Aim: We investigated the delivery of sorafenib (SFB) to breast cancer spheroids by natural killer cell-derived exosomes (NK-Exos). Methods: SFB-NK-Exos were constructed by electroporation. Their antitumor effects were evaluated by methyl thiazolyl tetrazolium, acridine orange/ethidium bromide, 4',6-diamidino-2-phenylindole, annexin/propidium iodide, scratch and migration assay, colony formation, RT-PCR, western blot and lipophagy tests. Result: The loading efficacy was 46.66%. SFB-NK-Exos-treated spheroids showed higher cytotoxic effects (33%) and apoptotic population (44.9%). Despite the reduction of SFB concentration in the SFB-NK-Exos formulation, similar cytotoxic effects to those of free SFB were observed. Increased intracellular trafficking, sustained release of the drug and selective inhibitory effects demonstrated efficient navigation. Conclusion: This is the first report for SFB loading into NK-Exos, which led to significant cytotoxic intensification against cancer cells.
Keywords: breast cancer; cytotoxic effect; drug release; exosome; nanocarrier; natural killer cell; sorafenib; spheroid.
What is this summary about? This study describes the delivery of an anticancer drug called sorafenib (SFB) to laboratory-grown spherical masses of cancer cells called spheroids. Saucer-like cellular structures called exosomes were used as drug-delivery tools. These exosomes were produced by a subgroup of immune cells called natural killer (NK) cells. NK cells are responsible for killing cancer cells. So, these exosomes share similar anticancer properties with NK cells. We wanted to test whether exosomes loaded with SFB would have better anticancer effects. What were the results? Using different methods, SFB was loaded within the exosomes and delivered to the spheroids. The obtained results showed that a combination of exosomes and SFB could improve the targeting efficacy, reducing the side effects to the normal cells and allowing continuous release of the drug. The spheroids were killed with higher efficacy following this treatment. What do the results of the study mean? The combination of NK cell-derived exosomes and SFB could lead to better cytotoxicity against cancer cells. Therefore, this strategy could have better anticancer effects compared with SFB treatment alone.