Characterization of Physiological Roles and Prognostic Importance of IR/IGF-IR Hybrid Receptors in Breast Cancer. Annual Summary Report December 15, 2009-December 14, 2010

摘要

An inducible dimerization system will be used to study the IR/IGF-IR Hybrid receptor by constructing chimeric IR and chimeric IGF-IR with different dimerization domains. Chimeric IR and chimeric IGFIR retroviral vectors for homo and heterodimeriation were generated. Stable MCF10A clones expressing only chimeric IR or chimeric IGF-IR allowing homodimerization were established. Homodimerizer AP20187 treatment was able to induce activation of chimeric IGF- IR and chimeric IR in a dose dependant manner and was able to activate AKT and ERK pathways. However, I have encounter technical difficulties in establishing cells expressing both chimeric IR and chimeric IGF-IR. To measure the IR/IGF-IR hybrid receptor on paraffin embedded specimens, a proximity ligation assay was used for dual detection of IR/IGF-IR hybrid receptor using both anti-IR and anti-IGF-IR antibodies. The PLA assay was optimized in both cell pellet and breast tissue specimens to detect IR/IGF-IR hybrid receptors. The presence of PLA signals was increased in cells had IR or IGF-IR overexpression and decreased in cells with IGF-IR knock down. The variability of signals was also observed in a tissue microarray with normal breast tissue and breast tumor.