Fig. 6

FBP1 downregulates c-Myc through inhibition of the ERK1/2 pathway in PDAC. a, PANC-1 cells were infected with control or FBP1-specific shRNAs. After 24 h, cells were treated with or without 2 μM of JQ1 for another 24 h. Cells were harvested for western blot analysis. b, PANC-1 cells were infected with lentivirus expressing control, IQGAP1-specific shRNAs. After 48 h infection, cells were transfected with indicated constructs and harvested for western blot analysis 24 h post transfection. Cells were treated with or without 20 μM of MG132 for 8 h before being harvested. c, PANC-1 cells were infected with lentivirus expressing control, IQGAP1-specific shRNAs. After 48 h infection, cells were treated with 10 μM of Trametinib for 24 h and harvested for western blot analysis. d, PANC-1 cells were transfected with indicated plasmids for 24 h and treated with 10 μM of Trametinib for another 24 h, and harvested for western blot analysis. e, PANC-1 cells were transfected with indicared plasmids. 24 h post transfection, cells were treated with 10 μM of Trametinib for 24 h. Cells were harvested for western blot analysis. Cells were treated with 20 μM of MG132 for 8 h before harvest. f-i, PANC-1 cells were infected with lentivirus expressing control, or c-Myc and/or FBP1-specific shRNAs. After 48 h infection and puromycin selection, cells were harvested for RT-qPCR analysis (f), MTS assay (g) and colony formation assay (h and i) after 48 h infection. For rt-qPCR, all data show mean values ± SD (error bar) (n = 3); for MTS assay, data are shown as means ± SD (n = 6); for colony formation assay, data are shown as means ± SD (n = 3). n.s., not significant; * P < 0.05; ** P < 0.01; ***P < 0.001. j-l, After 72 h infection, cells were injected into subcutaneous layer of the right flank of mice. The growth of tumor was measured every other day for 21 days (l), and tumors were harvested and measured the weight of tumor (k). Data present means ± SD (n = 4). n.s., not significant; **P < 0.01; ***P < 0.001. (m) A hypothetical model depicting JQ1 disrupts the interaction between FBP1 and TRIM28 and stabilizes FBP1.Next, FBP1 promoted c-Myc degradation through inhibiting the activation of ERK1/2. FBP1 serves as a therapeutic niche for patient-tailored therapies