Expression of mitochondrial Apo2.7 molecules and caspase-3 activation in human lymphocytes treated with the ribosome-inhibiting mistletoe lectins and the cell membrane permeabilizing viscotoxins.

Abstract

BACKGROUND:

It is unclear whether expression of newly described mitochondrial Apo2.7 molecules (7A6 antigen) is specific for apoptosis or may also occur in necrosis.

METHODS:

We incubated human lymphocytes with the apoptosis-inducing mistletoe lectin (ML) I and the cell membrane-permeabilizing viscotoxins (VT), and measured cell death-associated changes by flow cytometry.

RESULTS:

In ML I-treated lymphocytes, Apo2.7 expression and caspase-3 activation was recognized within 24 h. In VT-treated cells, we observed an Apo2.7 expression with low fluorescence level, while active caspase-3 and DNA fragments (TUNEL) were not detected within 24 h. In these cells, caspase-3 activation was recognized 48 h later. As a major subset of ML-treated cells expressing Apo2.7 molecules did not activated caspase-3, while all caspase-3(+) cells did express Apo2.7, one may suggest that the caspase pathway is activated secondarily to mitochondrial events.

CONCLUSIONS:

Expression of Apo2.7 is sensitive marker of cell death but may not be specific for apoptosis alone as it can be detected also in cells treated with cell membrane-permeabilizing toxins. On the other hand, this expression may be the consequence of an induction of distinct "death signals" resulting in apoptosis later on.

• Authors: A Büssing, W Vervecken, M Wagner, B Wagner, U Pfüller, M Schietzel
• Journal: Cytometry (Cytometry) Vol. 37 Issue 2 Pg. 133-9 (Oct 01 1999) ISSN: 0196-4763 [Print] United States
• PMID: 10486525 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 1999 Wiley-Liss, Inc.

Chemical References

• Lectins
• Membrane Proteins
• Plant Lectins
• Plant Preparations
• Plant Proteins
• Ribosome Inactivating Proteins, Type 2
• Toxins, Biological
• antigen 7A6
• mistletoe lectin I
• ribosome inactivating protein, Viscum
• viscotoxin
• CASP3 protein, human
• Caspase 3
• Caspases

Topics

• Apoptosis
• Caspase 3
• Caspases (metabolism)
• Cells, Cultured
• Enzyme Activation
• Flow Cytometry
• Humans
• In Situ Nick-End Labeling
• Lectins (pharmacology)
• Lymphocytes (drug effects, metabolism, ultrastructure)
• Membrane Proteins (metabolism)
• Microscopy, Electron
• Mistletoe
• Plant Lectins
• Plant Preparations
• Plant Proteins
• Plants, Medicinal
• Ribosome Inactivating Proteins, Type 2
• Time Factors
• Toxins, Biological (pharmacology)