title: Effects of carbon-ion beams on human pancreatic cancer cell lines that differ in genetic status.
abstract: The relative biologic effectiveness (RBE) of carbon-ion beams at 3 different linear energy transfer (LET) values (13, 50, and 80 keV/microm) accelerated by the Heavy Ion Medical Accelerator in Chiba on human pancreatic cancer cell lines differing in genetic status was determined. The RBE values were calculated as D10, the dose (Gy) required to reduce the surviving fraction to 10%, relative to X-rays. We also investigated apoptosis and the relationship between D10 and the cell cycle checkpoint using morphologic examination and flow cytometry analysis, respectively. The RBE values calculated by the D10 values ranged from 1.16 to 1.77 for the 13-keV/microm beam and from 1.83 to 2.46 for the 80-keV/microm beam. A correlation between the D10 values of each cell line and intensity of G2/M arrest was observed. In contrast, LET values did not clearly correlate with induction of apoptosis. These results suggest that carbon-ion beam therapy is a promising modality. Elucidation of the mechanisms of G2/M arrest and apoptosis may provide clues to enhancing the effects of radiation on pancreatic cancer.
authors.affiliation: Frontier Research Center, National Institute of Radiological Sciences, Chiba, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Matsui
authors.forename: Takehide
authors.initials: T
authors.lastname: Asano
authors.forename: Takashi
authors.initials: T
authors.lastname: Kenmochi
authors.forename: Mayumi
authors.initials: M
authors.lastname: Iwakawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Imai
authors.forename: Takenori
authors.initials: T
authors.lastname: Ochiai
mesh_terms: D017209:Apoptosis; D002244:Carbon; D002453:Cell Cycle; D045744:Cell Line, Tumor / Q000528:radiation effects*; D002470:Cell Survival; D006801:Humans; D007477:Ions; D018499:Linear Energy Transfer; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000532:radiotherapy*; D012062:Relative Biological Effectiveness
chemical_list: D007477:Ions; D002244:Carbon