Clarification of metastasis and angiogenesis inhibition by heavy ion

The purpose of this study is to investigate the effects on metastatic potential and angiogenesis of cancer cells and to clarify their mechanisms. We previously reported carbon ion beam irradiation suppressed activity of metastasis-related molecules, anillin and RhoA. They play very crucial role for formation or organization of actin structures, contributed to cell motility, migration and invasion. In this study, we demonstrated that carbon ion beam irradiation suppressed PI3K/Akt activity, the regulator of anillin and Rho family, though that was up-regulated by low-dose X-ray irradiation. Our study revealed that carbon ion beam irradiation enhanced the cell adhesion capabilities and up-regulated the expression of integrin α6β1. Integrin α6β1 is essential for adherence to the extracellular matrix. Here, we report that carbon ion beam irradiation suppressed the motility and tube formation capability of vascular endothelial cells. In addition, we investigated the effect of the combination of antiangiogenic agent and carbon ion beam irradiation, compared pre-IR or post-IR administration, in vivo. As a result, carbon ion beam irradiation and post-IR administration is more effective for suppression of lung metastasis than pre-IR administration. (author)