HL-60和SiHA细胞株ATM表达量与^(60)Co照射后细胞周期阻滞之间的关系

Relationship between Ataxia Telangiectasia Mutant (ATM)Expression of HL-60and SiHA Cell Lin es and Their Cell Cycle Arrest after ^(60)Co Radiation

背景与目的:毛细血管扩张性共济失调综合征(ataxiatelangiectasia,AT)是由ATM(ataxiatelangiectasiamutant)基因所致,其突出特点是对放射线非常敏感,因此,ATM表达与放射敏感性应存在相关性。本研究旨在探讨两种肿瘤细胞株ATM表达量与60Co照射后细胞周期阻滞功能之间的关系。方法:使用半定量RT-PCR和流式细胞仪技术检测HL-60细胞和SiHA细胞中ATMmRNA和ATM蛋白表达量,同时以6、10和15Gy60Co照射SiHA细胞,HL-60细胞仅以6、10Gy照射,于照射后6、12、24、48及60h观察细胞周期阻滞现象和细胞凋亡率的变化。结果:HL-60细胞ATM平均蛋白荧光强度为14.11±2.38,SiHA细胞为27.74±1.16,约为HL-60细胞的2倍;HL-60细胞ATMmRNA相对表达量为0.09,SiHA细胞为0.80,约为HL-60细胞的9倍。照射后HL-60细胞和SiHA细胞均表现G2/M期阻滞。射线对HL-60细胞周期阻滞功能明显较SiHA细胞弱。结论:放射线对HL-60细胞和SiHA细胞的周期阻滞功能与ATM表达量相符,即ATM表达量低,细胞周期阻滞功能差。

BACKGROUND &OBJECTIVE:Ataxia telang iectasia is caused by ataxia telang iectasia mutant (ATM)g ene and it is characterized by hyper sensi-tivity to the radiation.So the ATM expression should be related to the rad iation sensitivity.This study was desig ned to investig ate the relationship be tween ATM expression in two kinds of tumor cell lines and their cell cycle arrest after irradiation of ionization radiatio n to explore their self-protection f unction.METHODS :ATM mRNA and protein expression of HL-60and SiHA cell lines were measured by semi-quantitive revers e transcription polymerase chain re action(RT-PCR)and flow cytometry.The cells were ir radiated at the dose of 6,10,and15Gy by 60 Co and the chang e of apoptosis and cel l cycle arrest phenomenon at the time of 6,12,24,48,and 60hours a fter the radiation were observed.RESULTS :The ATM mean protein fluorescent int ensity of HL-60and SiHA cells were 14.11±2.38and 27.74±1.16,respectively.The ATM protein abund ance in SiHA was two times more than that in HL-60,and consistent with this ,the ATM RNA relative expression of HL-60and SiHA cells were 0.09and 0.80,respectively.The ATM transcript le vels in SiHA are 9times more than that in HL-60.The G 2 /M phase arrest after the radiation w as observed in both cell lines ,whereas SiHA exhibits a much s trong cell cycle arrest than HL-60.CONCLUSION:The cell cycle arrest of HL-60and SiH A cell lines to the irradiation corresponds to their ATM expression levels.The lower ATM expression,th e weaker response for cell cycle arrest induc ed by radiation.