Dietary antioxidant depletion: enhancement of tumor apoptosis and inhibition of brain tumor growth in transgenic mice

Apoptosis, or regulated cell suicide, eliminates unwanted and damaged cells , including precancerous and cancerous cells. Since reactive oxygen species (ROS) act as essential apoptotic mediators, we reasoned that increasing th e ROS level might enhance apoptosis and thereby slow down tumor growth, Her e, using a defined transgenic brain tumor model with known tumor apoptosis rates, we test the impact of antioxidant-depleted diet, capable of increasi ng ROS levels, or antioxidant-enriched diets on tumor growth, Dramatically increased apoptosis occurs within tumors, but not in normal tissues of anti oxidant-depleted mice. The presence of detectable increased oxidant stress within tumors indicates that the likely mechanism of enhanced tumor apoptos is is via ROS and DNA oxidative impairment. Importantly, due to the ROS-enh anced apoptosis, tumor growth is inhibited in mice fed an antioxidant-deple ted diet. In clear contrast, an antioxidant-rich diet had no impact on tumo r growth.