The NQO1 bioactivatable drug, -lapachone, alters the redox state of NQO1+pancreatic cancer cells, causing perturbation in central carbon metabolism

Many cancer treatments, such as those for managing recalcitrant tumors like pancreatic ductal adenocarcinoma, cause off-target toxicities in normal, healthy tissue, highlighting the need for more tumor-selective chemotherapies. -Lapachone is bioactivated by NAD(P)H:quinone oxidoreductase 1 (NQO1). This enzyme exhibits elevated expression in most solid cancers and therefore is a potential cancer-specific target. -Lapachone's therapeutic efficacy partially stems from the drug's induction of a futile NQO1-mediated redox cycle that causes high levels of superoxide and then peroxide formation, which damages DNA and causes hyperactivation of poly(ADP-ribose) polymerase, resulting in extensive NAD(+)/ATP depletion. However, the effects of this drug on energy metabolism due to NAD(+) depletion were never described. The futile redox cycle rapidly consumes O-2, rendering standard assays of Krebs cycle turnover unusable. In this study, a multimodal analysis, including metabolic imaging using hyperpolarized pyruvate, points to reduced oxidative flux due to NAD(+) depletion after -lapachone treatment of NQO1+ human pancreatic cancer cells. NAD(+)-sensitive pathways, such as glycolysis, flux through lactate dehydrogenase, and the citric acid cycle (as inferred by flux through pyruvate dehydrogenase), were down-regulated by -lapachone treatment. Changes in flux through these pathways should generate biomarkers useful for in vivo dose responses of -lapachone treatment in humans, avoiding toxic side effects. Targeting the enzymes in these pathways for therapeutic treatment may have the potential to synergize with -lapachone treatment, creating unique NQO1-selective combinatorial therapies for specific cancers. These findings warrant future studies of intermediary metabolism in patients treated with -lapachone.