Indole-3-carbinol (I3C)-induced apoptosis in nasopharyngeal cancer cells through Fas/FasL and MAPK pathway

The apoptotic effects of indole-3-carbinol (I3C) were exhibited in many human cancer cells. However, the apoptotic effects of I3C on nasopharyngeal cancer cells were still unknown. In this study, we first examined the potential effects of I3C on the induction of apoptosis in human nasopharyngeal cancer cells CNE-2 and further characterized the mechanism(s) involved in the effects. Apoptotic cells after treatment with I3C were analyzed by flow cytometry. The change in relative mitochondrial transmembrane potential in the CNE-2 cells was analyzed with rhodamine 123 staining. The protein levels of MAPK family and Fas/FasL were examined by Western blot. Our results indicated that I3C could induce apoptosis of CNE-2 cells in a dose- and time-dependent manner accompanied with increased mitochondrial membrane potential. Treatment with I3C significantly suppressed XIAP, c-IAP1 and Survivin protein, while elevated the expression of Omi, Smac and Cyto-c. Fas/FasL and MAPK pathway were involved in the induction of apoptosis. Taken together, these results demonstrated that I3C may induce mitochondria-mediated apoptosis via the Fas death receptor in CNE-2 cells. This molecular mechanism for apoptotic effect of I3C on nasopharyngeal cancer cells suggested that I3C might become a preventive and therapeutic agent against nasopharyngeal cancer.