title: DNA damage response in resting and proliferating peripheral blood lymphocytes treated by camptothecin or X-ray.
abstract: DNA damage response (DDR) in different cell cycle status of human peripheral blood lymphocytes (PBLs) and the role of H2AX in DDR were investigated. The PBLs were stimulated into cell cycle with phytohemagglutinin (PHA). The apoptotic ratio and the phosphorylation H2AX (S139) were flow cytometrically measured in resting and proliferating PBLs after treatment with camptothecin (CPT) or X-ray. The expressions of γH2AX, Bcl-2, caspase-3 and caspase-9 were detected by Western blotting. DDR in 293T cells was detected after H2AX was silenced by RNAi method. Our results showed that DNA double strand breaks (DSBs) were both induced in quiescent and proliferating PBLs after CPT or X-ray treatment. The phosphorylation of H2AX and apoptosis were more sensitive in proliferating PBLs compared with quiescent lymphocytes (P<0.05). The expression levels of anti-apoptotic proteins Bcl-2 were reduced and cleaved caspase-3 and caspase-9 were increased. No significant changes were observed in CPT-induced apoptosis in 293T cells between H2AX knocking down group and controls. It was concluded that proliferating PBLs were more vulnerable to DNA damage compared to non-stimulated lymphocytes and had higher apoptosis rates. γH2AX may only serve as a marker of DNA damage but exert no effect on apoptosis regulation.
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Tian
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Feng
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Min
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Wanjun
authors.initials: W
authors.lastname: Gong
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Xiaolan
authors.initials: X
authors.lastname: Li
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Deding
authors.initials: D
authors.lastname: Tao
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
authors.forename: Junbo
authors.initials: J
authors.lastname: Hu
authors.affiliation: Tongji Cancer Research Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China. jpgong@tjh.tjmu.edu.cn.
authors.forename: Jianping
authors.initials: J
authors.lastname: Gong
mesh_terms: D017209:Apoptosis / Q000502:physiology; D002166:Camptothecin / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism; D053453:Caspase 9 / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects / Q000528:radiation effects; D006657:Histones / Q000378:metabolism; D006801:Humans; D008214:Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000528:radiation effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D014965:X-Rays
chemical_list: C468783:H2AX protein, human; D006657:Histones; D019253:Proto-Oncogene Proteins c-bcl-2; C505407:CASP3 protein, human; C506433:CASP9 protein, human; D053148:Caspase 3; D053453:Caspase 9; D002166:Camptothecin