Suppression of proHB-EGF carboxy-terminal fragment nuclear translocation: a new molecular target therapy for gastric cancer.

Abstract

PURPOSE:

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.

EXPERIMENTAL DESIGN:

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.

RESULTS:

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.

CONCLUSIONS:

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.

• Authors: Takaya Shimura, Hiromi Kataoka, Naotaka Ogasawara, Eiji Kubota, Makoto Sasaki, Satoshi Tanida, Takashi Joh
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 14 Issue 12 Pg. 3956-65 (Jun 15 2008) ISSN: 1078-0432 [Print] United States
• PMID: 18559618 (Publication Type: Journal Article)

Chemical References

• Antibodies, Monoclonal
• Antibodies, Monoclonal, Humanized
• HBEGF protein, human
• Heparin-binding EGF-like Growth Factor
• Hydroxamic Acids
• Intercellular Signaling Peptides and Proteins
• KB R7785
• Kruppel-Like Transcription Factors
• Membrane Proteins
• Peptide Fragments
• Promyelocytic Leukemia Zinc Finger Protein
• ZBTB16 protein, human
• EGFR protein, human
• ErbB Receptors
• ADAM Proteins
• ADAM12 Protein
• ADAM12 protein, human
• Cetuximab
• Glycine

Topics

• ADAM Proteins (metabolism)
• ADAM12 Protein
• Antibodies, Monoclonal (administration & dosage, therapeutic use)
• Antibodies, Monoclonal, Humanized
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Cell Line, Tumor
• Cell Nucleus (drug effects, metabolism)
• Cetuximab
• Drug Delivery Systems
• Drug Evaluation, Preclinical
• ErbB Receptors (metabolism)
• Glycine (administration & dosage, analogs & derivatives, pharmacology)
• Heparin-binding EGF-like Growth Factor
• Humans
• Hydroxamic Acids (administration & dosage, pharmacology)
• Intercellular Signaling Peptides and Proteins (chemistry, metabolism)
• Kruppel-Like Transcription Factors (metabolism)
• Membrane Proteins (metabolism)
• Models, Biological
• Peptide Fragments (metabolism)
• Promyelocytic Leukemia Zinc Finger Protein
• Protein Structure, Tertiary
• Protein Transport (drug effects)
• Stomach Neoplasms (drug therapy, pathology)