Auto-loaded TRAIL-exosomes derived from induced neural stem cells for brain cancer therapy.

Transdifferentiation (TD), a somatic cell reprogramming process that eliminates pluripotent intermediates, creates cells that are ideal for personalized anti-cancer therapy. Here, we provide the first evidence that extracellular vesicles (EVs) from TD-derived induced neural stem cells (Exo-iNSCs) are an efficacious treatment strategy for brain cancer. We found that genetically engineered iNSCs generated EVs loaded with the tumoricidal gene product TRAIL at nearly twice the rate of their parental fibroblasts, and TRAIL produced by iNSCs was naturally loaded into the lumen of EVs and arrayed across their outer membrane (Exo-iNSC-TRAIL). Uptake studies in ex vivo organotypic brain slice cultures showed that Exo-iNSC-TRAIL selectively accumulates within tumor foci, and co-culture assays demonstrated that Exo-iNSC-TRAIL killed metastatic and primary brain cancer cells more effectively than free TRAIL. In an orthotopic mouse model of brain cancer, Exo-iNSC-TRAIL reduced breast-to-brain tumor xenografts by approximately 3000-fold compared to treatment with free TRAIL, with all Exo-iNSC-TRAIL treated animals surviving through 90 days post-treatment. In additional in vivo testing against aggressive U87 and invasive GBM8 glioblastoma tumors, Exo-iNSC-TRAIL also induced a statistically significant increase in survival. These studies establish a novel, easily generated, stable, tumor-targeted EV to efficaciously treat multiple forms of brain cancer.