Engineered exosomes in service of tumor immunotherapy: From optimizing tumor-derived exosomes to delivering CRISPR/Cas9 system.

Exosomes can be modified and designed for various therapeutic goals because of their unique physical and chemical characteristics. Researchers have identified tumor-derived exosomes (TEXs) as significant players in cancer by influencing tumor growth, immune response evasion, angiogeneis, and drug resistance. TEXs promote the production of specific proteins important for cancer progression. Due to their easy accessibility, TEXs are being modified through genetic, drug delivery, membrane, immune system, and chemical alterations to be repurposed as vehicles for delivering drugs to improve cancer treatment outcomes. In the complex in vivo environment, the clustered regularly interspaced short palindromic repeats and CRISPR-associated protein 9 (CRISPR/Cas9) system encounters challenges from degradation, neutralization, and immune responses, emphasizing the need for strategic distribution strategies for effective genome editing. Engineered exosomes present a promising avenue for delivering CRISPR/Cas9 in vivo. In this review, we will explore different techniques for enhancing TEXs using various engineering strategies. Additionally, we will discuss how these exosomes can be incorporated into advanced genetic engineering systems like CRISPR/Cas9 for possible therapeutic uses.