Related Articles The level of insulin growth factor-1 receptor expression is directly correlated with the tumor uptake of (111)In-IGF-1(E3R) in vivo and the clonogenic survival of breast cancer cells exposed in vitro to trastuzumab (Herceptin). Nucl Med Biol. 2008 Aug;35(6):645-53 Authors: Cornelissen B, McLarty K, Kersemans V, Reilly RM INTRODUCTION: Our objective was to define the relationships between tumor uptake of [(111)In]-IGF-1 and [(111)In]-IGF-1(E3R), an analogue which does not bind insulin growth factor-1 (IGF-1) binding proteins (i.e., IGFBP-3), and the level of IGF-1 receptor (IGF-1R) expression on human breast cancer (BC) xenografts in athymic mice, as well as the feasibility for tumor imaging. A second objective was to correlate IGF-1R (and HER2 density) with the cytotoxicity of trastuzumab in the absence/presence of IGFBP-3 or the IGF-1R tyrosine kinase inhibitor, AG1024. METHODS: The tumor and normal tissue uptake of [(111)In]-IGF-1 and [(111)In]-IGF-1(E3R) were determined at 4 h postinjection in mice implanted subcutaneously with MDA-MB-231, H2N, HR2 or MCF-7/HER2-18 human BC xenografts (8.5x10(4), 1.4x10(4), 4.0x10(4) and 1.0x10(5) IGF-1R/cell, respectively). The effect of co-injection of IGF-1 (50 mug) or IGFBP-3 (2 or 25 mug) was studied. The relationship between tumor uptake of [(111)In]-IGF-1(E3R) and IGF-1R density was examined. MicroSPECT/CT imaging was performed on mice with MCF-7/HER2-18 tumors injected with [ ...
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