Microcin E492, a channel-forming bacteriocin from Klebsiella pneumoniae, induces apoptosis in some human cell lines

hetz C.; Bono, MR.; Barros, LF; Lagos R.

Abstract

The cytotoxic effect of microcin E492, a low-molecular-mass channel-forming bacteriocin (7,887 Da) produced by a strain of Klebsiella pneumoniae, was characterized in HeLa cells. At low (5 ?g/ml) and intermediate (10 ?g/ml) concentrations, microcin E492 induced biochemical and morphological changes typical of apoptosis, such as cell shrinkage, DNA fragmentation, extracellular exposure of phosphatidylserine, caspase activation, and loss of mitochondrial membrane potential. Treatment with zVAD-fmk, a general caspase inhibitor, completely blocked the cytotoxic effect of this bacteriocin. At higher microcin concentrations (> 20 ?g/ml) a necrotic phenotype was observed. Induction of apoptosis by microcin E492 was associated with the release of calcium from intracellular stores, probably after microcin-triggered ion channel formation. Microcin E492 also presented a cytotoxic effect on Jurkat and RJ2.25 cells, but had no effect on KG-1 cells nor on a primary culture of human tonsil endothelial cells, suggesting that there is a specific interaction of the bacteriocin with components of the target cell surface. This report describes a bacteriocin that has the capacity to induce apoptosis in human cell lines.

Más información

Título según WOS: Microcin E492, a channel-forming bacteriocin from Klebsiella pneumoniae, induces apoptosis in some human cell lines
Título según SCOPUS: Microcin E492, a channel-forming bacteriocin from Klebsiella pneumoniae, induces apoptosis in some human cell lines
Título de la Revista: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Volumen: 99
Número: 5
Editorial: NATL ACAD SCIENCES
Fecha de publicación: 2002
Página de inicio: 2696
Página final: 2701
Idioma: English
URL: http://www.pnas.org/cgi/doi/10.1073/pnas.052709699
DOI:

10.1073/pnas.052709699

Notas: ISI, SCOPUS