The antimicrobial peptide, lactoferricin B, is cytotoxic to neuroblastoma cells in vitro and inhibits xenograft growth in vivo.
Antimicrobial peptides have been shown to exert cytotoxic activity towards cancer cells through their ability to interact with negatively charged cell membranes. In this study the cytotoxic effect of the antimicrobial peptide, LfcinB was tested in a panel of human neuroblastoma cell lines. LfcinB displayed a selective cytotoxic activity against both MYCN-amplified and non-MYCN-amplified cell lines. Non-transformed fibroblasts were not substantially affected by LfcinB. Treatment of neuroblastoma cells with LfcinB induced rapid destabilization of the cytoplasmic membrane and formation of membrane blebs. Depolarization of the mitochondria membranes and irreversible changes in the mitochondria morphology was also evident. Immuno- and fluorescence-labeled LfcinB revealed that the peptide co-localized with mitochondria. Furthermore, treatment of neuroblastoma cells with LfcinB induced cleavage of caspase-6, -7 and -9 followed by cell death. However, neither addition of the pan-caspase inhibitor, zVAD-fmk, or specific caspase inhibitors could reverse the cytotoxic effect induced by LfcinB. Treatment of established SH-SY-5Y neuroblastoma xenografts with repeated injections of LfcinB resulted in significant tumor growth inhibition. These results revealed a selective destabilizing effect of LfcinB on two important targets in the neuroblastoma cells, the cytoplasmic- and the mitochondria membrane.
Department of Biochemistry, Faculty of Medicine, University of Tromsø, Tromsø, Norway, and Childhood Cancer Research Unit, Department of Woman and Child Health, Karolinska Institutet, Stockholm, Sweden.
Liv Tone
LT
Eliassen
Gerd
G
Berge
Arild
A
Leknessund
Mari
M
Wikman
Inger
I
Lindin
Cecilie
C
Løkke
Frida
F
Ponthan
John Inge
JI
Johnsen
Baldur
B
Sveinbjørnsson
Per
P
Kogner
Trond
T
Flaegstad
Øystein
Ø
Rekdal
D000818:Animals; D000890:Anti-Infective Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D020128:Inhibitory Concentration 50; D007781:Lactoferrin / Q000493:pharmacokinetics / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D051336:Mitochondrial Membranes / Q000187:drug effects / Q000502:physiology; D009447:Neuroblastoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D051381:Rats; D023041:Xenograft Model Antitumor Assays
D000890:Anti-Infective Agents; C082171:lactoferricin B; D007781:Lactoferrin; D020169:Caspases