Transitional metals have a large variety of coordination numbers and geometries, accessible redox states in physiological conditions and a wide range of thermodynamic and reactivity properties which can be successfully tuned by selection of suitable ligands. These characteristics can be used to develop new drugs with numerous advantages over the organic based drugs. Historically, research in this field has focus on platinum and DNA targeting; however, anticancer drug research may be expanded to include alternative metal compounds with different mode of action resulting in markedly different cytotoxic response profiles. Copper complexes with selected ligands are being extensively studied as agents for the treatment of cancer. Current research on copper compounds as antitumoral compounds is being reviewed in this chapter particularly focused on the family of copper Casiopeinas.
1 February 2009 in Journal of Inorganic Biochemistry
The family of anticancer complexes that include the transition metal copper known as Casiopeínas® shows promising results. Two of these complexes are currently in clinical trials. The interaction of these compounds with DNA has been observed experimentally and several hypotheses regarding the mechanism of action have been developed, and these include the generation of reactive oxygen species, phosphate hydrolysis and/or base-pair intercalation. To advance in the understanding on how these ligands interact with DNA, we present a molecular dynamics study of 21 Casiopeínas with a DNA dodecamer using 10 μs of simulation time for each compound. All the complexes were manually inserted into the minor groove as the starting point of the simulations. The binding energy of each complex and the observed representative type of interaction between the ligand and the DNA is reported. With this extended sampling time, we found that four of the compounds spontaneously flipped open a base pair and moved inside the resulting cavity and four compounds formed stacking interactions with the terminal base pairs. The complexes that formed the intercalation pocket led to more stable interactions.
The synthesis of a range of new compartmental macrocyclic complexes based on 2,6-diformyl and -diketo phenol groups is described. The metal-free ligands have been prepared and structurally characterised for the first time, and this has led to the synthesis of novel cubane and platinum-group metal complexes. The synthesis of related dithiophenolato-bridged compartmental complexes of NiII, CuII and ZnII has been achieved and the relevance of these species to metalloproteins is discussed.
Background: Glioblastoma multiforme (GBM) is the most aggressive of the primary brain tumors, with a grim prognosis despite intensive treatment. In the past decades, progress in research has not significantly increased overall survival rate. Methods: The in vitro antineoplastic effect and mechanism of action of Casiopeina III-ia (Cas III-ia), a copper compound, on rat malignant glioma C6 cells was investigated. Results: Cas III-ia significantly inhibited cell proliferation, inducing autophagy and apoptosis, which correlated with the formation of autophagic vacuoles, overexpression of LC3, Beclin 1, Atg 7, Bax and Bid proteins. A decrease was detected in the mitochondrial membrane potential and in the activity of caspase 3 and 8, together with the generation of intracellular reactive oxygen species (ROS) and increased activity of c-jun NH2-terminal kinase (JNK). The presence of 3-methyladenine (as selective autophagy inhibitor) increased the antineoplastic effect of Cas III-ia, while Z-VAD-FMK only showed partial protection from the antineoplastic effect induced by Cas III-ia, and ROS antioxidants (N-acetylcysteine) decreased apoptosis, autophagy and JNK activity. Moreover, the JNK –specific inhibitor SP600125 prevented Cas III-ia-induced cell death. Conclusions: Our data suggest that Cas III-ia induces cell death by autophagy and apoptosis, in part due to the activation of ROS –dependent JNK signaling. These findings support further studies of Cas III-ia as candidate for treatment of human malignant glioma.