Overcoming blood-brain barrier and chemoresistance in glioblastoma by Angiopep-2-modified NK cell-derived extracellular vesicles for targeted delivery of temozolomide

Glioblastoma (GBM) remains incurable due to the blood-brain barrier (BBB) limiting drug delivery and intrinsic/acquired resistance to temozolomide (TMZ), the first-line chemotherapy. Here, we developed Angiopep-2 (Ang)-modified natural killer cell-derived extracellular vesicles (Ang-NK-EV) for targeted TMZ delivery (Ang-NK-EV@TMZ) to address these bottlenecks. NK-EV were prepared via freeze-thaw extrusion of NK-92 cells, loaded with TMZ, and surface-functionalized with Ang to target LRP1 (highly expressed at the BBB and on GBM cells). Characterization confirmed Ang-NK-EV@TMZ exhibited spherical morphology, preserved EV markers (TSG101, CD9/63/81), and retained NK cell-derived immune factors (IFN-γ, GZMB). In vitro, Ang modification enhanced GBM cell uptake (2.5-3.2-fold vs. NK-EV) and BBB transcytosis (2.8-3.5-fold vs. free TMZ). Ang-NK-EV@TMZ reversed TMZ resistance by modulating STING/ mTOR/ MGMT signaling (via IFN-γ) and inducing apoptosis (elevated cleaved caspase-3, γ-H2AX). It also triggered immunogenic cell death (increased ATP, HMGB1) and polarized macrophages to M1-like phenotypes. In orthotropic GBM models, Ang-NK-EV@TMZ accumulated in brain tumors, inhibited growth (7.2-fold lower bioluminescence vs. PBS), and extended median survival (42 days vs. 18 days for PBS). No significant organ toxicity or hemolysis was observed. This platform integrates targeted chemotherapy and immune modulation, highlighting NK-EV' potential for GBM therapy.