Promotion of TNF-α on malignant transformation of syrian hamster embryo cells irradiated with α-particles

Objective: To illustrate the role of tumor necrosis factor-α (TNF-α) in radiation-induced cancer and regulatory mechanism of protein tyrosine phosphorylation. Methods: Taking Syrian hamster embryo cells exposed to 0.5 Gy α-particles as the target, an array of biological indicators such as cell growth curve, transformation frequency (TF), colony formation efficiency (CFE) and tumor formation in nude mice were observed, and the activities of protein tyrosine kinases and protein tyrosine phosphatases were measured. Results: Neither 0.5 Gy α-particle irradiation nor TNF-α alone could induce transformation of SHE cells morphologically, but the TF, CFE and levels of protein tyrosine phosphorylation were obviously increased in SHE cells treated with 600 U/ml TNF-α after exposure to 0.5 Gy α-particles, and malignant transformation was proved by tumorigenicity assays. Conclusion: TNF-α promotes significantly the transformation of SHE cells induced by α-particles, and protein tyrosine phosphorylation is probably involved in regulation of the process