Hydrocarbon stapling modification of peptide alyteserin-2a: Discovery of novel stapled peptide antitumor agents.

Alyteserin-2a (ILGKLLSTAAGLLSNLNH 2 ) is isolated from the skin exudates of midwife toad and has a wide range of biological applications. However, the use of alyteserin-2a as an antitumor agent is limited due to its structural flexibility. In this study, a series of stapled peptides were prepared through hydrocarbon stapling modification without destroying the key residues, and their chemical and biological properties were further evaluated for enhancing the application potential of alyteserin-2a in the field of antitumor drugs development. Among them, alyteserin-2a-Sp3 displayed significant improvement in helicity levels, protease resistance, and antitumor activity compared to that of the template peptide alyteserin-2a, indicating that alyteserin-2a-Sp3 had a potential to become a lead compound for the development of novel antitumor drugs. This study confirms the important effect of hydrocarbon stapling strategy on the secondary structure, hydrolase stability, and biological activity of alyteserin-2a.