Fig. 6

H1047R and E545K knockin cells are hyper-responsive to neuregulin-1 beta 1 (NRG1β) treatment. A Parental SK-BR-3 cells treated with NRG1β and lapatinib show rescue from lapatinib at high concentrations of NRG1β, but only partial rescue when treated with low doses of NRG1β (2 ng/mL). B The H1047R cells show complete rescue from lapatinib with all doses of NRG1β, even at the highest dose of lapatinib, suggesting that the mutant cells are more responsive to ligand stimulation than their wildtype counterparts. C The E545K cells also show complete rescue from lapatinib inhibition by all doses of NRG1β. Value shown are median cell counts relative to untreated controls. Error bars are ± standard deviation