Kaffenberger W, van Beuningen D
Institute of Radiobiology, Federal Armed Forces Medical Academy, Munich, Germany.
Int J Radiat Biol. 1994 Dec;66(6):767-74.
Induced differentiation of the promyelocytic leukaemia cell line, HL-60, is associated with the acquisition of functional properties, like the expression of specific receptors and the competence to exert the respiratory burst (RB). In this system we evaluated the effects of ionizing radiation on the signal transduction processes involved in the activation of the respiratory burst/NADPH oxidase. HL-60 cells were X-irradiated with up to 1 Gy and induced towards granulocytic differentiation by treatment with 1.25% DMSO on day 0. The expression of the formyl peptide receptor (FPR), the development of responsiveness of the cells to its ligand (f-MLP) and to 4 beta-phorbol 12-myristate 13-acetate (PMA) were measured up to day 7 postinduction/irradiation. Using flow cytometry, fluorescinated formyl-hexapeptide or unlabelled f-MLP as ligands and dihydrorhodamine 123 (DHR 123) as an indicator of RB activity, respectively, the acquisition of functional responsiveness to both stimuli was determined. Immature FPR were identified at day 2 after induction which responded to the agonist from day 3 on. F-MLP receptor-mediated RB oxidase activation was completely radioresistant to 1 Gy, while protein kinase C (PKC)-stimulated triggering of the enzyme via PMA was inhibited by about 50% by 0.5 and 1.0 Gy. We conclude that different signal transduction pathways as triggered by f-MLP and PMA respectively exhibit differences in radiosensitivity, with PKC subspecies and downstream responses being possible sites of radiation damage.
早幼粒细胞白血病细胞系HL-60的诱导分化与功能特性的获得有关，如特定受体的表达以及产生呼吸爆发（RB）的能力。在这个系统中，我们评估了电离辐射对参与呼吸爆发/NADPH氧化酶激活的信号转导过程的影响。HL-60细胞在第0天用高达1 Gy的X射线照射，并通过用1.25%二甲亚砜处理诱导向粒细胞分化。在诱导/照射后第7天之前，检测甲酰肽受体（FPR）的表达、细胞对其配体（f-MLP）和4β-佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）的反应性发展。分别使用流式细胞术、荧光甲酰六肽或未标记的f-MLP作为配体以及二氢罗丹明123（DHR 123）作为RB活性的指标，确定对两种刺激的功能反应性的获得。诱导后第2天鉴定出未成熟的FPR，从第3天开始对激动剂有反应。F-MLP受体介导的RB氧化酶激活对1 Gy完全具有辐射抗性，而蛋白激酶C（PKC）通过PMA刺激触发该酶的作用在0.5和1.0 Gy时被抑制约50%。我们得出结论，分别由f-MLP和PMA触发的不同信号转导途径在放射敏感性上存在差异，PKC亚型和下游反应可能是辐射损伤的位点。
