A Lactoferricin B/Buforin Chimeric Peptide Causes a Rapid, Selective, Prolonged Cytotoxic Effect and Induces Apoptosis in HPV18-Positive Cervical Cancer Cells

This study focuses on the chimeric peptide KKWQWK-Ahx-RLLRRLLR and its interaction with cancer cells, specifically HPV18-positive cervical cancer HeLa and Ca Ski cells. The main objective of this study was to understand the mode of action of this chimera related to its cytotoxic activity, as well as the internalization processes and the type of cell death induced. For this purpose, several in vitro and in vivo assays were performed, showing that the uptake of the chimera is not energy-dependent and could involve a passive transport process. The results suggested that chimera internalization can be mediated by a specific interaction of the peptide with molecules on the cell membrane. The cytotoxic effect of the chimera in cervical cancer cells causes severe morphological changes, including rounding, shrinking, and vacuole formation. It was also determined that the chimera primarily induces early and late apoptosis in HeLa cells, without causing necrosis, and activates caspases 3 and 7. The chimera was localized in both the cytoplasm and the nucleus of the cancer cells, suggesting that the peptide could interact with intracellular targets. In conclusion, this study provides a broader understanding of the mechanism of action of the KKWQWK-Ahx-RLLRRLLR chimera on cancer cells, highlighting its ability to induce a fast, selective, and significantly cytotoxic effect in cervical cancer cells, which involves cell death through the apoptotic pathway. The toxicity assays in <i>Galleria mellonella</i> and zebra fish showed that the chimera is safe and can be considered for preclinical studies. This study demonstrated that the chemical binding of two sequences with low activity produces a chimeric entity with enhanced cytotoxic activity capable of cellular internalization and inducement of apoptosis.