Extrinsic or intrinsic apoptosis by curcumin and light : still a mystery

  • Curcumin—a rhizomal phytochemical from the plant Curcuma longa—is well known to inhibit cell proliferation and to induce apoptosis in a broad range of cell lines. In previous studies we showed that combining low curcumin concentrations and subsequent ultraviolet A radiation (UVA) or VIS irradiation induced anti-proliferative and pro-apoptotic effects. There is still debate whether curcumin induces apoptosis via the extrinsic or the intrinsic pathway. To address this question, we investigated in three epithelial cell lines (HaCaT, A431, A549) whether the death receptors CD95, tumor necrosis factor (TNF)-receptor I and II are involved in apoptosis induced by light and curcumin. Cells were incubated with 0.25–0.5 µg/mL curcumin followed by irradiation with 1 J/cm2 UVA. This treatment was combined with inhibitors specific for distinct membrane-bound death receptors. After 24 h apoptosis induction was monitored by quantitative determination of cytoplasmic histone-associated-DNA-fragments. Validation of our test system showed that apoptosis induced by CH11 and TNF-α could be completely inhibited by their respective antagonists. Interestingly, apoptosis induced by curcumin/light treatment was reversed by none of the herein examined death receptor antagonists. These results indicate a mechanism of action independent from classical death receptors speaking for intrinsic activation of apoptosis. It could be speculated that a shift in cellular redox balance might prompt the pro-apoptotic processes

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Author:Vesselina LaubachGND, Roland KaufmannGND, August BerndORCiDGND, Stefan KippenbergerORCiDGND, Nadja Nicole ZöllerORCiDGND
Pubmed Id:https://pubmed.ncbi.nlm.nih.gov/30791477
Parent Title (English):International journal of molecular sciences
Publisher:Molecular Diversity Preservation International
Place of publication:Basel
Document Type:Article
Year of Completion:2019
Date of first Publication:2019/02/19
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2019/04/11
Tag:apoptosis; curcumin; death receptor
Issue:4, Art. 905
Page Number:13
First Page:1
Last Page:13
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
Institutes:Medizin / Medizin
Dewey Decimal Classification:6 Technik, Medizin, angewandte Wissenschaften / 61 Medizin und Gesundheit / 610 Medizin und Gesundheit
Licence (German):License LogoCreative Commons - Namensnennung 4.0