Tumor-targeted Exosomal Delivery of Celastrol for Enhanced Therapeutic Efficacy in NSCLC.

[RATIONALE] Non-small cell lung cancer (NSCLC) continues to impose a significant global mortality burden, due to limited therapies, drug resistance, and treatment-related toxicity. Exosomes offer promise for the targeted delivery of therapeutic agents.

[METHODS] Exosomes were isolated from bovine colostrum and characterized for size, polydispersity index, and surface charge. Celastrol (CEL) was loaded onto exosomes (ExoCEL), and Folic Acid (FA)-functionalized exosomes (FA-ExoCEL) and validated using fluorescence quenching and protease sensitivity assay. Anticancer activity was assessed in NSCLC cell lines using colony formation, cell migration and uptake assays. Transcriptomic (RNA-seq) and protein analysis were performed to analyze gene expression changes. Biodistribution, oral uptake and potential toxicity were evaluated in wild-type mice, while oral antitumor efficacy was tested in orthotopic lung tumor models comparing CEL, ExoCEL and FA-ExoCEL. Synergistic activity with paclitaxel was assessed in chemoresistant cells.

[RESULTS] Exosomes were isolated, characterized and efficiently loaded with CEL. ExoCEL demonstrated superior antiproliferative effects in NSCLC cell lines and enhanced potency in drug-resistant A549TR cells compared to free CEL. ExoCEL significantly inhibited colony formation and cell migration in a dose-dependent manner. RNA Seq and protein analyses showed that CEL and ExoCEL reversed TGF-β-induced EMT, restored epithelial markers, suppressed mesenchymal, oncogenic and extracellular matrix related markers. In orthotopic lung tumor models, FA-ExoCEL achieved approximately 80-90% tumor inhibition, outperforming both free CEL and ExoCEL. Oral delivery of FA-ExoCEL resulted in efficient gastrointestinal uptake, selective tumor targeting, recovery of exosomal markers in circulation and no observed systemic toxicity. CEL exhibited strong synergy with paclitaxel, with exosomal delivery further enhancing paclitaxel efficacy in resistant cells.

[CONCLUSIONS] FA-ExoCEL represents a safe, scalable, and effective oral therapeutic strategy for NSCLC. By combining exosome-mediated delivery with folate-targeted tumor accumulation, this platform enhances CEL bioavailability, and improves antitumor efficacy, supporting its translational potential for lung cancer therapy.