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Defining Gene Functions in Tumorigenesis by Ex vivo Ablation of Floxed Alleles in Malignant Peripheral Nerve Sheath Tumor Cells
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PTEN deletion leads to up-regulation of a secreted growth factor pleiotrophin

Gang Li1, Yingchun Hu, Yanying Huo

  • 1Department of Molecular and Medical Pharmacology, UCLA School of Medicine, Los Angeles, California 90095-1735, USA. ligang@nic.bmi.ac.cn

The Journal of Biological Chemistry
|March 2, 2006
PubMed

Insights

Loss of the tumor suppressor PTEN increases the expression of pleiotrophin (PTN). PTN drives tumor growth in PTEN-deficient cancers, suggesting PTN as a potential therapeutic target.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Genetics

Background:

  • The tumor suppressor gene PTEN is frequently mutated in human cancers.
  • Understanding PTEN's regulatory targets is crucial for developing new cancer therapies.

Purpose of the Study:

  • To identify novel targets and signaling pathways regulated by PTEN.
  • To investigate the role of pleiotrophin (PTN) in PTEN-deficient tumors.

Main Methods:

  • Microarray analysis to compare gene expression in Pten-null and wild-type mouse embryonic fibroblasts (MEFs).
  • Validation of Ptn expression in MEFs and mammary tumors.
  • Investigating PTN regulation by the PTEN-PI3K-AKT pathway.
  • Small interfering RNA (siRNA) to knockdown Ptn expression.

Main Results:

  • Pleiotrophin (Ptn) expression was significantly upregulated in Pten-null MEFs and mammary tumors.
  • PTEN-PI3K-AKT signaling pathway regulates Ptn expression.
  • Knockdown of Ptn reduced Akt and GSK-3beta phosphorylation.
  • Ptn knockdown suppressed the growth and tumorigenicity of Pten-null MEFs.

Conclusions:

  • PTN plays a significant role in tumorigenesis associated with PTEN loss.
  • PTN represents a potential therapeutic target for PTEN-deficient cancers.

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