In spite of great advances in
cancer therapy, there is considerable current interest in developing
anticancer agents with a new mode of action because of the development of resistance by
cancer cells towards current anticancer drugs. A growing number of studies have shown that some of the
cationic antimicrobial peptides (AMPs), which are toxic to bacteria but not to normal mammalian cells, exhibit a broad spectrum of cytotoxic activity against
cancer cells. Such studies have considerably enhanced the significance of AMPs, both synthetic and from natural sources, which have been of importance both for an increased understanding of the immune system and for their potential as clinical
antibiotics. The electrostatic attraction between the negatively charged components of bacterial and
cancer cells and the positively charged AMPs is believed to play a major role in the strong binding and selective disruption of bacterial and
cancer cell membranes, respectively. However, it is unclear why some
host defense peptides are able to kill
cancer cells when others do not. In addition, it is not clear whether the molecular mechanism(s) underlying the antibacterial and anticancer activities of AMPs are the same or different. In this article, we review various studies on different AMPs that exhibit cytotoxic activity against
cancer cells. The suitability of
cancer cell-targeting AMPs as
cancer therapeutics is also discussed.