Effects of apigenin, lycopene and astaxanthin on 7β-hydroxycholesterol-induced apoptosis and Akt phosphorylation in U937 cells

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dc.contributor.author Lordan, Sinéad
dc.contributor.author O'Neill, Cora
dc.contributor.author O'Brien, Nora M.
dc.date.accessioned 2009-09-17T13:50:15Z
dc.date.available 2009-09-17T13:50:15Z
dc.date.copyright 2008
dc.date.issued 2008-08
dc.identifier.citation Lordan, S., O’ Neill, C. and O’ Brien, N.M. (2008) Effects of apigenin, lycopene and astaxanthin on 7-beta-hydroxycholesterol-induced apoptosis and Akt phosphorylation in U937 cells. British Journal of Nutrition, 100: 287-296 en
dc.identifier.volume 100 en
dc.identifier.issued 2 en
dc.identifier.startpage 287 en
dc.identifier.endpage 296 en
dc.identifier.issn 0007-1145
dc.identifier.uri http://hdl.handle.net/10468/69
dc.identifier.doi 10.1017/S0007114507898643
dc.description.abstract Oxysterols arise from the enzymic or non-enzymic oxidation of cholesterol and have been shown to be cytotoxic to certain cell lines. In particular, apoptosis induced by the oxysterol 7β-hydroxycholesterol (7β-OH) has been associated with the generation of oxidative stress, cytochrome c release and caspase activation. Due to the fundamental importance of apoptosis in pathological processes, the identification of substances capable of modulating this form of cell death is now actively researched. The objective of the present study was to investigate if apigenin, lycopene and astaxanthin could inhibit 7β-OH-induced apoptosis in U937 cells. Pretreatment with 0.1 µM-astaxanthin protected against apoptosis, while lycopene did not oppose the adverse effects of 7β-OH. At low concentrations, apigenin did not protect against oxysterol-induced apoptosis; however, at higher concentrations it intensified cell death. Additionally, we investigated the effect of 7β-OH, apigenin and astaxanthin on the activation of the serine threonine kinase Akt (phosphorylated Akt:Akt ratio) to determine whether the effect on cell viability and growth was linked to the Akt signalling pathway. Akt activation was decreased in the oxysterol-treated cells compared with control cells; however, this did not attain significance. Interestingly, activation of Akt was significantly reduced compared with control cells following incubation with apigenin and astaxanthin both in the absence and in the presence of 7β-OH. Our data suggest that apigenin, lycopene and astaxanthin failed to protect against 7β-OH-induced apoptosis, and the decrease in cell viability and the increase in apoptotic nuclei induced by the antioxidants appear to be associated with down regulation of Akt activity. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Cambridge University Press en
dc.rights © The Authors 2008 en
dc.subject Akt en
dc.subject Cytotoxicity en
dc.subject 7β-Hydroxycholesterol en
dc.subject.lcsh Antioxidants en
dc.subject.lcsh Protein kinases en
dc.subject.lcsh Apoptosis en
dc.subject.lcsh Oxysterols en
dc.title Effects of apigenin, lycopene and astaxanthin on 7β-hydroxycholesterol-induced apoptosis and Akt phosphorylation in U937 cells en
dc.type Article (peer-reviewed) en
dc.internal.authorurl http://www.ucc.ie/ucc/depts/biochemistry/staff/coneill.html en
dc.internal.authorurl http://www.ucc.ie/en/fns/Staff/AcademicStaff/ProfessorNoraOBrien/ en
dc.internal.authorcontactother Dr. Cora O'Neill, Department of Biochemistry, Biosciences Institute, University College Cork, Cork. Email: c.oneill@ucc.ie en
dc.internal.authorcontactother Professor Nora O'Brien, Department of Food and Nutritional Sciences, University College, Cork, Republic of Ireland. Email: nob@ucc.ie en
dc.internal.availability Full text available en
dc.description.version Published Version en
dc.internal.rssid 1291334
dc.contributor.funder Higher Education Authority en
dc.description.status Peer reviewed en
dc.identifier.journaltitle British Journal of Nutrition en
dc.internal.IRISemailaddress c.oneill@ucc.ie en

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