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NRF2 (nuclear factor erythroid 2-related factor 2) is a transcription factor which plays a major role in oxidative stress responses by regulating antioxidant gene expression. We have recently identified the ARF tumor suppressor as a key regulator of NRF2. ARF can significantly inhibit NRF2 transcriptional activities, and the ARF-NRF2 interaction may function as a novel checkpoint for oxidative stress responses. [ABSTRACT FROM AUTHOR]

Summary Although ARF can suppress tumor growth by activating p53 function, the mechanisms by which it suppresses tumor growth independently of p53 are not well understood. Here, we identified ARF as a key regulator of nuclear factor E2-related factor 2 (NRF2) through complex purification. ARF inhibits the ability of NRF2 to transcriptionally activate its target genes, including SLC7A11, a component of the cystine/glutamate antiporter that regulates reactive oxygen species (ROS)-induced ferroptosis. As a consequence, ARF expression sensitizes cells to ferroptosis in a p53-independent manner while ARF depletion induces NRF2 activation and promotes cancer cell survival in response to oxidative stress. Moreover, the ability of ARF to induce p53-independent tumor growth suppression in mouse xenograft models is significantly abrogated upon NRF2 overexpression. These results demonstrate that NRF2 is a major target of p53-independent tumor suppression by ARF and also suggest that the ARF-NRF2 interaction acts as a new checkpoint for oxidative stress responses. [ABSTRACT FROM AUTHOR]