RELATIONSHIP BETWEEN GAMMA-RAY-INDUCED G(2)/M DELAY AND CELLULAR RADIOSENSITIVITY
RELATIONSHIP BETWEEN GAMMA-RAY-INDUCED G(2)/M DELAY AND CELLULAR RADIOSENSITIVITY
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DOI：
10.1080/09553009414551311
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发表时间：
1994-10-01
影响因子：
2.6
通讯作者：
LITTLE, JB
中科院分区：
文献类型：
--
作者：
NAGASAWA, H;KENG, P;LITTLE, JB
通过抗Br-dUrd抗体和流式细胞术方法检查了细胞放射敏感性显着不同的七种人类和啮齿动物细胞系，以测量γ射线照射后S期细胞的进展及其在细胞周期G（2）期的积累。指数生长的细胞用10 μ M BrdUrd标记2小时，γ-照射，然后洗涤并在37 ℃培养。在2小时的间隔postirradiation，细胞收获和固定的流式细胞仪分析。分析了BrdUrd含量和DNA含量的两个参数分布。人鳞癌细胞系SCC-12 B.2（D-0 = 2.66戈伊）、SQ-20 B（D-0 = 2.39戈伊）和SCC-61（D-0 = 1.07戈伊）以及野生型CHO细胞（D-0 = 2.62戈伊）从S期到G（2）/M期的时间间隔约为450 min。2戈伊照射后，SCC-12 B.2、SQ-20 B、CHO和人二倍体AG 1521细胞均出现类似的小G（2）/M延迟（约1 h），而放射敏感的SCC-61细胞出现约2.2 h的G（2）/M延迟，两种极敏感的突变细胞株（分别为人AT纯合子和CHO xrs-5）出现5.0-7.7 h的G（2）/M延迟。然而，当细胞以产生相似存活水平（约10%）的剂量照射时，所有7个细胞的G（2）/M延迟的持续时间通常相似（2-4小时），线表明辐射诱导的G（2）/M延迟和细胞辐射敏感性之间的平行关系。这些结果表明，延迟时间可能与细胞接近有丝分裂时存在的未修复损伤的水平有关。
Seven human and rodent cell lines with markedly differing cellular radiosensitivities were examined by the anti-Br-dUrd antibody and flow cytometric method in order to measure the progression of S phase cells and their accumulation in the G(2) phase of the cell cycle after gamma-irradiation. Exponentially growing cells were labelled with 10 mu M BrdUrd for 2 h, gamma-irradiated, then washed and cultured at 37 degrees C. At 2-h intervals postirradiation, the cells were harvested and fixed for flow cytometric analysis. Two parameter distributions of BrdUrd content and DNA content were analysed. The time intervals for unirradiated labelled cells to prepress from S to G(2)/M phase were about 450 min for the human squamous cell carcinoma cell lines SCC-12B.2 (D-0 = 2.66 Gy), SQ-20B (D-0 = 2.39 Gy) and SCC-61 (D-0 = 1.07 Gy) as well as for wild-type CHO cells (D-0 = 2.62 Gy). After irradiation with 2 Gy, SCC-12B.2, SQ-20B, CHO and human diploid AG1521 cells showed similar small G(2)/M delays (about 1 h), whereas, a G(2)/M delay of about 2.2 h occurred in radiosensitive SCC-61 cells and delays of 5.0-7.7 h were observed in two extremely radiosensitive mutant cell strains (human AT homozygote and CHO xrs-5 respectively). When the cells were irradiated with doses yielding similar levels of survival (about 10%), however, the duration of the G(2)/M delay was generally similar (2-4 h) in all seven cell, lines indicating a parallel relationship between radiation-induced G(2)/M delay and cellular radiosensitivity. These results suggest that the delay time may be related to the level of unrepaired damage present in the cell as it approaches mitosis.