Fig. 2: FOXO3a and IRS1 regulated a negative feedback inhibition of IGF2-triggered IGF-1R/Akt/mTOR signaling in HER2-positive breast cancer cells.

a SKBR3 cells were treated with rhIGF2 at indicated concentrations for 6 h. The expression of p-IGF-1R, IGF-IR, p-Akt^(S473), p-Akt^(T308), Akt, p-S6K, S6K, p-FOXO3a, FOXO3a, and β-actin was examined by western blot assays. b SKBR3 cells were transfected with a control empty vector (Con) or the same vector containing an IRS1 cDNA (IRS1), followed by rhIGF2 treatment for 6 h. The expression of indicated proteins was examined by western blot assays. c SKBR3 cells were transfected with control shRNA (sh-Con) or specific FOXO3a shRNAs (sh-1# and sh-2#) followed by rhIGF2 treatment for 6 h. The expression of indicated proteins was examined by western blot assays. d SKBR3 cells with IRS1 gene deletion via CRISPR-Cas9 (sg-Con vs sg-1# and sg-2#) were treated by rhIGF2 treatment for 6 h. The expression of indicated proteins were examined by western blot assays. Data show a representative of three independent experiments (a–d). All data are provided in the Source Data file.