Fig. 3.

Increased autophagy as a mechanism of resistance. a Western blot analysis of HO-1, p62 and LC3B expression in SKBR3 breast cancer cell lines stably transfected with a plasmid containing the heme oxygenase-1 (HO-1) gene or an empty plasmid. β-actin was used as a loading control. b Western blot analysis of SKBR3 empty vector and HO-1 expressing cells following treatment with DMSO, lapatinib or sapatinib for 2 h. c–e Cells were treated for 48 h with c dimethyl sulfoxide (DMSO; 0.01%), d sapatinib (0.67 µM) or e lapatinib (5 µM) in the presence or absence of autophagy inhibitors 3-methyladenine (3-MA; 5 mM) or bafilomycin A1 (bafilomycin; 5 nM). Cells were stained with propidium iodide and percentage of cell death was analysed using a Tali Image Cytometer. Results presented as box and whisker plot, minimum of three biological repeats. All conditions were compared to DMSO control and single agent treatments. One-way ANOVA, Bonferroni’s post hoc test, not significant = NS, p < 0.05*, p < 0.01**, p < 0.001***