Silencing overexpression of FXYD3 protein in breast cancer cells amplifies effects of doxorubicin and γ-radiation on Na(+)/K(+)-ATPase and cell survival.
Breast Cancer Res Treat
; 155(2): 203-13, 2016 Jan.
Article
en En
| MEDLINE
| ID: mdl-26740212
FXYD3, also known as mammary tumor protein 8, is overexpressed in several common cancers, including in many breast cancers. We examined if such overexpression might protect Na(+)/K(+)-ATPase and cancer cells against the high levels of oxidative stress characteristic of many tumors and often induced by cancer treatments. We measured FXYD3 expression, Na(+)/K(+)-ATPase activity and glutathionylation of the ß1 subunit of Na(+)/K(+)-ATPase, a reversible oxidative modification that inhibits the ATPase, in MCF-7 and MDA-MB-468 cells. Expression of FXYD3 was suppressed by transfection with FXYD3 siRNA. A colorimetric end-point assay was used to estimate cell viability. Apoptosis was estimated by caspase 3/7 (DEVDase) activation using a Caspase fluorogenic substrate kit. Expression of FXYD3 in MCF-7 breast cancer cells was ~eightfold and ~twofold higher than in non-cancer MCF-10A cells and MDA-MB-468 cancer cells, respectively. A ~50 % reduction in FXYD3 expression increased glutathionylation of the ß1 Na(+)/K(+)-ATPase subunit and reduced Na(+)/K(+)-ATPase activity by ~50 %, consistent with the role of FXYD3 to facilitate reversal of glutathionylation of the ß1 subunit of Na(+)/K(+)-ATPase and glutathionylation-induced inhibition of Na(+)/K(+)-ATPase. Treatment of MCF-7 and MDA-MB- 468 cells with doxorubicin or γ-radiation decreased cell viability and induced apoptosis. The treatments upregulated FXYD3 expression in MCF-7 but not in MDA-MB-468 cells and suppression of FXYD3 in MCF-7 but not in MDA-MB-468 cells amplified effects of treatments on Na(+)/K(+)-ATPase activity and treatment-induced cell death and apoptosis. Overexpression of FXYD3 may be a marker of resistance to cancer treatments and a potentially important therapeutic target.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Neoplasias de la Mama
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Doxorrubicina
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Supervivencia Celular
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ATPasa Intercambiadora de Sodio-Potasio
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Silenciador del Gen
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Rayos gamma
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Proteínas de la Membrana
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Proteínas de Neoplasias
Límite:
Female
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Humans
Idioma:
En
Revista:
Breast Cancer Res Treat
Año:
2016
Tipo del documento:
Article
País de afiliación:
Australia