The metal-coordinated Casiopeína IIIEa induces the petite-like phenotype in Saccharomyces cerevisiae

Cytotoxic phenanthroline derivatives alter metallostasis and redox homeostasis in neuroblastoma cells

Copper homeostasis is generally investigated focusing on a single component of the metallostasis network. Here we address several of the factors controlling the metallostasis for neuroblastoma cells (SH-SY5Y) upon treatment with 2,9-dimethyl-1,10-phenanthroline-5,6-dione (phendione) and 2,9-dimethyl-1,10-phenanthroline (cuproindione). These compounds bind and transport copper inside cells, exert their cytotoxic activity through the induction of oxidative stress, causing apoptosis and alteration of the cellular redox and copper homeostasis network. The intracellular pathway ensured by copper transporters (Ctr1, ATP7A), chaperones (CCS, ATOX, COX 17, Sco1, Sco2), small molecules (GSH) and transcription factors (p53) is scrutinised.

Genotoxic assessment of the copper chelated compounds Casiopeinas: Clues about their mechanisms of action

Casiopeinas is the generic name of a group of copper chelated complexes designed to be used as antineoplastic. Some of these compounds have shown promising results, and in fact, one of them named Casiopeina III-ia has completed preclinical trials and is ready to start clinical phase I in Mexico. As part of the tests that have to be done to every molecule intended to be used in humans, bacterial assays are required because of their sensitivity, speed and reproducibility and among them, Ames test and the SOS Chromotest are widely used to evaluate DNA damage. With the aim to contribute to complete safety information related to genotoxicity and support the hypothesis about their mode of action, four different Casiopeinas (Cas II-gly, Cas III-Ea, Cas III-ia and Cas III-Ha) were tested for genotoxicity with these assays, as well as differential cytotoxicity upon Escherichia coli mutants defectives in some DNA repair mechanisms. However, although it is well known that these molecules produce DNA breakage, the results of the Chromotest and Ames test were negative. Despite this is controversial, a possible explanation is that there is a direct interaction between DNA and the Casiopeinas tested.

Genotoxicity of Casiopeina III-Ea in mouse bone marrow cells

Casiopeina III-Ea® (Cas III-Ea®) is a chelated copper complex with antineoplastic activity that is capable of reducing tumor size and inducing antiproliferative and apoptotic effects. However, little is known about its in vivo genotoxic effects. Therefore, this study evaluated two cytogenetic and two proliferative parameters 24 h after the administration of Casiopeina III-Ea® to male CD-1 mice. Three doses of Cas III-Ea® were administered by intraperitoneal injections of 1.69, 3.39 and 6.76 mg/kg (corresponding to 1/8, 1/4 and 1/2 of LD₅₀, respectively). A reduction in the mitotic index (MI) and an increased numbers of cells with structural chromosomal aberrations (SCA) were detected. Additionally, a low but significant increase in the frequency of sister chromatid exchange (SCE) was observed at the highest dose. Changes in the DNA replication index (RI) were not observed. These results indicate that Casiopeina III-Ea® shows cytotoxic and clastogenic activity in bone marrow cells from treated mice.

Investigation on the self-association of an inorganic coordination compound with biological activity (Casiopeína III-ia) in aqueous solution

From studies using different experimental techniques employed to determine the presence of aggregates e.g. isothermal titration calorimetry, surface tension, electrical conductivity, UV-Vis spectrophotometry, dynamic and static light scattering, it is clearly demonstrated that the compound [Cu(4, 4'-dimethyl-2, 2'-bipyridine)(acetylacetonato)H2O]NO3 (Casiopeína III-ia), promising member of a family of new generation compounds for cancer treatment, is able to auto associate in aqueous media. Physicochemical properties associated with the formation of the aggregates were determined in pure water and in phosphate buffer media in order to simulate physiological conditions. From isothermal titration calorimetry and electrical conductivity measurements we calculated the dissociation constant of the aggregates, KD . For pure water the values obtained in both techniques are 2.73 × 10-4 and 5.93 × 10-4 M respectively while for the buffer media we obtained 4.61 × 10-4 and 1.57 × 10-3 M. The enthalpy of dissociation, ∆HD , calculated from the calorimetric data shows that the presence of the phosphate ions has an energetic effect on the aggregate stability since in pure water a value of 18.79 kJ mol-1 was obtained in comparison with the buffer media where a value 4 times bigger was found (70.48 kJ mol-1). With the data collected from these techniques the number of monomers calculated which participate in the formation of the aggregates is around two. From our surface tension, electrical conductivity and UV-Vis spectrophotometry measurements the critical aggregate concentration, cac, was determined. For each technique specific concentration ranges were obtained but we can summarize that the cac in pure water is between 3 and 3.5 mM and for the buffer media is between 3.5 and 4 mM. Dynamic light scattering measurements provide us with the hydrodynamic diameter of the aggregates and from static light scattering measurements we determined the molecular weight of the Casiopeína III-ia aggregates to be of 1000.015 g mol-1 which is two times the molecular weight of the Casiopeína III-ia molecule. This value is in agreement with the number of monomers which participate in the formation of the aggregates obtained from isothermal titration calorimetry and electrical conductivity data analysis.