Fig. 3.
Chronic exposure of BS153 to erlotinib led to a resistant phenotype. BS153 was sensitive to erlotinib as well as to gefitinib (A; both 10 µg/mL), whereas BS153resE was relatively resistant to erlotinib (B; both 10 µg/mL) after 6 days of treatment. Proliferation increased when erlotinib was removed from BS153resE for 6 days. Values are means ± SD from octuplicate determinations. One of 3 independent experiments is shown. RLU, relative luminescence units.