ATOX1 Promotes Hepatocellular Carcinoma Carcinogenesis via Activation of the c-Myb/PI3K/AKT Signaling Pathway.

BACKGROUND AND AIMS: Despite advancements in diagnostic and therapeutic strategies, hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality. Antioxidant-1 (ATOX1) has been implicated in oncogenic processes across various cancer types; however, its specific role in HCC remains unclear. This study aimed to investigate the function of ATOX1 and its underlying molecular mechanisms in HCC. METHODS: Immunohistochemical analysis was conducted to assess ATOX1 expression in HCC tissues. Cell Counting Kit-8, colony formation, Transwell migration, flow cytometry, and reactive oxygen species (ROS) assays were employed to evaluate the malignant behaviors of tumor cells. A xenograft mouse model was employed to assess the effects of ATOX1 knockdown on tumor growth in vivo. DCAC50 treatment was performed to inhibit the copper transport function of ATOX1. RNA sequencing was conducted to explore the potential molecular mechanisms of ATOX1 in HCC. RESULTS: ATOX1 expression was significantly elevated in HCC tumor tissues. ATOX1 promoted cell proliferation, colony formation, and migration. Knockdown of ATOX1 suppressed tumor growth in vivo. Mechanistically, ATOX1 activated c-Myb, and thus enhanced the malignant phenotype of HCC cells via activation of the PI3K/AKT signaling pathway. Additionally, ATOX1 reduced intracellular copper accumulation and inhibited ROS production and apoptosis. Inhibition of ATOX1 by DCAC50 decreased cell proliferation while increasing ROS levels and apoptosis in HCC cells. Notably, acetylcysteine reversed the reduction in c-Myb expression induced by ATOX1 knockdown. CONCLUSIONS: ATOX1 may promote HCC carcinogenesis through the activation of the c-Myb/PI3K/AKT pathway and the inhibition of copper accumulation and oxidative stress.