Fig. 5: JNK activation drives an MCL-1 dependent state by modulating BIM:BCL-XL interactions.
From: LKB1 regulates JNK-dependent stress signaling and apoptotic dependency of KRAS-mutant lung cancers
A Scheme for approach to investigating BIM sequestration upon displacement from MCL-1. B Co-IP assessment of BIM bound to MCL-1 and BCL-XL in H2030 (LKB1-deficient) and SW1573 (LKB1 wild-type) cells after treatment with 0.1 µM trametinib for 24 h followed by 1 µM AMG 176 for 4 h. C Co-IP assessment of BIM bound to BCL-XL and MCL-1 in H2030 EV and LKB1 cells after treatment with 0.1 µM trametinib for 24 h followed by 1 µM AMG 176 for 4 h. D Co-IP assessment of BIM bound to BCL-XL and MCL-1 in H2030 EV (empty vector) with JNK knockdown after treatment with 0.1 µM trametinib for 24 h + 1 µM AMG 176 for 4 h. E Co-IP assessment of BIM bound to WT BCL-XL or BCL-XL mutants in H2030 EV (S62A) and H2030 LKB1 (S62E) cells after treatment with 0.1 µM trametinib for 24 h followed 1 µM AMG 176 for 4 h. HA-tag pull downs are specific for inducible constructs. F Quantification of Co-IP assessment of BIM bound to BCL-XL in H2030 and MGH1112 cells overexpressing BCL-XL WT or S62A mutants. Data are mean and S.E.M., each dot represents a biological replicate (N = 3-5, H2030: *p = 0.0433, MGH1112-1: *p = 0.0345, unpaired-parametric t test, 2-sided). G Effect of NUAK1/2 knockdown on BCL-XL S62 phosphorylation in response to treatment with 0.1 µM trametinib for 48 h (T) or trametinib for 48 h followed by 1 µM AMG 176 (TA) for 4 h. H Model depicting the mechanism by which LKB1 loss leads to an MCL-1-dependent state and sensitizes KRAS-mutant NSCLCs to combined KRAS or MEK + MCL-1 inhibition. Source data are provided as a Source Data file. Western blots and immunoprecipitation images are representative of at least 2 independent biological replicates.
