Cetuximab Attenuates Metastasis and u-PAR Expression in Non-Small Cell Lung Cancer: u-PAR and E-Cadherin are Novel Biomarkers of Cetuximab Sensitivity

• Published in: Cancer research (Chicago, Ill.) Ill.), 2009-03, Vol.69 (6), p.2461-2470
• Main Authors: NIKOLOVA, Dessislava A, ASANGANI, Irfan A, ALLGAYER, Heike, NELSON, Laura D, HUGHES, Dennis P. M, SIWAK, Doris R, MILLS, Gordon B, HARMS, Andrea, BUCHHOLZ, Erika, PILZ, Lothar R, MANEGOLD, Christian
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - pharmacology; Antibodies, Monoclonal, Humanized; Antineoplastic agents; Antineoplastic Agents - pharmacology; Biological and medical sciences; Biomarkers, Tumor - biosynthesis; Biomarkers, Tumor - genetics; Cadherins - biosynthesis; Cadherins - genetics; Carcinoma, Non-Small-Cell Lung - drug therapy; Carcinoma, Non-Small-Cell Lung - genetics; Carcinoma, Non-Small-Cell Lung - metabolism; Carcinoma, Non-Small-Cell Lung - pathology; Cetuximab; Chick Embryo; Epidermal Growth Factor - antagonists & inhibitors; ErbB Receptors - antagonists & inhibitors; ErbB Receptors - metabolism; Gene Expression; Humans; JNK Mitogen-Activated Protein Kinases - metabolism; Lung Neoplasms - drug therapy; Lung Neoplasms - genetics; Lung Neoplasms - metabolism; Lung Neoplasms - pathology; MAP Kinase Signaling System; Medical sciences; Neoplasm Metastasis; Pharmacology. Drug treatments; Pneumology; Promoter Regions, Genetic; Proto-Oncogene Proteins c-jun - metabolism; Receptors, Urokinase Plasminogen Activator - biosynthesis; Receptors, Urokinase Plasminogen Activator - genetics; Tumors; Tumors of the respiratory system and mediastinum
• ISSN: 0008-5472; 1538-7445
• DOI: 10.1158/0008-5472.CAN-08-3236

Cetuximab, which blocks ligand binding to epidermal growth factor receptor (EGFR), is currently being studied as a novel treatment for non-small cell lung cancer (NSCLC). However, its mechanisms of action toward metastasis, and markers of drug sensitivity, have not been fully elucidated. This study was conducted to (a) determine the effect of Cetuximab on invasion and NSCLC-metastasis; (b) investigate urokinase-type plasminogen activator receptor (u-PAR), a major molecule promoting invasion and metastasis, as a target molecule; (c) delineate molecular mediators of Cetuximab-induced metastasis inhibition; and (d) identify biomarkers of drug sensitivity in NSCLC. Cetuximab treatment resulted in reduced growth and Matrigel invasion of H1395 and A549 NSCLC cell lines, in parallel with reduced u-PAR mRNA and protein. u-PAR down-regulation was brought about by suppressing the binding of JunD and c-Jun to u-PAR promoter motif -190/-171 in vivo, and an inhibition of MAP/ERK kinase signaling. Furthermore, Cetuximab inhibited NSCLC proliferation and metastasis to distant organs in vivo as indicated by the chicken embryo metastasis assay. Low E-cadherin and high u-PAR, but not EGFR, was associated with resistance to Cetuximab in seven NSCLC cell lines. Furthermore, siRNA knockdown of u-PAR led to a resensitization to Cetuximab. Moreover, low E-cadherin and high u-PAR was found in 63% of resected tumor tissues of NSCLC patients progressing under Cetuximab therapy. This is the first study to show u-PAR as a target and marker of sensitivity to Cetuximab, and to delineate novel mechanisms leading to metastasis suppression of NSCLC by Cetuximab.