?-Tocopherol Induces Apoptosis in Androgen-Responsive LNCaP Prostate Cancer Cells via Caspase-Dependent and Independent Mechanisms
We found that ?-tocopherol, the predominant vitamin E form in diets, but not ?-tocopherol, which is the exclusive form of vitamin E in most supplements, exhibited antiproliferation effect on prostate (PC-3, LNCaP) and lung (A549) cancer cells. ?-Tocopherol induced apoptosis in androgen-sensitive LNCaP but not androgen-resistant PC-3 cells. Consequently, ?-tocopherol treatment caused cytochrome c release and caspase-9, -3 and -7 activation. However, the apoptosis could not be completely reversed by an irreversible pancaspase inhibitor, indicating that an alternative caspase-independent pathway may also be involved. Our study suggests that ?-tocopherol may be valuable in the prevention and therapy for certain types of cancer.
?-tocopherol apoptosis prostate cancer vitamin e caspase