Abstract
Purpose: :
Higher intakes and blood levels of zeaxanthin have been repeatedly associated with a lower incidence of a variety of malignant tumors. Zeaxanthin has also been shown to inhibit proliferation and induce apoptosis in various tumor cells. However, the effect of zeaxanthin on uveal melanoma cells has not been reported. The present study investigated the influence of zeaxanthin on viability of cultured human uveal melanoma cells compared to normal ocular cells.
Methods: :
Cell viability of three immortal cell lines of uveal melanoma (SP6.5, M17 and C918) in the presence of zeaxanthin was studied using the MTT test. Normal uveal melanocytes and retinal pigment epithelial cells (ARPE19) were used as controls. Cell apoptosis was determined by annexin V-FITC staining. All studies were conducted in triplicate.
Results: :
Zeaxanthin at 10-100 μM did not change the cell viability in normal uveal melanocytes or retinal pigment epithelial cells. Zeaxanthin at 30 μM significantly (P < 0.05) decreased the cell viability in 2 (SP6.5 and C918) of 3 uveal melanoma cell lines tested and very significantly decreased the cell viability in all uveal melanoma cell lines to 12-44% of the controls (melanoma cells not treated with zeaxanthin) at concentrations of 100 μM (P < 0.01). Annexin V-FITC staining showed that numerous apopototic cells were present in melanoma cells treated with 100 μM zeaxanthin.
Conclusions: :
Zeaxanthin inhibited proliferation of melanoma cells at 30 μM and caused apoptosis at 100 μM, but did not influence the cell viability of normal uveal melanocytes and retinal pigment epithelial cells at concentrations of 30-100 μM. These findings suggest that zeaxanthin has a specific cytotoxic effect on uveal melanoma cells.
Keywords: melanoma • uvea