytotoxic effects of both cisplatin and 1 were studied in a small panel of human cancer cells, and against a non-tumorigenic cell line in vitro. Thus, the human ovarian cancer cell line A2780 and its cisplatin resistant variant A2780cisR, were selected, being most sensitive to the treatment of the gold complex. Co-incubation of the metallodrugs with CuCl2 (a CTR1 substrate) increased the cytotoxic effects of both the Au(III) complex and cisplatin; while co-incubation with cimetidine (inhibitor of OCT2 and MATE) showed some effect only after 72 h incubation. ICP-MS (Inductively Coupled Plasma Mass Spectrometry) analysis of the cell extracts showed that co-incubation with CuCl2 increases Au and Cu accumulation in both cancer cell lines, in accordance with the enhanced antiproliferative effects. Conversely, for cisplatin, no increase in Pt content could be observed in both cell lines after co-incubation with either CuCl2 or cimetidine, excluding the involvement of CTR1, OCT2, and MATE in drug accumulation and overall anticancer effects. This result, together with the evidence for increased Cu content in A2780 cells after cisplatin co-treatment with CuCl2, suggests that copper accumulation is the reason for the observed enhanced anticancer effects in this cell line. Moreover, metal uptake studies in the same cell lines indicate that both 1 and cisplatin are not transported intracellularly by CTR1 and OCT2. Finally, preliminary fluorescence microscopy studies enabled the visualization of the sub-cellular distribution of the gold compound in A2780 cells, suggesting accumulation in specific cytosolic components/organelles

Synthèse de ligands ambidents "N2S2" / "N4" pour des applications en médecine nucléaire

Ce mémoire de thèse décrit la conception et la synthèse de nouveaux agents chélatants pour des applications en médecine nucléaire et plus particulièrement pour la tomographie par émission de positrons (TEP) et la radioimmunothérapie (RIT). Les isotopes du cuivre sont reconnus pour leurs applications en TEP et en RIT, notre attention s est donc plus portée sur la chélation de ce métal. Après avoir déterminé les caractéristiques nécessaires à l obtention de ligands du cuivre, nous présenterons une méthode de synthèse efficace et flexible assistée par irradiations micro-ondes. La particularité de ces ligands est leur ambidence, c'est-à-dire leur capacité potentielle à chélater les métaux soit par quatre atomes d azote (ligands N4 ) soit par deux atomes d azote et deux atomes de soufre (ligands N2S2 ). Cette ambidence est rendue possible par un squelette de type bis(hydrazone) sur lequel sont reliés deux cycles thiazoles pouvant tourner par libre rotation autour d une liaison simple. Une fois établi le fait que ces agents chélatants étaient aisément fonctionnalisables pour être greffés à un vecteur biologique, leurs capacités complexantes ont été évaluées. Les complexes obtenus sont étudiés par différentes techniques analytiques comme l EDX, les spectroscopies UV-visible, IR, de masse, des rayons X, afin de déterminer leur structure. Nous conclurons sur les premiers tests de chélation de 64Cu réalisés dans le but d effectuer de la TEPThis work describes the design and the synthesis of new chelating agents for applications in nuclear medicine and particularly for positron emission tomography (PET) and radioimmunotherapy (RIT). Copper isotopes are known for their use in PET or in RIT, so we focus our attention on the complexation of this metal. After having determined characteristics required to get copper ligands, we present an efficient and versatile microwave-assisted method to synthesize copper ligands. The particularity of these chelating agents is the fact that they are ambident: they are potentially able to chelate metal with four nitrogen atoms (ligands "N4") or with two nitrogen atoms and two sulfur atoms (ligands "N2S2"). This property is given by a bis(hydrazone) skeleton containing two thiazol rings which can spin by free rotation around a single bond. After check that these ligands are easily functionnalisable to be attached to a biological vector, their chelating power was estimated. The complexes obtained were examined by several analytic methods such as EDX, UV, IR, mass, X-ray spectroscopies, to find their structure. We conclude with the first 64Cu complexation tests carried out for PET applicationNANTES-BU Sciences (441092104) / SudocSudocFranceF

Development of trackable metal-based drugs: new generation of therapeutic agents

International audienceIn medicinal chemistry, the aim is not only to conceive ever more efficient molecules, but also to understand their mechanism of action. In very recent years, a new promising strategy was developed to tackle this issue: the conception of trackable therapeutic agents. Metal-based drugs are ideal to exploit this expanding area of research

Labeling of a self-hardening bone substitute using ruthenium tris-bipyridine complexes, for the analysis of its in vivo metabolism

GECOM-CONCOORD Conference, Plancoet, FRANCE, MAY 20-25, 2007A self-setting cellulose scaffold, used as a component of an injectable bone substitute, was labeled with ruthenium tris-bipyridine complexes functionalized by triethoxysilane groups. The labeling yield was found to vary according to the number and location of Si(OR)(3) groups present on the ruthenium complex backbone. For label loadings, less than similar to 0.1 wt%, no significant modification of the theological properties of the gel was observed

BODIPY atropisomer interconversion, face discrimination, and superstructure appending

International audienceA strategy was developed to append sterically hindered apical pickets on both faces of the BODIPY platform to prevent stacking and aggregation. Ortho-substitution of both the meso-phenyl ring and the boron-bound catechol affords the right directionality to append pickets, achieve face discrimination, featuring two inter-convertible atropisomers, and is reminiscent of the picket-fence strategy in porphyrins

Gold(I) N-heterocyclic carbene complexes with an "activable" ester moiety:Possible biological applications

While N-heterocyclic carbenes (NHC) are ubiquitous ligands in catalysts for organic or industrial synthesis, their potential to form transition metal complexes for medicinal applications has still to be exploited. Within this frame, new Au(I)–NHC compounds have been synthesized and structurally characterized via different methods. The solid state structure of one of these compounds was also established by X-ray crystallography. Of note, three of them bear a pentafluorophenolic ester group as a possible “activable” moiety for further functionalization, which allowed tethering an alkyl amine ligand or another Au(I)–phosphine complex featuring a pendant amine function via microwave activation. The obtained compounds have been tested for their antiproliferative effects in human ovarian cancer A2780 cells, and in non-tumorigenic human embryonic kidney HEK-293T cells, showing promising anticancer properties and a certain selectivity towards cancerous cells