Discovery and Characteristics of a Novel Antitumor Cyclopeptide Derived from Shark

Peptides pose a challenge in drug development due to their short half-lives in vivo. In this study, we conducted in vitro degradation experiments on SAIF, which is a shark-derived peptide that we previously studied. The degradation fragments were sequenced and a truncated peptide sequence was identified. The truncated peptide was then cloned and expressed via the E. coli system with traceless cloning to form a novel cyclic peptide in vitro oxidation condition via the formation of a disulfide bond between the N- and C-termini, which was named ctSAIF. ctSAIF exhibited high anti-HCC activity and enhanced enzymatic stability in vitro, and retained antitumor activity and good biocompatibility in systemic circulation in a HCC xenograft model. Our study discovered and characterized a novel shark-derived cyclic peptide with antitumor activity, laying a foundation for its further development as an antitumor drug candidate. The study also provided a new solution for peptide drug development.

Automated summary

In this study, degradation experiments were conducted on a peptide called SAIF, derived from sharks. A truncated peptide sequence was identified from the degradation fragments and expressed as a novel cyclic peptide called ctSAIF. ctSAIF demonstrated high anti-HCC activity, enhanced enzymatic stability, and showed antitumor activity and good biocompatibility in a HCC xenograft model. This study discovered and characterized a shark-derived cyclic peptide with antitumor activity, laying a foundation for its development as an antitumor drug candidate, and providing a new solution for peptide drug development.