RESUMO
A novel class of compounds designed to hit two anti-tumour targets, G-quadruplex structures and human carbonic anhydrases (hCAs) IX and XII is proposed. The induction/stabilisation of G-quadruplex structures by small molecules has emerged as an anticancer strategy, disrupting telomere maintenance and reducing oncogene expression. hCAs IX and XII are well-established anti-tumour targets, upregulated in many hypoxic tumours and contributing to metastasis. The ligands reported feature a berberine G-quadruplex stabiliser scaffold connected to a moiety inhibiting hCAs IX and XII. In vitro experiments showed that our compounds selectively stabilise G-quadruplex structures and inhibit hCAs IX and XII. The crystal structure of a telomeric G-quadruplex in complex with one of these ligands was obtained, shedding light on the ligand/target interaction mode. The most promising ligands showed significant cytotoxicity against CA IX-positive HeLa cancer cells in hypoxia, and the ability to stabilise G-quadruplexes within tumour cells.
Assuntos
Antineoplásicos , Anidrase Carbônica IX , Inibidores da Anidrase Carbônica , Anidrases Carbônicas , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Quadruplex G , Humanos , Quadruplex G/efeitos dos fármacos , Inibidores da Anidrase Carbônica/farmacologia , Inibidores da Anidrase Carbônica/química , Inibidores da Anidrase Carbônica/síntese química , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Relação Estrutura-Atividade , Estrutura Molecular , Anidrase Carbônica IX/antagonistas & inibidores , Anidrase Carbônica IX/metabolismo , Anidrases Carbônicas/metabolismo , Proliferação de Células/efeitos dos fármacos , Ligantes , Células HeLa , Antígenos de Neoplasias/metabolismo , Modelos MolecularesRESUMO
To investigate the potential of tumor-targeting photoactivated chemotherapy, a chiral ruthenium-based anticancer warhead, Λ/Δ-[Ru(Ph2phen)2(OH2)2]2+, was conjugated to the RGD-containing Ac-MRGDH-NH2 peptide by direct coordination of the M and H residues to the metal. This design afforded two diastereoisomers of a cyclic metallopeptide, Λ-[1]Cl2 and Δ-[1]Cl2. In the dark, the ruthenium-chelating peptide had a triple action. First, it prevented other biomolecules from coordinating with the metal center. Second, its hydrophilicity made [1]Cl2 amphiphilic so that it self-assembled in culture medium into nanoparticles. Third, it acted as a tumor-targeting motif by strongly binding to the integrin (Kd = 0.061 µM for the binding of Λ-[1]Cl2 to αIIbß3), which resulted in the receptor-mediated uptake of the conjugate in vitro. Phototoxicity studies in two-dimensional (2D) monolayers of A549, U87MG, and PC-3 human cancer cell lines and U87MG three-dimensional (3D) tumor spheroids showed that the two isomers of [1]Cl2 were strongly phototoxic, with photoindexes up to 17. Mechanistic studies indicated that such phototoxicity was due to a combination of photodynamic therapy (PDT) and photoactivated chemotherapy (PACT) effects, resulting from both reactive oxygen species generation and peptide photosubstitution. Finally, in vivo studies in a subcutaneous U87MG glioblastoma mice model showed that [1]Cl2 efficiently accumulated in the tumor 12 h after injection, where green light irradiation generated a stronger tumoricidal effect than a nontargeted analogue ruthenium complex [2]Cl2. Considering the absence of systemic toxicity for the treated mice, these results demonstrate the high potential of light-sensitive integrin-targeted ruthenium-based anticancer compounds for the treatment of brain cancer in vivo.
Assuntos
Antineoplásicos , Neoplasias Encefálicas , Complexos de Coordenação , Pró-Fármacos , Rutênio , Animais , Humanos , Camundongos , Rutênio/farmacologia , Rutênio/química , Pró-Fármacos/farmacologia , Pró-Fármacos/uso terapêutico , Pró-Fármacos/química , Integrinas , Peptídeos Cíclicos , Peptídeos , Neoplasias Encefálicas/tratamento farmacológico , Linhagem Celular Tumoral , Complexos de Coordenação/química , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/químicaRESUMO
We report the synthesis and the assessment of the anticancer potential of two series of diruthenium biscyclopentadienyl carbonyl complexes. Novel dimetallacyclopentenone compounds (2-4) were obtained (45-92% yields) from the thermal reaction (PhCCPh exchange) of [Ru2Cp2(CO)(µ-CO){µ-η1:η3-C(Ph)âC(Ph)C(âO)}], 1, with alkynes HCCR [R = C5H4FeCp (Fc), 3-C6H4(Asp), 2-naphthyl; Cp = η5-C5H5, Asp = OC(O)-2-C6H4C(O)Me]. Protonation of 1-3 by HBF4 afforded the corresponding µ-alkenyl derivatives 5-7, in 40-86% yields. All products were characterized by IR and NMR spectroscopy; moreover, cyclic voltammetry (1, 2, 5, 7) and single-crystal X-ray diffraction (5, 7) analyses were performed on representative compounds. Complexes 5-7 revealed a cytotoxic activity comparable to that of cisplatin in A549 (lung adenocarcinoma), SW480 (colon adenocarcinoma), and ovarian (A2780) cancer cell lines, and 2, 5, 6, and 7 overcame cisplatin resistance in A2780cis cells. Complexes 2, 5, and 7 (but not the aspirin derivative 6) induced an increase in intracellular ROS levels. Otherwise, 6 strongly stabilizes and elongates natural DNA (from calf thymus, CT-DNA), suggesting a possible intercalation binding mode, whereas 5 is less effective in binding CT-DNA, and 7 is ineffective. This trend is reversed concerning RNA, and in particular, 7 is able to bind poly(rA)poly(rU) showing selectivity for this nucleic acid. Complexes 5-7 can interact with the albumin protein with a thermodynamic signature dominated by hydrophobic interactions. Overall, we show that organometallic species based on the Ru2Cp2(CO)x scaffold (x = 2, 3) are active against cancer cells, with different incorporated fragments influencing the interactions with nucleic acids and the production of ROS.
Assuntos
Adenocarcinoma , Antineoplásicos , Neoplasias do Colo , Neoplasias Ovarianas , Humanos , Feminino , Linhagem Celular Tumoral , Cisplatino , Espécies Reativas de Oxigênio , Neoplasias Ovarianas/tratamento farmacológico , DNA , Antineoplásicos/químicaRESUMO
The interaction between the series of berberine derivatives 1-5 (NAX071, NAX120, NAX075, NAX077 and NAX079) and human telomeric G-quadruplexes (G4), which are able to inhibit the Telomerase enzyme's activity in malignant cells, was investigated. The derivatives bear a pyridine moiety connected by a hydrocarbon linker of varying length (n = 1-5, with n number of aliphatic carbon atoms) to the C13 position of the parent berberine. As for the G4s, both bimolecular 5'-TAGGGTTAGGGT-3' (Tel12) and monomolecular 5'-TAGGGTTAGGGTTAGGGTTAGGG-3' (Tel23) DNA oligonucleotides were considered. Spectrophotometric titrations, melting tests, X-ray diffraction solid state analysis and in silico molecular dynamics (MD) simulations were used to describe the different systems. The results were compared in search of structure-activity relationships. The analysis pointed out the formation of 1:1 complexes between Tel12 and all ligands, whereas both 1:1 and 2:1 ligand/G4 stoichiometries were found for the adduct formed by NAX071 (n = 1). Tel12, with tetrads free from the hindrance by the loop, showed a higher affinity. The details of the different binding geometries were discussed, highlighting the importance of H-bonds given by the berberine benzodioxole group and a correlation between the strength of binding and the hydrocarbon linker length. Theoretical (MD) and experimental (X-ray) structural studies evidence the possibility for the berberine core to interact with one or both G4 strands, depending on the constraints given by the linker length, thus affecting the G4 stabilization effect.
Assuntos
Berberina , Quadruplex G , Humanos , Análise Espectral , Telômero , EspectrofotometriaRESUMO
G-quadruplexes (G4) are now extensively recognised as a peculiar non-canonical DNA geometry that plays a prime importance role in processes of biological relevance whose number is increasing continuously. The same is true for the less-studied RNA G4 counterpart. G4s are stable structures; however, their geometrical parameters may be finely tuned not only by the presence of particular sequences of nucleotides but also by the salt content of the medium or by a small molecule that may act as a peculiar topology inducer. As far as the interest in G4s increases and our knowledge of these species deepens, researchers do not only verify the G4s binding by small molecules and the subsequent G4 stabilisation. The most innovative studies now aim to elucidate the mechanistic details of the interaction and the ability of a target species (drug) to bind only to a peculiar G4 geometry. In this focused review, we survey the advances in the studies of the binding of small molecules of medical interest to G4s, with particular attention to the ability of these species to bind differently (intercalation, lateral binding or sitting atop) to different G4 topologies (parallel, anti-parallel or hybrid structures). Some species, given the very high affinity with some peculiar G4 topology, can first bind to a less favourable geometry and then induce its conversion. This aspect is also considered.
Assuntos
Quadruplex G , DNA/química , LigantesRESUMO
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
Although ferrocene derivatives have attracted considerable attention as possible anticancer agents, the medicinal potential of diiron complexes has remained largely unexplored. Herein, we describe the straightforward multigram-scale synthesis and the antiproliferative activity of a series of diiron cyclopentadienyl complexes containing bridging vinyliminium ligands. IC50 values in the low-to-mid micromolar range were determined against cisplatin sensitive and resistant human ovarian carcinoma (A2780 and A2780cisR) cell lines. Notable selectivity towards the cancerous cells lines compared to the non-tumoral human embryonic kidney (HEK-293) cell line was observed for selected compounds. The activity seems to be multimodal, involving reactive oxygen species (ROS) generation and, in some cases, a fragmentation process to afford monoiron derivatives. The large structural variability, amphiphilic character and good stability in aqueous media of the diiron vinyliminium complexes provide favorable properties compared to other widely studied classes of iron-based anticancer candidates.
RESUMO
Invited for the cover of this issue is the group of Fabio Marchetti at the Università di Pisa and Paulâ J. Dyson at Ecole Polytechnique Fédérale de Lausanne (EPFL). Read the full text of the article at 10.1002/chem.201902885.
RESUMO
In this work, the interaction between an Auramine O (AuO) fluorescent molecular rotor and natural DNA, its thermodynamic aspects and the resulting variation of the optical properties upon binding are addressed by a combined spectroscopic (UV-vis and fluorescence) and computational approach. DNA binding causes a shift in the maximum of absorption from 432 nm to 444 nm, a decrease of the extinction coefficient and a dramatic enhancement of fluorescence emission, these results being in agreement with intercalation into the polynucleotide helix. Intercalation is indeed confirmed by the thermodynamic parameters for the binding reaction (in particular, the highly negative ΔH). Theoretical modelling at the TD-DFT level was done on a simplified model system consisting of the AuO molecule intercalated between two DNA base pairs. The evolution of the calculated vertical transitions quantitatively reproduces the experimentally observed hypo- and bathochromic shifts, thus confirming the intercalation hypothesis.
Assuntos
Benzofenoneídio/química , DNA/química , Modelos Químicos , Análise Espectral , Fluorescência , Simulação de Dinâmica MolecularRESUMO
Interfacial bioconjugation methods are developed for intact liquid emulsion droplets. Complex emulsion droplets having internal hydrocarbon and fluorocarbon immiscible structured phases maintain a dynamic interface for controlled interfacial reactivity. The internal morphological change after binding to biomolecules is readily visualized and detected by light transmission, which provides a platform for the formation of inexpensive and portable bio-sensing assays for enzymes, antibodies, nucleic acids and carbohydrates.
Assuntos
Técnicas Biossensoriais/métodos , Emulsões/química , Aminas/química , Anticorpos/análise , Enzimas/análise , Fluorocarbonos/química , Hidrocarbonetos/química , Ácidos Nucleicos/análise , Compostos de Sulfidrila/química , Tensoativos/químicaRESUMO
Aluminium ions are believed to play a role in a number of neurological and skeletal disorders in the human body. The study of the biological processes and molecular mechanisms that underlie these pathological disorders is rendered a difficult task due to the wide variety of complex species that result from the hydrolysis of Al(3+) ions. In addition, this ion displays a pronounced tendency to precipitate as a hydroxide, so certain complexing agents should be envisaged to stabilize Al(III) solutions in near physiological conditions. In this work, we show that the common buffer cacodylic acid (dimethylarsinic acid, HCac) interacts with Al(III) to give stable complexes, even at pH 7. After preliminary analyses of the speciation of the metal ion and also of the ligand, a systematic study of the formation of different Al/Cac complexes at different pH values has been conducted. UV-Vis titrations, mass spectrometry NMR measurements and DTF calculations were performed to enlighten the details of the speciation and stoichiometry of Al/Cac complexes. The results altogether show that Al/Cac dimer complexes prevail, but monomer and trimer forms are also present. Interestingly, it was found that cacodylate promotes the formation of such relatively simple complexes, even under conditions where the polymeric form, Al13O4(OH)24(7+), should predominate. The results obtained can help to shed some light into the reactivity of aluminium ions in biological environments.
RESUMO
The photophysical and DNA-binding properties of the cationic zinc(II) complex of 5-triethylammonium methyl salicylidene ortho-phenylenediiminato (ZnL(2+)) were investigated by a combination of experimental and theoretical methods. DFT calculations were performed on both the ground and the first excited states of ZnL(2+) and on its possible mono- and dioxidation products, both in vacuo and in selected solvents mimicked by the polarizable continuum model. Comparison of the calculated absorption and fluorescence transitions with the corresponding experimental data led to the conclusion that visible light induces a two-electron photooxidation process located on the phenylenediiminato ligand. Kinetic measurements, performed by monitoring absorbance changes over time in several solvents, are in agreement with a slow unimolecular photooxidation process, which is faster in water and slower in less polar solvents. Moreover, structural details of ZnL-DNA binding were obtained by DFT calculations on the intercalation complexes between ZnL and the d(ApT)2 and d(GpC)2 dinucleoside monophosphate duplexes. Two main complementary binding interactions are proposed: 1)â intercalation of the central phenyl ring of the ligand between the stacked DNA base pairs; 2)â external electrostatic attraction between the negatively charged phosphate groups and the two cationic triethylammonium groups of the Schiff-base ligand. Such suggestions are supported by fluorescence titrations performed on the ZnL/DNA system at different ionic strengths and temperatures. In particular, the values of the DNA-binding constants obtained at different temperatures provided the enthalpic and entropic contributions to the binding and confirmed that two competitive mechanisms, namely, intercalation and external interaction, are involved. The two mechanisms are coexistent at room temperature under physiological conditions.
Assuntos
Compostos Organometálicos/química , Fenilenodiaminas/química , Análise Espectral/métodos , Zinco/químicaRESUMO
The macrocyclic ligand (L), containing two terpyridine (terpy) and two ethylenediamine (en) groups arranged in a cyclic terpy-en-terpy-en sequence, forms a double-strand helicate Cu2L(4+) complex made especially stable by the formation of interstrand π-π stacking interactions involving opposite pyridine rings. The crystal structure of this complex shows the Cu(2+) cations in square pyramidal coordination environments defined by the donor atoms of half ligand chain composed, in sequence, by one pyridine ring, the connected ethylenediamine moiety and the two adjacent pyridine rings of the successive terpyridine. In aqueous solution, L forms both mono- and binuclear complexes with Cu(2+). The stability constants determined for these complexes evidence the combined action of the two metal ions in the assembly of the very stable helicate species, the binding of the first metal ion favoring the entrance of the second one. UV adsorption and emission spectra corroborate these equilibrium results. Furthermore, the Cu2L(4+) complex shows a significant inertness toward dissociation in acidic solutions. Also Zn(2+) forms mono- and binuclear complexes with L, although the Zn2L(4+) complex is much weaker than the Cu2L(4+) helicate and gives rise to fast dissociation reactions in acidic media. Experimental evidence allows neither to say that also the Zn(2+) complex has a helicate structure nor to exclude it.
RESUMO
Spectrophotometric, circular dichroism, calorimetric, displacement assay and kinetic analyses of the binding of the fluorescent dye coralyne to poly(A)2poly(U) have served to enlighten the ability of the dye to produce dramatic changes in the RNA structure. The sets of data assembled convey that coralyne is able to induce the triplex-to-duplex conversion and also the duplex-to-triplex conversion according to a non-reversible cycle governed by temperature, provided that the [dye]/[polymer] ratio (CD/CP) is maintained constant above unity. Alternatively, at room temperature the triplex is formed at (roughly) CD/CP < 1 and the duplex at CD/CP > 1.
Assuntos
Alcaloides de Berberina/química , RNA/química , Varredura Diferencial de Calorimetria , Dicroísmo Circular , Conformação de Ácido Nucleico , Poli A/química , Poli U/químicaRESUMO
AS101 (Ammonium trichloro (dioxoethylene-O,O') tellurate) is an important hypervalent Te-based prodrug. Recently, we started a systematic investigation on AS101 with the aim to correlate its promising biological effects as a potent immunomodulator drug with multiple medicinal applications and its specific chemical properties. To date, a substantial agreement on the rapid conversion of the initial AS101 species into the corresponding TeOCl3- anion does exist, and this latter species is reputed as the pharmacologically active one. However, we realized that TeOCl3- could quickly undergo further steps of conversion in an aqueous medium, eventually producing the TeO2 species. Using a mixed experimental and theoretical investigation approach, we characterized the conversion process leading to TeO2 occurring both in pure water and in reference buffers at physiological-like pH. Our findings may offer a valuable "chemical tool" for a better description, interpretation -and optimization- of the mechanism of action of AS101 and Te-based compounds. This might be a starting point for improved AS101-based medicinal application.
Assuntos
Pró-Fármacos , Pró-Fármacos/farmacologia , Pró-Fármacos/químicaRESUMO
Silver compounds are mainly studied as antimicrobial agents, but they also have anticancer properties, with the latter, in some cases, being better than their gold counterparts. Herein, we analyse the first example of a new Ag(I)-biscarbene that can bind non-canonical structures of DNA, more precisely G-quadruplexes (G4), with different binding signatures depending on the type of G4. Moreover, we show that this Ag-based carbene binds the i-motif DNA structure. Alternatively, its Au(I) counterpart, which was investigated for comparison, stabilises mitochondrial G4. Theoretical in silico studies elucidated the details of different binding modes depending on the geometry of G4. The two complexes showed increased cytotoxic activity compared to cisplatin, overcoming its resistance in ovarian cancer. The binding of these new drug candidates with other relevant biosubstrates was studied to afford a more complete picture of their possible targets. In particular, the Ag(I) complex preferentially binds DNA structures over RNA structures, with higher binding constants for the non-canonical nucleic acids with respect to natural calf thymus DNA. Regarding possible protein targets, its interaction with the albumin model protein BSA was also tested.
Assuntos
DNA , Quadruplex G , Prata , DNA/química , Prata/química , Humanos , Metano/química , Metano/análogos & derivados , Antineoplásicos/química , Antineoplásicos/farmacologia , Bovinos , Animais , Soroalbumina Bovina/química , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/síntese química , Corantes Fluorescentes/químicaRESUMO
Tris(pyrazolyl)methane (tpm), 2,2,2-tris(pyrazolyl)ethanol (tpmOH) and its esterification derivatives with ibuprofen and flurbiprofen (tpmIBU and tpmFLU) were used as ligands to obtain complexes of the type [Fe(tpmX)2]Cl2 (1-4). The tpmIBU and tpmFLU ligands and corresponding complexes 3 and 4 were characterized by IR and multinuclear NMR spectroscopy, and the structure of tpmIBU was elucidated by single crystal X-ray diffraction. Complexes 1-4 were also assessed for their behaviour in aqueous media (solubility in D2O, octanol/water partition coefficient, stability in physiological-like conditions). The antiproliferative activity of ligands and complexes was determined on A2780, A2780cis and A549 cancer cell lines and the non-cancerous HEK 293T and BJ cell lines. The ligands and complexes were investigated for their ability to inhibit COX-2 (cyclooxygenase) and HNE (4-hydroxynonenal) enzymes. Complexes 3 and 4 exhibited cytotoxicity that may be attributed predominantly to their bioactive fragments, while DNA binding and enhancement of ROS production do not appear to play any significant role.
Assuntos
Anti-Inflamatórios não Esteroides , Antineoplásicos , Complexos de Coordenação , Pirazóis , Humanos , Ligantes , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/síntese química , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios não Esteroides/síntese química , Pirazóis/química , Pirazóis/farmacologia , Pirazóis/síntese química , Proliferação de Células/efeitos dos fármacos , Linhagem Celular Tumoral , Compostos Ferrosos/química , Compostos Ferrosos/farmacologia , Metano/química , Metano/análogos & derivados , Metano/farmacologia , Ensaios de Seleção de Medicamentos Antitumorais , Ciclo-Oxigenase 2/metabolismo , Aldeídos/química , Aldeídos/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Estrutura Molecular , Ibuprofeno/química , Ibuprofeno/farmacologia , Modelos MolecularesRESUMO
The synthesis and full characterization of the new aqua-complex [(η(6)-p-cymene)Ru(OH2)(κ(2)-N,N-2-pydaT)](BF4)2, [2](BF4)2, and the nucleobase derivative [(η(6)-p-cymene)Ru(9-MeG)(κ(2)-N,N-2-pydaT)](BF4)2, [4](PF6)2, where 2-pydaT = 2,4-diamino-6-(2-pyridyl)-1,3,5-triazine and 9-MeG = 9-methylguanine, are reported here. The crystal structures of both [4](PF6)2 and the chloro complex [(η(6)-p-cymene)RuCl(κ(2)-N,N-2-pydaT)](PF6), [1](PF6), have been elucidated by X-ray diffraction. The former provided relevant information regarding the interaction of the metallic fragment [(η(6)-p-cymene)Ru(κ(2)-N,N-2-pydaT)](2+) and a simple model of DNA. NMR and kinetic absorbance studies have proven that the aqua-complex [2](BF4)2 binds to the N7 site of guanine in nucleobases, nucleotides, or DNA. A stable bifunctional interaction (covalent and partially intercalated) between the [(η(6)-p-cymene)Ru(κ(2)-N,N-2-pydaT)](2+) fragment and CT-DNA has been corroborated by kinetic, circular dichroism, viscometry, and thermal denaturation experiments. The reaction mechanism entails the very fast formation of the Ru-O-(PO3) linkage prior to the fast intercalation of the 2-pydaT fragment. Then, a Ru-N7-(G) covalent bond is formed at the expense of the Ru-O-(PO3) bond, yielding a bifunctional complex. The dissociation rate of the intercalated fragment is slow, and this confers additional interest to [2](BF4)2 in view of the likely correlation between slow dissociation and biological activity, on the assumption that DNA is the only biotarget. Furthermore, [2](BF4)2 displays notable pH-dependent cytotoxic activity in human ovarian carcinoma cells (A2780, IC50 = 11.0 µM at pH = 7.4; IC50 = 6.58 µM at pH = 6.5). What is more, complex [2](BF4)2 is not cross-resistant with cisplatin, exhibiting a resistance factor, RF(A2780cis), of 0.28, and it shows moderate selectivity toward the cancer cell lines, in particular, A2780cis (IC50 = 3.0 5 ± 0.08 µM), relative to human lung fibroblast cells (MRC-5; IC50 = 24 µM), the model for healthy cells.