Fig. 7: Targeting and therapeutic efficacy of dtEVs in PDX mouse models.

a Schematic (left) and fluorescence image (right) of subcutaneous PDX tumor intratumourally co-injected with PKH67-labeled IgG stEV (green) and PKH26-labeled CD64^ck_αROR1 dtEV (red). Broader tumor penetration is seen with dtEV. (Scale bar is 5 mm) b Biodistribution (left) of PKH-labeled LNP, stEV (IgG) and dtEV (αROR1) in PDX mice bearing subcutaneously implanted pancreatic tumors shows dtEV accumulated preferentially in the tumor (n of LNP, stEV_IgG and dtEV_αROR1 = 2, 3, and 3 mice). c Organ imaging (right) confirms the tumor accumulation. Change in d, volume and e, weight of PDX tumors (with KRAS^G12D and TP53^A138V mutations and EGFR⁺/ROR1⁺ expression) subcutaneously implanted in NOD/SCID mice after a 3-week treatment (yellow zone) with CD64^ck_αROR1 dtEVs carrying scramble RNA (SCR), CD64^ck_αROR1 dtEVs carrying 50/50 TP53 mRNA and siKRAS^G12D (dtEV), or CD64^ck_αROR1 dtEVs carrying 50/50 TP53 mRNA and siKRAS^G12D plus 20 mg/kg GEM once per week. EVs were delivered at a dose of 1 × 10¹¹ EVs 3 times per week. (n of SCR, dtEV, and dtEV+GEM = 5, 4, and 6 mice). f Number and area of metastatic tumor lesions in different organs (n of SCR, dtEV, and dtEV+GEM = 5, 4, and 6 mice). g Lung sections from treated PDX mice with hematoxylin and eosin (H&E) stain, DAPI (blue, nuclei), anti-cytokeratin (green, tumor marker), anti-KRAS (red), and anti-Flag (purple, delivered EV marker). Metastatic lesions in the lung were decreased by dtEVs with or without GEM [N: normal; T: tumor tissue]. h Tumor tissues of mice treated with dtEV or dtEV+GEM exhibited increased β-galactosidase expression and decreased K-i67 expression. i The therapeutic effect, characterized by increased β-galactosidase expression and decreased K-i67 expression, was also observed in metastatic lesions in the lung. The treatment period is highlighted in yellow in d. (*P < 0.05, **P < 0.01, ****P < 0.0001, as determined by unpaired two-sided Student’s t test. P-values are provided for selected comparisons.) The siRNA sequences are given in Supplementary Table 3. Source data are provided as a Source data file. (Scale bar of figures g, h, and i: 100 μm) g–i fluorescent and immunohistochemistry images are representative of three independent mice.