Organometallic chemistry, biology and medicine: ruthenium arene anticancer complexes

106Ru radiolabelling of the antitumour complex [(eta6-fluorene)Ru(en)Cl]PF6

The organometallic half-sandwich Ru(II) arene anticancer complex [(eta(6)-fluorene)Ru(en)Cl]PF(6) () has been synthesized in high yield and purity on a micromole scale with incorporation of the beta-emitting radioisotope (106)Ru (half-life = 1.01 y) using a refined procedure involving conversion of RuCl(3) into [(eta(6)-fluorene)RuCl(2)](2), and then [(eta(6)-fluorene)Ru(CH(3)CN)(2)Cl]PF(6) as intermediates. Distribution studies 0.25 h post i.v. injection of (106)Ru- at a dose of 25 mg kg(-1) show that (106)Ru is well distributed throughout the tissues of a rat. This appears to be the first report of the radiolabelling of a potential ruthenium antitumour agent for distribution/biological studies.

CE in anticancer metallodrug research – an update

With the current demographic development and the knowledge that the probability to be diagnosed with cancer increases with age, the search for new treatment options in cancer chemotherapy is of utmost importance for the society. Capillary electrophoretic methods have been applied in the last few years for studying the properties of metal-based drugs and drug candidates. Especially, the elucidation of the mode of action of such compounds could contribute significantly to design new drugs for overcoming the threat of cancer. This review article highlights the developments in metallodrug research applying CE during the last 4 years and follows a review from 2003 (Hartinger, C. G., Timerbaev, A. R., Keppler, B. K., Electrophoresis 2003, 24, 2023-2037). Most importantly the broadening of application areas of CE must be noted: especially the binding studies of metal complexes toward proteins (including the determination of association and rate constants), following redox reactions of metal complexes and their influence on the reactivity toward biotargets, etc. are important development areas of the last few years. In parallel with these new applications goes the usage of new or modified separation methods including microemulsion EKC or ACE, or the advantageous use of equipping the CE system with mass spectrometric detectors such as inductively coupled plasma (ICP) or ESI mass spectrometers (MS) for determining the degree of metallation of a protein or characterizing the adducts. Finally, upcoming requirements for expanding the method's application area are discussed including studies on new targets in the cell, analyzing real-world samples, methodological development, and contributions to improve the design of new anticancer agents.

Some uses of transition metal complexes as anti-cancer and anti-HIV agents

The success of the clinical uses of cisplatin, cis-[Pt(II)(NH(3))(2)Cl(2)], has stimulated considerable interest in using other metal complexes as new therapeutic agents. This perspective describes our recent work on several classes of gold(III), platinum(II), ruthenium(II, III, IV), iron(II) and vanadium(IV) complexes for anti-cancer and anti-HIV treatments.

Mixed-Ligand Copper(II)-phenolate Complexes: Effect of Coligand on Enhanced DNA and Protein Binding, DNA Cleavage, and Anticancer Activity

The copper(II) complex [Cu(tdp)(ClO4)].0.5H2O (1), where H(tdp) is the tetradentate ligand 2-[(2-(2-hydroxyethylamino)ethylimino)methyl]phenol, and the mixed ligand complexes [Cu(tdp)(diimine)]+ (2-5), where diimine is 2,2'-bipyridine (bpy) (2), 1,10-phenanthroline (phen) (3), 3,4,7,8-tetramethyl-1,10-phenanthroline (tmp) (4), and dipyrido-[3,2-d:2',3'-f]-quinoxaline (dpq) (5), have been isolated and characterized by analytical and spectral methods. Complexes 1 and [Cu(tdp)(phen)]ClO4 (3) have been structurally characterized, and their coordination geometries around copper(II) are described as distorted octahedral. The equatorially coordinated ethanolic oxygen in 1 is displaced to an axial position upon incorporating the strongly chelating phen, as in 3. The solution structures of all the complexes have been assessed to be square-based using electronic absorption and electron paramagnetic resonance (EPR) spectroscopy. The interaction of the complexes with calf thymus DNA (CT DNA) has been explored by using absorption, emission, and circular dichroic spectral and viscometric studies, and modes of DNA binding for the complexes have been proposed. Absorption spectral (Kb = 0.071 +/- 0.005 (2), 0.90 +/- 0.03 (3), 7.0 +/- 0.2 (4), 9.0 +/- 0.1 x 10(5) M(-1) (5)), emission spectral (Kapp = 4.6 (1), 7.8 (2), 10.0 (3), 12.5 (4), 25.0 x 10(5) M(-1) (5)), and viscosity measurements reveal that 5 interacts with DNA more strongly than the other complexes through partial intercalation of the extended planar ring of the coordinated dpq with the DNA base stack. Interestingly, only complex 4 causes a B to A conformational change upon binding DNA. All the complexes hydrolytically cleave pBR322 supercoiled DNA in 10% DMF/5 mM Tris-HCl/50 mM NaCl buffer at pH 7.1 in the absence of an activating agent, and the cleavage efficiency varies in the order 5 > 3 > 2 > 4 > 1 with 5 displaying the highest Kcat value (5.47 +/- 0.10 h(-1)). The same order of cleavage is observed for the oxidative cleavage of DNA in the presence of ascorbic acid as a reducing agent. Interestingly, of all the complexes, only 5 displays efficient photonuclease activity through double-strand DNA breaks upon irradiation with 365 nm light through a mechanistic pathway involving hydroxyl radicals. The protein binding ability of 1-5 has been also monitored by using the plasma protein bovine serum albumin (BSA), and 4 exhibits a protein binding higher than that of the other complexes. Further, the anticancer activity of the complexes on human cervical epidermoid carcinoma cell line (ME180) has been examined. Interestingly, the observed IC50 values reveal that complex 4, which effects conformational change on DNA and binds to BSA more strongly, exhibits a cytotoxicity higher than the other complexes. It also exhibits approximately 100 and 6 times more potency than cisplatin and mitomycin C for 24 and 48 h incubation times, respectively, suggesting that 4 can be explored further as a potential anticancer drug. Complexes 4 and 5 mediate the arrest of S and G2/M phases in the cell cycle progression at 24 h harvesting time, which progress into apoptosis.

Guanine binding to dirhodium tetracarboxylate anticancer complexes: quantum chemical calculations unravel an elusive mechanism

The reaction mechanism leading to metalated DNA fragments in which guanine-N7,O6 spans the metal-metal bond of dirhodium antitumour complexes in a bridging fashion at equatorial sites has been unravelled by a comprehensive prediction of intermediates and transition states.

Crystal structure based design of functional metal/protein hybrids

Preparation of metal/protein hybrids is growing into important topics in the field of bioinorganic chemistry. X-ray crystal structure analyses of them provide direct information on unique interactions of metal cations or metal cofactors to understand and design enzymatic functions. In this mini review, the authors focus on the recent studies on the metal/protein hybrids concerning crystal structure analyses since 2002 and our related works. The precise structural determination promise us to deeply understand coordination chemistry in protein scaffold and shows intriguing suggestions on rational design and application use for biocatalysts, metal drugs and so on.

Identification of (η6-arene)ruthenium(II) protein binding sites in E. coli cells by combined multidimensional liquid chromatography and ESI tandem mass spectrometry: specific binding of [(η6-p-cymene)RuCl2(DMSO)] to stress-regulated proteins and to helicases

An automated multidimensional protein identification technology, which combines biphasic liquid chromatography with electrospray ionisation tandem mass spectrometry (MS/MS), was employed to analyse tryptic peptides from Escherichia coli cells treated with the antiproliferation agent [(eta(6)-p-cymene)RuCl(2)(DMSO)], where DMSO is dimethyl sulfoxide. MS/MS spectra were recorded for molecular ions generated by neutral loss of p-cymene from intensive peptide ions coordinated by the (eta(6)-p-cymene)Ru(II) fragment. Matching of the MS/MS spectra of the ruthenated peptides to spectra of proteins in the E. coli database enabled the identification of five protein targets for [(eta(6)-p-cymene)RuCl(2)(DMSO)]. One of these is the constitutive cold-shock protein cspC, which regulates the expression of genes encoding stress-response proteins, and three of the other targets, ppiD, osmY and sucC, are proteins of the latter type. The DNA damage-inducible helicase dinG was likewise established as a protein target. Aspartate carboxylate functions were identified as the probable Ru binding sites in cspC, ppiD and dinG, and threonine and lysine side chains in osmY and sucC, respectively.

Bifunctional binding of cisplatin to DNA: why does cisplatin form 1,2-intrastrand cross-links with ag but not with GA?

The bifunctional binding of the anticancer drug cisplatin to two adjacent nucleobases in DNA is modeled using density functional theory. Previous experimental studies revealed that cisplatin binding to adjacent guanine and adenine is sensitive to nucleobase sequence. Whereas AG 1,2-intrastrand cross-links are commonly observed, the analogous GA adducts are not known. This study focuses on understanding this directional preference by constructing a full reaction profile using quantum chemical simulation methods. Monofunctional and bifunctional cisplatin adducts were generated, and the transition states that connect them were located for the dinucleotides d(pApG) and d(pGpA), assuming that initial platination takes place at the guanine site. Our computer simulations reveal a significant kinetic preference for formation of the AG over the GA adduct. The activation free energies of approximately 23 kcal/mol for AG and approximately 32 kcal/mol for GA suggest that bifunctional closure is approximately 6 orders of magnitude faster for AG than for GA. A strong hydrogen bond between one of the ammine ligands of cisplatin and the 5' phosphate group of the DNA backbone is responsible for the stabilization of the transition state that affords the AG adduct. This interaction is absent in the transition state that leads to the GA adduct because the right-handed helix of the DNA backbone places the phosphate out of reach for the ammine ligand. We found only an insignificant thermodynamic difference between AG and GA adducts and conclude that the preference of AG over GA binding is largely under kinetic control. The puckering of the deoxyribose ring plays an important role in determining the energetics of the bifunctional platination products. Whereas the 3'-nucleoside remains in the native C2'-endo/C3'-exo form of B-DNA, the deoxyribose of the 5'-nucleoside always adopts the C2'-exo/C3'-endo puckering in our simulations. A detailed analysis of the energies and structures of the bifunctional adducts revealed that the observed sugar puckering patterns are necessary for platinum to bind in a relaxed coordination geometry.

Ruthenium half-sandwich complexes as protein kinase inhibitors: derivatization of the pyridocarbazole pharmacophore ligand

A general route to ruthenium pyridocarbazole half-sandwich complexes is presented and applied to the synthesis of sixteen new compounds, many of which have modulated protein kinase inhibition properties. For example, the incorporation of a fluorine into the pyridine moiety increases the binding affinity for glycogen synthase kinase 3 by almost one order of magnitude. These data are supplemented with cyclic voltammetry experiments and a protein co-crystallographic study.

DNA binding and cytotoxicity of ruthenium(II) and rhenium(I) complexes of 2-amino-4-phenylamino-6-(2-pyridyl)-1,3,5-triazine

[Ru(tBu2bpy)2(2-appt)](PF6)2 [1.(PF6)2, tBu2bpy = 4,4'-di-tert-butyl-2,2'-bipyridine, 2-appt = 2-amino-4-phenylamino-6-(2-pyridyl)-1,3,5-triazine] and [Re(CO)3(2-appt)Cl] (2) were prepared and characterized by X-ray crystal analysis. The binding of 1.(PF6)2 and 2 to calf thymus DNA (ct DNA) led to increases in the DNA melting temperature (Delta Tm = +12 degrees C), modest hypochromism (29% and 5% of the absorption bands at lambda max = 450 and 376 nm, respectively), and insignificant shifts in the absorption maxima. The binding constants of 1.(PF6)2 and 2 with ct DNA, as determined by absorption titration, are (8.9 +/- 0.5) x 104 and (3.6 +/- 0.1) x 104 dm3 mol-1, respectively. UV-vis absorption titration, DNA melting studies, and competition dialysis using synthetic oligonucleotides [poly(dA-dT)2 and poly(dG-dC)2] revealed that 1.(PF6)2 and 2 exhibit a binding preference for AT sequences. A modeling study on the interaction between 1 or 2 and B-DNA revealed that the minor groove is the most favored binding site and an extensive hydrogen-bonding network is formed. As determined by MTT assays, 1.(PF6)2 and 2 exhibited moderate cytotoxicities toward several human cancer cell lines (KB-3-1, HepG2, and HeLa), as well as a multi-drug-resistant cancer cell line (KB-V-1). According to confocal microscopic and flow cytometric studies, 1.(PF6)2 and 2 induced apoptosis (50-60%) in cancer cells with <5% necrosis detected.

Osmium(II) and Ruthenium(II) Arene Maltolato Complexes: Rapid Hydrolysis and Nucleobase Binding

Density functional calculations show that aquation of [Os(eta6-arene)(XY)Cl]n+ complexes is more facile for complexes in which XY=an anionic O,O-chelated ligand compared to a neutral N,N-chelated ligand, and the mechanism more dissociative in character. The O,O-chelated XY=maltolato (mal) [M(eta6-p-cym)(mal)Cl] complexes, in which p-cym=p-cymene, M=OsII (1) and RuII (2), were synthesised and the X-ray crystal structures of 1 and 22 H2O determined. Their hydrolysis rates were rapid (too fast to follow by NMR spectroscopy). The aqua adduct of the OsII complex 1 was 1.6 pKa units more acidic than that of the RuII complex 2. Dynamic NMR studies suggested that O,O-chelate ring opening occurs on a millisecond timescale in coordinating proton-donor solvents, and loss of chelated mal in aqueous solution led to the formation of the hydroxo-bridged dimers [(eta6-p-cym)M(mu-OH)3M(eta6-p-cym)]+. The proportion of this dimer in solutions of the OsII complex 1 increased with dilution and it predominated at micromolar concentrations, even in the presence of 0.1 M NaCl (conditions close to those used for cytotoxicity testing). Although 9-ethylguanine (9-EtG) binds rapidly to Os(II) in 1 and more strongly (log K=4.4) than to RuII in 2 (log K=3.9), the OsII adduct [Os(eta6-p-cym)(mal)(9EtG)]+ was unstable with respect to formation of the hydroxo-bridged dimer at micromolar concentrations. Such insights into the aqueous solution chemistry of metal-arene complexes under biologically relevant conditions will aid the rational design of organometallic anticancer agents.

Ruthenation of duplex and single-stranded d(CGGCCG) by organometallic anticancer complexes

We have studied the interaction of the organometallic anticancer ruthenium(II) complexes [(eta(6)-p-cymene)Ru(en)Cl][PF(6)] (1) and [(eta(6)-biphenyl)Ru(en)Cl][PF(6)] (2) (en=ethylenediamine) with the single-stranded (ss) DNA hexamer d(CGGCCG) (I) and the duplex d(CGGCCG)(2) (II) by HPLC, ESI-MS, and one- and two-dimensional (1)H and (15)N NMR spectroscopy. For ss-DNA, all three G's are readily ruthenated with [(eta(6)-arene)Ru(en)](2+), but for duplex DNA there is preferential ruthenation of G3 and G6, and no binding to G2 was detected. For monoruthenated duplexes, N7 ruthenation of G is accompanied by strong hydrogen bonding between G-O6 and en-NH for the p-cymene adducts. Intercalation of the non-coordinated phenyl ring between G3 and C4 or G6 and C5 was detected in the biphenyl adducts of mono- and diruthenated duplexes, together with weakening of the G-O6NH-en hydrogen bonding. The arene ligand plays a major role in distorting the duplex either through steric interactions (p-cymene) or through intercalation (biphenyl).

Half-sandwich RuII-[9]aneS3 complexes with dicarboxylate ligands: synthesis, characterization and chemical behavior

With the aim of further developing the structure-activity relationship in biologically active half-sandwich Ru(ii)-[9]aneS(3) complexes ([9]aneS(3)=1,4,7-trithiacyclononane), a series of new mono- and dinuclear complexes bearing the chelating dicarboxylate ligands oxalate (ox), malonate (mal) and methylmalonate (mmal), have been synthesized and studied. Treatment of the precursor [Ru([9]aneS(3))(dmso)(3)][CF(3)SO(3)](2) (7) with equivalent amounts of K(2)(dicarb) afforded the corresponding neutral complexes with the general formula [Ru([9]aneS(3))(dmso-S)(eta(2)-dicarb)] (where dicarb=ox (1), mal (2) and mmal (3)), while using half an equivalent of K(2)(ox), the symmetric dimer [{Ru([9]aneS(3))(dmso-S)}(2)(mu-eta(4)-ox)][CF(3)SO(3)](2) (4) was isolated. The reaction of with the oxalato complex fac-[Ru(dmso-S)(3)(dmso-O)(eta(2)-ox)] (9) yielded two asymmetric dimers, namely [{Ru([9]aneS(3))(dmso-S)}(mu-eta(4)-ox){fac-Ru(dmso-S)(3)(CF(3)SO(3))}][CF(3)SO(3)] (5) and [{Ru([9]aneS(3))(dmso-S)}(mu-eta(4)-ox){fac-Ru(dmso-S)(3)(dmso-O)}][CF(3)SO(3)](2) (6), depending on the reaction conditions. All new complexes were structurally characterized, both in solution (by NMR spectroscopy) and in the solid state (by X-ray crystallography). The chemical behavior of the complexes in aqueous solution was studied by UV-Vis and NMR spectroscopy in view of their potential antitumor activity: the monomers partially release a dmso ligand to yield the monofunctional aqua adduct [Ru([9]aneS(3))(eta(2)-dicarb)(H(2)O)], while the dimers rapidly open up the oxalato bridge to give two mononuclear fragments. Splitting of the asymmetric dimers 5 and 6 occurs selectively and the ox moiety remains bonded to the fac-Ru(dmso-S)(3) fragment. A detailed comparison of the structural and chemical features of 1-6 with those of similar dicarboxylate complexes possessing the fac-Ru(dmso-S)(3) fragment in place of Ru([9]aneS(3)) allows us to draw a number of general conclusions on the binding preferences of dicarb ligands on the octahedral Ru(II) center.

Influence of the position of substituents in the cytotoxic activity of trans platinum complexes with hydroxymethyl pyridines

The synthesis and chemical characterization of two trans platinum complexes, (1) trans-[PtCl(2)NH(3)(2-hydroxymethylpyridine)] and (2) trans-[PtCl(2)NH(3)(3-hydroxymethylpyridine)], are described. The structures and chemical behaviour of these compounds have been compared to those of their isomer (3) trans-[PtCl(2)NH(3)(4-hydroxymethylpyridine)] previously studied. X-ray structures of all of them were solved and some interesting differences were found. The values of the dihedral angle (85 degrees , 57 degrees and 42 degrees for 1, 2 and 3, respectively) demonstrate how important is the position of substituent from a structural point of view. Studies of circular dichroism (CD), electrophoretic mobility (EM) in agarose gel and atomic force microscopy (AFM) showed differences in the modifications caused by the three complexes on DNA. Studies of antiproliferative activity of complexes 1 and 2 against cell tumour lines (HL-60) and apoptosis assays have also been carried out, showing that 1 as well as 2 are far less active than the previously described complex 3 (IC(50)=19; 19 and 3 microM, respectively). This fact probes that slight modifications on the drug's design may generate significant differences in the final antitumour activity by modifying the DNA-drug adducts, performance of resistance mechanisms and all the factors that play a fundamental role in Pt complexes' cytotoxicity.

Antitumour bis(cyclopentadienyl) metal complexes: titanocene and molybdocene dichloride and derivatives

This Perspective will focus on recent developments in the field of antitumour metallocenes structurally related to titanocene dichloride. Despite extensive testing of titanocene dichloride which culminated in phase I and II clinical trials, further trials have been abandoned. While DNA has been implicated as the major target related to anticancer activity, identification of the active species and mechanism of action has been poorly understood and hence the design of second generation titanocene derivatives has not been possible. Recent mechanistic studies have provided a plausible mechanism for delivery of Ti to cancer cells via transferrin mediated endocytosis. This mechanism requires the presence of labile Cp-Ti bonds that hydrolyse on a time scale to deliver Ti to transferrin. A large range of titanocene derivatives in which the cyclopentadienyl rings have been substituted by both electron withdrawing and donating groups, including aromatic, alkyl and cyclic amines, have been prepared and tested for activity in the last 5 years. These results have shown that subtle structural effects can have a significant effect on biological activity and that biological activity is highly cell line dependent. However, the biological chemistry and cellular studies required to determine the mechanism of action of these new titanocenes have not been reported. In contrast, the bioorganometallic chemistry and cellular studies of molybdocene dichloride have implicated interaction with cellular thiols as the key reaction related to biological activity. Tailoring of the pseudohalide ligands by tuning the strength of the Mo-S bonds provides the opportunity to enhance cell uptake. Further research is required to establish the origin of antitumour activity.

Synthesis and cyclometalation of a pyrido[3,2-e]-2,10b-diaza-cyclopenta[c]fluorene-1,3-dione scaffold

The synthesis of a pyrido[3,2-e]-2,10b-diaza-cyclopenta[c]fluorene-1,3-dione scaffold is disclosed, which was synthesized using a Suzuki cross-coupling reaction and an intramolecular Heck cyclization as the key steps. This heterocyclic system can serve as a bidentate ligand as demonstrated by the formation and structural analysis of a derived ruthenium complex. The new scaffold constitutes an interesting candidate for the development of organometallic protein kinase inhibitors.

Influence of the stereochemistry of sugars on the selectivity of formation of carbohydrate-derived cyclopentadienyl and indenyl ligands

Interaction of lithium cyclopentadienide with a suitable partially protected alpha-D-allofuranose triflate, 4, epimer at C3 of glucose, gives as a major product, besides the expected glucose-cyclopentadiene, 5, a glucose-disubstituted cyclopentadiene, 6. This unprecedented behaviour, which does not occur with alpha-D-glucofuranose and other sugars, is tentatively explained by a complexation of LiCp and the oxygen atoms of the isopropylidene function of one molecule of 4 and one of 5, giving a termolecular structure as the result of a template effect. The results of other experiments, such as the use of MgCp2 in place of LiCp or the complexation of oxygen atoms by lithium triflate, which changed the selectivity of the reaction largely in favour of the monosubstitution product 5, support this hypothesis. When lithium indenide is reacted with 4, glucose-monosubstituted and glucose-disubstituted indenes, 8 and 9, respectively, are formed, and 9 is obtained with almost total diastereoselectivity. This result can also be rationalised by a stereoselective complexation of lithium, as shown by separate experiments and by molecular mechanics calculations. Methyltricarbonyl molybdenum(II) complexes have been synthesised and characterised from glucose-monosubstituted 5 and glucose-disubstituted 6 cyclopentadienes.

Design of targeting ligands in medicinal inorganic chemistry

This tutorial review will highlight recent advances in medicinal inorganic chemistry pertaining to the use of multifunctional ligands for enhanced effect. Ligands that adequately bind metal ions and also include specific targeting features are gaining in popularity due to their ability to enhance the efficacy of less complicated metal-based agents. Moving beyond the traditional view of ligands modifying reactivity, stabilizing specific oxidation states, and contributing to substitution inertness, we will discuss recent work involving metal complexes with multifunctional ligands that target specific tissues, membrane receptors, or endogenous molecules, including enzymes.

Catalysis of regioselective reduction of NAD+ by ruthenium(II) arene complexes under biologically relevant conditions

Ruthenium(II) arene anticancer complexes [(eta6-arene)Ru(en)Cl]PF6 (arene is hexamethylbenzene, p-cymene, indan; en is ethylenediamine) can catalyse regioselective reduction of NAD+ by formate in water to form 1,4-NADH, at pD 7.2, 37 degrees C, and in the presence of air. The catalytic activity is markedly dependent on the arene, with the hexamethylbenzene (hmb) complex showing the highest activity. For [(eta 6-hmb)Ru(en)Cl]PF6, the rate of reaction is independent of NAD+ concentration and shows saturation kinetics with respect to formate concentration. A Km value of 58 mM and a turnover frequency at saturation of 1.46 h(-1) were observed. Removal of chloride and performing the reaction under argon led to higher reaction rates. Lung cancer cells (A549) were found to be remarkably tolerant to formate even at millimolar concentrations. The possibility of using ruthenium arene complexes coadministered with formate as catalytic drugs is discussed.

Synthesis, Characterization, and DNA Binding of New Water-Soluble Cyclopentadienyl Ruthenium(II) Complexes Incorporating Phosphines

The new water-soluble ruthenium(II) chiral complexes [RuCpX(L)(L')](n+) (X = Cl, I. L = PPh3; L' = PTA, mPTA; L = L' = PTA, mPTA) (PTA = 1,3,5-triaza-7-phosphaadamantane; mPTA = N-methyl-1,3,5-triaza-7-phosphaadamantane) have been synthesized and characterized by NMR and IR spectroscopy and elemental analysis. The salt mPTA(OSO2CF3) was also prepared and fully characterized by spectroscopic techniques. X-ray crystal structures of [RuClCp(PPh3)(PTA)] (2), [RuCpI(PPh3)(PTA)] (3), and [RuCpI(mPTA)(PPh3)](OSO2CF3) (9) have been determined. The binding properties toward DNA of the new hydrosoluble complexes have been studied using the mobility shift assay. The ruthenium chloride complexes interact with DNA depending on the hydrosoluble phosphine bonded to the metal, while the corresponding compounds with iodide, [RuCpI(PTA)2] (1), [RuCpI(PPh3)(PTA)] (3), [RuCpI(mPTA)2](OSO2CF3)2 (6), and [RuCpI(mPTA)(PPh3)](OSO2CF3) (9), do not bind to DNA.

Metal-based antitumour drugs in the post genomic era

The discovery of new metal-based antitumour drugs, whether cisplatin derivatives or those based on other metals, has been largely based on cell viability assays (IC50 values) and compounds that bind to DNA. This approach has been applied for more than 30 years during which time very few new drugs have entered clinical use. In this article we discuss what the future holds for metal-based drugs, in particular anti-metastasis drugs, in these enlightened times of the post genomic era.

In silico evolution of substrate selectivity: comparison of organometallic ruthenium complexes with the anticancer drug cisplatin

A comparative quantum chemical approach helps to clarify how the selectivity of anticancer metallopharmaceuticals towards potential biological targets can be controlled by metal and ligands.