抗菌胜肽廣泛應用於醫學及食品上，從細菌，哺乳類動物，包含人類的各種物種中已經鑑定出多種抗菌胜肽，其為具有抵禦細菌、病毒、真菌等生物的小分子蛋白，癌症為現今人類一項嚴重的問題，而近年來抗菌胜肽除了抑菌研究外，也發現具有抑制癌細胞生長的能力，因此抗癌潛力的研究也受到了重視與投入。
近年來，本實驗室致力於原生益菌及其衍生物相關研究，從Lactobacillus rhamnosus DSM 6594菌株搜尋其Quorum sensing裡的HPK蛋白，以此當作模板，使用融合引物與巢式聚合酶連鎖反應(FPNI-PCR)外部擴增探索序列，比對資料庫後篩選出具潛力MTK64，本篇論文發現其具有抑制人類大腸癌細胞SW480 的能力，在細胞存活率測試中，IC50的濃度為65.34μg/ml。並且透過流式細胞儀結果推測MTK64會誘導SW480大腸癌細胞走向細胞凋亡，接著利用西方點墨法測定與細胞凋亡相關蛋白的表現量，並由共軛焦顯微鏡觀察MTK64進入細胞後位置與型態的變化。綜合整體結果，MTK64沒有造成細胞膜受損，並可能透過進入細胞而誘導細胞的凋亡。

Antibacterial peptides (AMPs) are widely used in medicine and food. AMPs are small molecular weight proteins that have broad-spectrum antimicrobial activity against bacteria, viruses, and fungi, etc. Cancer is a serious problem in the world. A few studies found that some antimicrobial peptides had not only antimicrobial activity but also anticancer activity. Therefore, the research on anticancer peptide has got more attention.
Our lab found a potential antimicrobial peptides (MTK64) from Lactobacillus rhamnosus DSM 6594. In this thesis, we found that it has the ability to inhibit the proliferation of human colorectal cancer cell SW480, and the IC50 value of MTK64 was 65.34 μg/ml in the cell viability test.
Further, we use flow cytometry analysis. The result indicated that MTK64 may cause apoptosis in SW480 cells. Then we use Caspase3, Caspase8, Caspase9 to detecte the levels of these apoptosis marker by western blot analysis. We also observed cellular morphology and membrane permeability after MTK64 treatment.
In summary, MTK64 peptide can enter cells induce apoptosis but still remains cell membrane intact.

1. Izadpanah, A., & Gallo, R. L. (2005). Antimicrobial peptides. Journal of the American Academy of Dermatology, 52(3), 381-390. 
2. Papagianni, M. (2003). Ribosomally synthesized peptides with antimicrobial properties: biosynthesis, structure, function, and applications. Biotechnology advances, 21(6), 465-499.  
3. Nissen-Meyer, J., & Nes, I. F. (1997). Ribosomally synthesized antimicrobial peptides: their function, structure, biogenesis, and mechanism of action. Archives of microbiology, 167(2-3), 67-77. 
4. Cleveland, J., Montville, T. J., Nes, I. F., & Chikindas, M. L. (2001). Bacteriocins: safe, natural antimicrobials for food preservation. International journal of food microbiology, 71(1), 1-20. 
5. Heng, N. C., Wescombe, P. A., Burton, J. P., Jack, R. W., & Tagg, J. R. (2007). The diversity of bacteriocins in Gram-positive bacteria Bacteriocins (pp. 45-92): Springer.
6. Ellis, R. E., Yuan, J., & Horvitz, H. R. (1991). Mechanisms and functions of cell death. Annual review of cell biology, 7(1), 663-698. 
7. Beyaert, R., Van Loo, G., Heyninck, K., & Vandenabeele, P. (2002). Signaling to gene activation and cell death by tumor necrosis factor receptors and Fas International review of cytology (Vol. 214, pp. 225-272): Elsevier.
8. estjens, N., van Gurp, M., van Loo, G., Saelens, X., & Vandenabeele, P. (2004). Bcl-2 family members as sentinels of cellular integrity and role of mitochondrial intermembrane space proteins in apoptotic cell death. Acta haematologica, 111(1-2), 7-27. 
9. Edinger, A. L., & Thompson, C. B. (2004). Death by design: apoptosis, necrosis and autophagy. Current opinion in cell biology, 16(6), 663-669. 
10. Zelezetsky, I., & Tossi, A. (2006). Alpha-helical antimicrobial peptides—using a sequence template to guide structure–activity relationship studies. Biochimica et Biophysica Acta (BBA)-Biomembranes, 1758(9), 1436-1449. 
11. Li, H., Kolluri, S. K., Gu, J., Dawson, M. I., Cao, X., Hobbs, P. D., . . . Lin, F. (2000). Cytochrome c release and apoptosis induced by mitochondrial targeting of nuclear orphan receptor TR3. Science, 289(5482), 1159-1164. 
12. Mai, J. C., Mi, Z., Kim, S.-H., Ng, B., & Robbins, P. D. (2001). A proapoptotic peptide for the treatment of solid tumors. Cancer Research, 61(21), 7709-7712. 
13. Riedl, S., Zweytick, D., & Lohner, K. (2011). Membrane-active host defense peptides–challenges and perspectives for the development of novel anticancer drugs. Chemistry and physics of lipids, 164(8), 766-781. 
14. Schweizer, F. (2009). Cationic amphiphilic peptides with cancer-selective toxicity. European journal of pharmacology, 625(1), 190-194. 
15. Vanhoefer, U., Harstrick, A., Achterrath, W., Cao, S., Seeber, S., & Rustum, Y. M. (2001). Irinotecan in the treatment of colorectal cancer: clinical overview. Journal of Clinical Oncology, 19(5), 1501-1518. 
16. Huang, Y., Feng, Q., Yan, Q., Hao, X., & Chen, Y. (2015). Alpha-helical cationic anticancer peptides: a promising candidate for novel anticancer drugs. Mini reviews in medicinal chemistry, 15(1), 73-81. 
17. Garneau, S., Martin, N. I., & Vederas, J. C. (2002). Two-peptide bacteriocins produced by lactic acid bacteria. Biochimie, 84(5), 577-592. 
18. Didenko, V. V., & Hornsby, P. J. (1996). Presence of double-strand breaks with single-base 3'overhangs in cells undergoing apoptosis but not necrosis. The Journal of Cell Biology, 135(5), 1369-1376. 
19. Cotter, P. D., Hill, C., & Ross, R. P. (2005). Bacteriocins: developing innate immunity for food. Nature Reviews Microbiology, 3(10), 777-788. 
20. Kaufmann, S. H., & Earnshaw, W. C. (2000). Induction of apoptosis by cancer chemotherapy. Experimental cell research, 256(1), 42-49. 
21. Marr, A. K., Gooderham, W. J., & Hancock, R. E. (2006). Antibacterial peptides for therapeutic use: obstacles and realistic outlook. Current opinion in pharmacology, 6(5), 468-472.