Ewing’s肉瘤细胞X-射线照射后TNF-α和TGF-β mRNA表达的研究

Tumor Necrosis Factor-alpha (TNF-α) and Transforming Growth Factor-beta (TGF-β) Expression in Ewing's Sarcoma Cell Line after Irradiation

目的 研究Ewing’s肉瘤细胞系 (RM 82 )X 射线外照射后肿瘤坏死因子 (TNF α)和转化生长因子 (TGF β)mRNA表达水平的变化 ,探讨X 射线诱导内源性TNF α和TGF β产生的可能性及意义。 方法 应用实时荧光RT PCR ,检测接受不同剂量X 线照射 (2Gy ,5Gy ,10Gy ,2 0Gy ,30Gy ,4 0Gy)和受照后不同时间 (1h ,3h ,6h ,12h ,2 4h ,4 8h ,72h)。TNF α和TGF βmRNA表达水平的变化。 结果 RM 82细胞TNF αmRNA表达水平较外照射前显著升高。一方面受照后TNF αmRNA表达逐渐升高 ,照射剂量达 4 0Gy时TNF αmRNA表达水平达高峰 ,为正常对照组的 10 8倍 ;另一方面 ,照射后 3h后TNF αmRNA表达逐渐升高 ,6h达高峰 ,为正常对照组的 18倍。相反 ,TGF βmRNA表达水平X 射线照射前后无显著变化。结论 Ewing’s肉瘤细胞系 (RM 82 )接受X 线照射后TNF αmRNA表达明显升高 ,且呈现时间、剂量依赖性。放射治疗可诱导Ewing’s肉瘤细胞系 (RM 82 )产生TNF α,既可能提高放疗的敏感性 。

Objective To study the release of TNF-α and TGF-β mRNA in Ewing's sarcoma cell line (RM-82) in vitro and the regulation of TNF-α and TGF-β mRNA expression by ionizing radiation. Radiation-induced tumor cell production of TNF-α and TGF-β may enhance irradiation efficacy and improve the effect of tumor irradiation. On the other hand, endogenous tumor cell production of TNF-α and TGF-β may adversely affect normal tissue.Methods Ewing's sarcoma cell line (RM-82) were investigated for their TNF-α and TGF-β mRNA expression before and after exposure to different irradiation doses (2, 5, 10, 20, 30, 40 Gy) and after different time intervals (1, 3, 6, 12, 24, 48, 72 hours after irradiation).Results The Ewing's sarcoma cell line RM-82 produce constitutively significant quantities of TNF-α mRNA. The TNF-α mRNA levels of it were up-regulated following irradiation exposure in a time- and dose-dependent manner. Irradiation-mediated stimulation of the TNF-α mRNA release was appreciable between 1 and 24 hours post-irradiation. Dependent on the dose given, irradiation was found to cause increasing induction of TNF-α mRNA expression, with the maximal release after irradiation with 40 Gy. In contrast, RM-82 cells constitutively produce significant levels of TGF-β mRNA, but this TGF-β mRNA release was not modulated by irradiation.Conclusion The Ewing's sarcoma cell line RM-82 produce extremely large quantities of TNF-α following irradiation exposure 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 tissue and the clinical status of the host.