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. Int J Radiat Oncol Biol Phys 2012 Nov 15;84(4):e525-31
Date
07/28/2012Pubmed ID
22836051DOI
10.1016/j.ijrobp.2012.06.025Scopus ID
2-s2.0-84872045438 (requires institutional sign-in at Scopus site) 21 CitationsAbstract
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.
Author List
Li B, Torossian A, Sun Y, Du R, Dicker AP, Lu BMESH terms used to index this publication - Major topics in bold
AminopyridinesApoptosis
Carcinoma, Non-Small-Cell Lung
Cell Line, Tumor
Cell Survival
Drug Screening Assays, Antitumor
Humans
Lung Neoplasms
Neoplasm Proteins
Phosphorylation
Proto-Oncogene Proteins c-met
Pyrazoles
Radiation Tolerance
Radiation-Sensitizing Agents