Peptide-decorated polymeric nanomedicines for precision cancer therapy

The advancement of tissue and cell-specific drug delivery systems is a key to precision cancer therapy. Peptides, with easy synthesis, low immunogenicity and biological functions closely mimicking or surpassing natural proteins, have been actively engineered and explored to provide nanomedicines with the ability to overcome various extracellular and intracellular delivery barriers ranging from phagocytic clearance in the circulation, low tumor penetration, poor cancer cell selectivity, inferior cell penetration, to endosomal entrapment as well as poor blood brain barrier permeation for brain cancer therapy. Anti-tumor studies with peptide-decorated polymeric nanomedicines are currently in the experimental stage. Most of the reported peptide-directed polymeric nanomedicines do have a rather complex design requiring a multi-step reproducible fabrication process. Moreover, many of the proposed peptide-decorated polymeric nanomedicines are still not able to effectively overcome the drug delivery cascade barriers. Consequently, in order to facilitate clinical translation the complexity of the systems has to be reduced, while maintaining the added functions after the introduction of the different peptides and further progress has to be made in passing the various drug delivery barriers. In this review, we give an overview of the rational design, development and preclinical performance of peptide-decorated polymeric nanomedicines, and further discuss their challenges and future perspectives as a next generation cancer treatment modality.