Fig. 1: EI-52 inhibits ERK-MYD88 protein-protein interaction and induces cancer cell death.
From: Targeting ERK-MYD88 interaction leads to ERK dysregulation and immunogenic cancer cell death
A Chemical structure of EI-52. B Binding of EI-52 to ERK1 and ERK2 by fluorescence quenching. Representative of two independent experiments. C ERK1/2-MYD88 interaction inhibition by HTRF. Mean ± SEM from three independent experiments. D EI-52 docking on ERK. Negatively charged residues are in red. Zone A includes the Common Docking (CD) ___domain (red dotted circle). MKP3 peptide in magenta. Key hydrophobic/aromatic residues in yellow. E MYD88-ERK1 interaction by BiFC and flow cytometry. Mean VENUS Fluorescence Intensity ± SEM at varying EI-52 concentrations (left panel) from three independent experiments, Tukey’s one-way ANOVA; 8 vs 0 h *p = 0.0446, 10- and 12 vs 0 h ****p < 0.0001 (95% confidence interval). F PLA of endogenous MYD88 and ERK in HCT116 cells treated with EI-52 (8 μM) or DMSO for 3 h using antibodies against MYD88 and ERK. The interactions are visualized as red dots and the nuclei are counterstained with DAPI (blue). The number of interactions per cell, quantified by ImageJ, is expressed as the fold difference relative to DMSO treatment. Mean ± SEM from three independent experiments, two-tailed Student’s t-test; *p = 0.0161 (95% confidence interval). G PLA in HeLa cells transfected with 6His-WT or 6His-D319N ERK2 and Flag-MYD88. Cells were treated with EI-52 (10 μM) or DMSO for 8 h using anti-His and -Flag. Detection was carried out as in 1 F. Mean ± SEM from three independent experiments, Tukey’s one-way ANOVA; *p = 0.0303 (95% confidence interval). H Cell recovery and cell death following EI-52 or ERK kinase inhibitors over 48 h at 8 μM. Mean ± SEM from three independent experiments, two-way Tukey’s ANOVA; Cell recovery at 48 h EI-52 vs DMSO *p = 0.0123, LY32149966 vs DMSO p = 0.0145; Death at 48 h EI-52 vs DMSO *p = 0.0456 (95% confidence interval). I Apoptosis (annexin V/PI) in HCT116 cells treated for 24 h with DMSO or EI-52 (8 μM) by flow cytometry. Mean percentage of annexin V+ cells ± SEM from three independent experiments, two-tailed Student’s t-test; **F = 0.0016 (95% confidence interval). Source data are provided as a Source Data file.
