Expression of VEGF receptors in cocultured neuroblastoma cells.
BACKGROUND
VEGF is best known for its angiogenic properties. We have found that VEGF expression is increased in neuroblastoma cells cocultured with hepatocytes. In addition, we have previously shown that neuroblastoma cells cultured with exogenous VEGF have an increase in the expression of VEGF receptors. Therefore, we hypothesized that the expression of VEGF receptors would be up-regulated in neuroblastoma cells grown in the coculture environment.


METHODS
Two neuroblastoma cell lines (IMR-32 or SK-N-DZ) are used. These cells are cultured alone and in a coculture system with hepatocytes. Message for VEGF and the VEGF receptors KDR, flt-1, flt-4, neuropilin 1 (NRP-1), and neuropilin 2 (NRP-2) are measured with RT-PCR. Flt-4, NRP-1, and NRP-2 protein expression is measured with Western blot.


RESULTS
The receptors KDR and flt-1 are not detected in either cell line in either control or coculture conditions. Message for VEGF and flt-4 is significantly increased in the cocultured IMR-32 cells, while that for NRP-1 and NRP-2 is unchanged in these cells. VEGF and its receptors are unchanged in cocultured SK-N-DZ cells.


CONCLUSIONS
Neuroblastoma cells express specific VEGF receptors that are differentially regulated in the different cell lines. These findings suggest that the heterogeneity of neuroblastomas may limit the utility of targeting VEGF and its receptors as sole treatments for the tumor, and that successful therapies will be dependent upon the specific biology of the tumor.
Beierle
Elizabeth A
EA
Department of Surgery, JHMHSC, University of Florida, Gainesville, Florida 32610-0286, USA. beierea@surgery.ufl.edu
Dai
Wei
W
Langham
Max R
MR
Copeland
Edward M
EM
Chen
Mike K
MK
D015153:Blotting, Western; D002478:Cells, Cultured; D018920:Coculture Techniques; D004730:Endothelium, Vascular / Q000166:cytology; D006801:Humans; D009447:Neuroblastoma / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D040262:Receptors, Vascular Endothelial Growth Factor / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014471:Umbilical Veins / Q000166:cytology; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000235:genetics / Q000378:metabolism
D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; D040262:Receptors, Vascular Endothelial Growth Factor; D040321:Vascular Endothelial Growth Factor Receptor-3