Activation of HER family signaling as a mechanism of acquired resistance to ALK inhibitors in EML4-ALK-positive non-small cell lung cancer.

Abstract

PURPOSE:

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.

EXPERIMENTAL DESIGN:

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.

RESULTS:

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.

CONCLUSIONS:

EGF-mediated activation of HER family signaling is associated with ALK-TKI resistance in lung cancer positive for EML4-ALK.

• Authors: Junko Tanizaki, Isamu Okamoto, Takafumi Okabe, Kazuko Sakai, Kaoru Tanaka, Hidetoshi Hayashi, Hiroyasu Kaneda, Ken Takezawa, Kiyoko Kuwata, Haruka Yamaguchi, Erina Hatashita, Kazuto Nishio, Kazuhiko Nakagawa
• Journal: Clinical cancer research : an official journal of the American Association for Cancer Research (Clin Cancer Res) Vol. 18 Issue 22 Pg. 6219-26 (Nov 15 2012) ISSN: 1557-3265 [Electronic] United States
• PMID: 22843788 (Publication Type: Journal Article)
• Copyright: ©2012 AACR.

Chemical References

• Antineoplastic Agents
• EML4-ALK fusion protein, human
• NVP-TAE684
• Oncogene Proteins, Fusion
• Protein Kinase Inhibitors
• Pyrazoles
• Pyridines
• Pyrimidines
• Crizotinib
• ErbB Receptors

Topics

• Antineoplastic Agents (pharmacology)
• Apoptosis (drug effects)
• Carcinoma, Non-Small-Cell Lung (drug therapy)
• Cell Proliferation (drug effects)
• Crizotinib
• Drug Resistance, Neoplasm
• ErbB Receptors (metabolism)
• Humans
• Inhibitory Concentration 50
• Lung Neoplasms (drug therapy)
• Oncogene Proteins, Fusion (metabolism)
• Protein Kinase Inhibitors (pharmacology)
• Pyrazoles (pharmacology)
• Pyridines (pharmacology)
• Pyrimidines (pharmacology)
• Signal Transduction
• Tumor Cells, Cultured (drug effects)