KI17: A Bioinspired Peptide Derived from Talisia esculenta with In Vitro Anticancer and Immunomodulatory Activities

Cancer therapy remains limited by drug resistance and poor selectivity, while inflammation-driven tumor progression further complicates treatment outcomes. Antimicrobial peptides (AMPs) have emerged as promising therapeutic alternatives due to their multifunctional properties. In this study, we investigated the anticancer and immunomodulatory activities of KI17, a rationally designed peptide derived from GL18, a peptide fragment identified from the talisin protein of Talisia esculenta. KI17 exhibited dose-dependent antiproliferative effects against murine and human melanoma (B16F10-Nex2, SK-MEL-2, A375) and cervical cancer (HeLa) cell lines, while displaying reduced cytotoxicity toward non-tumoral BV-2 microglial cells, resulting in a favorable selectivity index. Mechanistic analyses revealed that KI17 induces morphological alterations, mitochondrial dysfunction, caspase activation, and late-stage apoptosis, together with G0/G1 cell cycle arrest accompanied by accumulation of the Sub-G0 population, indicating coordinated regulation of cell death and cell cycle progression. KI17 effectively suppressed lipopolysaccharide (LPS)-induced microglial activation, markedly reducing pro-inflammatory cytokine and nitric oxide production without compromising cell viability. These biological activities are consistent with the peptide's optimized physicochemical features, including increased cationicity, amphipathicity, and α-helical folding. Overall, our findings demonstrate that KI17 combines selective anticancer activity with potent immunomodulatory effects, highlighting its potential as a bioinspired peptide for further preclinical development in cancer therapy.