Figure 5.

MYC drives AZD8055 resistance in vitro. (A) Western blots for MYC and mTOR signaling markers on KEP1.23 and KEP2.E3 cell lines transduced with GFP or Myc-overexpressing lentiviral vectors and treated for 24 h with vehicle or 25 nM AZD8055. Data represent one experiment. (B and C) Dose–response curves of KEP cell lines expressing GFP or Myc, treated with AZD8055 (B) or everolimus (C) for 3 d and measured by SRB colorimetric assay. Data are represented as mean ± standard deviation of five replicas per group of one representative experiment of n ≥ 3 independent experiments. N.D, not determined. (D) Western blots for MYC and (p-)RPS6 on serum-starved SUM52PE and MDA-MB-468 cell lines transduced with control or MYC-overexpressing lentiviral vectors and treated for 6 h with either vehicle DMSO, 200 nM AZD8055, or 10 nM everolimus. Data represent one experiment of two independent experiments. (E–H) Representative images (E and G) and corresponding quantification using CellTiter-Blue reagent (F and H) of long-term colony formation assays with SUM52PE and MDA-MB-468 cells transduced with control or MYC-overexpressing lentiviral vectors and treated with AZD8055 (E and F) or everolimus (G and H). Cells were treated with indicated drug doses for 10 d, and values were normalized to untreated conditions within each cell line. Data in F and H are represented as mean ± standard deviation of three technical replica per group across one representative experiment of two independent experiments. Source data are available for this figure: SourceData F5.