Oxidative phosphorylation inhibitors inhibit proliferation of endometriosis cells.

Current therapeutic strategies for endometriosis focus on symptom management and are not curative. Here, we provide evidence supporting inhibition of oxidative phosphorylation (OXPHOS) as a novel treatment strategy for endometriosis. Additionally, we report an organotypic organ-on-a chip luminal model for endometriosis. The OXPHOS inhibitors, curcumin, plumbagin and the FDA approved anti-malarial agent, atovaquone, were tested against the endometriosis cell line, 12Z, in conventional as well as the new organotypic model. The results suggest that all three compounds inhibit proliferation and cause cell death of the endometriotic cells by inhibiting OXPHOS and causing an increase in intracellular oxygen radicals. The oxidative stress mediated by curcumin, plumbagin and atovaquone cause DNA double strand breaks as indicated by elevation of phospho-γH2Ax. Mitochondrial energetics shows significant decrease in oxygen consumption in 12Z cells. These experiments also highlight differences in mechanism of action as curcumin and plumbagin inhibit Complex I whereas atovaquone blocks Complex I, II and III. Real time assessment of cells in the lumen model showed inhibition of migration in response to the test compounds. Additionally, using two-photon lifetime imaging, we demonstrate that the 12Z cells in the lumen show decreased redox ratio (NAD(P)H/FAD) and lower fluorescence lifetime of NAD(P)H in the treated cells confirming major metabolic changes in response to inhibition of mitochondrial electron transport. The robust chemotoxic responses observed with atovaquone suggest that this anti-malarial agent may be repurposed for effective treatment of endometriosis.