A universal strategy of facilitating intracellular delivery of nanomedicines based on tuning ARF6 GTPase to its GTP-bound form

Intracellular delivery crossing the endomembrane barrier is the "last mile to target" for nano delivery systems carrying biomacromolecules, including genetic medicines. Nevertheless, a mass of nanomedicines is currently restricted by their equivocal safety and delivery efficiency. Here, we establish a universal strategy independent of nanomaterials. Such a policy broadly facilitates the intracellular delivery of all kinds of tested nanomedicines, subtly by inducing ARF6 GTPases to their overactivated GTP-bound state. ARF6, one member of ARF subfamily in small GTPases, is verified to regulate intracellular vesicle transport and lipid metabolism through GTP/GDP conversion. ARF6 biased to GTP-bound state causes the increased endocytosis and reduced exocytosis of eleven types of nanoparticles. This universal effect is derived from the formation of a hybrid type of endosomes triggered by overactivated ARF6 via regulating cholesterol-associated vesicles and lipid raft/caveolae pathways. Due to the mild microenvironment in hybrid endosomes, the internalized protein and nanoparticles are steadily delivered to the cytoplasm, avoiding the intensive degradation in lysosomes. Based on these findings, we identify QS11, a safe small molecule inhibitor of ARF GTPase-activating proteins, significantly enhances the antitumor efficacy of siEGFR-loaded nanoparticles by inducing ARF6 overactivation. In sum, these findings reveal that the tactics of tuning ARF6 GTPases to GTP-bound form will widely benefit cellular nano delivery.