A Role for H₂O₂ and TRPM2 in the Induction of Cell Death: Studies in KGN Cells

Area of Science:

• Oncology
• Cell Biology
• Biochemistry

Background:

• Human granulosa cell tumors (GCTs) express NADPH oxidase 4 (NOX4), a source of hydrogen peroxide (H₂O₂).
• Transient Receptor Potential Melastatin 2 (TRPM2) channels are H₂O₂-activated cation channels involved in cellular functions and cell death.
• The role of TRPM2 in GCTs and its potential therapeutic implications remain largely unexplored.

Purpose of the Study:

• To investigate the expression and functionality of TRPM2 channels in KGN cells derived from human GCT.
• To examine the in vivo relevance of TRPM2 and NOX4 expression in human GCT tissues.
• To explore the potential of targeting TRPM2 for GCT therapy.

Main Methods:

• KGN cells and GCT tissue microarrays (TMAs) were utilized.
• Techniques included live cell imaging, calcium and mitochondrial imaging, viability assays, fluorescence-activated cell sorting (FACS), Western blotting, and immunohistochemistry.
• Functional assays involved assessing the effects of H₂O₂ and TRPM2 inhibitors/scavengers.

Main Results:

• KGN cells produce H₂O₂ and express functional TRPM2 channels.
• H₂O₂ increased intracellular calcium levels via TRPM2, induced mitochondrial fragmentation, and promoted apoptotic cell death.
• Inhibiting or scavenging TRPM2 activity attenuated H₂O₂-induced cell death.
• Immunohistochemistry revealed co-expression of NOX4 and TRPM2 in all examined GCT samples.

Conclusions:

• GCTs possess a functional NOX4-TRPM2 system that can mediate susceptibility to cell death.
• Induction of oxidative stress via this pathway may represent a promising therapeutic strategy for GCTs.
• TRPM2 channels show potential as a therapeutic target for granulosa cell tumor treatment.