Effects of Carbon Ion Beam Alone or in Combination with Cisplatin on Malignant Mesothelioma Cells In Vitro and In Vivo

Malignant mesothelioma (MM) is extremely aggressive and a typical refractory cance. In this study we investigated how effective on killing MM cells by carbon ion beam alone or in combination with cisplatin (CDDP) in vitro and in vivo. MM cells MESO-1 and H226 were treated with carbon ion beam or X-ray irradiation alone or in combination with CDDP (25M). Carbon ion beam dose-independently suppressed H226 and MESO-1 cell viability and in combination with CDDP significantly enhanced its action. RBE of carbon ion beam was calculated as 2.8-2.9 at D10 level compared to X-ray. Apoptosis analysis showed that caspase 3/7 activity and the percentage of apoptotic cells was dose-dependently increased after carbon ion beam and it was further increased when combined with CDDP. Spheroid formation ability of cancer stem like CD24+/CD26+ cells was significantly inhibited by carbon ion beam combined with CDDP. In vivo study showed that carbon ion beam with 25Gy significantly suppressed H226 xenograft tumor. In conclusion, carbon ion beam combined with CDDP has superior potential to kill MM cells with enhanced apoptosis.第75回日本癌学会総