Ras-Related Small GTPases RalA and RalB Regulate Cellular Survival After Ionizing Radiation

Oncogenic activation of Ras renders cancer cells resistant to ionizing radiation (IR), but the mechanisms have not been fully characterized. The Ras-like small GTPases, RalA and RalB, are downstream effectors of Ras function and are critical for both tumor growth and survival. The Ral effector RalBP1/RLIP76 mediates survival of mice after whole body irradiation but the role of the Ral GTPases themselves in response to IR is unknown. We have investigated the role of RalA and RalB in cellular responses to IR

A nanotube based electron microbeam cellular irradiator for radiobiology research

A prototype cellular irradiator utilizing a carbon nanotube (CNT) based field emission electron source has been developed for microscopic image-guided cellular region irradiation. The CNT cellular irradiation system has shown great potential to be a high temporal and spatial resolution research tool to enable researchers to gain a better understanding of the intricate cellular and intercellular microprocesses occurring following radiation deposition, which is essential to improving radiotherapy cancer treatment outcomes. In this paper, initial results of the system development are reported. The relationship between field emission current, the dose rate, and the dose distribution has been investigated. A beam size of 23 μm has been achieved with variable dose rates of 1–100 Gy∕s, and the system dosimetry has been measured using a radiochromic film. Cell irradiation has been demonstrated by the visualization of H2AX phosphorylation at DNA double-strand break sites following irradiation in a rat fibroblast cell monolayer. The prototype single beam cellular irradiator is a preliminary step to a multipixel cell irradiator that is under development