Bombinin-BO1 induces hepatocellular carcinoma cell-cycle arrest and apoptosis via the HSP90A-Cdc37-CDK1 axis.

Bombinin-BO1 (BO1), a bombinin peptide derived from the skin secretion of , exhibits broad-spectrum antimicrobial activity. To date, the anticancer effect of BO1 remains unclear. This study confirmed cytotoxicity of BO1 on hepatocellular carcinoma cells by inducing S-phase cycle block and apoptosis. In addition, BO1 was found to be localized in cytoplasm through endocytosis. The combined results of pull down, mass spectrometry, and co-immunoprecipitation suggested that BO1 induced misfolding of CDK1 and degradation by competitively binding HSP90A with Cdc37. It was verified that overexpression of HSP90A in BO1-treated cells significantly inhibited degradation of CDK1. , BO1 inhibited tumor without being toxic to individuals. This study reveals the anti-tumor mechanism of BO1 in inducing cell-cycle arrest and apoptosis by interfering with HSP90A-Cdc37-CDK1 system. This is the first study to analyze the mechanism of BO1 regulation of tumor cells, providing theoretical basis for BO1 treatment of hepatocellular carcinoma.