Gamou S, Kim Y S, Shimizu N
Mol Cell Endocrinol. 1984 Sep;37(2):205-13. doi: 10.1016/0303-7207(84)90053-4.
EGF binding capacity was examined in 9 different human cell lines which were derived from colon, rectum and pancreas tumors. Among these cell lines, a pancreatic carcinoma cell line, UCVA-1, was found to possess a high number (0.9 X 10(6)/cell) of EGF receptors. This number is comparable to that of EGF receptors in human vulva epidermoid carcinoma A431 cells (2 X 10(6)/cell). However, it was found that, unlike A431 cells, the growth of UCVA-1 cells, in serum-containing and serum-free conditions, was not inhibited by EGF. The UCVA-1 cells have EGF receptor of Mr = 170 K and of two affinity types: Kd1 = 72 X 10(-9) M and Kd2 = 2 X 10(-8) M. The EGF receptors in UCVA-1 cells are less susceptible to proteolytic cleavage than those in A431 cells. In UCVA-1 cells, EGF is apparently processed via a receptor-mediated endocytosis. The UCVA-1 cell membrane contained EGF-stimulated protein kinase as was found in A431 cells. The stimulation of phosphorylation by EGF was only approximately 20% in UCVA-1 while it was over 100% in A431. When angiotensin II was used as a substrate, the relative activity of EGF-dependent tyrosine-specific protein phosphorylation was approximately 8 times less in UCVA-1 cell membrane. The EGF-stimulated phosphorylation was mostly on EGF receptors for both cell lines. However, several other components (Mr = 100 K, 80 K, 72 K and 65 K) were readily detected in A431 cells. These observations indicate that the EGF receptor/protein kinase relation differs in these two cell lines and suggests that it may be related to the growth-inhibitory effect of EGF seen in A431.
在9种源自结肠、直肠和胰腺肿瘤的不同人类细胞系中检测了表皮生长因子（EGF）结合能力。在这些细胞系中，发现一种胰腺癌细胞系UCVA - 1拥有大量（0.9×10⁶/细胞）的EGF受体。这个数量与人外阴表皮样癌A431细胞中的EGF受体数量（2×10⁶/细胞）相当。然而，发现与A431细胞不同，在含血清和无血清条件下，UCVA - 1细胞的生长不受EGF抑制。UCVA - 1细胞具有分子量为170K的EGF受体，且有两种亲和力类型：解离常数Kd1 = 72×10⁻⁹M和Kd2 = 2×10⁻⁸M。UCVA - 1细胞中的EGF受体比A431细胞中的更不易受到蛋白水解切割。在UCVA - 1细胞中，EGF显然是通过受体介导的内吞作用进行加工处理的。UCVA - 1细胞膜含有如在A431细胞中发现的EGF刺激的蛋白激酶。在UCVA - 1中，EGF对磷酸化的刺激仅约为20%，而在A431中超过100%。当使用血管紧张素II作为底物时，UCVA - 1细胞膜中EGF依赖性酪氨酸特异性蛋白磷酸化的相对活性约低8倍。对于这两种细胞系，EGF刺激的磷酸化主要发生在EGF受体上。然而，在A431细胞中很容易检测到其他几种成分（分子量分别为100K、80K、72K和65K）。这些观察结果表明，这两种细胞系中EGF受体/蛋白激酶的关系不同，并表明这可能与在A431中看到的EGF的生长抑制作用有关。
