Liboi E, Di Francesco P, Gallinari P, Testa U, Rossi G B, Peschle C
Department of Virology, Istituto Superiore di Sanità, Rome, Italy.
Biochem Biophys Res Commun. 1988 Feb 29;151(1):298-305. doi: 10.1016/0006-291x(88)90593-1.
We have previously indicated that epidermal growth factor (EGF) plays a fundamental role in the proliferation control of EL2 rat fibroblast line. It is shown here that transforming growth factor beta (TGF beta) stimulates both DNA synthesis and proliferation of EL2 cells, while exerting an inhibitory effect on the growth of murine NIH-3T3 fibroblasts. We also report the effect of TGF beta and EGF on c-fos expression in EL2 cells, as compared to that of TGF beta in NIH-3T3 fibroblasts. In EL2 cells EGF induces a transient c-fos expression at both mRNA and protein level, as previously observed in NIH-3T3 fibroblasts treated with platelet-derived or fibroblast growth factor (PDGF, FGF). Conversely, TGF beta induces in EL2 cells a sustained expression of fos mRNA and protein, which are still detectable at least 24 and 7 hr after treatment respectively. In NIH-3T3 fibroblasts TGF beta causes a sustained fos RNA expression, which is not associated, however, with detectable fos protein. We conclude that in fibroblasts stimulated by mitogens c-fos expression may be differentially modulated, depending of the growth factor and the cell line. This is seemingly due to differential regulation of fos gene expression, not only at the transcriptional and/or post-transcriptional level (transient or sustained fos RNA induction by EGF or TGF beta in EL2 cells), but also at the translational level (fos protein(s) induction by TGF beta in EL2 but not NIH-3T3 fibroblasts, possibly related to the stimulatory vs inhibitory effect of this factor on the growth of the former vs the latter line).
我们之前指出，表皮生长因子（EGF）在EL2大鼠成纤维细胞系的增殖控制中起重要作用。本文表明，转化生长因子β（TGFβ）刺激EL2细胞的DNA合成和增殖，同时对小鼠NIH-3T3成纤维细胞的生长产生抑制作用。我们还报告了TGFβ和EGF对EL2细胞中c-fos表达的影响，并与TGFβ对NIH-3T3成纤维细胞中c-fos表达的影响进行了比较。在EL2细胞中，EGF在mRNA和蛋白质水平均诱导c-fos的瞬时表达，这与之前在用血小板衍生生长因子或成纤维细胞生长因子（PDGF，FGF）处理的NIH-3T3成纤维细胞中观察到的情况一致。相反，TGFβ在EL2细胞中诱导fos mRNA和蛋白质的持续表达，分别在处理后至少24小时和7小时仍可检测到。在NIH-3T3成纤维细胞中，TGFβ导致fos RNA的持续表达，然而，这与可检测到的fos蛋白质无关。我们得出结论，在有丝分裂原刺激的成纤维细胞中，c-fos的表达可能受到不同的调节，这取决于生长因子和细胞系。这似乎是由于fos基因表达的差异调节，不仅在转录和/或转录后水平（EL2细胞中EGF或TGFβ诱导的瞬时或持续fos RNA），而且在翻译水平（TGFβ在EL2细胞中诱导fos蛋白质，但在NIH-3T3成纤维细胞中不诱导，这可能与该因子对前者和后者细胞系生长的刺激与抑制作用有关）。
