Functional assays to define agonists and antagonists of the sigma-2 receptor

Area of Science:

• Oncology
• Pharmacology
• Molecular Biology

Background:

• The sigma-2 receptor is a biomarker for proliferating tumors.
• Currently, no established functional assays exist to define sigma-2 receptor agonists and antagonists.
• Sigma-2 ligands can induce cancer cell death via apoptosis.

Purpose of the Study:

• To establish functional assays for determining sigma-2 receptor agonists and antagonists.
• To characterize novel sigma-2 ligands developed in-house.
• To categorize sigma-2 ligands based on their cytotoxic effects.

Main Methods:

• Utilized cell viability assays to measure cytotoxicity.
• Employed caspase-3 activity assays to assess apoptosis induction.
• Evaluated three classes of sigma-2 ligands in EMT-6 (mouse breast cancer) and MDA-MB-435 (human melanoma) cell lines.

Main Results:

• EC50 values for sigma-2 ligands ranged from 11.4μM to >200μM in cell viability assays.
• Results from cell viability assays were comparable to those from caspase-3 activity assays.
• Sigma-2 ligands were successfully categorized into agonists, partial agonists, and antagonists relative to siramesine.

Conclusions:

• Established functional assays for defining sigma-2 agonists and antagonists.
• The developed assays facilitate the characterization of sigma-2 receptor ligands and their functions.
• This work provides a foundation for further research into sigma-2 receptor targeted cancer therapies.