The photoreceptor protector zeaxanthin induces cell death in neuroblastoma cells

Background: The dietary carotenoid zeaxanthin protects against age-related eye disease by preventing apoptosis in photoreceptor cells. This study examined the effect of zeaxanthin on neuroblastoma cells in which apoptosis can be induced with lipid peroxidation products. Since zeaxanthin can inhibit lipid peroxidation and beta-carotene inhibits lipoxygenase (LOX) activity, it was of concern that zeaxanthin might inhibit apoptosis in these cancer cells. Materials and Methods: Apoptosis-resistant CHP100 neuroblastoma cells were treated with zeaxanthin. Apoptosis was assessed via an immunoassay for histone-associated DNA fragments and cytofluorimetric analysis of apoptotic body formation. The effect of zeaxanthin on the activity of two model LOXs and LOX-mediated lipid peroxidation in liposomes was assessed. Results: Zeaxanthin strongly induced apoptosis in neuroblastoma cells. Consistent with this finding, zeaxanthin did not inhibit LOX activity. Conclusion: Zeaxanthin is a remarkable dietary factor that is able to induce apoptosis in neuroblastoma cells while being able to prevent apoptosis in healthy cells.