T cell membrane cloaking tumor microenvironment-responsive nanoparticles with a smart "membrane escape mechanism" for enhanced immune-chemotherapy of melanoma.

The application of combination immune-chemotherapy makes up for the limitation of monotherapy and achieves superior antitumor activity against cancer. However, combinational therapy is always restricted by poor tumor targeted drug delivery efficacy. Herein, novel T cell membrane cloaking tumor microenvironment-responsive nanoparticles (PBA modified T cell membrane cloaking hyaluronic acid (HA)-disulfide bond-vitamin E succinate/curcumin, shortened as RCM@T) were developed. T cell membrane cloaking not only serves as a protection shell for sufficient drug delivery but also acts as a programmed cell death-1(PD-1) "antibody" to selectively bind the PD-L1 of tumor cells. When RCM@T is intravenously administrated into the blood stream, it accumulates at tumor sites and responds to an acidic pH to achieve a "membrane escape effect" and expose the HA residues of RCM for tumor targeted drug delivery. RCM accumulates in the cytoplasm via CD44 receptor mediated endocytosis and intracellularly releases antitumor drug in the intracellular redox microenvironment for tumor chemotherapy. T cell membrane debris targets the PD-L1of tumor cells for tumor immunotherapy, which not only directly kills tumor cells, but also improves the CD8+ T cell level and facilitates effector cytokine release. Taken together, the as-constructed RCM@T creates a new way for the rational design of a drug delivery system via the combination of stimuli-responsive drug release, chemotherapeutical agent delivery and cell membrane based immune checkpoint blockade immunotherapy.