A bombesin receptor subtype-3 peptide increases nuclear oncogene expression in a MEK-1 dependent manner in human lung cancer cells.
A synthetic peptide, (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) was used to investigate the signal transduction mechanisms of bombesin receptor subtype-3. Using NCI-1299#5 human lung cancer cells stably transfected with bombesin receptor subtype-3, 100 nM (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) elevated the cytosolic Ca2+ from 150 to 250 nM within 10 s. Addition of (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) caused phosphorylation of mitogen activated protein kinase in a time- and concentration-dependent manner. The mitogen activated protein kinase phosphorylation caused by (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) was inhibited by 2'-amino-3'-methyoxyflavone (PD98059), a mitogen activated protein kinase kinase (MEK-1) inhibitor. Using a luciferase reporter gene construct, (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) caused Elk-1 activation after 10 min and the increase in Elk-1 activation caused by (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) was inhibited by PD98059 as well as a dominant-negative MEK-1. (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) caused increased c-fos as well as c-jun mRNAs 1 h after addition to NCI-H1299#5 cells. The 47-fold increase in c-fos mRNA caused by 100 nM (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) was inhibited by PD98059, a dominant-negative MEK-1 and a substance P antagonist but not (3-phenylpropanoyl-D-Ala(24), Pro(26), Psi(26,27), Phe(27))GRP-(20-27) (BW2258U89), a GRP receptor antagonist. These results indicate that (D-Phe(6), beta-Ala(11), Phe(13), Nle(14))bombesin-(6-14) caused increased nuclear oncogene expression and upstream events include mitogen activated protein kinase phosphorylation and Elk-1 activation.
Weber
H C
HC
Section of Gastroenterology, Boston University School of Medicine, Boston, MA 02118, USA.
Walters
J
J
Leyton
J
J
Casibang
M
M
Purdom
S
S
Jensen
R T
RT
Coy
D H
DH
Ellis
C
C
Clark
G
G
Moody
T W
TW
D001839:Bombesin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005419:Flavonoids / Q000494:pharmacology*; D016762:Genes, fos / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D009857:Oncogenes / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D011518:Proto-Oncogene Proteins / Q000187:drug effects* / Q000378:metabolism; D012333:RNA, Messenger / Q000187:drug effects* / Q000378:metabolism; D018004:Receptors, Bombesin / Q000187:drug effects* / Q000378:metabolism; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D050807:ets-Domain Protein Elk-1
D004268:DNA-Binding Proteins; C494112:ELK1 protein, human; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D018004:Receptors, Bombesin; D014157:Transcription Factors; C107120:bombesin receptor subtype 3; D050807:ets-Domain Protein Elk-1; C076539:bombesin (6-14), D-Phe(6)-Leu(13)-psi(CH2NH)-Phe(14)-; D020929:Mitogen-Activated Protein Kinase Kinases; D001839:Bombesin; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; D002118:Calcium