Evidence for a potential tumor suppressor role for the Na,K-ATPase ß1-subunit

• Autores: Ayyappan K. Rajasekaran, S. A. Rajasekaran, E. M. Landaw, L.J. Inge, K. Yoshimoto, P.S. Mischel, Brian W. McBride
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 23, Nº. 4, 2008, págs. 459-467
• Idioma: inglés
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  • The Na,K-ATPase, consisting of two essential subunits (?, ß), plays a critical role in the regulation of ion homeostasis in mammalian cells. Recent studies indicate that reduced expression of the ß1 isoform (NaK-ß1) is commonly observed in carcinoma and is associated with events involved in cancer progression. In this study, we present evidence that repletion of NaK-ß1 in Moloney sarcoma virus-transformed Madin-Darby canine kidney cells (MSV-MDCK), a highly tumorigenic cell line, inhibits anchorage independent growth and suppresses tumor formation in immunocompromised mice. Additionally, using an in vitro cell-cell aggregation assay, we showed that cell aggregates of NaK-ß1 subunit expressing MSV-MDCK cells have reduced extracellular regulated kinase (ERK) 1/2 activity compared with parental MSV-MDCK cells. Finally, using immunohistochemistry and fully quantitative image analysis approaches, we showed that the levels of phosphorylated ERK 1/2 are inversely correlated to the NaK-ß1 levels in the tumors. These findings reveal for the first time that NaK-ß1 has a potential tumor-suppressor function in epithelial cells