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Sigma-2 ligands induce tumour cell death by multiple signalling pathways

C Zeng1, J Rothfuss, J Zhang

  • 1Department of Radiology, Division of Radiological Sciences, Washington University School of Medicine, 510 S Kingshighway Boulevard, St Louis, MO 63110, USA.

British Journal of Cancer
|January 19, 2012
PubMed
Abstract

Insights

Sigma-2 ligands trigger cancer cell death through apoptosis and autophagy. These compounds also disrupt cell cycle progression, offering potential therapeutic strategies for solid tumors.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • The sigma-2 receptor is a biomarker for proliferating cells in solid tumors.
  • Understanding sigma-2 ligand mechanisms is crucial for cancer therapy development.

Purpose of the Study:

  • Investigate the mechanisms of sigma-2 ligand-induced cell death in cancer cell lines.
  • Evaluate the impact of sigma-2 ligands on apoptosis, autophagy, and cell cycle pathways.

Main Methods:

  • Treatment of EMT-6 (breast cancer) and MDA-MB-435 (melanoma) cells with various sigma-2 ligands.
  • Assessment of DNA fragmentation, caspase activation, PARP-1 cleavage, vacuole formation, and autophagosome marker (LC3) expression.
  • Analysis of mTOR pathway effectors (p70S6K, 4EBP1) and cell cycle regulatory proteins (cyclins, pRb).

Main Results:

  • Sigma-2 ligands induced DNA fragmentation, caspase-3 activation, and PARP-1 cleavage, indicating apoptosis.
  • Ligands promoted vacuole formation and increased LC3 expression while inhibiting mTOR signaling, suggesting autophagy induction.
  • Cell cycle analysis revealed decreased expression of cyclins (D1, B1, E2) and reduced pRb phosphorylation, impairing cell cycle progression.

Conclusions:

  • Sigma-2 ligands induce cancer cell death through a combination of apoptosis and autophagy.
  • These ligands also interfere with multiple phases of the cell cycle.
  • The findings highlight the multifaceted mechanisms of sigma-2 ligands in cancer cell death induction.

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