FIBROBLAST GROWTH FACTOR-IV ENHANCED G(2) ARREST AND CELL-SURVIVAL FOLLOWING IONIZING-RADIATION

Fibroblast growth factors (FGFs) bind to cell membrane receptors and a ctivate signal transduction pathways related to cell growth, angiogene sis, and tumorigenesis. FGFs have been shown to be abundantly expresse d in some of the human tumors, which are known to be poorly responsive to radiation therapy. Using adrenal cortical carcinoma cells genetica lly engineered to express FGF-4, we have tested cellular survival foll owing exposure to ionizing radiation. We report here that FGF-4 enhanc es cellular capacity to survive ionizing radiation. Furthermore, cell cycle analysis shows a pronounced increase in the duration of G(2) arr est, suggesting perturbation of a cell cycle checkpoint. These finding s implicate fibroblast growth factor-mediated signal transduction in c ellular resistance of human tumors to radiation therapy.