Effects of the heavy ion beam irradiation on the expression of ICAM-1 and TGF-β1 on HUVEC

Abstract

PURPOSE: The adhesion of inflammatory cells to endothelial cells has been reported to be involved in radiation-induced fibrosis. In this process, intercellular adhesion molecule-1 (ICAM-1) and transforming growth factor-beta 1 (TGF-β1) are suggested to play important roles. We investigated about the radiation-induced ICAM-1 expression to elucidate the relative biological effectiveness (RBE) of carbon-ion beam to X-ray with or without an inhibitor of TGF-β1 receptor kinase (SB431542).MATERIALS AND METHODS: Cell cultures of human umbilical vein endothelial cells (HUVEC) were irradiated with single doses of 1-10Gy of the 140 KV X-ray and 0.1-5.0Gy of 220MeV carbon-ion beams (108 keV/μm). Fluorescence-activated cell sorting analysis was used to quantify ICAM-1 expression at 24 and 48 hours after irradiation with or without SB431542.RESULTS: The expression of ICAM-1 was increased after X-ray and carbon-ion beam irradiations. The expression of ICAM-1 was significantly increased with the stimulation of TGF-β1, and decreased significantly by addition of SB431542 after carbon-ion beam irradiation. The expression of ICAM-1 increased by 6 folds with carbon-ion beam irradiation of 0.1-5Gy as compared with untreated control cells, while X-ray irradiation increased by 2.3 folds. The ICAM-1 expression was about 3 times greater in carbon-ion beam irradiation than that in X-ray irradiation.CONCLUSION: The present results suggested that radiation-induced ICAM-1 expression on HUVEC was regulated by TGF-β1. The RBE of carbon-ion beam to X-ray was about 3 for the expression of ICAM-1.