| Institution: | 1. Biomedical Sciences Program, Graduate School, Khon Kaen University, Khon Kaen, Thailand;2. Department of Biochemistry, Protein and Proteomics Research Center for Commercial and Industrial Purposes (ProCCI), Faculty of Science, Khon Kaen University, Khon Kaen, Thailand;3. Department of Biochemistry, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand;4. Department of Biological Science and Technology, China Medical University, Taichung, Taiwan
Department of Medical Research, China Medical University Hospital, Taichung, Taiwan;5. Division of Pharmacognosy and Toxicology, Faculty of Pharmaceutical Science, Khon Kaen University, Khon Kaen, Thailand;6. Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen, Thailand;7. HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen, Thailand;8. Department of Biological Science and Technology, China Medical University, Taichung, Taiwan |
| Abstract: | The anticancer activity of cationic antimicrobial peptides (AMPs) has become more interesting because some AMPs have selective recognition against cancer cells. However, their antitumor properties and underlying mechanisms in cancer cells have not been clearly understood. In this study, we evaluated the effects of KT2 (lysine/tryptophan-rich AMP) on the cellular uptake and internalization mechanism, cell viability, surface charge of the cell membrane, membrane integrity, apoptotic cell death, and autophagy in human HCT 116 colon cancer cells. We found that KT2 interacted with the cell membrane of HCT 116 cells and was internalized into HCT 116 cells via clathrin-mediated and caveolae-mediated endocytosis mechanisms. The interaction of KT2 with cells caused cell membrane structure change, elevated membrane permeability, and KT2 also affected the lipid component. The results of atomic force microscopy showed cellular membrane defects of KT2-treated cells. The internalized KT2 induced nuclear condensation and apoptotic cell death. It elevated the apoptotic factor levels including those of cytochrome c and apoptosis-inducing factor. Furthermore, KT2 inhibited autophagy by the suppression of autophagy-related 5, autophagy-related 7, autophagy-related 16 like 1, and Beclin-1 proteins. In conclusion, these results revealed the cytotoxicity of cationic KT2 against HCT 116 cells and may help to clarify the interactions between cationic AMPs and cancer cells. |
