Abstract 1788: Exosomal formulation of cannabidiol (CBD) inhibits lung cancer proliferation and enhances uptake and tumor targeting Free

Lung cancer remains a leading cause of cancer-related deaths, with treatment specificity posing a major challenge. Thus, we aim to repurpose cannabidiol (CBD) as an antitumor agent, delivered via tumor-targeted exosomes (Exo). We demonstrated that oral CBD administration inhibited orthotopic lung tumor growth by ∼60% (p < 0.01), with enhanced efficacy (∼80%; p < 0.001) achieved using folic acid-functionalized exosomes loaded with CBD. We hypothesized that the enhanced antitumor efficacy is due to 1) increased accumulation at the tumor site due to FA-targeting; 2) improved cellular uptake of CBD via exosomal delivery; and 3) modulation of mechanistic pathways by CBD. To evaluate tumor targeting, FA-Exo labeled with Alexa Fluor-750 (AF750) were administered orally to tumor-bearing mice. Single doses of free AF750, Exo-AF750, and FA-Exo-AF750 were compared (n=3 per group). After 12 hr, mice were euthanized and imaged ex vivo using Odyssey LiCor Imager. For bioavailability studies, female C57BL/6 mice were given a single oral dose of 40 mg/kg CBD or ExoCBD, and tissue CBD levels were quantified 4 hr post-administration. Additionally, ER stress modulation by CBD was assessed in A549 lung cancer cells through analysis of key markers. FA-Exo-AF750 exhibited 3-fold higher signal in tumor tissues compared to non-functionalized exosomes (p<0.01). In bioavailability studies, ExoCBD demonstrated significantly higher CBD levels in the liver (5-fold) and mammary pads (10-fold) compared to free CBD (p<0.001). Notably, free CBD was undetectable in plasma, whereas ExoCBD achieved plasma CBD levels of 500 ng/mL, suggesting enhanced bioavailability and prolonged circulation time. In A549 lung cancer cells, CBD downregulated key ER stress markers, including PERK, IRE1α, BiP, CHOP, Calnexin, and PDI, anti-inflammatory marker NFκB and oncogenic CB2. Furthermore, combination of CBD with paclitaxel (PAC) substantially reduced the IC50 value of PAC against both drug-sensitive (12.5 to 5 nM) and drug-resistant (325 to 80 nM) A549 cells compared to PAC alone. In fact, the activity of PAC and CBD was synergistic against A549 cells, as shown by the combination index (CI = 0.62) calculated using Calcusyn software. Importantly, CBD reversed PAC resistance by downregulating MDR-1 in drug-resistant A549 cells. Overall, tumor-targeted exosomal formulations significantly enhance CBD’s bioavailability, tumor accumulation, and therapeutic efficacy. Combined with its ability to overcome chemotherapy resistance, these findings highlight the promise of CBD-loaded exosomes as a novel therapeutic against lung cancer.