Overexpression of Napsin A resensitizes drug‑resistant lung cancer A549 cells to gefitinib by inhibiting EMT

  • Authors:
    • Linshui Zhou
    • Xin Lv
    • Junchao Yang
    • Yuanhong Zhu
    • Zhen Wang
    • Tingzhen Xu
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  • Published online on: June 13, 2018     https://doi.org/10.3892/ol.2018.8963
  • Pages: 2533-2538
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Abstract

Lung cancer is one of the most common malignant tumors and also the leading cause of cancer‑related deaths in the world. Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‑TKI), such as gefitinib, have been used in the therapy of lung cancer. However, the acquisition of drug resistance is a major limitation in the clinical efficiency of EGFR‑TKIs. Epithelial‑mesenchymal transition (EMT) has been demonstrated to be an underlying mechanism of acquired resistance. A previous study has reported that Napsin A expression can inhibit EMT in lung cancer cells. The present study therefore investigated the effect of Napsin A on the sensitivity of EGFR‑TKI‑resistant lung cancer cells. First, a drug‑resistant lung cancer cell line was generated using the EGFR‑TKI gefitinib on A549 cells (termed here A549‑GFT). EMT was demonstrated to be induced in the drug resistant A549‑GFT cells, evidenced by reduced E‑cadherin expression and increased Vimentin expression compared with control A549 cells. Next, Napsin A was overexpressed in the cells by transfection of the Napsin A‑expression vector, PLJM1‑Napsin A. Western blot analysis confirmed that the protein expression levels of Napsin A were significantly elevated in the Napsin A‑overexpressing cells. Cell proliferation and apoptosis assays were performed to evaluate the effect of Napsin A overexpression on resistant A549 cells. The results of MTT assay demonstrated that Napsin A overexpression inhibited the proliferation of A549 and drug‑resistant A549‑GFT cells and that the proliferation of Napsin A‑overexpressing A549‑GFT cells was significantly inhibited by gefitinib treatment compared with control A549‑GFT cells. The results from the Annexin V/propidium iodide double staining apoptosis assay indicated that Napsin A overexpression enhanced gefitinib‑induced apoptosis in A549‑GFT cells. Additionally, EMT was reversed following Napsin A expression in A549‑GFT cells, as evidenced by the restoration of E‑cadherin and downregulation of Vimentin expression. Further investigation demonstrated that Napsin A overexpression resulted in inhibition of focal adhesion kinase, a critical factor in integrin signaling, in the resistant A549‑GFT cells. These data suggested that Napsin A resensitized the drug‑resistant A549‑GFT cells to gefitinib, possibly by reversing EMT via integrin signaling inhibition. Therefore, Napsin A combined with a TKI may be a more effective treatment strategy for lung cancer.
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August-2018
Volume 16 Issue 2

Print ISSN: 1792-1074
Online ISSN:1792-1082

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Spandidos Publications style
Zhou L, Lv X, Yang J, Zhu Y, Wang Z and Xu T: Overexpression of Napsin A resensitizes drug‑resistant lung cancer A549 cells to gefitinib by inhibiting EMT. Oncol Lett 16: 2533-2538, 2018.
APA
Zhou, L., Lv, X., Yang, J., Zhu, Y., Wang, Z., & Xu, T. (2018). Overexpression of Napsin A resensitizes drug‑resistant lung cancer A549 cells to gefitinib by inhibiting EMT. Oncology Letters, 16, 2533-2538. https://doi.org/10.3892/ol.2018.8963
MLA
Zhou, L., Lv, X., Yang, J., Zhu, Y., Wang, Z., Xu, T."Overexpression of Napsin A resensitizes drug‑resistant lung cancer A549 cells to gefitinib by inhibiting EMT". Oncology Letters 16.2 (2018): 2533-2538.
Chicago
Zhou, L., Lv, X., Yang, J., Zhu, Y., Wang, Z., Xu, T."Overexpression of Napsin A resensitizes drug‑resistant lung cancer A549 cells to gefitinib by inhibiting EMT". Oncology Letters 16, no. 2 (2018): 2533-2538. https://doi.org/10.3892/ol.2018.8963