Casiopeína IIgly-induced oxidative stress and mitochondrial dysfunction in human lung cancer A549 and H157 cells

Department of Medicine, National Jewish Health, Denver, CO 80206, USA.
Toxicology (Impact Factor: 3.62). 12/2009; 268(3):176-83. DOI: 10.1016/j.tox.2009.12.010
Source: PubMed


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.

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    • "HeLa cells treated with Cas IIgly demonstrated a significant release of apoptogenic factors such as cytochrome c and Bax, leading to caspase activation and subsequent cellular death by apoptosis (Mejia and Ruiz-Azuara 2008; Valencia-Cruz et al. 2013). Furthermore , previous findings have suggested that the Cas redox cycle promotes reactive oxygen species (ROS) production and intracellular glutathione (GSH) depletion, increasing levels of mitochondrial ROS and, consequently inducing mitochondrial dysfunction and apoptosis (Kachadourian et al. 2010). In this regard, Cas mitochondrial oxidative damages can be associated with the cardiotoxicity caused by doxorubicin (Doxo) (Zhou et al. 2001). "
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    ABSTRACT: Copper-based drugs, Casiopeinas (Cas), exhibit antiproliferative and antineoplastic activities in vitro and in vivo, respectively. Unfortunately, the clinical use of these novel chemotherapeutics could be limited by the development of dose-dependent cardiotoxicity. In addition, the molecular mechanisms underlying Cas cardiotoxicity and anticancer activity are not completely understood. Here, we explore the potential impact of Cas on the cardiac mitochondria energetics as the molecular mechanisms underlying Cas-induced cardiotoxicity. To explore the properties on mitochondrial metabolism, we determined Cas effects on respiration, membrane potential, membrane permeability, and redox state in isolated cardiac mitochondria. The effect of Cas on the mitochondrial membrane potential (Δψm) was also evaluated in isolated cardiomyocytes by confocal microscopy and flow cytometry. Cas IIIEa, IIgly, and IIIia predominately inhibited maximal NADH- and succinate-linked mitochondrial respiration, increased the state-4 respiration rate and reduced membrane potential, suggesting that Cas also act as mitochondrial uncouplers. Interestingly, cyclosporine A inhibited Cas-induced mitochondrial depolarization, suggesting the involvement of mitochondrial permeability transition pore (mPTP). Similarly to isolated mitochondria, in isolated cardiomyocytes, Cas treatment decreased the Δψm and cyclosporine A treatment prevented mitochondrial depolarization. The production of H2O2 increased in Cas-treated mitochondria, which might also increase the oxidation of mitochondrial proteins such as adenine nucleotide translocase. In accordance, an antioxidant scavenger (Tiron) significantly diminished Cas IIIia mitochondrial depolarization. Cas induces a prominent loss of membrane potential, associated with alterations in redox state, which increases mPTP opening, potentially due to thiol-dependent modifications of the pore, suggesting that direct or indirect inhibition of mPTP opening might reduce Cas-induced cardiotoxicity.
    Full-text · Article · Dec 2015 · Journal of Bioenergetics
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    • "In previous studies, another copper compound (Cas IIgly [Cu(4,7-dimethyl-1,10-phenanthroline)(glycine)(H2O)]NO3) was shown to induce a dramatic drop in intracellular levels of reduced glutathione (GSH) in human lung cancer H157 and in A547 cells. GSH was used as a source of electrons to catalyze the Fenton reaction leading to ROS formation and cell death [13]. ROS are regulators of mitogen-activated protein kinase (MAPKS), a family of serine/threonine kinases, which mediates intracellular signal transduction in response to different physiological stimuli and stressing conditions [14,15]. "
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    ABSTRACT: 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. 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. 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 NH(2)-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. 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.
    Full-text · Article · Apr 2012 · BMC Cancer
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    • "Such species may interact directly with DNA, yet results from experiments done elsewhere point towards other potential cell targets such as membrane lipids (Alemon-Medina et al., 2007) and mitochondria (Marin et al., 2003). Recently, Kachadourian et al. (2010) demonstrated that CasII-gly dramatically drops the intracellular levels of GSH in human lung cancer cells, and is able to use GSH as a source of electrons to catalyze the Fenton-like reaction , causing an over-production in the mitochondria of reactive oxygen species and a depolarization of the mitochondrial membrane . These suggest that CasII-gly initiates multiple possible sources of ROS over-production leading to mitochondrial dysfunction and cell death. "
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    ABSTRACT: Casiopeinas is the generic name of a group of coordination complexes with a central copper atom bound to organic ligands, designed to be an alternative to cancer therapy. Indeed, some of these compounds can reduce implanted tumors in mice. Casiopeinas were expressly designed to interact with the genetic material, so the aim of the present work is to determine if these compounds have genotoxic activity. The results indicate that casiopeinas produce DNA fragmentation and base oxidation and suggest that their mode of action is related to reactive oxygen species (ROS) generation after copper reduction.
    Full-text · Article · May 2011 · Toxicology in Vitro
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