Disrupting mitochondrial Ca2+ homeostasis causes tumor-selective TRAIL sensitization through mitochondrial network...

Area of Science:

• Oncology
• Cell Biology
• Biochemistry

Background:

• Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) shows promise as an anticancer agent but faces resistance from cancers like malignant melanoma and osteosarcoma.
• Intracellular calcium (Ca2+) homeostasis is crucial for cell survival, making Ca2+ dynamics a potential therapeutic target in cancer treatment.

Purpose of the Study:

• To investigate the effect of mitochondrial Ca2+ overload on TRAIL therapy efficacy in TRAIL-resistant cancer cells.
• To explore the role of mitochondrial Ca2+ homeostasis in regulating cancer cell death pathways and mitochondrial dynamics.

Main Methods:

• Utilized mitochondrial Na+/Ca2+ exchanger inhibitor (CGP-37157) and oxidative phosphorylation inhibitors (antimycin A, FCCP) to induce mitochondrial Ca2+ overload.
• Assessed TRAIL sensitivity, cell death mechanisms (apoptosis vs. non-apoptotic), and mitochondrial morphology (fragmentation/hyperfusion) in cancer cells.

Main Results:

• Mitochondrial Ca2+ overload significantly sensitized malignant melanoma and osteosarcoma cells to TRAIL-induced cytotoxicity.
• The overload shifted cell death from apoptosis to a non-apoptotic pathway and induced mitochondrial fragmentation.
• Both Ca2+ overload and Ca2+ removal interventions exacerbated TRAIL-induced mitochondrial network abnormalities.

Conclusions:

• Disturbing mitochondrial Ca2+ homeostasis, specifically through overload, enhances TRAIL efficacy in a tumor-selective manner.
• Mitochondrial Ca2+ levels are critical for maintaining mitochondrial dynamics and cancer cell survival.
• Targeting mitochondrial Ca2+ homeostasis presents a novel strategy to overcome TRAIL resistance in specific cancers with minimal impact on tumor selectivity.