364 THE TUMORSUPPRESSOR PTEN INFLUENCES METASTASES OF CLEAR CELL RENAL CELL CARCINOMA (CCRCC) BY DEPHOSPHORYLATION OF SHC

Abstract

You have accessJournal of UrologyKidney Cancer: Basic Research III1 Apr 2010364 THE TUMORSUPPRESSOR PTEN INFLUENCES METASTASES OF CLEAR CELL RENAL CELL CARCINOMA (CCRCC) BY DEPHOSPHORYLATION OF SHC Walburgis Brenner, Elke Schneider, Dirk Prawitt, Frederik C. Roos, Ekkehart Lausch, Christian Hampel, and Joachim W. Thüroff Walburgis BrennerWalburgis Brenner Mainz, Germany More articles by this author , Elke SchneiderElke Schneider Mainz, Germany More articles by this author , Dirk PrawittDirk Prawitt Mainz, Germany More articles by this author , Frederik C. RoosFrederik C. Roos Mainz, Germany More articles by this author , Ekkehart LauschEkkehart Lausch Freiburg, Germany More articles by this author , Christian HampelChristian Hampel Mainz, Germany More articles by this author , and Joachim W. ThüroffJoachim W. Thüroff Mainz, Germany More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.431AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Metastasis is regulated by intracellular processes. Among others, the tumor suppressor PTEN (phosphatase and tensin homologue deleted from chromosome 10) is involved in regulation of cell migration. PTEN is a dual specific phosphatase using the phospholipid PIP3 and the proteins FAK and Shc as its substrate. These signaling mediators cause enhanced cell motility, although the role of the different PTEN activities in this process is unknown. In this study we analyzed the role of PTEN in the migration of renal cancer cells. METHODS We quantified PTEN in 135 ccRCC by Western blot. The renal carcinoma cell line 786-0, which is inherent PTEN negative, was transfected by the functional PTEN gene. For analyses of the PTEN activities, transfections with mutated PTEN genes were performed. This led to a loss of the lipid phosphatase activity (G129E) and/or the protein phosphatase activity (C124S or delta exon 3), respectively. The activity of PTEN depends on its ability to bind to the cell membrane by the PDZ binding domain. Therefore, a PTEN gene construct was also created using an inactivated PDZ binding domain (delta PDZ). Cell proliferation was measured by a BrdU incorporation assay. Cell migration was analyzed in a Boyden chemotaxis chamber with fibronectin (10 μg/mL) as chemotaxin. The molecular effect of transfected PTEN mutants was analyzed by quantifying the phosphorylation of PTEN downstream targets Akt, FAK and Shc by Western blot. RESULTS In renal tumor tissue, we found a statistically significant lower PTEN expression in patients dying within 5 years after surgery, compared to those surviving this time period. Renal cancer cells transfected with the functional PTEN gene showed a profoundly diminished migration. This effect depended on the protein phosphatase activity and PDZ binding, since transfection with a mutated PTEN gene leading to a loss of protein phosphatase activity or of the PDZ binding domain, but not of lipid phosphatase activity, abolished this effect. Involved in this effect is Shc, since the protein phosphatase reduced PTEN mutant abolished the PTEN dependent reduction of phospho-Shc, but not of phospho-FAK. CONCLUSIONS PTEN plays a critical role in metastasis of RCC, depending on protein phosphatase activity via Shc and the PDZ binding domain. This new insight could be the basis of additional approaches complementing current cancer therapy in metastasing RCC. © 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e144 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Walburgis Brenner Mainz, Germany More articles by this author Elke Schneider Mainz, Germany More articles by this author Dirk Prawitt Mainz, Germany More articles by this author Frederik C. Roos Mainz, Germany More articles by this author Ekkehart Lausch Freiburg, Germany More articles by this author Christian Hampel Mainz, Germany More articles by this author Joachim W. Thüroff Mainz, Germany More articles by this author Expand All Advertisement Advertisement PDF DownloadLoading ...