(11f) Protein Array for Activity Screen of EGF Receptor (EGFR) Tyrosine Kinase Inhibitors In Cancer Cells

Protein tyrosine kinases are critical for regulating important cellular processes. Deregulation of kinase activity resulting from receptor overexpression, gene amplification, and increased enzymatic activity can lead to several diseases including cancer. As a result, protein kinases have emerged as promising drug target and several inhibitors are at different stages of development. Hence, there is an urgent need of a simple, robust yet cost-effective platform for high-throughput screening of small molecule drug candidates. A major challenge in developing kinase assay involves sensitive and specific detection of enzyme activity in the background of multiple tyrosine kinases present in cellular extracts and obtaining accurate measurements from small biopsy samples.

Here we report the development of protein array for quantitative profiling of epidermal growth factor receptor (EGFR) kinase activity. EGFR signaling pathways have been implicated in playing an important role in cancer development and progression. Many therapeutics are at different stages of development which are directed towards EGFR kinase domain. The extent of substrate phosphorylation upon incubation of EGFR substrate with lysates of cancer cells corresponded to the difference in activation status of EGFR in different cancer cell lines. Additionally, the ability of the diagnostic tool to quantify the extent of inhibition of EGFR activity by different tyrosine kinase inhibitors establishes the potential of this tool to screen for the most promising therapeutics for individual patients and monitor treatment progression.