Nrf2 Mutagenic Activation Drives Hepatocarcinogenesis

Nrf2, a master regulator of oxidative stress, is considered a prominent target for prevention of hepatocellular carcinoma (HCC), one of the leading causes of cancer-related deaths worldwide. Here we report that Nrf2-deficient mice resisted diethylnitrosamine (DEN)-induced hepatocarcinogenesis without affecting P450-mediated metabolic activation of DEN. Nrf2 expression, nuclear translocation, and transcriptional activity were enhanced in liver tumors. Overactivated Nrf2 was required for hepatoma growth in DEN-induced HCC. Following DEN treatment, Nrf2 genetic disruption reduced expression of pentose phosphate pathway-related enzymes, the depletion of which has been associated with an amelioration of HCC incidence. Conversely, enhanced Nrf2 activity was attributable to alterations in the ability to bind its endogenous inhibitor Keap1. Our findings provide a mechanistic rationale for Nrf2 blockade to prevent and possibly treat liver cancer. (C) 2017 AACR.