de Larco J E, Todaro G J
J Cell Physiol. 1978 Mar;94(3):335-42. doi: 10.1002/jcp.1040940311.
Fibroblastic and epithelioid clones have been isolated from the normal rat kidney line, NRK. These clones were studied for their ability to bind epidermal growth factor (EGF), susceptibility to transformation by mouse sarcoma virus (MSV), and alteration in EGF binding upon sarcoma virus transformation. The epithelioid clones bound much more EGF than the fibroblastic clones; Scatchard plots on two of these clones, one epithelioid and one fibroblastic, showed that the higher EGF binding (1.3 x 10(5) molecules per cell for the epithelioid clone and 1.3 x 10(4) molecules per cell for the fibroblastic clone) was due to a greater number or receptors on the epithelioid cells rather than to a difference in the apparent affinity constant. When the clones were transformed by Moloney murine sarcoma virus the EGF binding decreased, the effect being greater with the fibroblastic clones. In 20 out of 20 independently isolated sarcoma virus transformed fibroblastic clones, the level of EGF binding was either greatly reduced or completely eliminated. In contrast to EGF, another growth factor, multiplication stimulating activity (MSA), bound to a greater extent to the fibroblastic clones than the epithelioid clones, and its binding was not decreased by sarcoma virus transformation. The results show that loss of EGF binding ability correlates with expression of the murine sarcoma virus transformation.
已从正常大鼠肾细胞系NRK中分离出成纤维细胞样克隆和上皮样克隆。对这些克隆进行了研究，检测它们结合表皮生长因子（EGF）的能力、对小鼠肉瘤病毒（MSV）转化的敏感性以及肉瘤病毒转化后EGF结合的变化。上皮样克隆比成纤维细胞样克隆结合更多的EGF；对其中两个克隆（一个上皮样克隆和一个成纤维细胞样克隆）的Scatchard作图显示，较高的EGF结合量（上皮样克隆为每细胞1.3×10⁵个分子，成纤维细胞样克隆为每细胞1.3×10⁴个分子）是由于上皮样细胞上有更多数量的受体，而不是表观亲和常数存在差异。当这些克隆被莫洛尼鼠肉瘤病毒转化后，EGF结合减少，成纤维细胞样克隆的这种效应更明显。在20个独立分离的肉瘤病毒转化的成纤维细胞样克隆中，有20个克隆的EGF结合水平要么大幅降低，要么完全消除。与EGF相反，另一种生长因子，即增殖刺激活性（MSA），与成纤维细胞样克隆的结合程度比对上皮样克隆的结合程度更高，并且其结合不会因肉瘤病毒转化而减少。结果表明，EGF结合能力的丧失与鼠肉瘤病毒转化的表达相关。
