The impact of cell type on exosome-GNP complex distribution to cancer

Cancer is a multifactorial disease with an increasing incidence; cancer progression relies on dynamic interactions between mutated tumor cells and their complex tumorigenic microenvironment. Exosomes, which are bilayer lipid membrane extracellular vesicles, carry proteins, lipids, various RNA and DNA molecules and form the basis of an efficient cell-cell communication mechanism, are presumed to be involved in cancer progression. Conventional cancer therapies, such as radiotherapy and chemotherapy have many side effects resulting from lack of selectivity and the triggering of drug resistance mechanisms. Extensive research is performed on the use of exosomes as natural nanocarriers for drug delivery and targeted therapy. However, the lack of uniform method to track exosome activity and distribution in vivo diminishes the ability to develop an optimized exosome-drug delivery system for cancer therapy. In the current study, we compared the yield of systematically injected exosomes derived from different cell types (tumor and stem cells) to reach and accumulate at the tumor. In addition, the bio-distribution of the different exosomes was assessed and compared. In order to track the exosomes in vivo and to quantify its amount within the tumor, we labeled the exosomes with gold nanoparticles (GNP) which were proven as an optimal contrast agent for Computed Tomography (CT) imaging. Labeling and tracking the exosomes in vivo point out the differences in tumor targeting and bio-distribution between the different types of exosomes. The results of this study may serve future potential anti-tumor therapies using exosomes as therapy and delivery vehicles to possible drugs targeting tumors or diseased organs.