The Regulatory Role of Nuclear Respiratory Factor 1 in Bladder Cancer Cells

Anticancer Res. 2023 Apr;43(4):1521-1531. doi: 10.21873/anticanres.16301.


Background/aim: Nuclear respiratory factor 1 (NRF1) is a key mediator of genes involved in mitochondrial biogenesis and the respiratory chain; however, its role in bladder cancer remains unknown. Transitional cell carcinoma, also known as urothelial cell carcinoma, is the most common type of bladder cancer resistant to chemotherapy. An established high-grade and invasive transitional cell carcinoma line from patients with urinary bladder cancer, known as T24, has been extensively used in cancer research. In this study, we aimed to investigate the mechanisms through which NRF1 regulates proliferation and cell migration of bladder cancer cells using the T24 cell line.

Materials and methods: Cells were transfected with plasmid cloning DNA for NRF1 to evaluate the effect of NRF1 overexpression on bladder cancer cells. Western blot was used to examine epithelial and mesenchymal markers (E-cadherin and α-smooth muscle actin), transcriptional regulators for epithelial-mesenchymal transition (snail family transcriptional repressors), components of transforming growth factor-β1/SMADs signaling, high-mobility group box 1 (HMGB1), and receptor for advanced glycation end-products (RAGE). The in situ expression of E-cadherin, α-smooth muscle actin and SMAD7 was determined using immunofluorescence staining. Cell migration capacity was assessed by wound-healing assay.

Results: Transfection with NRF1 expression vector repressed the migration capacity of bladder cancer cells, diminishing HMGB1/RAGE expression and reducing transforming growth factor β-associated epithelial-mesenchymal transition in T24 cells.

Conclusion: Therapeutic avenues that increase NRF1 expression may serve as an adjunct to conventional treatments for bladder cancer.

Keywords: EMT; HMGB1; NRF1; Nuclear respiratory factor 1; RAGE; bladder cancer; epithelial–mesenchymal transition; high-mobility group box-1; mitochondrial biogenesis; receptor for advanced glycation end-products.

MeSH terms

  • Actins
  • Cadherins / metabolism
  • Carcinoma, Transitional Cell* / pathology
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Epithelial-Mesenchymal Transition / genetics
  • HMGB1 Protein* / genetics
  • HMGB1 Protein* / metabolism
  • Humans
  • Nuclear Respiratory Factor 1 / genetics
  • Receptor for Advanced Glycation End Products
  • Urinary Bladder Neoplasms* / pathology


  • HMGB1 Protein
  • Nuclear Respiratory Factor 1
  • Receptor for Advanced Glycation End Products
  • Actins
  • Cadherins