Antisense oligonucleotides (ASOs) bind to CD44 at the plasma membrane, triggering p90RSK-dependent phosphorylation of EPHA2 on Ser897. The EPHA2/CD44 complex is co-endocytosed into RAB5-positive early endosomes and trafficked via RAB11/17-positive recycling endosomes to the nuclear surface. At the nuclear-proximal compartment, lipid peroxidation renders the endosomal membrane leaky, enabling ASO escape into the perinuclear cytoplasm and subsequent nuclear entry, where ASOs direct KRAS mRNA degradation. G3BP1/2-nucleated condensates are recruited to membrane rupture sites as repair plugs, limiting productive ASO escape. Pharmacological (ISRIB) or genetic targeting of stress granule assembly suppresses this repair response and enhances ASO-mediated KRAS knockdown.
The EPHA2/CD44 nuclear capture pathway and SG–mediated endosomal repair in KRAS-mutant PDAC cells. ASOs (red) bind CD44 at the plasma membrane, triggering p90RSK-dependent phosphorylation of EPHA2 on Ser897 (P). The EPHA2–CD44 complex is co-endocytosed into RAB5-positive early endosomes and trafficked via RAB11/17-positive recycling endosomes to the nuclear surface (nuclear capture). At this nuclear-proximal compartment, lipid peroxidation renders the endosomal membrane leaky, enabling ASO escape into the perinuclear cytoplasm and subsequent nuclear entry, where ASOs direct KRAS mRNA degradation. G3BP1/2-nucleated condensates are observed at membrane rupture sites as repair plugs, limiting productive ASO escape. Pharmacological (ISRIB) or genetic targeting of SG assembly suppresses this repair response and enhances ASO-mediated KRAS knockdown. Figure generated using BioRender.com (https://www.biorender.com/).