Multivalent targeting based delivery of therapeutic peptide using AP1-ELP carrier for effective cancer therapy

Elastin-like polypeptide (ELP)-based drug delivery has been utilized for various applications including cancer therapies for many years. Genetic incorporation of internalization ligands and cell-targeting peptides along with ELP polymer enhanced tumor accumulation and retention time as well as stability and activities of the drug conjugates. Herein, we described a unique delivery system comprised of genetically engineered ELP incorporated with multiple copies of IL-4 receptor targeting peptide (AP1) periodically and proapoptotic peptide (KLAKLAK)₂ referred to as AP1-ELP-KLAK. It triggered thermal-responsive self-assembly into a nanoparticle-like structure at physiological body temperature and stabilized its helical conformation, which is critical for its membrane-disrupting activities. Increased IL-4 receptor specific cellular internalization was associated with the enhanced cytotoxic effect of (KLAKLAK)2 peptide. Additionally, multivalent presentation of targeting ligands by AP1-ELP-KLAK significantly enhanced intratumoral localization and prolonged the retention time compared to ELP-KLAK, non-targeted control. Systemic administration of AP1-ELP-KLAK significanltly inhibited tumor growth by provoking cell apoptosis in various tumor xenograft models without any specific organ toxicity. Thus, our newly designed AP1-ELP-KLAK polymer nanoparticle is a promising candidate for effective cancer therapy and due to the simple preparative procedures of ELPs, this platform can be used as a good carrier for tumor-specific delivery of other therapeutics.