Fig. 4

Effect of RAD001 (RAD), neratinib (Ner), or their combination with endocrine agents on cell signalling pathways governing cell cycle. Endocrine-resistant and -sensitive BC cell lines were treated for 24 h with the drug combinations indicated. Whole-cell extracts were assessed for expression on S6 kinase, ERK1/2, AKT, and ERBB signalling together with markers of cell cycle and apoptosis by immunoblotting. IC₅₀ values were used for RAD001 and neratinib together with standard concentrations of oestradiol (E2; 0.01 nM), 4-hydroxytamoxifen (4-OHT; 10 nM), and fulvestrant (ICI; 1 nM) (with exception of HCC1428-LTED where 10 nM was used). ERBB pathways are highlighted in pink, ERK1/2 in blue, mTORC1/AKT in green, and cell cycle in orange. wt-MCF7 (2 nM RAD001, 500 nM neratinib); MCF7-LTED (4 nM RAD001, 750 nM neratinib); wt-SUM44 (3 nM RAD001, 700 nM neratinib); SUM44-LTED (3 nM RAD001, 700 nM neratinib); wt-HCC1428 (3 nM RAD001, 1000 nM neratinib); HCC1428-LTED (10 nM RAD001, 500 nM neratinib)