Expression of protein tyrosine phosphatase alpha (RPTPα) in human breast cancer correlates with low tumor grade, and inhibits tumor cell growth in vitro and in vivo

Elena Ardini, Roberto Agresti, Elda Tagliabue, Marco Greco, Piera Aiello, Liang Tung Yang, Sylvie Ménard, Jan Sap

Research output: Contribution to journalArticlepeer-review

Abstract

Tyrosine phosphorylation is controlled by a balance of tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Whereas the contribution of PTKs to breast tumorigenesis is the subject of intense scrutiny, the potential role of PTPs is poorly known. RPTPα is implicated in the activation of Src family kinases, and regulation of integrin signaling, cell adhesion, and growth factor responsiveness. To explore its potential contribution to human neoplasia, we surveyed RPTPα protein levels in primary human breast cancer. We found RPTPα levels to vary widely among tumors, with 29% of cases manifesting significant overexpression. High RPTPα protein levels correlated significantly with low tumor grade and positive estrogen receptor status. Expression of RPTPα in breast carcinoma cells led to growth inhibition, associated with increased accumulation in G0 and G1, and delayed tumor growth and metastasis. To our knowledge, this is the first example of a study correlating expression level of a specific bona fide PTP with neoplastic disease status in humans.

Original languageEnglish
Pages (from-to)4979-4987
Number of pages9
JournalOncogene
Volume19
Issue number43
Publication statusPublished - Oct 12 2000

Keywords

  • Breast cancer
  • c-Src
  • PTP
  • Tumor marker
  • Tyrosine phosphatase

ASJC Scopus subject areas

  • Molecular Biology
  • Cancer Research
  • Genetics

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