Mai Xu, M.D., Ph.D.

DEPARTMENT OF Radiology
Keywords: DNA repair, hyperthermia, radiation

Dr. Xu’s research focuses on cellular responses to moderate hyperthermia (39ºC to 42.5ºC) and/or ionizing radiation. In the case of hyperthermia, cell lines of heat resistance to 41.1ºC (continued cell proliferation at the elevated temperature) and sensitivity to 41.1ºC have been isolated from the wild-type NSY human colon adenocarcinoma cells. The mechanisms of heat resistance to 41.1ºC are under investigation by using this cell system. In the mechanistic study of heat-induced radiosensitization Dr. Xu examined the Mre11 protein in its localization and association with its functional partner Rad50. Dr. Xu’s research group found that moderate hyperthermia altered the intracellular localization of Mre11 and its association with Rad50. This observation is consistent with the possibility that the heat-induced perturbation in Mre11 localization and its association with Rad50 contributes to a reduction in the repair of DNA double strand breaks and a subsequent increase in radiosensitivity. Recently the research group used RNAi technology to further confirm that the DNA double strand break repair protein Mre11 is one of the targets for radiosensitization by moderate hyperthermia. Dr. Xu’s interest also includes the identification of proteins modified or induced by stress and tumor immuno-targeting therapy.