A new biology of cell penetrating peptides

Abstract

As pharmacokinetic modifiers, cell penetrating peptides (CPPs) have proven utility for the delivery of otherwise impermeable cargoes into the discrete intracellular compartments of eukaryotic cells. Methods for the molecular optimisation of CPP sequences can significantly increase the performance of novel vectors matched to a specific delivery function. Moreover, the ‘information rich’ composition and inherent molecular flexibility of many CPPs can also facilitate their interaction with intracellular proteins and other cellular structures. This proteomimetic property of CPPs has been exploited in the design of bioportides, bioactive CPPs that regulate cellular functions often by binding relatively flat PPI interfaces to achieve a dominant negative action. This new biology of CPPs is rapidly gathering momentum through the design and synthesis of a bewildering variety of peptides that may be, in whole or part, linear, helical, cyclic and/or chimeric in nature. A particular emphasis of contemporary CPP‐centred drug discovery is the unmet medical need of cancer, though the biomedical scope of bioportide applications is impressively broad including cellular signalling and reprogramming. We are hopeful that one or more of the fascinating studies described herein will translate into the clinic to establish bioportide technologies as a viable option for drug discovery.