comparing the epidermal growth factor interaction with four different cell lines intriguing effects imply strong dependency of cellular context比较表皮生长因子与四个不同的细胞系的影响意味着强烈的依赖性的细胞环境.pdfVIP

Comparing the Epidermal Growth Factor Interaction with Four Different Cell Lines: Intriguing Effects Imply Strong Dependency of Cellular Context ¨ 1,2 2 1,2 Hanna Bjorkelund *, Lars Gedda , Karl Andersson 1 Ridgeview Instruments AB, Uppsala, Sweden, 2 Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences, Uppsala University, Uppsala, Sweden Abstract The interaction of the epidermal growth factor (EGF) with its receptor (EGFR) is known to be complex, and the common over-expression of EGF receptor family members in a multitude of tumors makes it important to decipher this interaction and the following signaling pathways. We have investigated the affinity and kinetics of 125I-EGF binding to EGFR in four human tumor cell lines, each using four culturing conditions, in real time by use of LigandTracerH. Highly repeatable and precise measurements show that the overall apparent affinity of the 125I-EGF – EGFR interaction is greatly dependent on cell line at normal culturing conditions, ranging from KD200 pM on SKBR3 cells to KD8 nM on A431 cells. The 125I-EGF – EGFR binding curves (irrespective of cell line) have strong signs of multiple simultaneous interactions. Furthermore, for the cell lines A431 and SKOV3, gefitinib treatment increases the 125I-EGF - EGFR affinity, in particular when the cells are starved. The 125I-EGF - EGFR interaction on cell line U343 is sensitive to starvation while as on SKBR3 it is insensitive to gefitinib and starvation. The intriguing pattern of the binding characteristics proves that the cellular context is important when deciphering how EGF interacts with EGFR. From a general perspective, care is advisable when generalizing ligand-receptor interaction res