miR-138-5p reverses gefitinib resistance in non-small cell lung cancer cells via negatively regulating G protein-coupled receptor 124

Biochem Biophys Res Commun. 2014 Mar 28;446(1):179-86. doi: 10.1016/j.bbrc.2014.02.073. Epub 2014 Feb 28.


Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR TKIs) such as gefitinib are clinically effective treatments for non-small cell lung cancer (NSCLC) patients with EGFR activating mutations. However, therapeutic effect is ultimately limited by the development of acquired TKI resistance. MicroRNAs (miRNAs) represent a category of small non-coding RNAs commonly deregulated in human malignancies. The aim of this study was to investigate the role of miRNAs in gefitinib resistance. We established a gefitinib-resistant cell model (PC9GR) by continually exposing PC9 NSCLC cells to gefitinib for 6 months. MiRNA microarray screening revealed miR-138-5p showed the greatest downregulation in PC9GR cells. Re-expression of miR-138-5p was sufficient to sensitize PC9GR cells and another gefitinib-resistant NSCLC cell line, H1975, to gefitinib. Bioinformatics analysis and luciferase reporter assay showed that G protein-coupled receptor124 (GPR124) was a direct target of miR-138-5p. Experimental validation demonstrated that expression of GPR124 was suppressed by miR-138-5p on protein and mRNA levels in NSCLC cells. Furthermore, we observed an inverse correlation between the expression of miR-138-5p and GPR124 in lung adenocarcinoma specimens. Knockdown of GPR124 mimicked the effects of miR-138-5p on the sensitivity to gefitinib. Collectively, our results suggest that downregulation of miR-138-5p contributes to gefitinib resistance and that restoration of miR-138-5p or inhibition GPR124 might serve as potential therapeutic approach for overcoming NSCLC gefitinib resistance.

Keywords: G protein-coupled receptors; Gefitinib resistance; MicroRNA; Non-small cell lung cancer; Tyrosine kinase inhibitor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / drug therapy
  • Adenocarcinoma / genetics
  • Adenocarcinoma / metabolism
  • Adenocarcinoma of Lung
  • Antineoplastic Agents / pharmacology
  • Carcinoma, Non-Small-Cell Lung / drug therapy
  • Carcinoma, Non-Small-Cell Lung / genetics*
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Cell Line, Tumor
  • Down-Regulation
  • Drug Resistance, Neoplasm / genetics
  • Drug Resistance, Neoplasm / physiology
  • Gefitinib
  • Gene Knockdown Techniques
  • Humans
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / genetics*
  • Lung Neoplasms / metabolism*
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism*
  • Quinazolines / pharmacology*
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Neoplasm / genetics
  • RNA, Neoplasm / metabolism
  • Receptors, G-Protein-Coupled / antagonists & inhibitors
  • Receptors, G-Protein-Coupled / genetics*
  • Receptors, G-Protein-Coupled / metabolism*


  • ADGRA2 protein, human
  • Antineoplastic Agents
  • MIRN138 microRNA, human
  • MicroRNAs
  • Quinazolines
  • RNA, Messenger
  • RNA, Neoplasm
  • Receptors, G-Protein-Coupled
  • Gefitinib