||Effects of Carbon Ion Beam Alone or in Combination with Cisplatin on Triple Negative Breast Cancer Stem-Like Cells In Vitro and In Vivo
崔, 星 ,
Vares, Guillaume ,
唐澤, 久美子 ,
堀本, 義哉 ,
Eun Ho, Kim白井, 敏之
AimsTo explore whether a carbon ion beam alone or in combination with cisplatin has beneficial effects by targeting putative triple negative (TN) breast cancer stem cells (CSCs) in vitro and in vivo compared to that of X-ray. Materials and MethodsHuman breast CSCs sorted from MDA-MB-231 and MDA-MB-453 cells were treated with carbon ion beam or X-ray irradiation alone or in combination with cisplatin, and then colony, spheroid and tumor formation assays, RT-PCR Array analysis, immunofluorescence γH2AX foci assay, and in vivo xenograft tumor control analysis were performed. ResultsThe colony, spheroid formation as well as tumorigenicity assays confirmed that CD44-/CD24- and CD44+/ESA+ cells exactly have CSC properties compared to CD44-/CD24- and CD44-/ESA- cells. CSCs were more highly enriched after X-ray or cisplatin compared to carbon ion beam. The relative biological effectiveness (RBE) values for the carbon ion beam relative to X-ray at the D10 levels for CSCs were 2.01-2.23. Carbon ion beam combined with cisplatin significantly suppressed colony and spheroid formation compared to that of X-ray combined with cisplatin as well as carbon ion alone. RT-PCR Array analysis showed that carbon ion beam combined with cisplatin significantly induced apoptosis-related Cytochrome c, almost completely eliminated expression of CSC markers CD44 and ESA, and significantly inhibited angiogenesis-, metastasis-related HIF1α and CD26 compared to that of carbon ion beam, X-ray alone, or X-ray combined with cisplatin. Immunofluorescence assay showed that not only the number but also the size of γH2AX foci in CSCs were lager 24 h after carbon ion beam combined with cisplatin compared to that of X-ray combined with cisplatin as well as carbon ion alone. In vivo study showed that 30 Gy of carbon ion bea alone or 20 Gy combined with 5 mg/kg cisplatin effectively destroyed xenograft tumor bulk with dramatically undetectable CSC markers compared to that of X-ray. ConclusionCarbon ion beam combined with cisplatin has superior potential to kill TN breast CSCs in vitro and in vivo with unrepairable severe DNA damage and enhanced apoptosis as well as autophagy.
The 15th International Congress of Radiation Research (ICRR 2015)