Glucocorticoids suppress renal cell carcinoma progression by enhancing Na,K-ATPase beta-1 subunit expression

PLoS One. 2015 Apr 2;10(4):e0122442. doi: 10.1371/journal.pone.0122442. eCollection 2015.

Abstract

Glucocorticoids are commonly used as palliative or chemotherapeutic clinical agents for treatment of a variety of cancers. Although steroid treatment is beneficial, the mechanisms by which steroids improve outcome in cancer patients are not well understood. Na,K-ATPase beta-subunit isoform 1 (NaK-β1) is a cell-cell adhesion molecule, and its expression is down-regulated in cancer cells undergoing epithelial-to mesenchymal-transition (EMT), a key event associated with cancer progression to metastatic disease. In this study, we performed high-throughput screening to identify small molecules that could up-regulate NaK-β1 expression in cancer cells. Compounds related to the glucocorticoids were identified as drug candidates enhancing NaK-β1 expression. Of these compounds, triamcinolone, dexamethasone, and fluorometholone were validated to increase NaK-β1 expression at the cell surface, enhance cell-cell adhesion, attenuate motility and invasiveness and induce mesenchymal to epithelial like transition of renal cell carcinoma (RCC) cells in vitro. Treatment of NaK-β1 knockdown cells with these drug candidates confirmed that these compounds mediate their effects through up-regulating NaK-β1. Furthermore, we demonstrated that these compounds attenuate tumor growth in subcutaneous RCC xenografts and reduce local invasiveness in orthotopically-implanted tumors. Our results strongly indicate that the addition of glucocorticoids in the treatment of RCC may improve outcome for RCC patients by augmenting NaK-β1 cell-cell adhesion function.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Carcinoma, Renal Cell / drug therapy*
  • Carcinoma, Renal Cell / enzymology*
  • Carcinoma, Renal Cell / pathology
  • Cell Adhesion / drug effects
  • Cell Line, Tumor
  • Dexamethasone / pharmacology
  • Disease Progression
  • Fluorometholone / pharmacology
  • Glucocorticoids / pharmacology*
  • HeLa Cells
  • High-Throughput Screening Assays
  • Humans
  • Kidney Neoplasms / drug therapy*
  • Kidney Neoplasms / enzymology*
  • Kidney Neoplasms / pathology
  • Male
  • Mice
  • Mice, Hairless
  • Mice, SCID
  • Neoplasm Invasiveness / prevention & control
  • Promoter Regions, Genetic / drug effects
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Neoplasm / genetics
  • RNA, Neoplasm / metabolism
  • Sodium-Potassium-Exchanging ATPase / genetics
  • Sodium-Potassium-Exchanging ATPase / metabolism*
  • Triamcinolone / pharmacology
  • Up-Regulation / drug effects
  • Xenograft Model Antitumor Assays

Substances

  • ATP1B1 protein, human
  • Glucocorticoids
  • RNA, Messenger
  • RNA, Neoplasm
  • Triamcinolone
  • Dexamethasone
  • Sodium-Potassium-Exchanging ATPase
  • Fluorometholone