Mitochondrial inhibition enhances the sensitivity of pancreatic ductal adenocarcinoma cells to oncolytic adenovirus

The metabolism of cancer cells is associated with resistance to anticancer therapies. Pancreatic ductal adenocarcinoma (PDAC) cells exhibit glycolytic and non-glycolytic subtypes. Although oncolytic virotherapy is a novel antitumor modality, the relationship between metabolism and virus sensitivity remains unclear. We demonstrated the cytopathic activity of telomerase-specific, replication-competent oncolytic adenoviruses OBP-301 and p53-armed OBP-702 against PDAC cells. Here, we show the role of metabolism in the virus sensitivity of PDAC cells. The virus sensitivity of human PDAC cells of glycolytic (MIA PaCa-2, PK-45H) and non-glycolytic (PK-59, Capan-2) subtypes was assessed by evaluating replication, glycolysis, and glutamine metabolism through exposure to hypoxia and glucose deprivation or treatment with the mitochondrial metabolism inhibitor CPI-613. Glycolytic PDAC cells were sensitive, and non-glycolytic cells were resistant to oncolytic adenoviruses, which was improved by hypoxia and glucose deprivation or CPI-613 treatment to induce glycolytic activation. OBP-702-mediated p53 activation modulated glutamine metabolism to promote virus sensitivity. In vivo experiments demonstrated the antitumor efficacy of combination therapy with CPI-613 and OBP-702, and the utility of positron emission tomography/computed tomography metabolic parameters for assessing glycolytic activity. Our results suggest that non-glycolytic PDAC cells are refractory to oncolytic adenoviruses. CPI-613 is a promising reagent for overcoming virotherapy resistance in PDAC tumors.