Functional expression of bombesin receptor in most adult and pediatric human glioblastoma cell lines; role in mitogenesis and in stimulating the mitogen-activated protein kinase pathway.
Functional bombesin receptors were identified in most human glioblastoma cell lines examined (approximately 85% of lines). Bombesin stimulated the release of intracellular Ca2+ in human adult (U-373MG, D-247MG, U-118MG, U-251MG, D-245MG, U-105MG, D-54MG, A-172MG, and D-270MG lines) and pediatric (SJ-S6 and SJ-G2 lines) glioblastoma cell lines. Stimulation of the glioblastoma cell line U-373MG with bombesin or gastrin-releasing peptide (GRP) induced mitogenesis, measured by [3H]thymidine incorporation into DNA, and stimulated the tyrosine phosphorylation of the mitogen-activated protein (MAP) kinases (Erk1 and Erk2). The stimulation of the MAP kinase phosphorylation in U-373MG cells was time- and peptide concentration-dependent. Both bombesin and GRP showed similar potencies in stimulation of intracellular Ca2+ release and activation of the MAP kinase pathway in U-373MG cells, whereas neuromedin B (NMB) peptide was less potent. Bombesin and GRP induced the release of cytosolic Ca2+ in a concentration-dependent manner. Because bombesin and GRP were more potent than NMB peptide in increasing the cytosolic Ca2+ levels in U-373MG cells, we concluded that the BB2 subtype (also known as GRP-preferring receptor subtype) of the bombesin receptor is expressed in this cell line. The bombesin receptor antagonist ([Leu13-psi(CH2NH)Leu14]bombesin) blocked bombesin induced Ca2+ release and attenuated MAP kinase activation in U-373MG cells demonstrating that bombesin is acting through a receptor-dependent mechanism. This study indicates that functional bombesin receptors are widely expressed in human glioblastoma cell lines.
Sharif
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Department of Molecular Pharmacology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
Luo
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Sharif
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D000328:Adult; D001839:Bombesin / Q000031:analogs & derivatives / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002455:Cell Division; D002648:Child; D004789:Enzyme Activation / Q000187:drug effects; D019886:Gastrin-Releasing Peptide; D005909:Glioblastoma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D015287:Neurokinin B / Q000031:analogs & derivatives / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D010766:Phosphorylation; D018004:Receptors, Bombesin / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism
D010455:Peptides; D018004:Receptors, Bombesin; C057644:bombesin, Leu(13)-psi-CH2NH-Leu(14)-; D014443:Tyrosine; D019886:Gastrin-Releasing Peptide; D015287:Neurokinin B; C038393:neuromedin B; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D001839:Bombesin; D002118:Calcium