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The processing of intracellular reactive oxygen species (ROS) by nuclear factor erythroid-derived 2-like 2 (Nrf2) and NADPH quinone oxidoreductase 1 (Nqo1) is important for tumor metastasis. However, the clinical and biological significance of Nrf2/Nqo1 expression in hepatocellular carcinoma (HCC) remains unclear. We aimed to clarify the clinical importance of Nrf2/Nqo1 expression in HCC and evaluate the association of Nrf2/Nqo1 expression with HCC metastasis. We also evaluated the impact of Nqo1 modulation on HCC metastatic potential. We used spheroids derived from HCC cell lines. In anchorage-independent culture, HCC cells showed increased ROS, leading to the upregulation of Nrf2/Nqo1. Futile stimulation of Nqo1 by β-lapachone induces excessive oxidative stress and dramatically increased anoikis sensitivity, finally diminishing the spheroid formation ability, which was far stronger than depletion of Nqo1. We analyzed 117 cases of primary HCC who underwent curative resection.Overexpression of Nrf2/Nqo1 in primary HCC was associated with tumor size, high α-fetoprotein, and des-γ-carboxy-prothrombin levels. Overexpression of Nrf2/Nqo1 was also associated with multiple intrahepatic recurrences (P = .0073) and was an independent risk factor for poor prognosis (P = .0031). NADPH quinone oxidoreductase 1 plays an important role in anchorage-independent survival, which is essential for survival for circulation and distant metastasis of HCC cells. These results suggest that targeting Nqo1 activity could be a potential strategy for HCC adjuvant therapy. K E Y W O R D Shepatocellular carcinoma, metastasis, Nqo1, Nrf2, oxidative stress | 1229 SHIMOKAWA et Al. | INTRODUC TI ONHepatocellular carcinoma is the second leading cause of cancer-related death worldwide and predominant in many countries such as France, Italy, Japan, and China. 1,2 Patients with HCC frequently suffer from intrahepatic or extrahepatic recurrence, which contribute to approximately 90% of HCC-related deaths. 3,4 Cancer cells metastasize through several steps: detachment from the primary site, invasion through local tissue, intravasation into blood or lymph vessels, survival in circulation, extravasation, and formation of new tumors at distant sites. 5,6 When disengaging from the ECM and circulating in the bloodstream, cancer cells confront excessive oxidative stress 7-9 and need to acquire the ability to overcome ROS and detachment-induced apoptosis, also known as anoikis. 10Nuclear factor erythroid-derived 2-like 2 is a key transcription factor for processing intracellular ROS. 11 In the quiescent state, Keap1 and Cullin-3 interact with Nrf2 to facilitate ubiquitination S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section. How to cite this article: Shimokawa M, Yoshizumi T, Itoh S, et al. Modulation of Nqo1 activity intercepts anoikis resistance and reduces metastatic potential of hepatocellular carcinoma.

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The tyrosine kinase inhibitor lenvatinib is used to treat advanced hepatocellular carcinoma (HCC). Ferroptosis is a type of cell death characterized by the iron‐dependent accumulation of lethal lipid reactive oxygen species (ROS). Nuclear factor erythroid‐derived 2‐like 2 (Nrf2) protects HCC cells against ferroptosis. However, the mechanism of lenvatinib‐induced cytotoxicity and the relationships between lenvatinib resistance and Nrf2 are unclear. Thus, we investigated the relationship between lenvatinib and ferroptosis and clarified the involvement of Nrf2 in lenvatinib‐induced cytotoxicity. Cell viability, lipid ROS levels, and protein expression were measured using Hep3B and HuH7 cells treated with lenvatinib or erastin. We examined these variables after silencing fibroblast growth factor receptor‐4 (FGFR4) or Nrf2 and overexpressing‐Nrf2. We immunohistochemically evaluated FGFR4 expression in recurrent lesions after resection and clarified the relationship between FGFR4 expression and lenvatinib efficacy. Lenvatinib suppressed system Xc− (xCT) and glutathione peroxidase 4 (GPX4) expression. Inhibition of the cystine import activity of xCT and GPX4 resulted in the accumulation of lipid ROS. Silencing‐FGFR4 suppressed xCT and GPX4 expression and increased lipid ROS levels. Nrf2‐silenced HCC cells displayed sensitivity to lenvatinib and high lipid ROS levels. In contrast, Nrf2‐overexpressing HCC cells displayed resistance to lenvatinib and low lipid ROS levels. The efficacy of lenvatinib was significantly lower in recurrent HCC lesions with low‐FGFR4 expression than in those with high‐FGFR4 expression. Patients with FGFR4‐positive HCC displayed significantly longer progression‐free survival than those with FGFR4‐negative HCC. Lenvatinib induced ferroptosis by inhibiting FGFR4. Nrf2 is involved in the sensitivity of HCC to lenvatinib.