X线照射后肺癌细胞肿瘤坏死因子mRNA的表达

TNF α mRNA expression in lung cancer cell lines induced by ionizing radiation

目的探讨X线诱导和调节肺癌细胞株NCI-H596和A549肿瘤坏死因子(TNF-α)mRNA的表达作用及其临床意义。方法应用实时荧光定量RT-PCR技术,定量检测NCI-H596和A549细胞株照射前和接受不同剂量(2,5,10,20,30和40Gy)的X线照射后,以及受照30Gy后不同时间TNF-αmRNA的表达。同时进行集落形成试验,检测NCI-H596和A549细胞株的放射敏感性。结果集落形成试验结果显示,未照射的NCI-H596细胞株集落形成率为0.12～0.24;A549细胞株集落形成率为0.37～0.45。照射后,A549细胞的存活分数(SF)在2Gy时为47.3%±9.0%,4Gy时为18.0%±3.0%,6Gy时为6.0%±2.0%,8Gy时为1.4%±0.3%;NCI-H596细胞的SF在2Gy时为55.2%±51.0%,4Gy时为15.9%±9.2%,6Gy时为3.5%±1.7%;8Gy时为0.9%±0.6%;二者SF差异无统计学意义,二者的D0值和Dq值差异亦无统计学意义(P>0.05)。实时荧光定量RT-PCR检测显示,NCI2H596细胞受照后TNF-αmRNA表达逐渐升高,照射剂量达40Gy时,TNF-αmRNA表达水平达高峰,为对照组的83倍;受照后,1hTNF-αmRNA表达逐渐升高,6h达高峰,为对照组的568倍。A549细胞受照后,1hTNF-αmRNA表达即达高峰,为对照组的136倍。结论X线可诱导肺癌细胞株A549和NCI2H596产生TNF-α,且呈剂量、时间依赖性,可提高肺癌放射治疗的疗效,也可对正常组织和?

Objective The aim of this study is to investigate the release of TNF α mRNA in two lung cancer cell lines in vitro and the regulation of TNF α mRNA expression by ionizing radiation. Methods Two lung cancer cell lines (A549 and NCI H596)were investigated for their TNF α mRNA expression before and after exposure to different irradiation doses (2, 5, 10, 20, 30 and 40 Gy) and at different time intervals (1, 3, 6, 12, 24, 48 and 72 hours after irradiation). The TNF α mRNA expression was quantified by fluorescence based real time quantitative RT PCR. Colony formation assays were performed after irradiation with a dose of 2, 4, 6, and 8 Gy to determine the clonogenic survival. Results Dependent on the dose given, irradiation was found to cause increasing induction of TNF α mRNA expression of NCI H596 cells, reaching maximal level after 40 Gy irradiation, which was 83 times higher than that of normal controls. On the other hand, dependent on the time after irradiation, TNF α mRNA expression of NCI H596 and A549 cells was increased, reaching maximal level at 6h for NCI H596 cells, which was 568 times higher than that of normal control cells. TNF α mRNA expression of A549 cells was increased to maximum at 1 h after irradiation and was 136 times higher than that of control cells. Colony formation efficiency (number of colonies divided by the number of inoculated cells) of unirradiated control A549 and NCI H596 cells was 0.37 0.45 and 0.12 0.24, respectively. The survival fraction (SF) of A549 cells was 47.3%±9.0% at 2 Gy, 18.0%±3.0% at 4 Gy, 6.0%±2.0% at 6 Gy, 1.4%±0.3% at 8 Gy. The SF of NCI H596 cells was 55.2%±51.0% at 2 Gy, 15.9%±9.2% at 4 Gy, 3.5%±1.7% at 6 Gy; 0.9%± 0.6% at 8 Gy. The curves of TNF α expression of the two tumor cell lines were nearly identical, therefore the radiosensitivity of these cell lines was similar. Statistically there was no significant difference for D 0 and D q ( P > 0.05). Conclusion The two lung cancer cell lines studied express TNF α following irradiation in a time and irradiation dose dependent manner. Radiation induced TNF α production of tumor cells may be of paramount importance not only for tumor behaviour, but also in respect to potential damage to normal tissues and the clinical status of the host.