title: Contribution of caspase-independent pathway to apoptosis in malignant glioma induced by carbon ion beams.
abstract: High linear energy transfer (LET) carbon ion beam (CIB) is becoming the best tool for external radiotherapy of inoperable tumors because of its greater cell killing than conventional low LET gamma or X-rays. In the present study, whether the caspase-independent pathway exerts the important contribution in CIB-induced cell apoptosis was explored. Herein we showed, despite the absence of caspase activity using a pan caspase inhibitor Z-VAD-FMK, that apoptosis induced by high LET CIB were clearly observed in the glioma cells. Simultaneously, the increased 8-OHdG level, PARP-1 activity and AIF translocation occurred in response to CIB irradiation. Moreover, it was distinctly higher in the nuclear translocation frequency along with PARP-1 activation when the caspase protease cascade was suppressed in the irradiated glioma cells. Nuclear colocalization between PARP-1 and AIF as well as a positive association of the PARP-1 mRNA expression with AIF translocation frequency indicated that PARP-1 activation controlled the translocation of AIF to the nucleus. Our findings strongly demonstrated that caspase-independent cell apoptosis provided a prominent compensation in the glioma cell death involving the PARP-1/AIF signaling pathway at 24 h after CIB exposure, and likely triggered by oxidative damage to DNA. The knowledge on the molecular mechanism of AIF-mediated cell death may be very useful for the improvement of the therapeutic efficacy of malignant gliomas with heavy charged particles.
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Luwei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Jiawei
authors.initials: J
authors.lastname: Yan
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Qiuyue
authors.initials: Q
authors.lastname: Zhao
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Cuixia
authors.initials: C
authors.lastname: Di
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Sun
authors.initials: S
authors.lastname: Chao
authors.affiliation: School of Stomatology, Lanzhou University, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Jie
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Heavy Ion Radiation Medicine, Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, Gansu 730000, P.R. China.
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis; D051033:Apoptosis Inducing Factor / Q000235:genetics / Q000378:metabolism; D020169:Caspases / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D005910:Glioma / Q000378:metabolism* / Q000532:radiotherapy; D063193:Heavy Ion Radiotherapy / Q000379:methods*; D006801:Humans; D018499:Linear Energy Transfer; D000071137:Poly (ADP-Ribose) Polymerase-1 / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects*
chemical_list: C494829:AIFM1 protein, human; D051033:Apoptosis Inducing Factor; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D020169:Caspases