The Warburg effect and tumor hypoxia underlie a unique cancer metabolism characterized by glucose dependency and abnormal mitochondrial function. We have previously shown that this phenotype can be exploited therapeutically by glucose restriction with the ketogenic diet, dietary ketone supplementation, or hyperbaric oxygen (HBOT). We hypothesized that combining these therapies would be an effective non-toxic treatment regimen, so we tested this combination therapy in the VM-M3 mouse model of metastatic cancer. Treated mice exhibited decreased tumor growth rate, decreased metastatic spread to the lungs, kidneys, spleen, adipose, and liver, decreased liver tumor vascularization, and lived twice as long as controls. To further characterize the effects of these therapies, we measured proliferation, viability, ROS production, and expression of key signaling molecules in VM-M3 cells exposed to the following conditions: high glucose (control; 25mM), low glucose (LG; 3mM), ketone supplementation (βHB; 5mM), hyperbaric oxygen (HBOT; 90 min, 2.5 ATA), or combination therapy (LG+BHB+HBOT). Proliferation of VM-M3 cells was measured with trypan blue hemocytometry and was significantly decreased from controls at 24, 48, 72, and 96 hours. Viability of VM-M3 cells was measured by fluorescence microscopy with calcein and EthD-1 and was decreased by 19.2% in LG, 12.5% in βHB, and 38.2% in LG+βHB+HBOT treated cells compared to control. ROS (superoxide) production was measured by fluorescent microscopy with DHE and was increased by 46% in HBOT and by 48% in LG+βHB+HBOT treated cells. Treatment with βHB significantly decreased expression of HIF-1α and pAkt compared to control as measured with western blot. HBOT also inhibited HIF-1α expression but increased pAkt expression in vitro. This study strongly supports further investigation into mechanisms of action and the use of these metabolic therapies as a potential cancer treatment.
Citation Format: Angela Poff, Nathan Ward, Thomas Seyfried, Dominic D'Agostino. Ketosis and hyperbaric oxygen elicit potent anti-cancer effects in vitro and in vivo. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1159. doi:10.1158/1538-7445.AM2015-1159