Drosophila-based in vivo assay for the validation of inhibitors of the epidermal growth factor receptor/Ras pathway.

Overexpression of epidermal growth factor receptor (EGFR) is a common phenomenon observed in most cancers. Clinical treatment of such cancer involves the use of chemotherapeutic agents such as ge ? tinib and erlotinib which are inhibitors of tyrosine kinase (TK). These small molecules bind to the ATP-binding sites of the TK domain of EGFR.Our in silico analysis suggests that the TK domains of Drosophila and human EGFR are highly conserved. We therefore employed the Drosophila system to validate the in silico observations made with two important anticancer drugs.Since a large number of mutant flies are available,it was possible to investigate the various components of the EGFR/Ras/Raf/MAPK pathways and the phosphorylation status of diphosphorylated extracellular signal-regulated kinase (dp-ERK1/2). These studies confirm the binding of the anilinoquinazolines to the Drosophila EGFR protein and modulation of its activity. Thus,Drosophila appears to be a robust and simple model system for screening newer anticancer drugs that act as TK inhibitors (TKIs).