Protein phosphatase activity of PTEN inhibited the invasion of glioma cells with epidermal growth factor receptor mutation type III expression
✍ Scribed by Xiu-Mei Cai; Bei-Bei Tao; Li-Ying Wang; Yu-Long Liang; Jia-Wei Jin; Yong Yang; Ya-Li Hu; Xi-Liang Zha
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- French
- Weight
- 457 KB
- Volume
- 117
- Category
- Article
- ISSN
- 0020-7136
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✦ Synopsis
Abstract
PTEN is a major tumor suppressor gene that has been shown to inhibit cell invasion. Its mutation has been found in 20–40% of malignant gliomas. Meanwhile, the type III EGFR mutation (EGFRvIII), which was frequently found in gliomas, promoted cell invasion. In the present study, the effects of PTEN on cell invasion were investigated in U87ΔEGFR glioblastoma cells with EGFRvIII expression but missing PTEN. The cell invasion was downregulated by transfection of phosphatase‐active forms of PTEN (wild‐type and G129E) but not by PTEN (C124A) with an inactive phosphatase domain; the effects were correlated with decreased tyrosine phosphatase levels of FAK at Tyr^397^, which was increased by EGFRvIII. Overexpression of FAK mutant (Y397F) could partially mimic the effect of PTEN on cell invasion. Although EGFRvIII increased the levels of P‐Akt and PTEN eliminated it, PI‐3K inhibitors, wortmannin or Ly294002, could not decrease the cell invasion. In conclusion, PTEN could inhibit cell invasion even in the presence of the constitutively active EGFR; this inhibition depended on its protein phosphatase activity, partially by dephosphorylating FAK, but not depended on its lipid phosphatase activity. © 2005 Wiley‐Liss, Inc.