SQSTM1/p62 Protein Oxidation Facilitates Nrf2 Activation and Pro-survival Autophagy under Therapeutic Oxidative Stress

Alternol, a natural compound, exhibits potent anti-tumor activity by selectively inducing oxidative stress in prostate cancer cells; however, the molecular mechanisms that coordinate adaptive survival responses to this stress remain poorly defined. In this study, we demonstrate that Alternol treatment triggers a robust, ROS-dependent autophagic response and Nrf2 transactivation in both cell lines and xenograft models. We identify that Alternol specifically drives the rapid, large-scale aggregation of SQSTM1/p62 through direct protein oxidation at Cys105 and Cys113. Distinct from traditional kinase-driven models, this structural aggregation is a primary redox-sensing event that occurs independently of, and prior to, p62 phosphorylation at Ser349 and Ser403. These oxidized p62 aggregates function as a signaling platform that sequesters KEAP1 for autophagic degradation, thereby liberating Nrf2 for nuclear translocation and the induction of downstream antioxidant genes such as AOX1 . Genetic depletion of p62 or disruption of its aggregation capacity via C105/113A mutation blunts KEAP1 turnover and Nrf2 activation, significantly sensitizing cancer cells to Alternol-induced apoptosis. Collectively, our findings define a novel "oxidation-aggregation" axis of p62 as a pivotal survival mechanism, suggesting that targeting the physical aggregation of p62 could provide a promising strategy to overcome adaptive resilience and enhance the efficacy of pro-oxidant cancer therapies.