Epidermoid carcinoma-derived antimicrobial peptide (ECAP) inhibits phosphorylation by protein kinases in vitro.

Animal peptide antibiotics are thought to mediate their cytotoxic and growth inhibitory action on bacteria, fungi, and cancer cells through a membrane-targeted mechanism. Although the membrane interactions of the peptide antibiotics and their penetration through the membranes have been studied in several models, the precise chain of events leading to cell death or growth arrest is not established yet. In this study we used in vitro kinase assays followed by imaging analyses to examine the effect of human cationic antimicrobial peptide ECAP on the activity of the protein kinases.

A protein kinase inhibitor from A431 subline overexpressing TGF alpha possesses antimicrobial activity.

During the last decade the key role of antimicrobial peptides in innate immunity has been argued. They were found in plants and in different phylogenic groups of animals (insects, amphibia, and even in mammals). We report the production of a human peptide antibiotic that was previously characterized as an EGF receptor tyrosine kinase inhibitor in epidermoid carcinoma A431/1522 cell subline overexpressing TGF alpha.