Inducible nitric oxide synthase is repressed by Nuclear Factor Erythroid 2-Related Factor 2 in KRAS-driven pancreatic cancer cells

ABSTRACT: Nitric oxide is a pleiotropic free radical produced by three nitric oxide synthases (NOS1-3), of which the inducible NOS2 is involved in carcinogenesis. In this study, RNA-seq, ChIP-seq, and qRT-PCR experiments combined with bioinformatic analysis showed that NRF2 is a repressor of the NOS2 gene by maintaining a distal enhancer located 22 Kb downstream of the transcription start site (TSS) in a poised state. NRF2 depletion primed the activation of this enhancer, exerting a pioneering activity before achieving full activation. Specifically, NRF2 controls the inducible expression of NOS2 in response to intracellular oxidative stress and extracellular oxygen partial pressure. Abrogation of NOS2 expression using esiRNAs partially reduced or severely impaired the ability to form 3D spheroids respectively of WT and NRF2-depleted Panc-1 cells. Mechanistically, NOS2 and nitric oxide release are required to sustain the epithelial-to- mesenchymal transition (EMT) process. Importantly, silencing of NOS2 blocked 3D Matrigel invasion of NRF2-depleted Panc-1 cells, demonstrating that a short circuit in the reciprocal regulation of NOS2 and NRF2 attenuates PDAC cell malignancy. Overall, our data demonstrate for the first time that: i) NRF2 is a repressor of the NOS2 gene in pancreatic cancer cells; ii) identify a poised enhancer whose priming is triggered in conditions that simulate or stimulate NRF2 depletion; iii) NOS2 activity is required for NRF2-depleted Panc-1 cells to maintain their malignancy and invasiveness.

ORGANISM(S): Homo sapiens

PROVIDER: GSE235472 | GEO | 2024/12/22

REPOSITORIES: GEO