Role of IGF-binding protein 3 in the resistance of EGFR mutant lung cancer cells to EGFR-tyrosine kinase inhibitors

• Published in: PloS one Vol. 8; no. 12; p. e81393
• Main Authors: Choi, Yun Jung, Park, Gun Min, Rho, Jin Kyung, Kim, Sun Ye, So, Gwang Sup, Kim, Hyeong Ryul, Choi, Chang-Min, Lee, Jae Cheol
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 05.12.2013; Public Library of Science (PLoS)
• Subjects: Antineoplastic Agents - pharmacology; Apoptosis; Biotechnology; Cancer; Care and treatment; Cell culture; Cell growth; Cell Line, Tumor; Culture media; Drug Resistance, Neoplasm; Enzyme-linked immunosorbent assay; Epidermal growth factor receptors; ErbB Receptors - antagonists & inhibitors; Erlotinib Hydrochloride; Gefitinib; Gene Expression Regulation, Neoplastic - drug effects; Humans; Inhibitors; Insulin; Insulin-Like Growth Factor Binding Protein 3 - blood; Insulin-Like Growth Factor Binding Protein 3 - genetics; Insulin-Like Growth Factor Binding Protein 3 - metabolism; Insulin-like growth factor-binding protein 3; Insulin-like growth factors; Kinases; Lung cancer; Lung diseases; Lung Neoplasms - pathology; Mutation; Patients; Phenols (Class of compounds); Protein binding; Protein Kinase Inhibitors - pharmacology; Protein-tyrosine kinase; Quinazolines - pharmacology; Signaling; Transcription; Transfection; Tumor cell lines; Tyrosine; Tyrosine kinase inhibitors; Western blotting
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0081393

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.