Search

The copper-based drug Casiopeina II-gly (CasII-gly) shows potent antineoplastic effect and diminishes mitochondrial metabolism on several human and rodent malignant tumors. To elucidate whether CasII-gly also affects glycolysis, (a) the flux through the complete pathway and the initial segment and (b) the activities of several glycolytic enzymes of AS-30D hepatocarcinoma cells were determined. CasII-gly (IC₅₀ = 0.74-6.7 μM) was more effective to inhibit 24-72 h growth of several human carcinomas than 3-bromopyruvate (3BrPyr) (IC₅₀ = 45-100 μM) with no apparent effect on normal human-proliferating lymphocytes and HUVECs. In short-term 60-min experiments, CasII-gly increased tumor cell lactate production and glycogen breakdown. CasII-gly was 1.3-21 times more potent than 3BrPyr and cisplatin to inhibit tumor HK. As CasII-gly inhibited the soluble and mitochondrial HK activities and the flux through the HK-TPI glycolytic segment, whereas PFK-1, GAPDH, PGK, PYK activities and HPI-TPI segment flux were not affected, the data suggested glycogenolysis activation induced by HK inhibition. Accordingly, glycogen-depleted as well as oligomycin-treated cancer cells became more sensitive to CasII-gly. The inhibition time-course of HK by CasII-gly was slower than that of OxPhos in AS-30D cells, indicating that glycolytic toxicity was secondary to mitochondria, the primary CasII-gly target. In long-term 24-h experiments with HeLa cells, 5 μM CasII-gly inhibited OxPhos (80%), glycolysis (40%), and HK (42%). The present data indicated that CasII-gly is an effective multisite anticancer drug simultaneously targeting mitochondria and glycolysis.

Casiopeínas are a new generation of anticancer drugs that have shown great in vitro and in vivo antineoplastic activities. Information about interaction drug-excipient, for developing a based-nanoparticle drug delivery system, has not been investigated yet. In order to elucidate if chitosan (CS) modifies the copper complex due to its interaction with Cu(2+) ion, different studies in aqueous media between CS and Casiopeina III-ia (Cas III-ia) were carried out. CS-Cas III-ia mixtures were characterized by viscosity curves, UV-vis, EPR, and in vivo activity against HeLa cell line. Rheological behavior showed a decrease of viscosity when the drug was present due to diminished electrostatic interactions of charged amine group. UV-vis results illustrate that Cas III-ia is not stable at low pH as a result of interaction with acetic acid. However, when chitosan is present at the acidic solution Cas III-ia is stable. These results are supported by EPR studies. Finally, activity of the drug against HeLa cell line was not modified. Therefore, the present work presents evidence that there is no breaking of copper complex due to interaction between CS and Cas III-ia in acidic media. In addition, Cas III-ia maintains both its stability and effectiveness against cancer cell line., (2010 Elsevier Ltd. All rights reserved.)

Casiopeínas are a series of mixed chelate copper complexes that are being evaluated as anticancer agents. Their effects in the cell include oxidative damage and mitochondrial dysfunction, yet the molecular mechanisms leading to such effects remain unclear. We tested whether [Cu(4,7-dimethyl-phenanthroline)(glycinate)]NO(3) (Casiopeína IIgly or Cas IIgly) could alter cellular glutathione (GSH) levels by redox cycling with GSH to generate ROS and cellular oxidative stress. Cas IIgly induced a dramatic drop in intracellular levels of GSH in human lung cancer H157 and A549 cells, and is able to use GSH as source of electrons to catalyze the Fenton reaction. In both cell lines, the toxicity of Cas IIgly (2.5-5 microM) was potentiated by the GSH synthesis inhibitor l-buthionine sulfoximine (BSO) and diminished by the catalytic antioxidant manganese(III) meso-tetrakis(N,N'-diethylimidazolium-2-yl)porphyrin (MnTDE-1,3-IP(5+)), thus supporting an important role for oxidative stress. Cas IIgly also caused an over-production of reactive oxygen species (ROS) in the mitochondria and a depolarization of the mitochondrial membrane. Moreover, Cas IIgly produced mitochondrial DNA damage that resulted in an imbalance of the expression of the apoproteins of the mitochondrial respiratory chain, which also can contribute to increased ROS production. These results suggest that Cas IIgly initiates multiple possible sources of ROS over-production leading to mitochondrial dysfunction and cell death., ((c) 2009 Elsevier Ireland Ltd. All rights reserved.)

Herein we present the synthesis, structural and spectroscopic characterization of coordination compounds of cobalt(II), copper(II) and zinc(II) with 2-methylbenzimidazole (2mbz), 2-phenylbenzimidazole (2phbz), 2-chlorobenzimidazole (2cbz), 2-benzimidazolecarbamate (2cmbz) and 2-guanidinobenzimidazole (2gbz). Their cytotoxic activity was evaluated using human cancer cell lines, PC3 (prostate), MCF-7 (breast), HCT-15 (colon), HeLa (cervic-uterine), SKLU-1 (lung) and U373 (glioblastoma), showing that the zinc(II) and copper(II) compounds [Zn(2mbz)(2)Cl(2)].0.5H(2)O, [Zn(2cmbz)(2)Cl(2)].EtOH, [Cu(2cmbz)Br(2)].0.7H(2)O and [Cu(2gbz)Br(2)] had significant cytotoxic activity. The isostructural cobalt(II) complexes showed not significant activity. The cytotoxic activity is related to the presence of halides in the coordination sphere of the metal ion. Recuperation experiments with HeLa cells, showed that the cells recuperated after removing the copper(II) compounds and, on the contrary, the cells treated with the zinc(II) compounds did not. These results indicate that the mode of action of the coordination compounds is different.

Mixed chelate copper(II) complexes patented and mark title registered as Casiopeínas are antineoplastic agents with general formulas [Cu(N-N)(alpha-l-amino acidato)]NO(3) and [Cu(N-N)(O-O)]NO(3), where the N-N donor is an aromatic substituted diimine (1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy)) and the O-O donor is acetylacetonate (acac) or salicylaldehydate (salal). In the present work, the series of complexes [Cu(N-N)(acac)]NO(3) and [Cu(N-N)(gly)]NO(3) with several substituents on the diimine ligand were selected to perform a quantitative structure-activity relationship (QSAR) study. Two main analysis were performed: (1) the study of the influence of the substituents on diimine ligand on physicochemical properties such as half-wave potential (E(1/2)) and their relationship with medial lethal dose (LD50) or medial inhibitory concentration (IC50) on several tumor cell lines and (2) the study of the influence of the secondary ligand when acac is changed for glycinate (gly). Results showed that the presence of the central fused aromatic ring in the phen containing complexes is necessary to preserve the antiproliferative activity. The QSAR equations showed a strong relationship between the IC50 and E(1/2); the most active complexes are the weaker oxidants. The change of secondary ligand from acac to gly has less influence on biological activity than the changes on the diimine ligand.

In this work we present the synthesis, structural and spectroscopic characterisation of a series of cobalt(II) and zinc(II) coordination compounds with benzimidazole (bz) and its 2-benzimidazole derivatives: 2-aminobenzimidazole (2ab), albendazole (abz) and tris(2-benzimidazolylmethyl)amine (ntb). The compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus, Micrococcus luteus, Salmonella typhi, Pseudomonas aeruginosa, Escherichia coli and Proteus vulgaris. Their cytotoxic activity was also evaluated using human cancer lines, HeLa, HCT-15 and SKLU-1. The halide tetrahedral compounds [Co(bz)2Br2] 3, [Zn(2ab)2Cl2].0.5H2O 11, [Co(abz)Cl2(H2O)].3H2O 14, [Co(abz)Br2(H2O)] 15, [Zn(abz)Cl2(H2O)].3H2O 17 and [Zn(abz)Br2(H2O)].H2O 18 displayed similar minimal inhibition concentration (MIC) values against Micrococcus luteus and Escherichia coli, comparable to those of amoxicillin and chloramphenicol. Additionally, 11 showed a wide range of activity towards Gram(+) and Gram(-) microorganisms. The tetradentate ntb and its trigonal bipyramidal cobalt(II) and zinc(II) compounds were active, regardless of the anion present in the complex. Compound [Co(abz)Cl2(H2O)].3H2O 14 showed promising activity in HeLa cells, while [Co(ntb)Br]Br.H2O 21 inhibited Hela and HCT-15 cell lines.

The newly synthesized copper coordination compound Casiopeína IIgly (Cas IIgly) is a promising alternative drug in the treatment of cancer, since it has shown cytotoxicity and genotoxicity in different tumour models. Given its enhanced effects after ascorbic acid-mediated copper reduction, Cas IIgly's activity is thought to be related to oxidative damage. In the present work, oxidized Cas IIgly failed to induce cytosolic oxidative damage in HeLa cells (only 0.9% of the cell population), and in 2.3% of the treated cells when previously reduced, as evaluated through the oxidation of dihydrorhodamine 123 (DHR 123). However, it showed cytotoxicity, since HeLa cells treated with 10-80 microg/mL Cas IIgly proliferated only at 30% of their normal rate, and at 15% when treated with reduced Cas IIgly. This cytotoxicity is strongly abolished in the presence of the hydroxyl scavenger dimethyl sulfoxide. The decrease, from 3994 to 530 nanograms of reduced glutathione (GSH) per million cells after treatment with 80 microg/mL Casiopeína IIgly, indicates that this drug causes the expenditure of this naturally occurring antioxidant. These results altogether suggest that, albeit Cas IIgly induced cytotoxicity is not related to cytosolic DHR 123 oxidation, it may be related to oxidative damage.

The aim of this study was to evaluate the in vitro and in vivo effects of the new chemotherapy agent Casiopeina III-ia [(4,4'-dimethyl-2,2'-bipiridine)(acetylacetonate) Copper (II) nitrate] on HCT-15 (p53-/-) colon cellular line. In vitro, the drug reduced the viability and induced necrosis and apoptosis in a dose dependent manner, without affecting cell cycle phases. Apoptosis was related to Bax increasing levels, suggesting a caspase-dependent mechanism of death, as verified by nucleosomal fragmentation of DNA. In vivo, the antitumor activity of Casiopeina III-ia was tested in HCT-15 cells transplanted to nude mice. In this study we will show that the novel antineoplastic agent Casiopeina III-ia is active on this colon tumor line, setting out as a good candidate for the treatment of colon tumors refractory to chemotherapy.

The 99 lethal dose in an acute toxicity study of two anticancer novel molecules named casiopeinas((R)) in dogs was calculated to be 200 mg/m(2) for casiopeina III-ia and 160 mg/m(2) for casiopeina IIgly. Considering therapeutic dose ranges from 3.6 to 18 mg/m(2) for the former and 1.2 to 3 mg/m(2) for the latter, true therapeutic margin of safety varies from 4.7 to 23.6 mg/m(2) and from 20 to 50 mg/m(2), respectively. For both casiopeinas intravenous administration of the corresponding lethal dose in 100 ml of 5% dextrose solution in a time period of 30 min. induced death after an almost uneventful latency time period of 30-50 min. Then, after an apparently sudden onset, changes in blood gases indicated respiratory distress (PO(2) from 82.5% to 26.5% for casiopeina III-ia and from 88.6% to 37.5% for casiopeina IIgly; end-tidal CO(2) from 38 to 8.1 mmHg for the first and from 35.1 to 11.2 mmHg for the second, this was almost simultaneously confirmed by the onset of tachypnoea (from 16 to almost 60 breaths/min. for both casiopeinas) and by a drop in arterial blood pressure (from 117 to 51 mmHg for casiopeina III-ia and from 108 to 49 mmHg for casiopeina IIgly). Reflex tachycardia occurs at the beginning of intravenous administration followed by bradycardia a few minutes later (from 158 to 63 beats/min. for casiopeina III-ia and from 148 to 56 beats/min. for casiopeina IIgly). Finally, cardiac arrest occurred no later than 25 min. towards the end of these events lung oedema appeared as fluid dripping from the endotracheal tube. Death occurred in a mean of 15 +/- 5 min. S.D. from the beginning of the end of the latency period. For both casiopeina's data allow the speculation that lung oedema is caused by a joined toxicity to the lung capillary bed, and particularly to the heart. Carvedilol premedication for 8 days delayed the outcome of lung oedema by approximately 8 hr but could not prevent it.

In this work, we investigated the effects of Casiopeina II-gly (Cas IIgly)--a new copper compound exhibiting antineoplastic activity--on glioma C6 cells under both in vitro and in vivo conditions, as an approach to identify potential therapeutic agents against malignant glioma. The exposure of C6 cells to Cas IIgly significantly inhibited cell proliferation, increased reactive oxygen species (ROS) formation, and induced apoptosis in a dose-dependent manner. In cultured C6 cells, Cas IIgly caused mitochondrio-nuclear translocation of apoptosis induction factor (AIF) and endonuclease G at all concentrations tested; in contrast, fragmentation of nucleosomal DNA, cytochrome c release, and caspase-3 activation were observed at high concentrations. Administration of N-acetyl-L-cystein, an antioxidant, resulted in significant inhibition of AIF translocation, nucleosomal DNA fragmentation, and caspase-3 activation induced by Cas IIgly. These results suggest that caspase-dependent and caspase-independent pathways both participate in apoptotic events elicited by Cas IIgly. ROS formation induced by Cas IIgly might also be involved in the mitochondrio-nuclear translocation of AIF and apoptosis. In addition, treatment of glioma C6-positive rats with Cas IIgly reduced tumor volume and mitotic and cell proliferation indexes, and increased apoptotic index. Our findings support the use of Cas IIgly for the treatment of malignant gliomas.

To elucidate some of the subcellular and biochemical mechanisms of toxicity of metal-based antineoplastic drugs, mitochondria and cells were exposed to Casiopeinas), a new class of copper-based compounds with high antineoplastic activity. The rates of respiration and swelling, the H(+) gradient, and the activities of succinate (SDH) and 2-oxoglutarate dehydrogenases (2-OGDH) and ATPase were measured in mitochondria isolated from rat liver, kidney, heart, and hepatoma AS-30D. Also, oligomycin-sensitive respiration and ATP content in hepatoma AS-30D cells were determined. Casiopeinas) (CS) II-gly and III-i inhibited the rates of state 3 and uncoupled respiration in mitochondria. CS II was 10 times more potent than CS III. The sensitivity to CS II was 4-5-fold higher in mitochondria incubated with 2-OG than with succinate. Thus, at low concentrations (< or =10 nmol (mg protein)(-1); 10 microM), CS II disturbed mitochondrial functions only when 2-OG was present, due to a specific inhibition of 2-OGDH. At high concentrations (> or =15nmol (mg protein)(-1)), CS II-induced stimulation of basal respiration, followed by a strong inhibition, which correlated with K(+)-dependent swelling and cytochrome c release, respectively; K(+)-channel openers induce a similar mitochondrial response. Mitochondria from liver, kidney and hepatoma showed a similar sensitivity towards CS II, whereas heart mitochondria were more resistant. Oxidative phosphorylation and ATP content were also decreased in tumor cells by CS II. The data suggested that CS affected several different mitochondrial sites, bringing about inhibition of respiration and ATP synthesis, which could compromise energy-dependent processes such as cellular duplication.

A sensitive and specific liquid chromatographic method using extraction with zinc sulfate has been developed for the determination of Casiopeina IIIi and validated over the linear range 5-100 microg/ml in 1 ml of rat plasma. The analysis was performed on a Symmetry C(18) (5 microm) column. The mobile phase was methanol: 0.01 M phosphate buffer pH 6.5 (40:60, v/v). The column effluent was monitored at 262 nm. The results showed that the assay is sensitive at 5 microg/ml. Maximum intra-day coefficient of variation was 10.6%. The recovery obtained in plasma was 87.2%. The method was used to perform protein binding studies by equilibrium dialysis in rat plasma and was found to be satisfactory.