Activation of HER Family Signaling as a Mechanism of Acquired Resistance to ALK Inhibitors in EML4-ALK―Positive Non―Small Cell Lung Cancer

• Published in: Clinical cancer research Vol. 18; no. 22; pp. 6219 - 6226
• Main Authors: TANIZAKI, Junko, OKAMOTO, Isamu, HATASHITA, Erina, NISHIO, Kazuto, NAKAGAWA, Kazuhiko, OKABE, Takafumi, SAKAI, Kazuko, TANAKA, Kaoru, HAYASHI, Hidetoshi, KANEDA, Hiroyasu, TAKEZAWA, Ken, KUWATA, Kiyoko, YAMAGUCHI, Haruka
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 15-11-2012
• Subjects: Antineoplastic agents; Antineoplastic Agents - pharmacology; Apoptosis - drug effects; Biological and medical sciences; Carcinoma, Non-Small-Cell Lung - drug therapy; Cell Proliferation - drug effects; Drug Resistance, Neoplasm; Humans; Inhibitory Concentration 50; Lung Neoplasms - drug therapy; Medical sciences; Oncogene Proteins, Fusion - metabolism; Pharmacology. Drug treatments; Pneumology; Protein Kinase Inhibitors - pharmacology; Pyrazoles - pharmacology; Pyridines - pharmacology; Pyrimidines - pharmacology; Receptor, Epidermal Growth Factor - metabolism; Signal Transduction; Tumor Cells, Cultured - drug effects; Tumors of the respiratory system and mediastinum; Lung disease; Respiratory disease; Acquired; Lung cancer; Activation; Malignant tumor; non-small cell lung carcinoma; Resistance; Signal transduction; Regulation(control); C-Onc gene; Bronchus disease; Inhibitor; Mechanism of action; Anaplastic lymphoma kinase; Protooncogene; Cancer
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.ccr-12-0392

Anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKI) such as crizotinib show marked efficacy in patients with non-small cell lung cancer positive for the echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion protein. However, acquired resistance to these agents has already been described in treated patients, and the mechanisms of such resistance remain largely unknown.
We established lines of EML4-ALK-positive H3122 lung cancer cells that are resistant to the ALK inhibitor TAE684 (H3122/TR cells) and investigated their resistance mechanism with the use of immunoblot analysis, ELISA, reverse transcription and real-time PCR analysis, and an annexin V binding assay. We isolated EML4-ALK-positive lung cancer cells (K-3) from a patient who developed resistance to crizotinib and investigated their characteristics.
The expression of EML4-ALK was reduced at the transcriptional level, whereas phosphorylation of epidermal growth factor receptor (EGFR), HER2, and HER3 was upregulated, in H3122/TR cells compared with those in H3122 cells. This activation of HER family proteins was accompanied by increased secretion of EGF. Treatment with an EGFR-TKI induced apoptosis in H3122/TR cells, but not in H3122 cells. The TAE684-induced inhibition of extracellular signal-regulated kinase (ERK) and STAT3 phosphorylation observed in parental cells was prevented by exposure of these cells to exogenous EGF, resulting in a reduced sensitivity of cell growth to TAE684. K-3 cells also manifested HER family activation accompanied by increased EGF secretion.
EGF-mediated activation of HER family signaling is associated with ALK-TKI resistance in lung cancer positive for EML4-ALK.