Naturally Equipped Urinary Exosomes Coated Poly (2−ethyl−2−oxazoline)−poly (D, L−lactide) Nanocarriers for the Pre−Clinical Translation of Breast Cancer

Recently, biomimetic nanoparticles for tumor−targeted therapy have attracted intensifying interest. Although exosomes are an excellent biomimetic material, numerous challenges are still hindering its clinical applications, such as low yield, insufficient targeting efficiency, and high cost. In this work, urinary exosomes (UEs) with high expression of CD9 and CD47 were extracted from breast cancer patients by a non−invasive method. Here, a nanotechnology approach is reported for tumor homologous targeting via CD9 and phagocytosis escape via CD47 through UE−coated poly (2−ethyl−2−oxazoline)−poly (D, L−lactide) (PEOz−PLA) nanoparticles (UEPP NPs). The cytotoxic agent doxorubicin (DOX)−loaded UEPP (UEPP−D) NPs with an initial particle size of 61.5 nm showed a burst release under acidic condition mimicking the tumor microenvironment. In vitro experiments revealed that UEPP−D NPs exhibited significantly improved cellular uptake, cytotoxicity, and apoptosis in MCF−7 cell lines as compared to DOX−loaded PEOz−PLA nanoparticles (PP−D NPs) and free DOX. More importantly, anti−phagocytosis and pharmacokinetic studies confirmed that UEPP−D NPs had superior immune escape ability and significantly prolonged the drug’s bloodstream circulation in vivo. Finally, UEPP−D NPs showed a markedly higher antitumor efficacy and lower side−toxicity in MCF−7 tumor bearing nude mice model. Thus, this versatile nano−system with immune escape, homologous targeting, and rapid response release characteristics could be a promising tool for breast cancer treatment.