Background: Lung squamous cell carcinoma (LUSC) currently has limited therapeutic options because of the relatively few validated targets and the lack of clinical drugs for some of these targets. Although NRF2/NFE2L2 pathway activation commonly occurs in LUSC, NRF2 has predominantly been studied in other cancer models. Here, we investigated the function of NRF2 in LUSC, including in organoid models, and we explored the activity of a small molecule NRF2 inhibitor ML385, which has not previously been investigated in LUSC.Methods: We first explored the role of NRF2 signaling in LUSC cancer cell line and organoid proliferation through NRF2 knockdown or ML385 treatment, both in vivo and in vitro. Next, we performed Western blot and immunofluorescence assays to determine the effect of NRF2 inhibition on PI3K‐mTOR signaling. Finally, we used cell viability and clonogenic assays to explore whether ML385 could sensitize LUSC cancer cells to PI3K inhibitors.Results: We find that downregulation of NRF2 signaling inhibited proliferation of LUSC cancer cell lines and organoids, both in vivo and in vitro. We also demonstrate that inhibition of NRF2 reduces PI3K‐mTOR signaling, with two potential mechanisms being involved. Although NRF2 promotes AKT phosphorylation, it also acts downstream of AKT to increase RagD protein expression and recruitment of mTOR to lysosomes after amino acid stimulation. We also find that ML385 potentiates LUSC growth inhibition by a pan‐PI3K inhibitor, which correlates with stronger inhibition of PI3K‐mTOR signaling.Conclusions: Our data provide additional support for NRF2 promoting LUSC growth through PI3K‐mTOR activation and support development of NRF2 inhibitors for the treatment of LUSC.

Cisplatin resistance is a major cause of poor prognosis in non-small cell lung cancer (NSCLC). Cisplatin-induced lung cancer cell death is associated with ferroptosis, a type of recently identified programmed cell death. Nrf2 is a critical component of the antioxidant system, and its protumorigenic activity in lung cancer has been extensively studied. However, the role of Nrf2 in cisplatin-induced ferroptosis and drug resistance remains elusive. Here, we demonstrated that cisplatin treatment induced ferroptosis in parental A549 lung adenocarcinoma cells and that this effect was significantly reduced in cisplatin-resistant A549/DDP cells. Knocking down Nrf2-sensitized A549/DDP cells to cisplatin-induced cytotoxicity by enhancing ferroptosis. Moreover, we demonstrated that Nrf2 promotes the expression of HMOX1 and that the Nrf2-HMOX1 pathway is critical for mediating its anti-ferroptotic function. Additionally, immunohistochemical analysis of NSCLC specimens revealed that Nrf2 expression was correlated with HMOX1 and high levels of Nrf2 and HMOX1 were associated with poor patient survival. These findings suggest that the HMOX1-Nrf2 pathway significantly influences treatment outcomes in NSCLC. Ultimately, we demonstrated that treatment with the Nrf2 inhibitor ML385 promoted ferroptosis by inhibiting the Nrf2-HMOX1 pathway, restoring cisplatin sensitivity in drug-resistant cells. Our findings provide insights into the mechanism underlying cisplatin resistance and suggest that targeting the Nrf2-HMOX1 pathway enhances cisplatin-induced ferroptosis and improves NSCLC treatment outcomes.

Epithelial-mesenchymal transition (EMT), including developmental (Type I), wound healing (Type II), and pathological (Type III) subtypes, constitutes a critical driver of cancer metastasis. This review analyzes the redox interplay between nuclear factor erythroid 2-related factor 2 (Nrf2) and reactive oxygen species (ROS) in EMT regulation and cancer progression. Nrf2 maintains redox homeostasis through antioxidant gene activation while paradoxically promoting tumor survival and drug resistance via Keap1-dependent degradation and phosphorylation-mediated stabilization. ROS generated through mitochondrial and NADPH oxidase pathways exhibit dual functionality: moderate levels activate EMT transcription factors to drive metastasis and cancer stem cells (CSCs) plasticity, whereas excessive ROS induce apoptosis and ferroptosis. While Nrf2 typically suppresses EMT through ROS neutralization and epithelial integrity preservation, chronic Nrf2 activation in CSCs paradoxically sustains metastatic potential through redox buffering. This synthesis delineates the spatiotemporal regulation of Nrf2-ROS-EMT networks across tumor microenvironments, emphasizing therapeutic opportunities through redox balance modulation and pathway-specific Nrf2 inhibition in advanced malignancies.