VEGF upregulates Bcl-2 expression and is associated with decreased apoptosis in neuroblastoma cells.
OBJECTIVE
Both the expression of Bcl-2 and the amount of vascular endothelial growth factor (VEGF) are increased in neuroblastoma cells cocultured with hepatocytes. The authors hypothesize that VEGF upregulates Bcl-2 expression by the neuroblastoma cells and protects them from apoptotic stimuli.


METHODS
To determine whether VEGF will induce Bcl-2 expression in neuroblastoma cells, the cells are plated with standard media (control) or media supplemented with VEGF. After 24 hours, Bcl-2 expression is measured. To determine whether VEGF protects neuroblastoma cells from apoptosis, the cells are subjected to tumor necrosis factor alpha (TNF-alpha) or serum starvation to induce apoptosis either with or without VEGF added to the culture media. The cells are collected and apoptosis measured using the deoxynucleotidyltransferase-mediated dUTP neck end labeling (TUNEL) method.


RESULTS
VEGF increases Bcl-2 expression by 33% over cells cultured in standard media. Serum starving the tumor cells or adding TNF-alpha significantly increases the percentage of apoptotic cells. The addition of VEGF significantly protects the neuroblastoma cells from the apoptotic effects of both serum starvation and TNF-alpha.


CONCLUSIONS
VEGF increases the expression of Bcl-2 and also abrogates TNF-alpha and serum starvation-induced apoptosis in neuroblastoma cells in vitro. VEGF may promote neuroblastoma survival not only through angiogenesis, but also by altering apoptosis and its regulating proteins.
Beierle
Elizabeth A
EA
University of Florida, Gainesville, FL, USA.
Strande
Louise F
LF
Chen
Mike K
MK
D017209:Apoptosis / Q000502:physiology*; D002460:Cell Line; D016895:Culture Media, Serum-Free; D016228:Endothelial Growth Factors / Q000502:physiology*; D022781:Hepatocytes / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D007158:Immunologic Techniques; D020287:In Situ Nick-End Labeling / Q000379:methods; D008222:Lymphokines / Q000502:physiology*; D009447:Neuroblastoma / Q000737:chemistry / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000378:metabolism; D015854:Up-Regulation / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016895:Culture Media, Serum-Free; D016228:Endothelial Growth Factors; D008222:Lymphokines; D019253:Proto-Oncogene Proteins c-bcl-2; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors