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Establishment and Characterization of Three Afatinib-resistant Lung Adenocarcinoma PC-9 Cell Lines Developed with Increasing Doses of Afatinib
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[Mechanism of miR-221 contributes to gefitinib resistance in PC-9 cells]

Y Y Gao1, X H Kang, Y Wang

  • 1Department of Oncology, the First Affiliated Hospital of Xinxiang Medical University, Xinxiang 453100, China.

Zhonghua Yi Xue Za Zhi
|November 16, 2018
PubMed

Insights

MicroRNA-221 (miR-221) overexpression induces gefitinib resistance in PC-9 cells by downregulating apoptotic protease activating factor-1 (APAF-1). This finding offers insights into overcoming drug resistance in non-small cell lung cancer treatment.

Area of Science:

  • Molecular Biology
  • Oncology
  • Genetics

Background:

  • Gefitinib is a targeted therapy for non-small cell lung cancer (NSCLC) but resistance limits its efficacy.
  • MicroRNAs play crucial roles in gene regulation and cancer development, including drug resistance.

Purpose of the Study:

  • To investigate the role of microRNA-221 (miR-221) in gefitinib resistance in PC-9 NSCLC cells.
  • To elucidate the underlying molecular mechanisms, focusing on apoptotic protease activating factor-1 (APAF-1).

Main Methods:

  • PC-9 cells were stably transfected to overexpress miR-221 (PC-9/miR-221) or a control (PC-9/NC).
  • Quantitative real-time PCR (qRT-PCR) and Western blot were used to assess miR-221, APAF-1, and related protein expression.
  • Cell proliferation (CCK-8 assay), apoptosis (Flow Cytometry), and target validation (Dual-Luciferase Reporter Assay) were performed.

Main Results:

  • miR-221 overexpression significantly increased gefitinib resistance (higher IC50) and reduced apoptosis in PC-9 cells.
  • miR-221 significantly downregulated both APAF-1 mRNA and protein expression, confirmed by luciferase assays.
  • Downregulation of APAF-1 and cleaved caspase-3 was observed in miR-221 overexpressing cells, indicating impaired apoptosis.

Conclusions:

  • MicroRNA-221 overexpression confers gefitinib resistance in PC-9 cells.
  • This resistance is mediated by the downregulation of APAF-1, a key regulator of apoptosis.
  • Targeting miR-221 or restoring APAF-1 expression may represent therapeutic strategies to overcome gefitinib resistance.
Keywords:
Drug resistance, neoplasmGefitinibLung neoplasmsMicroRNAs

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