Higher levels of c-Met expression and phosphorylation identify cell lines with increased sensitivity to AMG-458, a novel selective c-Met inhibitor with radiosensitizing effects.

Abstract

PURPOSE:

c-Met is overexpressed in some non-small cell lung cancer (NSCLC) cell lines and tissues. Cell lines with higher levels of c-Met expression and phosphorylation depend on this receptor for survival. We studied the effects of AMG-458 on 2 NSCLC cell lines.

METHODS AND MATERIALS:

3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assays assessed the sensitivities of the cells to AMG-458. Clonogenic survival assays illustrated the radiosensitizing effects of AMG-458. Western blot for cleaved caspase 3 measured apoptosis. Immunoblotting for c-Met, phospho-Met (p-Met), Akt/p-Akt, and Erk/p-Erk was performed to observe downstream signaling.

RESULTS:

AMG-458 enhanced radiosensitivity in H441 but not in A549. H441 showed constitutive phosphorylation of c-Met. A549 expressed low levels of c-Met, which were phosphorylated only in the presence of exogenous hepatocyte growth factor. The combination of radiation therapy and AMG-458 treatment was found to synergistically increase apoptosis in the H441 cell line but not in A549. Radiation therapy, AMG-458, and combination treatment were found to reduce p-Akt and p-Erk levels in H441 but not in A549. H441 became less sensitive to AMG-458 after small interfering RNA knockdown of c-Met; there was no change in A549. After overexpression of c-Met, A549 became more sensitive, while H441 became less sensitive to AMG-458.

CONCLUSIONS:

AMG-458 was more effective in cells that expressed higher levels of c-Met/p-Met, suggesting that higher levels of c-Met and p-Met in NSCLC tissue may classify a subset of tumors that are more sensitive to molecular therapies against this receptor.

• Authors: Bo Li, Artour Torossian, Yunguang Sun, Ruihong Du, Adam P Dicker, Bo Lu
• Journal: International journal of radiation oncology, biology, physics (Int J Radiat Oncol Biol Phys) Vol. 84 Issue 4 Pg. e525-31 (Nov 15 2012) ISSN: 1879-355X [Electronic] United States
• PMID: 22836051 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2012 Elsevier Inc. All rights reserved.

Chemical References

• 1-(2-hydroxy-2-methylpropyl)-N-(5-(7-methoxyquinolin-4-yloxy)pyridin-2-yl)-5-methyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazole-4-carboxamide
• Aminopyridines
• Neoplasm Proteins
• Pyrazoles
• Radiation-Sensitizing Agents
• Proto-Oncogene Proteins c-met

Topics

• Aminopyridines (pharmacology)
• Apoptosis (drug effects, radiation effects)
• Carcinoma, Non-Small-Cell Lung (drug therapy, metabolism, pathology, radiotherapy)
• Cell Line, Tumor (drug effects, radiation effects)
• Cell Survival
• Drug Screening Assays, Antitumor (methods)
• Humans
• Lung Neoplasms (drug therapy, metabolism, pathology, radiotherapy)
• Neoplasm Proteins (antagonists & inhibitors, metabolism)
• Phosphorylation
• Proto-Oncogene Proteins c-met (antagonists & inhibitors, metabolism)
• Pyrazoles (pharmacology)
• Radiation Tolerance (drug effects)
• Radiation-Sensitizing Agents (pharmacology)