Paulsson Y, Hammacher A, Heldin C H, Westermark B
Nature. 1987;328(6132):715-7. doi: 10.1038/328715a0.
The growth of normal diploid fibroblasts is generally thought to be tightly controlled by exogenous growth factors such as platelet-derived growth factor (PDGF) and epidermal growth factor (EGF). Subversion of a growth factor pathway at a regulatory point is considered to be a key event in neoplastic transformation and tumorigenesis. Thus, simian sarcoma virus has acquired the gene encoding the B-chain of PDGF and there is direct experimental proof that SSV-transformation is mediated by a PDGF-like growth factor. There is accumulating evidence that PDGF-like molecules are also synthesized and released by certain normal cells, suggesting an important role of cellularly produced PDGF in development and tissue regeneration. We now present evidence that a transient expression of the gene encoding the PDGF A-chain, and the synthesis and release of functional A-chain homodimers, is an early event in the prereplicative phase of normal human foreskin fibroblasts exposed to PDGF or EGF. Since these cells are PDGF-responsive, the results imply the existence of a positive autocrine signal that may serve as an amplifier of the mitogenic response under certain conditions.
正常二倍体成纤维细胞的生长通常被认为受到外源性生长因子如血小板衍生生长因子（PDGF）和表皮生长因子（EGF）的严格控制。生长因子途径在调控点的颠覆被认为是肿瘤转化和肿瘤发生的关键事件。因此，猿猴肉瘤病毒获得了编码PDGF B链的基因，并且有直接的实验证据表明SSV转化是由一种类PDGF生长因子介导的。越来越多的证据表明，某些正常细胞也合成并释放类PDGF分子，这表明细胞产生的PDGF在发育和组织再生中具有重要作用。我们现在提供证据表明，编码PDGF A链的基因的瞬时表达以及功能性A链同源二聚体的合成和释放，是正常人包皮成纤维细胞在暴露于PDGF或EGF时复制前期的早期事件。由于这些细胞对PDGF有反应，结果表明存在一种正自分泌信号，在某些条件下可能作为有丝分裂反应的放大器。
