Pyroglutamyl-histidyl-glycine, the endogenous colon mitosis inhibitor, regulates cyclic AMP level in non-tumorigenic colonic epithelial cells.
BACKGROUND
We have proposed that the mitosis inhibiting peptide, pyroGlu-His-Gly (pEHG), a colon-specific negative feedback regulator of cell proliferation, works through a G protein-coupled receptor (GPCR), as do many other pyroglutamyl-peptides.


METHODS
Non-tumorigenic YAMC (colon mucosa of Immorto mice), IMCE (Immorto-Min mouse hybrid) and human hepatoma (HepG2) cell lines were exposed to pEHG. cAMP concentrations were measured with a protein binding assay, mRNA levels with real-time PCR and Ca2+ concentration with an inverted fluorescence microscope on Fura-2/AM-loaded cells.


RESULTS
pEHG (1 nM) increased the intracellular concentration of cAMP after 5-10 min in YAMC cells, but not in HepG2 cells. No effect was seen on cytosolic Ca2+, or in the expression of the proliferation and differentiation regulatory genes c-fos, egr-1 or fosB in YAMC or IMCE cells.


CONCLUSIONS
pEHG stimulates the second messenger cAMP, but has no effect on intracellular Ca2+ or the gene expression of c-fos, egr-1 or fosB.
Reichelt
Wenche H
WH
Institute of Pediatric Research, University of Oslo, The National Hospital, NO-0027 Oslo, Norway. w.h.reichelt@klinmed.uio.no
Iversen
Jens-Gustav H
JG
Paulsen
Jan Erik
JE
Elgjo
Kjell
K
Reichelt
Karl L
KL
D000818:Animals; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D003106:Colon / Q000187:drug effects* / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics; D051766:Early Growth Response Protein 1; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D016762:Genes, fos / Q000187:drug effects; D017874:Immediate-Early Proteins / Q000235:genetics; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D009842:Oligopeptides / Q000494:pharmacology*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D013268:Stimulation, Chemical; D014157:Transcription Factors / Q000235:genetics
D004268:DNA-Binding Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D017874:Immediate-Early Proteins; D009842:Oligopeptides; D014157:Transcription Factors; C023866:pyroglutamyl-histidyl-glycine; D000242:Cyclic AMP; D011761:Pyrrolidonecarboxylic Acid