Oxidative Stress Converts Benign Lesions to Cancer via a Self-Amplifying NRF2-EZH2 Loop [Quantseq_Nrf2Kras]

Whether oxidative stress (OxS) acts mutationally or epigenetically to increase cancer risk is unknown. Pancreatic ductal carcinoma (PDAC) evolves from benign, low-grade PanIN (pancreatic intraepithelial neoplasia) lesions that frequently express oncogenic KRAS. Postulating that known risk factors convert benign PanIN to malignant progenitors via OxS and epigenetic mechanisms, we established a novel system to test this hypothesis.  Transient incubation of organoids, derived from pancreata with KrasG12D-induced low-grade PanIN, with H2O2 triggered irreversible malignant conversion mediated by an epigenetic network composed of NRF2, its direct transcriptional target EZH2, and EZH2-interacting transcription factors. Pharmacological or genetic activation of this network, maintained by a single NRF2 site in the EZH2 promoter, also triggered rapid malignant conversion and upregulation of malignancy-supportive metabolic genes that remained elevated in established PDAC.