Highly Selective Tumor Targeting With Phage Display and Laser Capture Microdissection

摘要

BT474 xenograft modal was successfully established in our lab. Tumor stroma enriched BT474 modal was tested using BT474 cell lines and human breast fibroblast cell lines. Mixture of BT474 cells and human breast fibroblast cells did not yield a xenograft with sufficient fibroblast component. LCM panning of human tumor specimens was performed with selection on blood vessels. More than 200 monoclones were evaluated for binding. Although clones were identified with some blood vessel binding the affinity was too low for subsequent in vivo imaging studies. Three BT474 cell binding scFv clones 799, 785, 794 were selected and single chain antibody of these clones were successfully expressed, purified and prepared in large scale. These scFvs were evaluated in vivo but preferential binding to the tumor relative to normal tissue (especially kidney) was not sufficient. Antibodies that bind different targets on BT474 cells were selected and successfully labeled infrared fluorescence dyes of different wavelengths. The labeling procedure was shown to not interfere with antibody affinity. The labeled antibodies (Herceptin and anti-EpCAM) were administered in vivo and successfully demonstrated to bind preferentially and additively in the tumor xenograft.