Liboi E, Pelosi E, Testa U, Peschle C, Rossi G B
Mol Cell Biol. 1986 Jun;6(6):2275-8. doi: 10.1128/mcb.6.6.2275-2278.1986.
Extensive evidence supports a two-step model for the control of fibroblast growth, which includes first the action of a competence factor (e.g., platelet-derived growth factor) followed by the stimulus of a progression factor (e.g., epidermal growth factor [EGF]). We investigated whether this model may be applied to the euploid EL2 fibroblast line recently isolated from rat embryos (E. Liboi, M. Caruso, and C. Basilico, Mol. Cell. Biol. 4:2925-2928, 1984). Our results clearly show that EGF alone leads EL2 cells to proliferate in serum-free conditions at a rate corresponding to 50 to 60% of that observed in the presence of 10% calf serum. It is of interest that, when resting EL2 cells were exposed to EGF, transcription of both c-myc and c-fos was markedly induced. Altogether, these observations suggest that, in contrast with the model of fibroblast growth mentioned above, EL2 cells require the presence of a single growth factor (EGF) for induction of DNA synthesis, and the expression of myc and fos proto-oncogenes may represent an obligatory step in the pathway of commitment of EL2 cells to proliferation. In addition, we showed that EGF may induce EL2 cells to acquire some properties of transformed cells, such as growth in agar and loss of contact inhibition. This suggests that the particular response to EGF of the EL2 line may be strictly connected with the expression of a transformed phenotype.
大量证据支持一种控制成纤维细胞生长的两步模型，该模型首先包括一种感受态因子（如血小板衍生生长因子）的作用，随后是一种促有丝分裂因子（如表皮生长因子[EGF]）的刺激。我们研究了该模型是否适用于最近从大鼠胚胎中分离出的整倍体EL2成纤维细胞系（E. Liboi、M. Caruso和C. Basilico，《分子细胞生物学》4:2925 - 2928，1984）。我们的结果清楚地表明，单独的EGF可使EL2细胞在无血清条件下以相当于在10%小牛血清存在时所观察到的速率的50%至60%的速度增殖。有趣的是，当静止的EL2细胞暴露于EGF时，c - myc和c - fos的转录均被显著诱导。总之，这些观察结果表明，与上述成纤维细胞生长模型相反，EL2细胞诱导DNA合成需要单一生长因子（EGF）的存在，并且myc和fos原癌基因的表达可能代表EL2细胞进入增殖途径中的一个必要步骤。此外，我们表明EGF可诱导EL2细胞获得一些转化细胞的特性，如在琼脂中生长和失去接触抑制。这表明EL2细胞系对EGF的特殊反应可能与转化表型的表达密切相关。
