A vasoactive intestinal peptide antagonist inhibits the growth of glioblastoma cells.
The effects of a vasoactive intestinal peptide (VIP) receptor antagonist (VIPhyb) on human glioblastoma cells were characterized. Pituitary adenylate cyclase activating polypeptide (125I-PACAP-27) bound with high affinity to U87, U118, and U373 cells. Specific 125I-PACAP-27 binding to U87 cells was inhibited, with high affinity, by PACAP but not VIP or VIPhyb (IC50 = 10, 1500, and 500 nM, respectively). By reverse transcriptase-polymerase chain reaction (RT-PCR), a major 305 bp band was observed indicative of PAC1 receptors. PACAP-27 caused cAMP elevation and the increase in cAMP caused by PACAP-27, was inhibited by the VIPhyb. Also, PACAP-27 caused cytosolic Ca2+ elevation in Fura-2AM loaded U87 cells and the VIPhyb inhibited this increase. Using the MTT growth assay, the VIPhyb was shown to inhibit glioblastoma growth in a concentration-dependent manner. Using a clonogenic assay in vitro, 10 microM VIPhyb significantly inhibited proliferation of U87, U118, and U373 cells. In vivo, 0.4 microg/kg VIPhyb inhibited U87 xenograft proliferation in nude mice. These results suggest that the VIPhyb antagonizes PAC1 receptors on glioblastoma cells and inhibits their proliferation.
Sharma
A
A
National Cancer Institute, Medicine Branch, Rockville, MD 20850, USA.
Walters
J
J
Gozes
Y
Y
Fridkin
M
M
Brenneman
D
D
Gozes
I
I
Moody
T W
TW
D000818:Animals; D002118:Calcium / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D003600:Cytosol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005909:Glioblastoma / Q000378:metabolism*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D009479:Neuropeptides / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009496:Neurotensin / Q000378:metabolism / Q000494:pharmacology*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018005:Receptors, Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000187:drug effects* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014183:Transplantation, Heterologous; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism / Q000494:pharmacology*
C495401:ADCYAP1 protein, human; C495402:Adcyap1 protein, mouse; D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D018005:Receptors, Vasoactive Intestinal Peptide; D011993:Recombinant Fusion Proteins; C069189:(VIP-neurotensin) hybrid antagonist; D014660:Vasoactive Intestinal Peptide; D009496:Neurotensin; D000242:Cyclic AMP; D002118:Calcium