Figure 4 from The Lysine Demethylase KDM4C Is an Oncogenic Driver and Regulates ERK Activity in KRAS-Mutant Pancreatic Ductal Adenocarcinoma

Compensatory upregulation of KDM4A restores cell-intrinsic ERK signaling in KDM4C-null cells but not immune surveillance. A, Western blot panel shows that late-passage KDM4C KO clones of both AsPC1 and KPC-mT4 (KO-late) restored pERK levels. B–D, ERK reactivation rescues the reduction in colony formation and proliferation in both AsPC1 and KPC-mT4 KO cells observed in earlier passages. Bar plots show number of colonies calculated by ImageJ. For each sample, two wells have been analyzed, and the statistical significance is calculated using one-way ANOVA. For both AsPC1 and KPC-mT4 cells, the difference between parental and adapted KDM4C KO clones was not significant. E, Lentiviral shRNA knockdown of KDM4C recapitulates the adaptation to KDM4C depletion in adapted cells. Western blot panel compares early-passage (day 7 after transduction) and late-passage (day 40 after transduction) in AsPC1 cells. Late-passage KDM4C knockdown cells have adapted to the loss of KDM4C and restored ERK activation. F, Western blot validating KDM4A upregulation in adapted KPC-mT4 KDM4C KO clones. G, RNA-seq results from AsPC1 early-passage KDM4C KO cells correlate with the ERK inhibitor (ERKi) transcriptome signature, whereas late-passage adapted cells are inversely correlated. H and I, Bar graphs showing significant reduction in the tumor growth of adapted KPC-mT4 KDM4C KO cells when transplanted into the immunocompetent B6 mice compared with KDM4C WT control (n = 5), whereas the reverse is observed when the same cells are transplanted into immune-compromised athymic mice (n = 8), significance determined by unpaired t test; *, P ≤ 0.05.