肿瘤坏死因子-α对α粒子致叙利亚地鼠胚胎细胞恶性转化的促进作用

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

目的阐明辐射致癌过程中肿瘤坏死因子α（ＴＮＦα）的作用及蛋白质酪氨酸磷酸化调节机理。方法以０５Ｇｙα粒子照射的叙利亚地鼠胚胎（ＳＨＥ）细胞为靶细胞，观察细胞生长曲线、转化频率（ＴＦ）、软琼脂克隆形成率（ＣＦＥ）和裸鼠致瘤性，并测定细胞中蛋白质酪氨酸激酶和酪氨酸磷酸酶活性。结果单纯０．５Ｇｙα粒子照射或ＴＮＦα不能使ＳＨＥ细胞发生恶性转化，６００Ｕ／ｍｌＴＮＦα处理０．５Ｇｙα粒子照射的ＳＨＥ细胞后，细胞获得了长期传代的能力，ＴＦ、ＣＦＥ以及细胞中蛋白质酪氨酸磷酸化水平均明显增高，裸鼠致瘤性试验为阳性。结论ＴＮＦα对α粒子致ＳＨＥ细胞转化有显著促进作用。

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 0.5Gy 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.