Measuring Tyrosine Kinase Inhibitor Effects on Cell Signaling Pathways (Beatson 2008)

A recent wave of anti-cancer compounds that target tyrosine kinases (TKIs) has been moving through the drug development pipeline. Assessment and screening of lead compounds in simple model systems is relatively straight forward. Until recently, however, determining the impact of these compounds in complex biology of patient-derived cells and tissues has been diffcult. Proposed genetic or protein biomarkers can act as surrogates to a response, but measuring the signaling pathway in both the target cells and surrounding normal tissue will provide a more direct metric. This has proven diffcult due to the limited nature of primary material and complexity of tissue structure. Here we describe a novel nano-immunoassay platform (FireflyTM) that has two significant advantages over traditional immunoassays: (1) extremely sensitive protein detection, and (2) physical isoform separation, which allows for quantitation of protein isoforms as well as post-translational modifications such as phosphorylation. Applications of this technology that will be described include: 1. Effect of TKIs on signaling in punch biopsies of non-small cell lung cancer cells 2. Signaling pathway response from chronic myleogenous leukemia patients to therapies targeted to the bcr/abl translocation