Discovery of a Highly Potent and Selective Oncolytic Peptide NF27 through Structure−Activity Relationship Studies

Oncolytic peptides specifically induce cancer cell death by rupturing the cell membrane, but their structure−activity relationship (SAR) remains poorly understood and no peptides have been clinically approved. Here, we designed and evaluated CKS1-derived peptides to identify key SAR features, including the role of a proline-induced hinge and the spatial distribution of hydrophilic and hydrophobic amino acids. Among them, NF27 showed potent and broad anticancer activity with minimal toxicity toward healthy cells and low hemolysis. Mechanistic studies revealed that cell size and cell−cell junctions correlate with sensitivity to oncolytic peptides. NF27-induced cell death was immunogenic and promoted infiltration of immune cells in murine tumors. In murine tumor models, NF27 effectively suppressed tumor growth and achieved complete eradication in some cases, with no observable systemic toxicity. These findings establish fundamental SAR principles for oncolytic peptides and identify NF27 as a promising therapeutic candidate.