title: Copper induced apoptosis in Caco-2 and Hep-G2 cells: Expression of caspases 3, 8 and 9, AIF and p53.
abstract: Copper (Cu) is an essential trace metal needed to ensure cell function. However, when present at high concentrations it becomes toxic to organisms. Cell death, induced by toxic levels of copper, was previously observed in in vitro studies. However, there is no consensus about the cell death pathway induced by Cu and it is still not known whether this occurs as a result of the direct action of the metal or by indirect effects. In the present work, we intend to identify the influence of different Cu concentrations in the induction of apoptosis and to explore the potential signaling pathways, using two different in vitro cell culture models (Caco-2 and Hep-G2). Cells were exposed, during 6, 12, 24 and 48h, to Cu concentrations corresponding to IC50 and 1/8 of IC50, according to the viability assays. Then, considering the different apoptosis pathways, the expression of caspases 3, 8 and 9, apoptosis inducing factor (AIF) and p53 genes was analyzed by quantitative real time PCR. The results suggested that different Cu concentrations could trigger different apoptotic pathways, at different times of exposure. In both cell lines, apoptosis seems to be initiated by caspase independent pathway and intrinsic pathway, followed by extrinsic pathway. In conclusion, this study demonstrates that Cu induces the activation of apoptosis through caspase dependent and independent pathways, also suggesting that apoptosis activation mechanism is dependent on the concentration, time of exposure to Cu and cell type.
authors.affiliation: University of Trás-os-Montes and Alto Douro (UTAD), School of Life Sciences and Environment, Department of Biology and Enviroment, Quinta de Prados, 5001-801 Vila Real, Portugal. Electronic address: stefsantos.01@hotmail.com.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Santos
authors.affiliation: University of Trás-os-Montes and Alto Douro (UTAD), School of Life Sciences and Environment, Department of Biology and Enviroment, Quinta de Prados, 5001-801 Vila Real, Portugal; Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Quinta de Prados, 5001-801 Vila Real, Portugal.
authors.forename: Amélia M
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Quinta de Prados, 5001-801 Vila Real, Portugal; Institute of Biotechnology and Bioengineering, Centre of Genomic and Biotechnology (IBB/CGB), Department of Genetic and Biotechnology (DGB), Quinta de Prados, 5001-801 Vila Real, Portugal.
authors.forename: Manuela
authors.initials: M
authors.lastname: Matos
authors.affiliation: University of Trás-os-Montes and Alto Douro (UTAD), School of Life Sciences and Environment, Department of Biology and Enviroment, Quinta de Prados, 5001-801 Vila Real, Portugal; Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), Quinta de Prados, 5001-801 Vila Real, Portugal. Electronic address: smonteir@utad.pt.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Monteiro
authors.affiliation: Center for Neuroscience and Cell Biology, University of Coimbra (CNBC-UC), 3004-504 Coimbra, Portugal. Electronic address: ritaa80@cnc.cj.uc.pt.
authors.forename: Ana R
authors.initials: AR
authors.lastname: Álvaro
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor / Q000235:genetics / Q000378:metabolism*; D018938:Caco-2 Cells; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D053181:Caspase 8 / Q000235:genetics / Q000378:metabolism*; D053453:Caspase 9 / Q000235:genetics / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D019327:Copper Sulfate / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D008113:Liver Neoplasms / Q000201:enzymology* / Q000473:pathology; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*
chemical_list: C494829:AIFM1 protein, human; D051033:Apoptosis Inducing Factor; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D019327:Copper Sulfate
keywords: AIF; Apoptosis; Caspases; Copper; In vitro; p53