RESUMO
A series of new gold(I) and silver(I) N-heterocyclic carbenes bearing a 1-thio-ß-d-glucose tetraacetate moiety was synthesized and chemically characterized. The compounds' stability and solubility in physiological conditions were investigated employing a multitechnique approach. Interaction studies with biologically relevant proteins, such as superoxide dismutase (SOD) and human serum albumin (HSA), were conducted via UV-vis absorption spectroscopy and high-resolution ESI mass spectrometry. The biological activity of the compounds was evaluated in the A2780 and A2780R (cisplatin-resistant) ovarian cancer cell lines and the HSkMC (human skeletal muscle) healthy cell line. Inhibition studies of the selenoenzyme thioredoxin reductase (TrxR) were also carried out. The results highlighted that the gold complexes are more stable in aqueous environment and capable of interaction with SOD and HSA. Moreover, these carbenes strongly inhibited the TrxR activity. In contrast, the silver ones underwent structural alterations in the aqueous medium and showed greater antiproliferative activity.
Assuntos
Antineoplásicos , Proliferação de Células , Ensaios de Seleção de Medicamentos Antitumorais , Ouro , Compostos Heterocíclicos , Metano , Prata , Tiorredoxina Dissulfeto Redutase , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Prata/química , Prata/farmacologia , Ouro/química , Ouro/farmacologia , Metano/análogos & derivados , Metano/química , Metano/farmacologia , Compostos Heterocíclicos/química , Compostos Heterocíclicos/farmacologia , Compostos Heterocíclicos/síntese química , Proliferação de Células/efeitos dos fármacos , Tiorredoxina Dissulfeto Redutase/antagonistas & inibidores , Tiorredoxina Dissulfeto Redutase/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Estrutura Molecular , Relação Estrutura-Atividade , Linhagem Celular Tumoral , Superóxido Dismutase/metabolismo , Superóxido Dismutase/antagonistas & inibidoresRESUMO
Photoactivatable Pt(IV) prodrugs represent nowadays an intriguing class of potential metal-based drugs, endowed with more chemical inertness in their oxidized form and better selectivity for the target with respect to the clinically established Pt(II) compounds. In fact, they have the possibility to be reduced by light irradiation directly at the site of interest. For this reason, we synthesized a new Pt(IV) complex, [Pt(OCOCH3)3(4'-phenyl-2,2':6',2''-terpyridine)][CF3SO3] (1), that is well soluble in aqueous medium and totally unreactive towards selected model biomolecules until its reduction. The highlight of this work is the rapid and efficient photoreduction of 1 with visible light (460 nm), which leads to its reactive Pt(II) analogue. This behavior was made possible by taking advantage of an efficient catalytic system based on flavin and NADH, which is naturally present in the cellular environment. As a comparison, the reduction of 1 was also studied with simple UV irradiation, but both UV-Vis spectrophotometry and 1H-NMR spectrometry showed that the flavin-catalyzed reduction with visible light was faster. Lastly, the reactivity against two representative biological targets, i.e., human serum albumin and one monofilament oligonucleotide fragment, was evaluated by high-resolution mass spectrometry. The results clearly pointed out that the prodrug 1 did not interact with these targets until its photoreduction to the Pt(II) analogue.
Assuntos
Antineoplásicos , Pró-Fármacos , Humanos , Antineoplásicos/química , Compostos Organoplatínicos/química , Luz , Espectroscopia de Ressonância Magnética , Pró-Fármacos/químicaRESUMO
A panel of four novel gold(I) complexes, inspired by the clinically established gold drug auranofin (1-Thio-ß-D-glucopyranosatotriethylphosphine gold-2,3,4,6-tetraacetate), was prepared and characterized. All these compounds feature the replacement of the triethylphosphine ligand of the parent compound auranofin with a trimethylphosphite ligand. The linear coordination around the gold(I) center is completed by Cl-, Br-, I- or by the thioglucose tetraacetate ligand (SAtg). The in-solution behavior of these gold compounds as well as their interactions with some representative model proteins were comparatively analyzed through 31PNMR and ESI-MS measurements. Notably, all panel compounds turned out to be stable in aqueous media, but significant differences with respect to auranofin were disclosed in their interactions with a few leading proteins. In addition, the cytotoxic effects produced by the panel compounds toward A2780, A2780R and SKOV-3 ovarian cancer cells were quantitated and found to be in the low micromolar range, since the IC50 of all compounds was found to be between 1 µM and 10 µM. Notably, these novel gold complexes showed large and similar inhibition capabilities towards the key enzyme thioredoxin reductase, again comparable to those of auranofin. The implications of these results for the discovery of new and effective gold-based anticancer agents are discussed.
Assuntos
Antineoplásicos , Neoplasias Ovarianas , Fosfitos , Humanos , Feminino , Auranofina/farmacologia , Auranofina/química , Ouro/química , Linhagem Celular Tumoral , Ligantes , Antineoplásicos/farmacologia , Antineoplásicos/químicaRESUMO
Although important progress has been made, cancer still remains a complex disease to treat. Serious side effects, the insurgence of resistance and poor selectivity are some of the problems associated with the classical metal-based anti-cancer therapies currently in clinical use. New treatment approaches are still needed to increase cancer patient survival without cancer recurrence. Herein, we reviewed two promising-at least in our opinion-new strategies to increase the efficacy of transition metal-based complexes. First, we considered the possibility of assembling two biologically active fragments containing different metal centres into the same molecule, thus obtaining a heterobimetallic complex. A critical comparison with the monometallic counterparts was done. The reviewed literature has been divided into two groups: the case of platinum; the case of gold. Secondly, the conjugation of metal-based complexes to a targeting moiety was discussed. Particularly, we highlighted some interesting examples of compounds targeting cancer cell organelles according to a third-order targeting approach, and complexes targeting the whole cancer cell, according to a second-order targeting strategy.
Assuntos
Antineoplásicos , Complexos de Coordenação , Neoplasias , Elementos de Transição , Humanos , Complexos de Coordenação/farmacologia , Complexos de Coordenação/uso terapêutico , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Ouro/uso terapêuticoRESUMO
In this work, we have analysed the binding of the Pt(II) complexes ([PtCl(4'-phenyl-2,2':6',2â³-terpyridine)](CF3SO3) (1), [PtI(4'-phenyl-2,2':6',2â³-terpyridine)](CF3SO3) (2) and [PtCl(1,3-di(2-pyridyl)benzene) (3)] with selected model proteins (hen egg-white lysozyme, HEWL, and ribonuclease A, RNase A). Platinum coordination compounds are intensively studied to develop improved anticancer agents. In this regard, a critical issue is the possible role of Pt-protein interactions in their mechanisms of action. Multiple techniques such as differential scanning calorimetry (DSC), electrospray ionization mass spectrometry (ESI-MS) and UV-Vis absorbance titrations were used to enlighten the details of the binding to the different biosubstrates. On the one hand, it may be concluded that the affinity of 3 for the proteins is low. On the other hand, 1 and 2 strongly bind them, but with major binding mode differences when switching from HEWL to RNase A. Both 1 and 2 bind to HEWL with a non-specific (DSC) and non-covalent (ESI-MS) binding mode, dominated by a 1:1 binding stoichiometry (UV-Vis). ESI-MS data indicate a protein-driven chloride loss that does not convert into a covalent bond, likely due to the unfavourable complexes' geometries and steric hindrance. This result, together with the significant changes of the absorbance profiles of the complex upon interaction, suggest an electrostatic binding mode supported by some stacking interaction of the aromatic ligand. Very differently, in the case of RNase A, slow formation of covalent adducts occurs (DSC, ESI-MS). The reactivity is higher for the iodo-compound 2, in agreement with iodine lability higher than chlorine.
Assuntos
Antineoplásicos/química , Compostos Organoplatínicos/química , Proteínas/química , Termodinâmica , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Gold and silver N-heterocyclic carbenes (NHCs) are emerging for therapeutic applications. Multiple techniques are here used to unveil the mechanistic details of the binding to different biosubstrates of bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) silver chloride [Ag(EIA)2]Cl and bis(1-(anthracen-9-ylmethyl)-3-ethylimidazol-2-ylidene) gold chloride [Au(EIA)2]Cl. As the biosubstrates, we tested natural double-stranded DNA, synthetic RNA polynucleotides (single-poly(A), double-poly(A)poly(U) and triple-stranded poly(A)2poly(U)), DNA G-quadruplex structures (G4s), and bovine serum albumin (BSA) protein. Absorbance and fluorescence titrations, mass spectrometry together with melting and viscometry tests show significant differences in the binding features between silver and gold compounds. [Au(EIA)2]Cl covalently binds BSA. It is here evidenced that the selectivity is high: low affinity and external binding for all polynucleotides and G4s are found. Conversely, in the case of [Ag(EIA)2]Cl, the binding to BSA is weak and relies on electrostatic interactions. [Ag(EIA)2]Cl strongly/selectively interacts only with double strands by a mechanism where intercalation plays the major role, but groove binding is also operative. The absence of an interaction with triplexes indicates the major role played by the geometrical constraints to drive the binding mode.
Assuntos
Ouro/química , Compostos Heterocíclicos/química , Metano/análogos & derivados , Prata/química , Algoritmos , DNA/química , Substâncias Macromoleculares/química , Metano/química , Modelos Teóricos , Estrutura Molecular , Desnaturação de Ácido Nucleico , RNA/química , Soroalbumina Bovina/química , Análise Espectral , Relação Estrutura-Atividade , TermodinâmicaRESUMO
AuIII complexes with N-heterocyclic carbene (NHC) ligands have shown remarkable potential as anticancer agents, yet their fate in vivo has not been thoroughly examined and understood. Reported herein is the synthesis of new AuIII -NHC complexes by direct oxidation with radioactive [124 I]I2 as a valuable strategy to monitor the in vivo biodistribution of this class of compounds using positron emission tomography (PET). While in vitro analyses provide direct evidence for the importance of AuIII -to-AuI reduction to achieve full anticancer activity, in vivo studies reveal that a fraction of the AuIII -NHC prodrug is not immediately reduced after administration but able to reach the major organs before metabolic activation.
Assuntos
Antineoplásicos/farmacologia , Ouro/farmacologia , Compostos Heterocíclicos/farmacologia , Metano/análogos & derivados , Animais , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Ouro/química , Compostos Heterocíclicos/química , Humanos , Radioisótopos do Iodo , Ligantes , Metano/química , Metano/farmacologia , Camundongos , Estrutura Molecular , Tomografia por Emissão de Pósitrons , Distribuição Tecidual , Células Tumorais CultivadasRESUMO
A group of mixed-ligand Pt(II) complexes bearing acetylacetonate and sulphur ligands were recently developed in the University of Lecce as a new class of prospective anticancer agents that manifested promising pharma-cological properties in preliminary in vitro and in vivo tests. Though modelled on the basis of cisplatin, these Pt(II) complexes turned out to exhibit a profoundly distinct mode of action as they were found to act mainly on non-genomic targets rather than on DNA. Accordingly, we have explored here their reactions with two representative model proteins through an established ESI-MS procedure with the aim to describe their general interaction mechanism with protein targets. A pronounced reactivity with the tested proteins was indeed documented; the nature of the resulting metallodrug-protein interactions could be characterised in depth in the various cases. Preferential binding to protein targets compared to DNA is supported by independent ICP-OES measurements. The implications of these findings are discussed.
Assuntos
Antineoplásicos/química , Quelantes/química , Citocromos c/química , Compostos Organoplatínicos/química , Ubiquitina/química , Antineoplásicos/síntese química , Sítios de Ligação , Quelantes/síntese química , Humanos , Hidroxibutiratos/química , Ligantes , Estrutura Molecular , Compostos Organoplatínicos/síntese química , Pentanonas/química , Ligação Proteica , Soluções , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Gold compounds form a new class of promising metal-based drugs with a number of potential therapeutic applications, particularly in the fields of anticancer and antimicrobial treatments. Previous research revealed that a group of structurally diverse gold compounds cause conspicuous inhibition of the protease activities of the human proteasome. Given the pharmacological importance of protease inhibition, the present study further explored whether these gold compounds might inhibit a few other proteases that are accepted druggable targets for disease treatment. In particular, four distinct cysteine proteases were considered here: cathepsin B and L that play a primary role in tumor-cell invasion and metastasis; rhodesain, the major cathepsin L-like cysteine protease of Trypanosoma brucei rhodesiense and CPB2.8ΔCTE, a Leishmania mexicana mature cysteine protease. Based on the encouraging results obtained for some of the tested gold compounds on the two parasitic cysteine proteases, especially against CPB2.8ΔCTE, with IC50s in the micromolar range, we next evaluated whether those gold compounds might contrast effectively the growth of the respective protozoa and indeed important antiprotozoal properties were disclosed; on the other hand a certain lack of selectivity was highlighted. Also, no direct or clear correlation could be established between the in vitro antiprotozoal properties and the level of protease inhibition. The implications of these results are discussed in relation to possible pharmaceutical applications.
Assuntos
Antiprotozoários/farmacologia , Cisteína Endopeptidases/química , Inibidores de Cisteína Proteinase/farmacologia , Compostos Organoáuricos/farmacologia , Proteínas de Protozoários/antagonistas & inibidores , Animais , Antiprotozoários/síntese química , Catepsina B/antagonistas & inibidores , Catepsina B/química , Catepsina L/antagonistas & inibidores , Catepsina L/química , Linhagem Celular , Inibidores de Cisteína Proteinase/síntese química , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Humanos , Concentração Inibidora 50 , Leishmania infantum/efeitos dos fármacos , Leishmania infantum/enzimologia , Leishmania infantum/crescimento & desenvolvimento , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/enzimologia , Camundongos , Compostos Organoáuricos/síntese química , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/enzimologia , Plasmodium falciparum/crescimento & desenvolvimento , Complexo de Endopeptidases do Proteassoma/química , Proteínas de Protozoários/química , Proteínas Recombinantes/química , Trypanosoma brucei brucei/efeitos dos fármacos , Trypanosoma brucei brucei/enzimologia , Trypanosoma brucei brucei/crescimento & desenvolvimento , Trypanosoma brucei rhodesiense/efeitos dos fármacos , Trypanosoma brucei rhodesiense/enzimologia , Trypanosoma brucei rhodesiense/crescimento & desenvolvimento , Trypanosoma cruzi/efeitos dos fármacos , Trypanosoma cruzi/enzimologia , Trypanosoma cruzi/crescimento & desenvolvimentoRESUMO
The X-ray structure of the adduct formed in the reaction between the gold N-heterocyclic carbene compound Au(NHC)Cl (with NHC = 1-butyl-3-methyl-imidazole-2-ylidene) and the model protein thaumatin is reported here. The structure reveals binding of Au(NHC)(+) fragments to distinct protein sites. Notably, binding of the gold compound occurs at lysine side chains and at the N-terminal tail; the metal binds the protein after releasing Cl(-) ligand, but retaining NHC fragment.
Assuntos
Ouro/química , Metano/análogos & derivados , Compostos Organometálicos/química , Proteínas de Plantas/química , Cristalografia por Raios X , Metano/química , Modelos Moleculares , Conformação ProteicaRESUMO
In the last few years gold(III) complexes have attracted growing attention in the medicinal chemistry community as candidate anticancer agents. In particular some organogold(III) compounds manifested quite attractive pharmacological behaviors in preclinical studies. Here we compare the chemical and biological properties of the novel organogold(III) complex [Au(bipy(dmb)-H)(NH(CO)CH3)][PF6] (Aubipy(aa)) with those of its parent compounds [Au(bipy(dmb)-H)(OH)][PF6] (Aubipy(c)) and [Au2(bipy(dmb)-H)2)(µ-O)][PF6]2 (Au2bipy(c)), previously synthesized and characterized. The three study compounds were comparatively assessed for their antiproliferative actions against HCT-116 cancer cells, revealing moderate cytotoxic effects. Proapoptotic and cell cycle effects were also monitored. Afterward, to gain additional mechanistic insight, the three gold compounds were challenged against the model proteins HEWL, RNase A and cytochrome c and reactions investigated through UV-Vis and ESI-MS analysis. A peculiar and roughly invariant protein metalation profile emerges in the three cases consisting of protein binding of {Au(bipy(dmb)-H)} moieties. The implications of these results are discussed in the frame of current knowledge on anticancer gold compounds.
Assuntos
Antineoplásicos/farmacologia , Compostos Organoáuricos/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Células HCT116 , Humanos , Modelos Moleculares , Estrutura Molecular , Compostos Organoáuricos/síntese química , Compostos Organoáuricos/química , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
The dibromido analogue of cisplatin, cis-PtBr2(NH3)2 (cisPtBr2 hereafter), has been prepared and characterised. Its solution behaviour in standard phosphate buffer, at pH 7.4, was investigated spectrophotometrically and found to reproduce quite closely that of cisplatin; indeed, progressive sequential release of the two halide ligands typically occurs as in the case of cisplatin, with a roughly similar kinetics. Afterward, patterns of reactivity toward model proteins and standard ctDNA were explored and the nature of the resulting interactions elucidated. The antiproliferative properties were then evaluated in four representative cancer cell lines, namely A549 (human lung cancer), HCT116 (human colon cancer), IGROV-1 (human ovarian cancer) and FLG 29.1 (human acute myeloid leukaemia). Cytotoxic properties in line with those of cisplatin were highlighted. From these studies an overall chemical and biological profile emerges for cisPtBr2 closely matching that of cisplatin; the few slight, but meaningful differences that were underscored might be advantageously exploited for clinical application.
Assuntos
Antineoplásicos/farmacologia , Brometos/farmacologia , Cisplatino/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Brometos/química , Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Proteínas Filagrinas , Células HCT116 , Humanos , Ligantes , Estrutura Molecular , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
The so called "copper trafficking system" in mammalian cells is primarily devoted to the regulation of copper transport and homeostasis. This system, now well characterized, consists of a few strictly interconnected proteins that assist copper entrance inside cells and then promote metal transfer and delivery to essential copper-dependent cellular proteins (Boal and Rosenzweig 2009a; Banci et al., Mol Life Sci 67:2563-2589, 2010). Yet, the "copper trafficking system" may also facilitate the entrance inside cells of non-physiological metal species such as clinically established platinum drugs. ESI and MALDI MS methods are exploited here to characterize the interactions occurring between the experimental anticancer organogold(III) drug, Aubipyc, and the copper chaperone Atox1, a key protein of the copper trafficking system. The nature of the adducts that are formed when reacting Aubipyc with Atox1 is elucidated in detail. Characterization of the Aubipyc/Atox1 system is further supported by circular dichroism experiments. Binding competitions with mercury and bismuth ions were also explored. The relevance and the biological implications of the present results are discussed.
Assuntos
2,2'-Dipiridil/análogos & derivados , Antineoplásicos/química , Metalochaperonas/química , Compostos Organoáuricos/química , 2,2'-Dipiridil/química , Transporte Biológico , Bismuto/química , Dicroísmo Circular , Cobre/química , Proteínas de Transporte de Cobre , Humanos , Cinética , Mercúrio/química , Chaperonas Moleculares , Ligação Proteica , Soluções , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , TermodinâmicaRESUMO
Two novel gold carbene compounds, namely, chlorido (1-butyl-3-methyl-imidazole-2-ylidene) gold(I) (1) and bis(1-butyl-3-methyl-imidazole-2-ylidene) gold(I) (2), were prepared and characterized as prospective anticancer drug candidates. These compounds consist of a gold(I) center linearly coordinated either to one N-heterocyclic carbene (NHC) and one chloride ligand (1) or to two identical NHC ligands (2). Crystal structures were solved for both compounds, the resulting structural data being in good agreement with expectations. We wondered whether the presence of two tight carbene ligands in 2 might lead to biological properties distinct from those of the monocarbene complex 1. Notably, in spite of their appreciable structural differences, these two compounds manifested similarly potent cytotoxic actions in vitro when challenged against A2780 human ovarian carcinoma cells. In addition, both were able to overcome resistance to cisplatin in the A2780R line. Solution studies revealed that these gold carbene complexes are highly stable in aqueous buffers at physiological pH. Their reactivity with proteins was explored: no adduct formation was detected even upon a long incubation with the model proteins cytochrome c and lysozyme; in contrast, both compounds were able to metalate, to a large extent, the copper chaperone Atox-1, bearing a characteristic CXXC motif. The precise nature of the resulting gold-Atox-1 adducts was elucidated through ESI-MS analysis. On the basis of these findings, it is proposed that the investigated gold(I) carbene compounds are promising antiproliferative agents warranting a wider pharmacological evaluation. Most likely these gold compounds produce their potent biological effects through selective metalation and impairment of a few crucial cellular proteins.
Assuntos
Antineoplásicos/química , Complexos de Coordenação/química , Ouro/química , Metano/análogos & derivados , Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Feminino , Humanos , Metano/química , Estrutura Molecular , Neoplasias Ovarianas/tratamento farmacológicoRESUMO
Three gold(I) linear compounds, sharing the general formula [AuI(LPh3)], have been synthesized and characterized. The nature of the ligand has been modified by moving down among some of the elements of group 15, i.e. phosphorus, arsenic and antimony. The structures of derived compounds have been solved through XRD and the reactivity behaviour towards selected biomolecules has been investigated through a multi-technique approach involving NMR, high-resolution mass spectrometry and IR. Moreover, the biological activity of the investigated compounds has been comparatively analyzed through classical methodologies and the disclosed differences are discussed in detail.
Assuntos
Antineoplásicos , Auranofina , Auranofina/química , Antimônio/farmacologia , Ligantes , Antineoplásicos/farmacologia , Antineoplásicos/químicaRESUMO
The reactivity of cis-diamminediiodidoplatinum(II), cis-PtI2(NH3)2, the iodo analogue of cisplatin, with hen egg white lysozyme (HEWL) was investigated by electrospray ionization mass spectrometry and X-ray crystallography. Interestingly, the study compound forms a stable 1:1 protein adduct for which the crystal structure was solved at 1.99 Å resolution. In this adduct, the Pt(II) center, upon release of one ammonia ligand, selectively coordinates to the imidazole of His15. Both iodide ligands remain bound to platinum, with this being a highly peculiar and unexpected feature. Notably, two equivalent modes of Pt(II) binding are possible that differ only in the location of I atoms with respect to ND1 of His15. The structure of the adduct was compared with that of HEWL-cisplatin, previously described; differences are stressed and their important mechanistic implications discussed.
Assuntos
Cisplatino/química , Modelos Moleculares , Muramidase/química , Platina , Cisplatino/análogos & derivados , Cisplatino/metabolismo , Cristalografia por Raios X , Muramidase/metabolismo , Platina/química , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Protein metalation processes are crucial for the mechanism of action of several anticancer metallodrugs and warrant deeper characterisation. We have explored the reactions of three cytotoxic gold(III) compounds-namely [(bipy(2Me))(2)Au(2)(µ-O)(2)][PF(6)](2) (where bipy(2Me) is 6,6'-dimethyl-2,2'-bipyridine) (Auoxo6), [(phen(2Me))(2)Au(2)(µ-O)(2)][PF(6)](2) (where phen(2Me) is 2,9-dimethyl-1,10-phenanthroline) (Au(2)phen) and [(bipy(dmb)-H)Au(OH)][PF(6)] [where bipy(dmb)-H is deprotonated 6-(1,1-dimethylbenzyl)-2,2'-bipyridine] (Aubipyc)-with two representative model proteins, i.e. horse heart cytochrome c and hen egg white lysozyme, through UV-visible absorption spectroscopy and electrospray ionisation mass spectrometry (ESI MS) to characterise the inherent protein metalation processes. Notably, Auoxo6 and Au(2)phen produced stable protein adducts where one or more "naked" gold(I) ions are protein-coordinated; very characteristic is the case of cytochrome c, which upon reaction with Auoxo6 or Au(2)phen preferentially forms "tetragold" adducts with four protein-bound gold(I) ions. In turn, Aubipyc afforded monometalated protein adducts where the structural core of the gold(III) centre and its +3 oxidation state are conserved. Auranofin yielded protein derivatives containing the intact auranofin molecule. Additional studies were performed to assess the role played by a reducing environment in protein metalation. Overall, the approach adopted provides detailed insight into the formation of metallodrug-protein derivatives and permits trends, peculiarities and mechanistic details of the underlying processes to be highlighted. In this respect, electrospray ionisation mass spectrometry is a very straightforward and informative research tool. The protein metalation processes investigated critically depend on the nature of both the metal compound and the interacting protein and also on the solution conditions used; thus, predicting with accuracy the nature and the amounts of the adducts formed for a given metallodrug-protein pair is currently extremely difficult.
Assuntos
Antineoplásicos/farmacologia , Citocromos c , Compostos de Ouro/farmacologia , Muramidase , Animais , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Galinhas , Citocromos c/química , Compostos de Ouro/química , Compostos de Ouro/uso terapêutico , Cavalos , Muramidase/química , Ligação Proteica/efeitos dos fármacos , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
A variety of gold(III) and gold(I) derivatives of 2-(2'-pyridyl)benzimidazole (pbiH) were synthesized and fully characterized and their antiproliferative properties evaluated in a representative ovarian cancer cell line. The complexes include the mononuclear species [(pbi)AuX(2)] (X = Cl, 1; OAc, 2), [(pbiH)AuCl] (3), [(pbiH)Au(PPh(3))][PF(6)] (4-PF(6)), and [(pbi)Au(L)] (L = PPh(3), 5; TPA, 6), and the binuclear gold(I)/gold(I) and gold(I)/gold(III) derivatives [(PPh(3))(2)Au(2)(µ(2)-pbi)][PF(6)] (10-PF(6)), [ClAu(µ(3)-pbi)AuCl(2)] (7),and [(PPh(3))Au(µ(3)-pbi)AuX(2)][PF(6)] (X = Cl, 8-PF(6); OAc, 9-PF(6)). The molecular structures of 6, 7, and 10-PF(6) were determined by X-ray diffraction analysis. The chemical behavior of these compounds in solution was analyzed both by cyclic voltammetry in DMF and absorption UV-vis spectroscopy in an aqueous buffer. Overall, the stability of these gold compounds was found to be acceptable for the cellular studies. For all complexes, relevant antiproliferative activities in vitro were documented against A2780 human ovarian carcinoma cells, either resistant or sensitive to cisplatin, with IC(50) values falling in the low micromolar or even in the nanomolar range. The investigated gold compounds were found to overcome resistance to cisplatin to a large degree. Results are interpreted and discussed in the frame of current knowledge on cytotoxic and antitumor gold compounds.
Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Benzimidazóis/química , Benzimidazóis/farmacologia , Compostos Organoáuricos/química , Compostos Organoáuricos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cristalografia por Raios X , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Modelos Moleculares , Neoplasias Ovarianas/tratamento farmacológico , Ovário/efeitos dos fármacosRESUMO
Six diiodido-diamine platinum(II) complexes, either cis or trans configured, were prepared, differing only in the nature of the amine ligand (isopropylamine, dimethylamine, or methylamine), and their antiproliferative properties were evaluated against a panel of human tumor cell lines. Both series of complexes manifested pronounced cytotoxic effects, with the trans isomers being, generally, more effective than their cis counterparts. Cell cycle analysis revealed different modes of action for these new Pt(II) complexes with respect to cisplatin. The reactivity of these platinum compounds with a number of biomolecules, including cytochrome c, two sulfur containing modified amino acids, 9-ethylguanine, and a single strand oligonucleotide, was analyzed in depth by mass spectrometry and NMR spectroscopy. Interestingly, significant differences in the reactivity of the investigated compounds toward the various model biomolecules were observed: in particular we observed that trans complexes preferentially release their iodide ligands upon biomolecule binding, while the cis isomers may release the amine ligands with retention of iodides. Such differences in reactivity may have important mechanistic implications and a relevant impact on the respective pharmacological profiles.
Assuntos
Antineoplásicos/química , Platina/química , Antineoplásicos/farmacologia , Proliferação de Células/efeitos dos fármacos , Citometria de Fluxo , Isomerismo , Espectroscopia de Ressonância Magnética , Platina/farmacologia , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
A novel gold(I) complex inspired by the known medicinal inorganic compounds auranofin and thimerosal, namely ethylthiosalicylate(triethylphosphine)gold(I) (AFETT hereafter), was synthesized and characterised and its structure was resolved through X-ray diffraction. The solution behavior of AFETT and its interactions with two biologically relevant proteins (i.e. human serum albumin and haemoglobin) and with a synthetic dodecapeptide reproducing the C-terminal portion of thioredoxin reductase were comparatively analyzed through 31P NMR and ESI-MS. Remarkable binding properties toward these biomolecules were disclosed. Moreover, the cytotoxic effects produced by AFETT on two ovarian cancer cell lines (A2780 and A2780 R) and one colorectal cancer cell line (HCT116) were analyzed and found to be strong and nearly superimposable to those of auranofin. Interestingly, for both compounds, the ability to induce downregulation of vimentin expression in A2780 R cells was evidenced. Despite its close similarity to auranofin, AFETT is reported to exhibit some peculiar and distinctive features such as a lower lipophilicity, an increased water solubility and a faster reactivity towards the selected target biomolecules. These differences might confer to AFETT significant pharmaceutical and therapeutic advantages over auranofin itself.