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Catalase expression in MCF-7 breast cancer cells is mainly controlled by PI3K/Akt/mTor signaling pathway

Christophe Glorieux1, Julien Auquier2, Nicolas Dejeans3

  • 1Université catholique de Louvain, Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group, Brussels, Belgium.

Biochemical Pharmacology
|March 18, 2014
PubMed

Insights

Transcription factor FoxO3a does not regulate catalase expression. The PI3K/Akt/mTOR pathway impacts catalase expression in MCF-7 cells but not in resistant Resox cells.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Cancer Research

Background:

  • Catalase is a key antioxidant enzyme crucial for cellular defense against oxidative stress.
  • Down-regulation of catalase in tumors suggests a role in cancer progression, but regulatory mechanisms are poorly understood.
  • The transcription factor FoxO3a and the PI3K signaling pathway are implicated in regulating gene expression, including potentially catalase.

Purpose of the Study:

  • To investigate the role of the transcription factor FoxO3a and the PI3K signaling pathway in regulating catalase expression.
  • To elucidate the mechanisms underlying catalase overexpression in oxidative stress-resistant breast cancer cells.

Main Methods:

  • Utilized MCF-7 breast cancer cells and a derived oxidative stress-resistant cell line (Resox) with altered catalase expression.
  • Employed gene knockdown and overexpression strategies for FoxO3a.
  • Inhibited PI3K and mTOR signaling pathways using LY295002 and rapamycin, respectively.
  • Assessed protein expression and phosphorylation levels of key signaling molecules (Akt, FoxO3a, GSK3β, p70S6K).

Main Results:

  • FoxO3a modulation (knockdown/overexpression) did not alter catalase expression in either cell line.
  • Resox cells exhibited decreased Akt expression but enhanced Akt phosphorylation compared to MCF-7 cells.
  • PI3K/mTOR inhibition increased catalase expression in MCF-7 cells but not in Resox cells, indicating differential pathway dependency.
  • FoxO3a phosphorylation was increased in Resox cells, correlating with higher Akt activity.

Conclusions:

  • FoxO3a is not a critical regulator of catalase expression in the studied breast cancer models.
  • MCF-7 cells are sensitive to PI3K/Akt/mTOR signaling for catalase regulation, whereas Resox cells have acquired resistance to this pathway.
  • The findings highlight distinct regulatory mechanisms of catalase in cancer cells with varying oxidative stress resistance.
Keywords:
AktBreast cancerCatalaseFoxO3aHEPESLY294002MOPSOxidative stressPI3KPenicillinRapamycinSodium orthovanadateSodium β-glycerophosphateTetrasodium pyrophosphate[γ-(32)P]ATP-MgmTORstreptomycin

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