Boosting Copper-Triggered Cancer Cell Death With Mitochondrial Uncouplers

Gastric cancer is notoriously difficult to treat, partly because tumors develop resistance to conventional therapies. A novel cell death pathway called cuproptosis — triggered by excess copper accumulation in mitochondria — has emerged as a promising alternative therapeutic angle, particularly since gastric cancer tissues already display abnormally elevated copper levels.

Cuproptosis depends on active mitochondrial respiration, mediated by the protein FDX1, which drives toxic aggregation of lipoylated proteins like DLAT. Researchers at Qingdao University hypothesized that artificially stimulating mitochondrial respiration via uncoupling could make cancer cells more vulnerable to cuproptosis. Mitochondrial uncouplers work by dissipating the proton gradient across the inner mitochondrial membrane, forcing cells to burn more fuel without producing ATP efficiently.

Using the classical uncoupler FCCP alongside clinically relevant compounds — niclosamide, nitazoxanide, and oxyclozanide — the team validated mitochondrial uncoupling through measurable increases in oxygen consumption, elevated NAD+/NADH ratios, membrane potential depolarization, and reduced ATP production. When combined with elesclomol (a copper-delivering anticancer agent), these uncouplers potently amplified cancer cell death far beyond either agent alone.

Mechanistically, uncoupling upregulated both FDX1 and DLAT protein expression and promoted DLAT oligomerization — the toxic aggregation central to cuproptosis. The researchers also observed broad metabolic remodeling in treated cells, suggesting a systemic shift in how cancer cells process energy.

Clinical implications are notable: niclosamide, nitazoxanide, and oxyclozanide are existing approved drugs with known safety profiles, making translation feasible. However, these findings remain preclinical and cell-based; in vivo validation and human trial data are needed before clinical adoption.