(4-(n-hydroxyamino)-2r-isobutyl-3s-methylsuccinyl)-l-phenylglycine-n-methylamide and Stomach-Neoplasms

Helicobacter pylori, a microaerophilic gram-negative bacterium, colonizes the human stomach. About 50% of the world's population is infected, and this infection is considered as the major risk factor for the development of gastric adenocarcinomas in 1% of infected subjects. Carcinogenesis is characterized by the process of epithelial-to-mesenchymal transition (EMT), in the course of which fully differentiated epithelial cells turn into depolarized and migratory cells. Concomitant disruption of adherence junctions (AJ) is facilitated by growth factors like hepatocyte growth factor 1 (HGF-1), but has been also shown to depend on ectodomain shedding of E-cadherin. The aim of this study was to investigate the impact of infection with H. pylori of NCI-N87 gastric epithelial cells on the shedding of E-cadherin and HGF-receptor c-Met. Our results show that infection with H. pylori provokes shedding of the surface proteins c-Met and E-cadherin. Evidence is provided that ADAM10 contributes to the shedding of c-Met and E-cadherin.

Topics: ADAM Proteins; ADAM10 Protein; Amyloid Precursor Protein Secretases; Cadherins; Cell Line; Disease Progression; Epithelial Cells; Gene Expression; Glycine; Helicobacter Infections; Helicobacter pylori; Humans; Hydroxamic Acids; Membrane Proteins; Metalloendopeptidases; Peptide Fragments; Protease Inhibitors; Proto-Oncogene Proteins c-met; RNA, Small Interfering; Stomach; Stomach Neoplasms; Transfection

Inactivation of epidermal growth factor (EGF) receptor (EGFR) represents a promising strategy for the development of selective therapies against epithelial cancers and has been extensively studied as a molecular target for cancer therapy. However, little attention has been paid to remnant cell-associated domains created by cleavage of EGFR ligands. The present study focused on recent findings that cleavage of membrane-anchored heparin-binding EGF-like growth factor (proHB-EGF), an EGFR ligand, induces translocation of the carboxyl-terminal fragment (CTF) of HB-EGF from the plasma membrane to the nucleus and regulates cell cycle.. Two gastric cancer cell lines, MKN28 and NUGC4, were used. KB-R7785, an inhibitor of proHB-EGF shedding, was used to suppress HB-EGF-CTF nuclear translocation with cetuximab, which inhibits EGFR phosphorylation. Cell growth was analyzed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay, apoptosis was evaluated by assay of caspase-3 and caspase-7, and cell cycle was investigated by flow cytometry.. Immunofluorescence study confirmed that KB-R7785 inhibited HB-EGF-CTF nuclear translocation under conditions of proHB-EGF shedding induction by 12-O-tetradecanoylphorbol-13-acetate in gastric cancer cells. KB-R7785 inhibited cell growth in a dose-dependent manner and high-dose KB-R7785 induced apoptosis. Moreover, KB-R7785 induced cell cycle arrest and increased sub-G1 DNA content. KB-R7785 suppressed cyclin A and c-Myc expression. All effects of KB-R7785 were reinforced by combination with cetuximab.. These results suggest that both inhibition of EGFR phosphorylation and inhibition of HB-EGF-CTF nuclear translocation play crucial roles in inhibitory regulation of cancer cell growth. Suppression of HB-EGF-CTF nuclear translocation might offer a new strategy for treating gastric cancer.

Topics: ADAM Proteins; ADAM12 Protein; Antibodies, Monoclonal; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cell Nucleus; Cetuximab; Drug Delivery Systems; Drug Evaluation, Preclinical; ErbB Receptors; Glycine; Heparin-binding EGF-like Growth Factor; Humans; Hydroxamic Acids; Intercellular Signaling Peptides and Proteins; Kruppel-Like Transcription Factors; Membrane Proteins; Models, Biological; Peptide Fragments; Promyelocytic Leukemia Zinc Finger Protein; Protein Structure, Tertiary; Protein Transport; Stomach Neoplasms