Ishikawa J, Maeda S, Sugiyama T, Nishimura R, Mizoguchi A, Kamidono S
Department of Urology, Kobe University School of Medicine, Japan.
Int J Cancer. 1989 Dec 15;44(6):1000-4. doi: 10.1002/ijc.2910440610.
Southern blot analysis of 6 human bladder carcinoma cell lines revealed amplification of the epidermal growth factor receptor (EGFR) gene in the KU1 cell line. The amplification of the gene was about 4-fold as compared with that of human placental DNA. Several restriction endonuclease digestions revealed that there was no gross rearrangement of the EGFR gene in KU1. Northern blot analysis showed normal 10 and 5.6 kb of EGFR gene-related mRNA species. 125I-EGF binding revealed 2 distinct EGF binding sites on KU1 cells: high-affinity sites 5.7 X 10(5) receptors per cell with 1.1 nM Kd and low-affinity sites 2.3 X 10(6) receptors per cell with 7.4 nM Kd. The number of the EGFR was compatible with that of the A431 squamous carcinoma cell ine which has an amplified, rearranged and over-expressed EGFR gene. Solid-phase immuno-isolation analysis showed a single 170 kDa EGFR protein in KU1 as well as in A431. Unlike other cell lines with amplified and over-expressed EGFR gene, anchorage-dependent growth of KU1 was stimulated but not inhibited by EGF. Moreover, anchorage-independent growth of KU1 was stimulated by EGF.
对6种人膀胱癌细胞系进行的Southern印迹分析显示，KU1细胞系中表皮生长因子受体（EGFR）基因发生扩增。与人类胎盘DNA相比，该基因的扩增约为4倍。几种限制性内切酶消化结果表明，KU1中EGFR基因没有明显的重排。Northern印迹分析显示EGFR基因相关的mRNA种类正常，分别为10 kb和5.6 kb。125I-EGF结合实验显示KU1细胞上有2个不同的EGF结合位点：高亲和力位点，每个细胞有5.7×10(5)个受体，解离常数（Kd）为1.1 nM；低亲和力位点，每个细胞有2.3×10(6)个受体，Kd为7.4 nM。EGFR的数量与A431鳞状癌细胞系相符，后者的EGFR基因发生了扩增、重排且过度表达。固相免疫分离分析显示KU1和A431中均有单一的170 kDa EGFR蛋白。与其他EGFR基因扩增且过度表达的细胞系不同，EGF刺激而非抑制KU1的贴壁依赖性生长。此外，EGF刺激KU1的非贴壁依赖性生长。
