Sato S, Kohno K, Ono M, Sato Y, Kuwano M
Department of Biochemistry Oita Medical School, Japan.
Biochem Biophys Res Commun. 1991 Dec 31;181(3):1273-80. doi: 10.1016/0006-291x(91)92076-v.
Anchorage-independent growth of normal rat kidney (NRK) fibroblast in soft agar depends on both transforming growth factor beta (TGF beta) and epidermal growth factor (EGF). To examine whether c-fos protein is involved in phenotypic transformation of NRK cells, we have transfected and isolated several NRK cell lines that carry the human c-fos gene fused to the metallothionein IIA promoter. A transfectant, Nf-1, had constitutive levels of the human c-fos expression. Anchorage-independent growth of Nf-1 was already stimulated by EGF alone, and the colony sizes of Nf-1 were comparable to those of the parental NRK in the presence of both EGF and TGF beta. Anchorage-independent growth of NRK could be observed in the presence of TGF beta or retinoic acid or platelet derived growth factor (PDGF) and EGF. No growth of NRK in soft agar appeared when basic fibroblast growth factor (bFGF) and EGF were present. By contrast, anchorage-independent growth of Nf-1 was surprisingly enhanced by EGF and TGF beta or retinoic acid or PDGF or bFGF. Expression of the human c-fos gene may compensate the signal to phenotypic transformation induced by TGF beta as well as retinoic acid or PDGF or bFGF.
正常大鼠肾（NRK）成纤维细胞在软琼脂中不依赖贴壁生长依赖于转化生长因子β（TGFβ）和表皮生长因子（EGF）。为了研究c-fos蛋白是否参与NRK细胞的表型转化，我们转染并分离了几种携带与金属硫蛋白IIA启动子融合的人c-fos基因的NRK细胞系。一种转染细胞系Nf-1具有组成型水平的人c-fos表达。单独的EGF就已经刺激了Nf-1的不依赖贴壁生长，并且在同时存在EGF和TGFβ的情况下，Nf-1的集落大小与亲代NRK的集落大小相当。在存在TGFβ、视黄酸或血小板衍生生长因子（PDGF）以及EGF的情况下，可以观察到NRK的不依赖贴壁生长。当存在碱性成纤维细胞生长因子（bFGF）和EGF时，NRK在软琼脂中不生长。相比之下，EGF和TGFβ、视黄酸、PDGF或bFGF令人惊讶地增强了Nf-1的不依赖贴壁生长。人c-fos基因的表达可能补偿了由TGFβ以及视黄酸、PDGF或bFGF诱导的表型转化信号。
