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Updated: Aug 8, 2026

Monitoring Kinase and Phosphatase Activities Through the Cell Cycle by Ratiometric FRET
13:38

Monitoring Kinase and Phosphatase Activities Through the Cell Cycle by Ratiometric FRET

Published on: January 27, 2012

FADD phosphorylation is critical for cell cycle regulation in breast cancer cells

S Matsuyoshi1, K Shimada, M Nakamura

  • 1Department of Pathology, Nara Medical University School of Medicine, Nara 634-8521, Japan. smatsu@naramed-u.ac.jp

British Journal of Cancer
|February 2, 2006
PubMed

Insights

Long-term tamoxifen therapy induces cell cycle arrest in breast cancer via c-jun N-terminal kinase (JNK) activation. This pathway, involving Fas-associated death domain-containing protein (FADD) phosphorylation, is a potential therapeutic target independent of oestrogen receptor status.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Anti-oestrogen therapies are vital for hormone receptor-positive breast cancers.
  • Detailed molecular mechanisms and signal transduction pathways remain unclear.

Purpose of the Study:

  • To elucidate the molecular mechanisms of tamoxifen's efficacy.
  • To investigate the role of c-jun N-terminal kinase (JNK) and Fas-associated death domain-containing protein (FADD) in breast cancer cell cycle arrest and response to therapy.

Main Methods:

  • Utilized MCF-7 (oestrogen receptor-positive) and MDA-MB-231 (ER-negative) breast cancer cell lines.
  • Employed dominant-negative mutants of MKK7 and FADD (S194A).
  • Performed immunohistochemical analysis on human breast cancer specimens.

Main Results:

  • Long-term tamoxifen treatment induced G2/M cell cycle arrest via JNK activation, dependent on FADD phosphorylation at serine 194.
  • Inhibition of MKK7 or mutant FADD (S194A) reduced tamoxifen's cytotoxicity.
  • Similar signaling pathways were activated by paclitaxel in ER-negative cells.
  • Phosphorylated JNK and FADD expression correlated inversely with metastatic potential in human breast cancer tissues.

Conclusions:

  • JNK-mediated phosphorylation of FADD is crucial for inhibiting cell growth and metastasis.
  • This pathway is independent of oestrogen receptor status.
  • The JNK/FADD signaling axis represents a promising therapeutic target for breast cancer treatment.

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