title: Consequence of gastrin-releasing peptide receptor activation in a human colon cancer cell line: a proteomic approach.
abstract: Gastrin-releasing peptide (GRP) and its receptor (GRPR) are aberrantly up-regulated in colon cancer. When expressed, they act as morphogens, retaining tumor cells in a better differentiated state and retarding metastasis. To identify targets activated in response to GRPR signaling we studied Caco-2 and HT-29 cells, colon cancer cell lines that expresses GRPR as a function of confluence. Total cell protein was extracted from pre-confluent cells (expressing GRP/GRPR) cultured in serum-free media in the presence or absence of GRPR-specific antagonist; as well as from confluent cells that do not express GRPR. Overall, we identified 5 proteins that are specifically down-regulated after GRP/GRPR expression: Bach2, creatine kinase B, p47, and two that could not be identified; and 6 proteins that are up-regulated: gephyrin, HSP70, HP1, ICAM-1, ACAT, and one that could not be identified. These findings suggest that the mechanism(s) by which GRP/GRPR mediate its morphogenic effects in colon cancer involve the actions of a number of hitherto unappreciated proteins.
authors.affiliation: Department of Medicine, University of Illinois at Chicago and Chicago Veterans Administration Medical Center (West Side Division), Chicago, Illinois 60612, USA.
authors.forename: Tom
authors.initials: T
authors.lastname: Ruginis
authors.forename: Lauren
authors.initials: L
authors.lastname: Taglia
authors.forename: Damien
authors.initials: D
authors.lastname: Matusiak
authors.forename: Bao-Shiang
authors.initials: BS
authors.lastname: Lee
authors.forename: Richard V
authors.initials: RV
authors.lastname: Benya
mesh_terms: D045744:Cell Line, Tumor; D003110:Colonic Neoplasms; D016895:Culture Media, Serum-Free; D015180:Electrophoresis, Gel, Two-Dimensional; D019886:Gastrin-Releasing Peptide / Q000502:physiology*; D006801:Humans; D011485:Protein Binding; D020543:Proteome / Q000378:metabolism*; D018004:Receptors, Bombesin / Q000819:agonists / Q000096:biosynthesis*; D015398:Signal Transduction; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D016895:Culture Media, Serum-Free; D020543:Proteome; D018004:Receptors, Bombesin; D019886:Gastrin-Releasing Peptide