p53-Dependent G(1) arrest and p53-independent apoptosis influence the radiobiologic response of glioblastoma
p53-Dependent G(1) arrest and p53-independent apoptosis influence the radiobiologic response of glioblastoma
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DOI：
10.1016/s0360-3016(96)00244-1
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发表时间：
1996-08-01
影响因子：
7
通讯作者：
Israel, MA
中科院分区：
文献类型：
--
作者：
HaasKogan, DA;Yount, G;Israel, MA
目的：在许多恶性肿瘤中，p53肿瘤抑制基因的缺失与肿瘤进展、疾病复发、抗肿瘤治疗反应差以及预后不良有关。我们研究了p53介导的辐射诱导的细胞凋亡和G(1)阻滞对多形胶质母细胞瘤（GM）细胞的辐射抗性的贡献。方法和材料：使用线性二次型和修复饱和数学模型定量体外辐射存活，使用表达p53显性阴性突变的逆转录病毒载体生成仅p53状态不同的胶质母细胞瘤细胞等基因衍生物。采用荧光活化细胞分选仪（FAGS）分析、末端脱氧核苷酸转移酶标记技术和染色质形态学检测辐射诱导的细胞凋亡。细胞在G(1)期早期同步，并测量有丝分裂和标记指数。结果：辐射诱导的GM细胞凋亡与功能性轻型p53 （wt p53）无关。降低对辐射诱导的细胞凋亡的易感性与较低的α值有关，这是克隆源性辐射生存曲线肩部的特征。使用p53活性不同的等基因转基因细胞，我们发现p53介导的功能，辐射诱导的G(1)阻滞，也可以影响a和克隆性辐射抗性的值。p53显性负突变体使wt p53功能失活，导致α值显著降低，但细胞对辐射诱导的凋亡的易感性没有改变。克隆衍生物U87-LUX。表达功能wt p53的8的Eta alpha （Gy(-1)）值为0.609，而缺乏wt p53功能的等基因克隆衍生物U87-175.4的alpha （GS(-1)）值为0.175。结论：我们得出结论，两种不同的细胞对辐射的反应，p53不依赖的细胞凋亡和p53依赖的G(1)-阻滞，影响表征胶质母细胞瘤细胞辐射反应的放射生物学参数，进一步了解转基因辐射抗性的分子基础将导致现有治疗方式的改进和新的治疗方法的发展。
Purpose: Loss of the p53 tumor suppressor gene has been associated with tumor progression, disease relapse, poor response to antineoplastic therapy, and poor prognosis in many malignancies. We have investigated the contribution of p53-mediated radiation-induced apoptosis and G(1) arrest to the well described radiation resistance of glioblastoma multiforme (GM) cells.Methods and Materials: Radiation survival in vitro was quantitated using linear quadratic and repair-saturation mathematical models, Isogenic derivatives of glioblastoma cells differing only in their p53 status were generated using a retroviral vector expressing a dominant negative mutant of p53. Radiation-induced apoptosis was assayed by Flourescence-activated cell sorter (FAGS) analysis, terminal deoxynucleotide transferase labeling technique, and chromatin morphology. Cells were synchronized in early G(1) phase and mitotic and labeling indices were measured.Results: Radiation-induced apoptosis of GM cells was independent of functional mild-type p53 (wt p53). Decreased susceptibility to radiation-induced apoptosis was associated with lower alpha values characterizing the shoulder of the clonogenic radiation survival curve. Using isogenic GM cells differing only in their p53 activity, we found that a p53-mediated function, radiation-induced G(1) arrest, could also influence the value of a and clonogenic radiation resistance. Inactivation of wt p53 function by a dominant negative mutant of p53 resulted in a significantly diminished alpha value with no alteration in cellular susceptibility to radiation-induced apoptosis. The clonal derivative U87-LUX.8 expressing a functional wt p53 had an Eta alpha (Gy(-1)) value of 0.609, whereas the isogenic clonal derivative U87-175.4 lacking wt p53 function had an alpha (GS(-1)) value of 0.175.Conclusion: We conclude that two distinct cellular responses to radiation, p53-independent apoptosis and p53-dependent G(1)-arrest, influence radiobiological parameters that characterize the radiation response of glioblastoma cells, Further understanding of the molecular basis of GM radiation resistance will lead to improvement in existing therapeutic modalities and to the development of novel treatment approaches.