Rational engineering and yeast surface display of Epinecidin-1 peptides reveal antimicrobial activity and selective anticancer effects.

BACKGROUND: The global escalation of antimicrobial resistance has created an urgent demand for novel antimicrobial strategies beyond conventional antibiotics. Antimicrobial peptides (AMPs) constitute a key component of innate immunity and display broad-spectrum activity; however, their clinical translation is often limited by host toxicity, instability, and insufficient selectivity. METHODS AND RESULTS: In this study, amino acid sequence of Epinecidin-1 (Epi-1), a marine-derived AMP isolated from Epinephelus coioides, was engineered using a rational design strategy and displayed on the surface of Saccharomyces cerevisiae via yeast surface display. Nine Epi-1 peptide variants differing in net charge and molecular weight were generated. Their surface expression was verified by flow cytometry, and selected variants were inactivated and evaluated for antimicrobial activity against six clinically relevant bacterial pathogens. Cytotoxicity and antiproliferative effects were also assessed using human embryonic kidney cells (HEK293) and MDA-MB-231 triple-negative breast cancer cells. Several Epi-1 variants exhibited efficient surface display and significant antimicrobial activity. No cytotoxic effects were observed in HEK293 cells across tested concentrations. However, they induced a time-dependent reduction in MDA-MB-231 cell viability. CONCLUSION: These findings demonstrate that yeast-displayed Epinecidin-1 variants retain antimicrobial efficacy while exhibiting minimal toxicity toward normal cells. The study highlights yeast surface display as a powerful platform for engineering and screening AMP derivatives for therapeutic and cosmetic applications.