Abstract
In recent years, the anticancer potential of antimicrobial peptides (AMPs), which exhibit toxicity toward eukaryotic cancer cells but not to normal mammalian cells, has received attention and investment. Previously, our laboratory screened a novel anticancer AMP named m2163 from Lactobacillus casei ATCC 334. M2163 was confirmed to suppress human colorectal cancer cell line SW480 growth, but the mechanism and pathway are not well understood. This study focuses on the apoptotic and necrotic effects of m2163 in SW480 cell. The caspases inhibitor Z-VAD-FMK as apoptosis inhibitor and RIPK1 inhibitor Necrostain-1 as necrosis inhibitor were used to analyze how m2163 utilize the two processes, and then also try to find out more possible anticancer mechanism of m2163. We used MTT assay to test the proliferation inhibition of m2163 in SW480 cell, Annexin V-FITC/PI double staining for observing induced apoptosis and necrosis, nucleic acid dye PI for testing the change of cell membrane permeability, free-radical indicator DCFDA for detecting the generation of ROS, fluorescein labeling for cellular localization. The experiment results revealed that m2163 can induce apoptosis and necrosis in SW480 cell and the proportion may vary with dosage. Furthermore, there are pathways not associated with caspases and RIPK1 in the anticancer mechanism of m2163. The generation of ROS may help killing cells, but the connection with apoptosis and necrosis is not obvious. M2163 generally attach on SW480 cell membrane. As for cell cytoplasm, it is not clear yet.