Dysregulated mitochondria play a multifaceted role in tumorigenesis through regulation of energy production, biomass, redox state, and engagement of cell death pathways. Perturbations in mitochondrial fluxes (i.e inhibition of electron chain complexes activity, impaired electron flow) have substantial effects on cell viability, suggesting that targeting mitochondrial function could be effective for therapeutic response in cancer. BPM31510, containing oxidized coenzyme Q10 elicits an anti-Warburg effect is currently in phase II clinical trials for solid tumors. Previously, we have demonstrated the anti-cancer properties of BPM31510 in breast and pancreatic xenograft models. Here, we examined the mechanism of action of BPM31510 in vitro. Using a multi-cancer cell panel, BPM31510 was shown to be consistently and selectively cytotoxic to cancer cells, compared to normal and non-tumorigenic controls, and sensitivity did not correlate to cell doubling time or mutational status. Treatment with BPM 31510 (EC50) in breast and pancreatic cancer cells resulted in a time- and dose-dependent decrease in mitochondrial membrane potential which preceded an increase in early and late apoptosis cells, suggesting BPM31510 initiates a mitochondrial mediated cell death pathway. Using a fluorescently labeled CoQ10 we were able to trace the subcellular location of the CoQ10, which predominantly accumulates in mitochondria and lipid droplets in a time dependent manner. Additionally, the mitochondrial enrichment of CoQ10 is accompanied by morphological changes that varied amongst the different cancer cell types. As CoQ10 is a redox molecule required for electron transfer activity between complexes, we hypothesized that disruption of Q-pool homeostasis would alter complex activity. To investigate this, Complex driven respiration was measured in cells treated with BPM31510 and compared to untreated. Alterations in mitochondrial respiration characterized by a dose-dependent decrease in succinate (Complex II) and glycerol-3-phosphate (Complex III)-fueled respiration were observed in cells treated with BPM31510, while no changes were seen in pyruvate driven respiration (Complex I), suggesting that BPM31510 specifically impairs respiration responses that are more dependent on Q-pool functionality. As impairment of the electron transport chain increases intracellular oxidative stress, we next investigated if BPM 31510 treatment increases ROS levels. After 24h treatment, BPM31510 significantly increased ROS levels in treated cancer cells compared to untreated. Furthermore, BPM31510 induced death could be in part prevented by co-treatment with antioxidants. Together, these data demonstrates BPM31510 has anti-cancer activity in multiple cancer cell types and define a unique and novel functional link between mitochondrial Q-pool disruption and the mechanism of action of BPM31510.
Citation Format: Tulin Dadali, Katerina Krumova, Anne R. Diers, Pallavi Awate, Ryan Ng, Arleide Lee, Stephane Gesta, Vivek K. Vishnudas, Rangaprasad Sarangarajan, Niven R. Narain. BPM31510 modulates mitochondrial complex activity to influence oxidative stress in effectuating cell death in multiple cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1497. doi:10.1158/1538-7445.AM2017-1497