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

Abstract

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.