Objective: Disulfiram has been repurposed as a potential candidate to suppress various cancers. However, its anti-tumor effects and molecular mechanisms of oral squamous cell carcinoma remain unclear. In this study, we aimed to assess the anti-cancer activity and underlying mechanisms of disulfiram in the context of oral squamous cell carcinoma.
Materials and methods: We tested the cytotoxicity of disulfiram in oral squamous cell carcinoma using a 3D culture model and a PDX model. Cell proliferation, cell death, and related signaling pathways were evaluated. Mitochondrial DNA copy number, mitochondrial respiration, mitochondrial mass, and mitochondrial complexes were analyzed.
Results: Disulfiram can induce excessive autophagy in oral squamous cell carcinoma cells as a result of OXPHOS deficiency. Disulfiram-induced OPA1 degradation can impair the functional cristae structure, which results in a dramatic reduction in mitochondrial respiration capability as well as ATP production. Subsequently, energy deprivation leads to excessive autophagy through AMPK activation. In addition, exogenous ATP blocked the activation of AMPK and rescued disulfiram-induced cell death.
Conclusion: DSF targets mitochondrial inner membrane protein OPA1 to disturb the energy supply, triggering excessive autophagy, and cell death in OSCC. Our study suggests OPA1-dependent ATP generation is pharmacologically targetable in OSCC treatment.
Keywords: OPA1 protein; OSCC; OXPHOS; autophagy; crista; disulfiram.
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