Gastrin-releasing peptide is a growth factor for human neuroblastomas.
OBJECTIVE
To evaluate whether gastrin-releasing peptide (GRP) and GRP receptor (GRP-R) expression correlate with tumor behavior and to examine the mitogenic actions of GRP on neuroblastomas.


BACKGROUND
Neuroblastoma is the most common solid tumor of infants and children. Despite recent advances in multimodality treatment regimens, the survival for advanced-stage tumors remains dismal. Neuroblastomas are known to produce GRP; however, the proliferative effects of GRP on neuroblastomas have not been elucidated.


METHODS
Sections of paraffin-embedded neuroblastomas from 33 patients were analyzed for GRP and GRP-R protein expression by immunohistochemistry. Functional binding of GRP-R to the Ca2+ signaling pathway was examined. In addition, the proliferative effect of GRP on neuroblastoma cells (SK-N-SH, IMR-32, SH-SY5Y, LAN-1) was determined.


RESULTS
Immunohistochemical analysis showed GRP and GRP-R protein expression in neuroblastomas; an increased expression of GRP-R was noted in a higher percentage of undifferentiated tumors compared with tumors that were benign. GRP-R mRNA was confirmed in neuroblastoma cell lines. GRP treatment resulted in intracellular calcium [Ca2+]i mobilization in two cell lines (SK-N-SH, LAN-1). GRP treatment stimulated growth of all four neuroblastoma cell lines; this effect was inhibited in SK-N-SH cells by pretreatment with GRP antibody.


CONCLUSIONS
These findings show increased GRP-R expression in the more aggressive and undifferentiated neuroblastomas. The synchronous expression of GRP and its receptor, GRP-R, suggests a role for these proteins in tumor growth. Moreover, these findings show enhanced proliferation of neuroblastoma cells in vitro after GRP treatment, suggesting that GRP may act as an autocrine and/or paracrine growth factor for neuroblastomas. Treatment with specific GRP-R antagonists may provide novel adjuvant therapy for neuroblastomas in children.
Kim
Sunghoon
S
Department of Surgery, The University of Texas Medical Branch, Galveston, Texas 77555-0353, USA.
Hu
Wanqin
W
Kelly
David R
DR
Hellmich
Mark R
MR
Evers
B Mark
BM
Chung
Dai H
DH
D002118:Calcium / Q000378:metabolism; D002455:Cell Division; D002460:Cell Line; D002675:Child, Preschool; D019886:Gastrin-Releasing Peptide / Q000378:metabolism / Q000502:physiology*; D006133:Growth Substances / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D009447:Neuroblastoma / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D018004:Receptors, Bombesin / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014407:Tumor Cells, Cultured
D006133:Growth Substances; D012333:RNA, Messenger; D018004:Receptors, Bombesin; D019886:Gastrin-Releasing Peptide; D002118:Calcium