Erlotinib impairs EGFR and ERK1/2 phosphorylation in ERL-resistant cell lines.

<p>A) Representative western blots with EGFR and ERK1/2 antibodies and B) pEGFR (Y1068) and pERK1/2 (T202/Y204) antibodies in the indicated parental and ERL-resistant cell lines treated with EGF (100 μg/ml), ERL (Erlotinib, 100 nM) or vehicle (DMSO) at different time points (8’, 30’, 1hr, 3hrs). Densitometric analyses of band signals were normalized with GAPDH, the number indicates the signals quantification at 30’ upon ERL-treatment. For RA2 cell line double amount of total cell lysate was loaded to analyze EGFR expression.