Antitumor effects and cell selectivity of temporin-1CEa, an antimicrobial peptide from the skin secretions of the Chinese brown frog (Rana chensinensis)

Many antimicrobial peptides from amphibian exhibit additional anticancer properties due to a similar mechanism of action at both bacterial and cancer cells. We have previously reported the cDNA sequence of the antimicrobial peptide temporin-1CEa precursor cloned from the Chinese brown frog Ram chensinensis. In this study, we purified, synthesized and structurally characterized temporin-1CEa from the skin secretions of R. chensinensis. The cytotoxicity and cell selectivity of temporin-1CEa were further examined on twelve human carcinoma cell lines and on normal human umbilical vein smooth muscle cells (HUVSMCs). Our results indicated that temporin-1CEa has the amino acid sequence of FVDLKKIA-NIINSIF-NH2, and exhibits 50-56% identity with temporin family peptides from other frog species. The CD spectra for temporin-1CEa adopted a well-defined alpha-helical structure in 50% TFE/water solution. The results of MTT assay showed that temporin-1CEa exhibits cytotoxicity to all tested cancer cell lines in a concentration-dependent manner, being MCF-7 cells the most sensitive. Moreover, temporin-1CEa had lower hemolytic effect to human erythrocytes and had no significant cytotoxicity to normal HUVSMCs at concentrations showed potent antitumor activity. In summary, temporin-1CEa, an amphiphilic alpha-helical cationic peptide, may represent a novel anticancer agent for breast cancer therapy, considering its cancer cell selectivity and relatively lower cytotoxicity to normal cells. (C) 2011 Elsevier Masson SAS. All rights reserved.