Role of IGF-Binding Protein 3 in the Resistance of EGFR Mutant Lung Cancer Cells to EGFR-Tyrosine Kinase Inhibitors

Yun Jung Choi,Chang-Min Choi,Jin Kyung Rho,Jae Cheol Lee,Gun Min Park,Gwang Sup So,Hyeong Ryul Kim,Sun Ye Kim,Giuseppe Viglietto

doi:10.1371/journal.pone.0081393

Yun Jung Choi, Chang-Min Choi + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0081393

Copy DOI

Journal: PloS one	Publication Date: Dec 5, 2013
Citations: 9	License type: CC BY 3.0

Affiliation: University of Ulsan, Asan Medical Center, Daehang Hospital

Abstract

Most patients treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs) eventually develop acquired resistance. Loss of expression of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) has been suggested as a possible mechanism of resistance to EGFR-TKIs in the A431 and HN11 cell lines. Here, we investigated IGFBP-3 expression in two EGFR mutant lung cancer cell lines with resistance to EGFR-TKIs and examined the value of serum IGFBP-3 level as a marker of resistance. The effect of the induction or suppression of IGFBP-3 expression on resistance was also evaluated. HCC827 sublines with resistance to gefitinib (HCC827/GR) and erlotinib (HCC827/ER) were established. Loss of IGFBP-3 expression was detected by Western blotting in both cell lines without changes in transcriptional activity, and ELISA showed significantly lower amounts of secreted IGFBP-3 in the culture media of the mutant cell lines than in that of the parental line. Despite the loss of IGFBP-3 expression, IGFR signalling activity remained unchanged. Forced expression of IGFBP-3 by adenovirus-mediated transfection or recombinant IGFBP-3 slightly increased the growth-inhibitory and apoptotic effects of EGFR-TKIs, whereas suppression of IGFBP-3 did not affect sensitivity to EGFR-TKI. Serum IGFBP-3 levels measured by ELISA before and after the development of EGFR-TKI resistance in 20 patients showed no significant changes (1815.3±94.6 ng/mL before treatment vs. 1778.9±87.8 ng/mL after EGFR-TKI resistance). In summary, although IGFBP-3 downregulation is associated with the acquisition of resistance to EGFR-TKIs regardless of the mechanism, its effect on resistance was not significant, indicating that IGFBP-3 may not play an important role in resistance to EGFR-TKIs and serum IGFBP-3 level is not a reliable indicator of resistance.

Highlights

EGFR is a transmembrane receptor that belongs to a family of four related proteins, EGFR (ErbB-1), HER2/neu (ErbB-2), HER3 (ErbB-3) and HER4 (ErbB-4) [1]
This was supported by combination treatment with EGFR-tyrosine kinase inhibitors (TKIs) and PHA665752, a MET inhibitor, which effectively suppressed the growth of HCC827/GR cells
Two distinct ligands (IGF-1 and insulin-like growth factor (IGF)-2) plus insulin, and two receptors (IGF-1R and the insulin receptor) capable of both homo- and heteropolymerisation mediate the actions of this pathway [22]

Summary

Introduction

EGFR is a transmembrane receptor that belongs to a family of four related proteins, EGFR (ErbB-1), HER2/neu (ErbB-2), HER3 (ErbB-3) and HER4 (ErbB-4) [1]. EGFR forms homo- or heterodimers with other ErbB receptors leading to the activation of intracellular signalling cascades. Non-small cell lung cancers (NSCLCs) that harbour activating mutations and/or amplification of the EGFR locus are sensitive to EGFR-tyrosine kinase inhibitors (TKIs) such as gefitinib (Iressa; AstraZeneca International) and erlotinib (Tarceva; OSI Pharmaceuticals) [3,4,5,6,7,8,9]. 70–80% of NSCLCs harbouring a somatic mutation in the tyrosine kinase domain of the EGFR gene respond to gefitinib/erlotinib [3,4,10]. Acquired resistance has been associated with a secondary mutation in the EGFR gene, T790M [11,12], which has been detected in approximately 50% of cancers with acquired resistance to EGFR-TKIs [13,14]. Overexpression of the AXL kinase has been associated with resistance to EGFR-TKIs [17]

Methods

Results

Conclusion