Anticancer effects of fenretinide in human medulloblastoma.

N-(4-hydroxyphenyl) retinamide (4-HPR, fenretinide) a synthetic retinoid is in clinical trials for the treatment of several malignancies. However, its biological effects and therapeutic value in childhood brain tumor medulloblastoma (MB) has not been investigated. In this study, we report for the first time that fenretinide (2.5-10 microM) induces apoptotic cell death in human MB cells. We observed significant inhibition of cell survival in four MB cell lines (D425MED, D458MED, D283MED and D341MED) as determined by MTT assays. These results were further supported by inhibition of anchorage-independent colony formation in soft agar. Fenretinide-induced decrease in cell viability was in part due to activation of caspase-3 dependent cell death, which was further supported by the cleavage of poly(ADP-ribose) polymerase-1 (PARP-1), a caspase-3 substrate. Cell death was partially prevented by the antioxidant, l-ascorbic acid suggesting that free radical intermediates might be involved in fenretinide effects. These results suggest that pharmacologically achievable concentrations of fenretinide are effective in killing MB cells and thus show its therapeutic potential to treat human MB.