Abstract: Objective To investigate the effect of antimicrobial peptide Merecidin on human lung cancer A549 cells and its mechanism. Methods Experimental group: control group (Ctrl), cisplatin intervention group (cisplatin), merecidin intervention group (merecidin), caspase inhibitor group (z-VAD-fmk), caspase inhibitor + merecidin intervention group (z-VAD-fmk+ merecidin). Cell proliferation was detected by MTT assay, and apoptosis was detected by Annexin V/PI double staining. Western blot was used to detect the protein expressions of caspase-3, caspase-8, caspase-9, active caspase-3, Bcl-2, and Bax. Results The antibacterial peptide Merecidin significantly inhibited the proliferation of A549 cells (P<0.05). The IC50 value after 24h treatment of merecidin was 34.8 μmol/L. The apoptotic rate of the merecidin 25/35 μmol/L group was significantly higher than that of the ctrl group (P<0.05). The apoptosis rate of the z-VAD-fmk+merecidin 25/35 μmol/L group did not decrease than the merecidin 25/35 μmol/L group (P<0.05). The expression of active caspase-3 was detected in the merecidin 25/35 μmol/L group, but not detected in the cisplatin 40 μmol/L group. Compared with Ctrl group, the protein expressions of caspase-3, caspase-8 and caspase-9 were not increased, Bcl-2 protein expression was down-regulated (P<0.05), Bax protein expression was increased (P<0.05). Conclusion Antimicrobial peptide merecidin can inhibit the proliferation of human lung adenocarcinoma A549 cells and induce apoptosis.

Key words: Key word: antimicrobial peptide merecidin, A549 cells, apoptosis