We have tested several novel modulators that target the pathways relevant to ionizing radiation and metabolism. We have used clonogenic survival assays of human tumor cells in vitro to characterize the temporal components and dose-dependency of the response to ionizing radiation. We have also begun testing these modulators in in vivo xenograft models to determine the correlation with our in vitro results. We have also begun investigating potential mechanisms and related pathways in order to better understand our results.