New gold pincer-type complexes: synthesis, characterization, DNA binding studies and cytotoxicity
| Autor: | Snežana Radisavljević, Siniša Radulović, Aleksandar Tot, Andreas Scheurer, Ana Simović, Romana Masnikosa, Jana Korzekwa, Nevenka Gligorijević, Ioannis Bratsos |
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| Rok vydání: | 2018 |
| Předmět: |
Stereochemistry
Intercalation (chemistry) Substituent Guanosine Antineoplastic Agents Chemistry Techniques Synthetic 010402 general chemistry 01 natural sciences Fluorescence spectroscopy Inorganic Chemistry chemistry.chemical_compound Coordination Complexes Cell Line Tumor Pyridine Animals Humans 010405 organic chemistry Cell Cycle Associative substitution DNA 0104 chemical sciences Molecular Docking Simulation Kinetics chemistry Nucleic Acid Conformation Gold Two-dimensional nuclear magnetic resonance spectroscopy |
| Zdroj: | Dalton Transactions |
| Popis: | © 2018 The Royal Society of Chemistry. With the aim of assessing whether Au(iii) compounds with pincer type ligands might be utilized as potential antitumor agents, three new monofunctional Au(iii) complexes of the general formula [Au(N-N'-N)Cl]Cl2, where N-N'-N = 2,6-bis(5-tert-butyl-1H-pyrazol-3-yl)pyridine (H2LtBu, 1), 2,6-bis(5-tert-butyl-1-methyl-1H-pyrazol-3-yl)pyridine (Me2LtBu, 2) or 2,6-bis((4S,7R)-1,7,8,8-tetramethyl-4,5,6,7-tetrahydro-1H-4,7-methanoindazol-3-yl)pyridine (Me2∗L, 3) were synthesized. All complexes were characterized by elemental analysis, spectroscopic techniques (IR, UV-Vis, 1D and 2D NMR) and mass spectrometry (MALDI TOF MS). The chemical behavior of the complexes under physiological conditions was studied by UV-Vis spectroscopy, which showed that all compounds were remarkably stable and that the gold center remained in the 3+ oxidation state. The kinetics and the mechanism of the reaction of complexes 1-3 with guanine derivatives (i.e. guanosine (Guo) and guanosine-5′-monophosphate (5′-GMP)) and calf thymus DNA (CT DNA) were studied by stopped-flow spectroscopy. The three complexes displayed moderately different rate constants in their reactions with Guo, 5′-GMP and CT DNA, which can be explained by the steric hindrance and σ-donicity of the methyl substituent on the bis-pyrazolylpyridine fragment in complexes 2 and 3. The measured enthalpies and entropies of activation (ΔH≠ > 0, ΔS≠ < 0) supported an associative mechanism for the substitution process. The interaction of the newly synthesized complexes 1-3 with CT DNA was investigated by UV-Vis and fluorescence spectroscopy, and also by viscosity measurements, which all indicated that complexes 1-3 bound to CT DNA with moderate binding affinity (Kb = 1.6-5.7 × 103 M-1) and stabilized the duplex of CT DNA. Molecular docking indicated that complexes 1-3 interacted with DNA via intercalation. Complex 1 reduced the cell survival of all the investigated cell lines (A549, A375, and LS-174) with IC50 values being up to 20 μM. We have shown that 1 induced perturbations of the cell cycle and led to apoptosis in human melanoma A375 cells. Complex 1 also affected the level of reactive oxygen species (ROS) in the same cells. However, pre-treatment of A375 cells with NAC (ROS scavenger) reversed the effect of 1 on their survival. |
| Databáze: | OpenAIRE |
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