Chan D W, Gately D P, Urban S, Galloway A M, Lees-Miller S P, Yen T, Allalunis-Turner J
Department of Biological Sciences, University of Calgary, Alberta, Canada.
Int J Radiat Biol. 1998 Aug;74(2):217-24. doi: 10.1080/095530098141591.
Cells derived from individuals in which the ataxia telangiectasia (ATM) gene is mutated are hypersensitive to ionizing radiation. Whether differences in ATM protein levels exist among human malignant glioma cell lines and whether such differences are correlated with cellular radiosensitivity were determined.
Polyclonal antibodies were raised to separate regions of the ATM protein. ATM protein expression in human malignant glioma cell lines, SV40 transformed normal human fibroblasts and SV40 transformed AT fibroblasts was analysed by Western blotting. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to assess the presence of ATM transcript.
While ATM protein was detected in all cell extracts, significant differences in the level of expression were observed. There was no apparent correlation between cellular radiosensitivity and differences in ATM protein levels in these human glioma cells. Extremely low levels of ATM protein were observed in M059J cells, which provide the only example of DNA-dependent protein kinase (DNA-PKcs) deficiency in a cell line of human origin.
Variations in the levels of ATM protein are insufficient to explain the differences in cellular radiosensitivity observed in a panel of human malignant glioma cell lines.
共济失调毛细血管扩张症（ATM）基因突变个体来源的细胞对电离辐射高度敏感。本研究旨在确定人类恶性胶质瘤细胞系中ATM蛋白水平是否存在差异，以及这种差异是否与细胞放射敏感性相关。
制备针对ATM蛋白不同区域的多克隆抗体。通过蛋白质免疫印迹法分析人类恶性胶质瘤细胞系、SV40转化的正常人成纤维细胞和SV40转化的共济失调毛细血管扩张症成纤维细胞中ATM蛋白的表达。采用逆转录聚合酶链反应（RT-PCR）评估ATM转录本的存在情况。
虽然在所有细胞提取物中均检测到ATM蛋白，但观察到表达水平存在显著差异。在这些人类胶质瘤细胞中，细胞放射敏感性与ATM蛋白水平差异之间无明显相关性。在M059J细胞中观察到极低水平的ATM蛋白，该细胞系是人类来源细胞系中唯一存在DNA依赖性蛋白激酶（DNA-PKcs）缺陷的例子。
ATM蛋白水平的变化不足以解释一组人类恶性胶质瘤细胞系中观察到的细胞放射敏感性差异。
