Discovery of two Bombinin peptides with antimicrobial and anticancer activities from the skin secretion of Oriental Fire-bellied toad, Bombina orientalis

Abstract

Amphibian skin secretions are known to contain numerous peptides with a large array of biological activities. Bombinins are a group of amphibian derived peptides with broad spectrum antimicrobial activities that have been only identified from the ancient toad species, Bombina. In this study, we described the identification and characterization of a novel bombinin precursor which encoded a bombinin like peptide (BLP-7) and a novel bombinin H type peptide (named as Bombinin H-BO) from the skin secretion of Oriental fire-bellied toad, Bombina orientalis. The primary structures of both mature peptides were determined by combinations of molecular cloning of peptide precursor-encoding cDNAs and mass spectrometry techniques. Secondary structure prediction revealed that both peptides had cationic amphipathic α-helical structural features. The synthetic replicate of BLP-7 displayed more potent antimicrobial activity than Bombinin H-BO against Gram-positive and Gram-negative bacteria and yeast. Also, in vitro antitumor assay showed that both peptides possessed obvious anti-proliferative activity on 3 human hepatoma cells (Hep G2/SK-HEP-1/Huh7) at the nontoxic doses. These results indicate the peptide family of bombinins could be a potential source of drug candidates for anti-infection and anticancer therapy.

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A novel bombinin precursor encoded a bombinin like peptide and a novel bombinin H type peptide was identified and characterized from the skin secretion of Oriental fire-bellied toad, Bombina orientalis by utilizing the combinations of molecular cloning and mass spectrometry techniques. The synthetic version of each peptide displayed a wide range of bioactivities including antimicrobial and anticancer activities and with low haemolytic effect, which might have the potential to become new drug candidates for anticancer and antimicrobial therapy.

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