title: Low‑dose radiation‑induced apoptosis in human leukemia K562 cells through mitochondrial pathways.
abstract: High‑dose total body irradiation (TBI) has an established role as preparative regimen for bone‑marrow transplantation in the treatment of chronic myelogenous leukemia (CML), but this regimen still has a relatively high rate of acute and late toxicity. Low‑dose radiation (LDR) induces apoptosis of tumor cells and has numerous beneficial effects on normal tissues, including radiation homeostasis and adaptive response. Based on the previous evidence, in the present study, K562 cells were exposed to LDR, high‑dose radiation (HDR), and LDR in combination with HDR to investigate the possible mechanism of the apoptotic effect and hypersensitivity induced by LDR. The apoptotic rate increased in all radiation groups in a time‑dependent manner. An upregulation of Bax protein expression and a downregulation of Bcl‑xl in a dose‑dependent manner in human leukemia K562 cells was observed. However, the expression of p53 protein did not change in all of the radiation cell groups. The mitochondrial membrane potential (ΔΨm) in K562 cells decreased in all of the radiation cell groups in a dose‑dependent manner. Furthermore, the decrease of ΔΨm was enhanced in the LDR/HDR group compared with that in the LDR or HDR groups. The activity of caspase‑3 was enhanced in all of the radiation groups. In the LDR/HDR group, the activity of caspase‑3 was higher than that in the HDR or LDR groups. The present study provided preliminary experimental evidence of LDR being beneficial in combination with TBI in the treatment of CML.
authors: Department of Radiotherapy, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China.
authors: Yong
authors: Y
authors: Xin
authors: Department of Radiotherapy, Huzhou Central Hospital, Huzhou, Zhejiang 313000, P.R. China.
authors: Hai-Bin
authors: HB
authors: Zhang
authors: Department of Radiotherapy, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China.
authors: Tian-You
authors: TY
authors: Tang
authors: Department of Radiotherapy, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China.
authors: Gui-Hong
authors: GH
authors: Liu
authors: Department of Radiotherapy, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China.
authors: Jian-She
authors: JS
authors: Wang
authors: Jiangsu Key Laboratory of Biological Cancer Therapy, Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China.
authors: Guan
authors: G
authors: Jiang
authors: Department of Radiotherapy, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China.
authors: Long-Zhen
authors: LZ
authors: Zhang
mesh_terms: D017209:Apoptosis / Q000528:radiation effects*; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism; D004307:Dose-Response Relationship, Radiation; D015536:Down-Regulation; D006801:Humans; D020014:K562 Cells; D008928:Mitochondria / Q000528:radiation effects*; D051028:bcl-2-Associated X Protein / Q000235:genetics / Q000378:metabolism*; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C494826:BAX protein, human; C494811:BCL2L1 protein, human; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; C505407:CASP3 protein, human; D053148:Caspase 3