摘要
通过对小鼠乳腺癌放射敏感细胞SX 9照射前、后细胞周期分布及其 p5 3基因状态等研究 ,初步探讨其放射敏感性与照射后细胞周期阻滞的关系。方法 利用克隆形成法比较SX 9与SR 1细胞照射后细胞存活份数及流式细胞术研究其细胞周期分布的差异 ;RT PCR克隆并鉴定p5 3基因 ;DNA电泳、流式细胞术和苔盼蓝染色研究细胞死亡方式。 结果 SX 9细胞对γ射线高度敏感 ,照射后G1 期阻滞消失 ,但仍存在G2 期阻滞 ;其 p5 3基因第 5外显子存在突变 ,DNA电泳检测不到DNAladder;苔盼蓝染色检测到的细胞死亡比例与对照组无显著差异。结论 γ射线照射放射敏感细胞SX 9细胞周期改变与其亲本细胞SR 1明显不同。SX 9亲本细胞SR 1细胞存在G1 ,G2 期阻滞。DNA电泳及苔盼蓝染色检测结果与SX 9细胞相同。结果表明SX 9细胞对放射敏感不是由于照射后细胞凋亡所致 ,而是由于其失去增殖能力引起增殖死亡的结果。
Objective To investigate cell cycle distribution of radiosensitive cell line SX-9 after X-ray irradiation and the relationship between radiosensitivity and cell cycle distribution. Methods The survival fraction of SX-9 to SR-1 was compared with clonegenic assay,cell cycle distribution and p53 gene status were investigated with FCM and RT-PCR respectively. Results SX-9 is radiosensitive compared with its parental cell line SR-1. Because of its p53 mutation in exson 5,only G 2 arrest was found in SX-9 cell line .Apoptosis was not observed in either of these two cell lines after DNA electrophoresis,flow cytometry and trypan blue staining. Conclusions Irradiation of serum-starved synchronous cells show a prolonged delay in G 2 for radiosensitive cell line SX-9 and in G 1 and G 2 for its parental cell line SR-1,whereas no differences are found in DNA electrophoresis,flow cytometry and trypan blue staining between these two cell lines. It implicates the deficiency in the rejoining of DNA DSB during G 2-phase delay as a possible cause for its radiosensitivity,although the mechanism is not fully understood.
出处
《中华放射肿瘤学杂志》
CSCD
北大核心
2000年第2期124-127,共4页
Chinese Journal of Radiation Oncology
基金
国家自然科学基金资助项目 !(3990 0 0 31)
