NF-kappaB-independent induction of endothelial cell apoptosis by the vascular disrupting agent DMXAA.
BACKGROUND
DMXAA (5,6-dimethylxanthenone-4-acetic acid; AS1404), a vascular disrupting agent currently in clinical trials, induces tumour endothelial cell apoptosis in vivo in mice and in cancer patients. DMXAA activates NF-kappaB in many different cell types. In this study, whether DMXAA-induced endothelial cell apoptosis was NF-kappaB dependent was determined.


METHODS
HUVEC endothelial and T24 endothelial-like cells were treated with DMXAA and apoptosis was measured by terminal deoxynucleotidyl transferase biotin-dUTP nick end labelling (TUNEL). NF-kappaB activation was measured by electrophoretic mobility shift assays (EMSA). T24 cells were transfected with IkappaBalphaM, a mutant form of the IkappaBalpha gene which cannot be phosphorylated and degraded, hence preventing NF-kappaB expression.


RESULTS
No NF-kappaB up-regulation was detected in apoptotic HUVEC treated with DMXAA. The IkappaBalphaM-transfected T24 cells showed similar apoptotic responses to those of parental cells.


CONCLUSIONS
The DMXAA-induced apoptosis is neither mediated by, nor inhibited by, the expression of the NF-kappaB pathway.
Woon
See-Tarn
ST
Auckland Cancer Society Research Centre, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand.
Hung
Sandy S C
SS
Wu
Derek C F
DC
Schooltink
Mary Ann
MA
Sutherland
Rachel
R
Baguley
Bruce C
BC
Chen
Qi
Q
Chamley
Lawrence W
LW
Ching
Lai-Ming
LM
D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D014162:Transfection; D044004:Xanthones / Q000494:pharmacology*
D000970:Antineoplastic Agents; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; C000606205:Nfkbia protein, mouse; D044004:Xanthones; C066668:vadimezan; D000072000:NF-KappaB Inhibitor alpha