Figure 3 from E2F1-Associated Purine Synthesis Pathway Is a Major Component of the MET-DNA Damage Response Network

Impact of MET inhibition on the purine synthesis pathway. A, Transcript levels of purine synthesis enzymes are downregulated upon 24 hours of METi for EBC-1 and GTL-16 cells (N = 2). B, mRNA levels of PRPS1, PPAT, and GART upon METi in MET-driven (EBC-1 and GTL-16) and non-MET-driven (HCC821 and H820) cell lines assessed by quantitative real-time PCR (N = 3, unpaired Student t test, *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001). C, Whole-cell lysates were subjected to Western blotting using specific antibodies against GART following treatment either with vehicle or 50 nmol/L tepotinib for 24, 48, and 72 hours in MET-driven (EBC-1 and GTL-16) and non-MET-driven (HCC821 and H820) cell lines. Representative images of N = 3 independent experiments are shown. D, GART expression levels in EBC-1 (top) and HCC827 (bottom) tumor xenografts treated by vehicle or METi. Representative images (top) and quantification of GART-positive area (bottom) are provided [(EBC-1: N = 5 (control), N = 5 (tepotinib); HCC827: N = 3 (control), N = 2 (tepotinib); unpaired Student t test, *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001)]. E, MET, PRPS1, PPAT, GART, PFAS, PAICS, ADSL, and ATIC transcript distribution in normal tissue vs. primary tumor in lung, colorectal, stomach, and head and neck cancer TCGA datasets.