A small cytotoxic peptide from frog elicits potent antitumor immunity to prevent local tumor growth and metastases.

Aim: Anticancer immunochemotherapy represents an attractive paradigm to improve therapeutic responses and reduce side effects. Results & methodology: Here, we show that a naturally occurring host defense peptide, HN-1 inhibited multiplemalignant cells proliferation and tumor growth in a xenografted human breast tumor model. Acting through MAPK/NF-kappa B pathways, HN-1 induced a caspase-independent mitochondrial apoptosis, as indicated by a p53-dependent increase of Bax/Bcl-2 ratio and the nuclear translocation of apoptosis inducing factor. Besides, HN-1 augmented CD4(+)/CD8(+) T cells in 4T1 mammary carcinoma model, by enhancing the serum levels of cancer immunity-associated effectors. Meanwhile, HN-1 decreased the angiogenesis and infiltration of the tumor-associated macrophages. Conclusion: HN-1 induces caspase-independent cancer cells apoptosis and boosts cancer-resolving immunity without inducing potentially harmful pro-inflammatory responses.