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Nrf2 pathway regulates multidrug-resistance-associated protein 1 in small cell lung cancer

Lili Ji1, Hui Li, Pan Gao

  • 1Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, China.

Plos One
|May 14, 2013
PubMed

Insights

The Nrf2-ARE pathway regulates multidrug-resistance-associated protein-1 (MRP1) expression, a key factor in multi-drug resistance (MDR). Targeting Nrf2 may offer a new strategy to overcome MDR in cancer treatment.

Area of Science:

  • Molecular Biology
  • Cancer Research
  • Biochemistry

Background:

  • Multidrug-resistance-associated protein-1 (MRP1) is crucial for multi-drug resistance (MDR) in cancer.
  • The regulatory mechanisms of MRP1, particularly in tumor tissues, remain incompletely understood.
  • Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor involved in cellular defense and chemo-resistance.

Purpose of the Study:

  • To investigate the role of the Nrf2-antioxidant response element (ARE) pathway in regulating MRP1 expression.
  • To determine if Nrf2 influences MRP1 expression and MDR in lung cancer cells.
  • To explore the therapeutic potential of targeting the Nrf2 pathway for overcoming MDR.

Main Methods:

  • Comparison of Nrf2-ARE pathway activity and MRP1 expression in H69 and H69AR lung cancer cells.
  • Nrf2 knockdown experiments in H69AR cells to assess effects on MRP1 expression and drug sensitivity.
  • Analysis of the MRP1 gene promoter for putative AREs using reporter gene and ChIP assays.
  • Immunohistochemical analysis of Nrf2 and MRP1 expression in human cancer tissues.

Main Results:

  • H69AR cells with MDR exhibited higher Nrf2-ARE pathway activity and MRP1 expression than H69 cells.
  • Nrf2 knockdown in H69AR cells led to decreased MRP1 expression and restored sensitivity to chemotherapy drugs.
  • The MRP1 promoter contains functional AREs (ARE1 and ARE2) that interact with Nrf2.
  • Both Nrf2 and MRP1 were significantly upregulated in tumor tissues compared to adjacent non-tumor tissues, with a positive correlation between their expression.

Conclusions:

  • The Nrf2-ARE pathway is essential for the regulation of MRP1 expression.
  • Nrf2 plays a significant role in mediating MRP1-dependent multi-drug resistance in cancer.
  • Nrf2 represents a promising therapeutic target for overcoming chemo-resistance in MDR cancers.

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