Characteristics of the antitumor activities in tumor cells and modulation of the inflammatory response in RAW264.7 cells of a novel antimicrobial peptide, chrysophsin-1, from the red sea bream (Chrysophrys major).

The antimicrobial peptide, chrysophsin-1, exhibits antimicrobial activities with similar efficiencies for both gram-negative and gram-positive bacteria. In this study, we examined the antitumor activity and modulation of the inflammatory response of a synthetic chrysophsin-1 peptide. In vitro results showed that chrysophsin-1 had greater inhibitory effects against human fibrosarcoma (HT-1080), histiocytic lymphoma (U937), and epithelial carcinoma (HeLa) cells. LDH release by HeLa cells was comparable to that of an MTS assay after treatment with 1.5-3 μg/ml chrysophsin-1 for 24h. Under SEM and TEM observations, we found no intact cell membranes after chrysophsin-1 treatment of HeLa cells for 8h. The suggested mechanism of the cytotoxic activity of chrysophsin-1 was disruption of cancer cell membranes. In addition, we also examined caspase-3, -8, and -9 activities by Western blotting; the results excluded the participation of apoptosis in chrysophsin-1's effect on HeLa cells. Stimulation by lipopolysaccharide induced tumor necrosis factor (TNF)-α which was able to modulate chrysophsin-1 treatment of RAW264.7 cells and inhibited endogenous TNF-α release but did not block its secretion. With data from this study, we demonstrate that chrysophsin-1 has antimicrobial and antitumor activities and modulates the inflammatory response in RAW264.7 cells.