Brevilaterin B from Brevibacillus laterosporus has selective antitumor activity and induces apoptosis in epidermal cancer

Abstract Brevibacillus laterosporus, a newly discovered genus, had been shown to be one of the best candidates for producing multiple antimicrobial peptides (AMPs). Herein, we discovered a new bioactivity of Brevilaterin B, an AMP produced by Br. laterosporus S62-9, and investigated the details about its Anticancer. Proliferation, membrane permeability and apoptotic rate were checked using CCK-8 Assay, LDH Assay and Annexin V-FITC/PI Kits. ROS levels and mitochondrial membrane potential were detected using the fluorescent probe DCFH-DA and JC-1. Brevilaterin B exhibited broad anticancer activity in a dose-dependent manner. It selectively inhibited the proliferation of epidermal cancer cell A431 but had no effect on normal cells at 2 µg/mL. Typical morphological characteristics of apoptosis and an apoptotic ratio of 71.0% in A431 were observed after treatment with 2-3 µg/mL of Brevilaterin B. In A431 cells, 21.3% ROS generated and 48.8% reduction in mitochondrial membrane potential further occurred, indicating the main site of action was the mitochondrion. Brevilaterin B secreted by Br. laterosporus S62-9 has potential application as an anticancer medicament, increasing its commercial value. It’s believed to be the first report of the anticancer activity of this type of AMPs.