Fig. 1

Assessment of IR signaling. Box plots depicting the expression of insulin receptor (IR) (A) and IR-mediated signaling pathway (B) in ER-positive and ER-negative breast cancer (BC) patients of the TCGA cohort. C Kaplan–Meier curve showing the correlation of IR-mediated signaling pathway with overall survival (OS) of ER-positive BC patients of the TCGA dataset. p-values are reported in each panel. Protein levels of phosphorylated IR (pIR) (D), AKT (pAKT) (E) and ERK (pERK1/2) (F) in BCAHC-1 cells exposed for 30 min to vehicle or 10 nM insulin in the presence or absence of 1 µM IR inhibitor OSI-906, 1 µM PI3K inhibitor alpelisib and 100 nM MEK inhibitor trametinib, as indicated. Protein levels of pIR (G), pAKT (H) and pERK1/2 (I) in BCAHC-1 cells treated with vehicle (−) or 10 nM insulin (Ins) for 30 min alone or in combination with 2 mM metformin (Met), which was added to culture medium 18 h before the treatment with vehicle or insulin. Side panels show densitometric analysis of the blots normalized to IR, AKT and ERK2 that served as loading control, as indicated. Results shown are representative of at least three independent experiments. (*) indicates significant differences with respect to vehicle sample (p < 0.05); (black square) indicates significant differences with respect to Ins treated sample (p < 0.05)