Exosomes as Delivery Systems for Targeted Tumour Therapy: A Systematic Review and Meta-analysis of In vitro Studies

Background: Delivery systems with low immunogenicity and toxicity are believed to enhance the efficacy of specific targeted drug delivery to cancer cells. Exosomes are potential natural nanosystems that can enhance the delivery of therapeutic agents for targeted cancer therapy. Objective: This study provides a precise effect size of exosomes as nanovesicles for in vitro delivery of anticancer agents. Methods: In this systematic review and meta-analysis, the efficacy of exosomes as nanocarriers for the delivery of therapeutic molecules was investigated using the random-effects model. We did comprehensive literature searches through CINAHL, Cochrane, PubMed, Scopus, and Science Direct of in vitro studies that reported exosomes as delivery systems for cancer therapy. Results: After the screening of eligible articles, a total of 50 studies were enrolled for the metaanalysis. The results showed that cancer cells treated with exosome-loaded anticancer agents for at least 6 h significantly decreased cell viability and increased cytotoxicity with the standardized mean difference (SMD) of -1.47 (-2.18, -0.76; (p<0.0001) and -1.66 (-2.71, -0.61; p<0.002). Exosomes effectively delivered drugs and exogenous miRNAs, siRNAs, viruses, and enzymes to cancer cells in vitro. Conclusion: This meta-analysis provides evidence of exosomes as efficient nanocarriers for the delivery of anticancer drugs.