Cytotoxic peptides with insulin-releasing activities from skin secretions of the Italian stream frog Rana italica (Ranidae)

JM Conlon, V Musale, S Attoub, ML Mangoni, J Leprince, L Coquet, T Jouenne, YHA Abdel-Wahab, Peter Flatt, AC Rinaldi

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16 Citations (Scopus)


Peptidomic analysis of norepinephrine-stimulated skin secretions from Italian stream frog Rana italica led to the purification and characterization of two host-defense peptides differing by a single amino acid residue belonging to the brevinin-1 family (brevinin-1ITa and -1ITb), a peptide belonging to the temporin family (temporin-ITa) and a component identified as prokineticin Bv8. The secretions contained relatively high concentrations of the methionine-sulphoxide forms of brevinin-1ITa and -1ITb suggesting that these peptides may have a role as antioxidants in the skin of this montane frog. Brevinin-1ITa (IVPFLLGMVPKLVCLITKKC) displayed potent cytotoxicity against non-small cell lung adenocarcinoma A549 cells (LC50 = 18 μM), breast adenocarcinoma MDA-MB-231 cells (LC50 = 8 μM) and colorectal adenocarcinoma HT-29 cells (LC50 = 18 μM), but the peptide was also strongly hemolytic against mouse erythrocytes (LC50 = 7 μM). Temporin-ITa (VFLGAIAQALTSLLGKL.NH2) was between three and fivefold less potent against these cells. Brevinin-1ITa inhibited growth of both Gram-positive Staphylococcus epidermidis and Gram-negative Escherichia coli as well as a strain of the opportunist yeast pathogen Candida parapsilosis, whereas temporin-ITa was active only against S. epidermidis and C. parapsilosis. Both peptides stimulated the release of insulin from BRIN-BD11 clonal β-cells at concentrations ≥1 nM, but brevinin-1ITa was cytotoxic to the cells at concentrations ≥3 μM.
Original languageEnglish
Pages (from-to)769-776
JournalJournal of Peptide Science
Issue number10
Early online date11 Jul 2017
Publication statusPublished online - 11 Jul 2017


  • Frog skin
  • Antimicrobial peptide
  • Cytotoxicity
  • Ranidae
  • Insulin release


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