Figure 1.

Upregulation of MYC in AZD8055-resistant KEP tumors. (A) Scheme representing the experimental setup to generate vehicle-treated control and AZD8055-treated sensitive and resistant KEP mammary tumors used for the multiomic data analyses. Endpoint was reached when mammary tumor volume was >1,500 mm³. (B) mTOR downstream phosphosites measured by RPPA (8 control, 5 sensitive, and 15 resistant KEP tumors) and MS-based phosphoproteomics (6 control, 4 sensitive, and 8 resistant KEP tumors). Intensities from each assay were standardized using Z-scores. Gray cells in MS data indicate missing values. (C) Phosphosite-specific signature analysis based on the PTMSigDB database (Krug et al., 2019). The average intensities for each KEP tumor group were used to identify representative signatures. *FDR < 0.05. (D) Copy number (CN) ratio (log₂CN/2) of 10 control, 6 sensitive, and 13 resistant KEP tumors for all chromosomes and chromosome 15 (inset) highlighting focal MYC amplifications in resistant tumors. (E) Myc mRNA expression (log₂CPM) across 9 control, 10 sensitive, and 14 resistant KEP tumors. (F) Pearson’s correlation analysis of Myc copy number ratio (log₂CN/2) versus Myc mRNA expression (log₂CPM). P value was calculated with two-tailed t-transformations of Pearson’s correlation coefficient. (G) Z-score standardized MYC protein levels across 8 control, 5 sensitive, and 15 resistant KEP tumors as measured by RPPA. (H) H-score quantifications of MYC staining intensities across 13 control, 11 sensitive, and 15 resistant tumors. (I) Representative MYC IHC stainings of control, sensitive, and resistant KEP tumors in H. Scale bars, 50 μm. In E–H, data are represented as median ± interquartile range (IQR; box) and quartiles ± 1.5 × IQR (whiskers), and one-way ANOVA and Tukey’s post-hoc test were performed to compute adjusted P values (*P < 0.05; **P < 0.01; ***P < 0.001; n.s, not significant). Source data are available for this figure: SourceData F1.