title: Gastrin-releasing peptide promotes the growth of HepG2 cells via EGFR-independent ERK1/2 activation.
abstract: Gastrin-releasing peptide (GRP) plays an important role in regulating tumor growth and migration. However, little is known about its role in human hepatocellular carcinoma (HCC) cells. This study explored the effect of GRP on the growth of HCC HepG2 cells and the underlying mechanisms. Expression of GRP and its cognate receptor (GRPR) were detected by immunocytochemisty, reverse transcription-PCR and Western blotting and compared between two human HCC cell lines (HepG2 and MHCC97H) and a normal hepatic cell line (HL-7702). The effects of GRP on cell proliferation and signaling pathways were examined by Western blotting, MTT assay and flow cytometry. Both GRP and GRPR were overexpressed in HepG2 and MHCC97H cells. GRP activated MAPK/ERK1/2 in HepG2 cells, leading to enhanced proliferation, reduced apoptosis and accelerated cell cycle progression. The effect of GRP on ERK1/2 was effectively attenuated by the GRPR antagonist PD176252 or MEK inhibitor U0126, but not by the TNF-alpha protease inhibitor TAPI-1 or the EGFR tyrosine kinase inhibitor PD153035. The effect of GRP on the growth of HepG2 cells was significantly attenuated by PD176252 or U0126. GRP serves as a mitogen for HepG2 and MHCC97H cells. GRP promotes the growth of HepG2 cells through interaction with GRPR co-expressed in tumor cells, and subsequently activates MAPK/ERK1/2 via EGFR-independent mechanisms.
authors.affiliation: Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, PR China.
authors.forename: Xinqiu
authors.initials: X
authors.lastname: Li
authors.forename: Yunfu
authors.initials: Y
authors.lastname: Lv
authors.forename: Aihua
authors.initials: A
authors.lastname: Yuan
authors.forename: Shanyong
authors.initials: S
authors.lastname: Yi
authors.forename: Yong
authors.initials: Y
authors.lastname: Ma
authors.forename: Zongfang
authors.initials: Z
authors.lastname: Li
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D004789:Enzyme Activation / Q000187:drug effects; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D019886:Gastrin-Releasing Peptide / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D011799:Quinazolines / Q000494:pharmacology; D018004:Receptors, Bombesin / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D007211:Indoles; D011799:Quinazolines; D018004:Receptors, Bombesin; D019886:Gastrin-Releasing Peptide; C512478:EGFR protein, human; D066246:ErbB Receptors; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C116774:PD 176252; C088860:4-((3-bromophenyl)amino)-6,7-dimethoxyquinazoline