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Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death
09:18

Identification of Intracellular Signaling Events Induced in Viable Cells by Interaction with Neighboring Cells Undergoing Apoptotic Cell Death

Published on: December 27, 2016

Apoptotic effects of signal transduction inhibitors on human tumor cells with different PTEN expression

Georg Pfeiler1, Felicitas Horn, Claus Lattrich

  • 1Department of Obstetrics and Gynecology, University of Regensburg, Caritas Hospital St. Josef, Landshuter Strasse 65, 93053 Regensburg, Germany.

Oncology Reports
|October 5, 2007
PubMed

Insights

Tumor cells can evade targeted therapies by altering apoptosis pathways. PTEN expression is crucial for the effectiveness of receptor-targeting drugs like tamoxifen and trastuzumab, but not for MAPK inhibitors.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cancer Therapeutics

Background:

  • Targeted cancer therapies aim to induce apoptosis (programmed cell death) in tumor cells.
  • Tumor cells can develop resistance to therapy by altering apoptotic signaling pathways, often involving mutations in the PTEN gene.
  • Understanding the role of PTEN in therapy response is critical for improving treatment efficacy.

Purpose of the Study:

  • To investigate the dependency of targeted therapy-induced apoptosis on PTEN expression in various cancer cell lines.
  • To compare the effect of receptor-targeting drugs and mitogen-activated protein kinase (MAPK) inhibitors on apoptosis in relation to PTEN levels.

Main Methods:

  • Western blot analysis was used to assess PTEN expression in breast, ovarian, and endometrial cancer cell lines.
  • Apoptosis was induced using tamoxifen, trastuzumab, ZD1839 (Iressa), and MAPK inhibitors.
  • Apoptotic effects were quantified by measuring cytoplasmic histone-DNA complexes after 24 hours of treatment.

Main Results:

  • PTEN expression varied significantly across the tested cancer cell lines, from high to undetectable levels.
  • The apoptotic response to receptor-targeting drugs (tamoxifen, trastuzumab, ZD1839) was dependent on both receptor expression and PTEN expression.
  • No correlation was found between PTEN expression and the apoptosis rate when cells were treated with MAPK inhibitors.

Conclusions:

  • PTEN expression is a significant factor in the efficacy of certain targeted therapies, particularly those targeting specific receptors.
  • The findings highlight the importance of evaluating PTEN status for predicting patient response to therapies like tamoxifen and trastuzumab.
  • MAPK inhibitors may offer an alternative therapeutic strategy for tumors with altered PTEN expression, as their efficacy is not linked to PTEN levels.

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