Cell-penetrating peptides: A tool for effective delivery in gene-targeted therapies.

The current landscapes of novel therapeutic approaches rely mostly on gene-targeted technologies, enabling to fight rare genomic diseases, from infections to cancer and hereditary diseases. Although, reaching the action-site for this novel treatments requires to deliver nucleic acids, or other macromolecules into cells, which may pose difficult tasks to pharmaceutical companies. To overcome this technological limitation, a wide variety of vectors have been developed in the past decades and have proven to be successful in delivering various therapeutics. Cell-penetrating peptides (CPP) have been one of the technologies widely studied and have been increasingly used to transport small RNA/DNA, plasmids, antibodies, and nanoparticles into cells. Despite the already proved huge potential that these peptide-based approaches may suggest, few advances have been put to pharmacological or clinical use. This review will describe the origin, development, and usage of CPP to deliver therapeutic agents into cells, with special emphasis on their current application to gene-therapies. Specifically, we will describe the current trials being conducted to treat cancer, gene disorders, and autoimmune diseases using CPP-based therapies.