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

Huynh TP, Barwe SP, Lee SJ, McSpadden R, Franco OE, Hayward SW, Damoiseaux R, Grubbs SS, Petrelli NJ, Rajasekaran AK - PLoS ONE (2015)

Bottom Line: 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.Treatment of NaK-β1 knockdown cells with these drug candidates confirmed that these compounds mediate their effects through up-regulating NaK-β1.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.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America; Nemours Center for Childhood Cancer Research, A. I. DuPont Hospital for Children, Wilmington, Delaware, United States of America.

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.

No MeSH data available.


Related in: MedlinePlus

Steroidal drugs enhance NaK-β1 promoter activity.Compounds were tested at 1 nM to 250 μM and the luciferase activity was measured in light units (LU). There is a clear dose-dependent response in TRIAM, DEX, and FLUOR exposed HeLa cells.
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pone.0122442.g001: Steroidal drugs enhance NaK-β1 promoter activity.Compounds were tested at 1 nM to 250 μM and the luciferase activity was measured in light units (LU). There is a clear dose-dependent response in TRIAM, DEX, and FLUOR exposed HeLa cells.

Mentions: Triamcinolone (TRIAM) and fluorometholone (FLUOR) were further studied based on their solubility and strength of induction of NaK-β1 promoter activity compared to DEX (S1 Table). Compounds identified by HTS were verified by dosing studies, which demonstrated a dose-dependent increase in NaK-β1 promoter activity with increasing drug concentrations in HeLa cells (Fig 1). Next, we assessed if NaK-β1 protein levels were augmented with drug treatment by immunoblot analysis. With the addition of drugs, NaK-β1 expression was elevated in serum free as well as in charcoal-stripped serum (CS) (Fig 2A). Furthermore, the increased NaK-β1 was properly targeted to the cell membrane as assessed by a cell surface biotinylation assay (Fig 2B).


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

Huynh TP, Barwe SP, Lee SJ, McSpadden R, Franco OE, Hayward SW, Damoiseaux R, Grubbs SS, Petrelli NJ, Rajasekaran AK - PLoS ONE (2015)

Steroidal drugs enhance NaK-β1 promoter activity.Compounds were tested at 1 nM to 250 μM and the luciferase activity was measured in light units (LU). There is a clear dose-dependent response in TRIAM, DEX, and FLUOR exposed HeLa cells.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383530&req=5

pone.0122442.g001: Steroidal drugs enhance NaK-β1 promoter activity.Compounds were tested at 1 nM to 250 μM and the luciferase activity was measured in light units (LU). There is a clear dose-dependent response in TRIAM, DEX, and FLUOR exposed HeLa cells.
Mentions: Triamcinolone (TRIAM) and fluorometholone (FLUOR) were further studied based on their solubility and strength of induction of NaK-β1 promoter activity compared to DEX (S1 Table). Compounds identified by HTS were verified by dosing studies, which demonstrated a dose-dependent increase in NaK-β1 promoter activity with increasing drug concentrations in HeLa cells (Fig 1). Next, we assessed if NaK-β1 protein levels were augmented with drug treatment by immunoblot analysis. With the addition of drugs, NaK-β1 expression was elevated in serum free as well as in charcoal-stripped serum (CS) (Fig 2A). Furthermore, the increased NaK-β1 was properly targeted to the cell membrane as assessed by a cell surface biotinylation assay (Fig 2B).

Bottom Line: 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.Treatment of NaK-β1 knockdown cells with these drug candidates confirmed that these compounds mediate their effects through up-regulating NaK-β1.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.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology Institute, University of California Los Angeles, Los Angeles, California, United States of America; Nemours Center for Childhood Cancer Research, A. I. DuPont Hospital for Children, Wilmington, Delaware, United States of America.

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.

No MeSH data available.


Related in: MedlinePlus