Schardt C, Rotsch M, Erbil C, Göke R, Richter G, Havemann K
Department of Internal Medicine, Marburg, Germany.
Exp Cell Res. 1993 Jan;204(1):22-9. doi: 10.1006/excr.1993.1004.
Small cell lung cancer (SCLC) cell lines were investigated for the expression of insulin-like growth factor (IGF) II receptor by means of radioreceptor assays, cross-linking techniques, and Northern blot analysis. 125I-IGF II binds to both the IGF I and the IGF II receptor on intact SCLC cells. Detailed receptor assays performed on microsomal and plasma membranes gave evidence that 125I-IGF II binds with high affinity (70-80 pM) to the IGF I receptor and with low affinity (2-4 nM) to the IGF II receptor, and not conversely. The presence of mannose-6-phosphate enhanced the binding of 125I-IGF II to the IGF II receptor of SCLC. Mannose-6-phosphate also increased the efficiency of N-hydroxysuccinimide ester in cross-linking 125I-IGF II to the IGF II receptor and facilitated the cross-linking of 125I-IGF II to a second protein of 240-250 kDa. Soluble IGF II receptor was also detected in conditioned media of SCLC cell lines.
通过放射受体分析、交联技术和Northern印迹分析，对小细胞肺癌（SCLC）细胞系进行了胰岛素样生长因子（IGF）II受体表达的研究。125I-IGF II与完整SCLC细胞上的IGF I受体和IGF II受体均结合。对微粒体膜和质膜进行的详细受体分析表明，125I-IGF II与IGF I受体以高亲和力（70-80 pM）结合，与IGF II受体以低亲和力（2-4 nM）结合，反之则不然。6-磷酸甘露糖的存在增强了125I-IGF II与SCLC的IGF II受体的结合。6-磷酸甘露糖还提高了N-羟基琥珀酰亚胺酯将125I-IGF II交联到IGF II受体的效率，并促进了125I-IGF II与240-250 kDa第二种蛋白质的交联。在SCLC细胞系的条件培养基中也检测到了可溶性IGF II受体。
