Abstract An iron-dependent mechanism of cell death, ferroptosis, occurs with intracellular iron accumulation and is associated with lipid peroxidation. Previous studies have shown that lipid peroxidation-induced ROS leads to DNA damage and promotes the progression of steatosis to advanced HCC. Therefore, we aim to study ferroptosis in a cell model with hepatocytes co-cultured with ACM (adipocyte culture medium) and low dose H2O2 for a high-fat/high ROS environment in vitro; an animal model with high-fat content and accompanying low dose carbon tetrachloride in vivo to observe the possibility of hepatocyte steatosis due to ferroptosis. Animal model: Mice were fed a Western diet and provided with high fructose/glucose-containing sugar drinking water (WFSD) for 7 months while receiving a monthly extra-low dose of CCl4. Tissue staining: Liver sections were performed to observe histological abnormalities in each group. Cell model: Pre-adipocytes, 3T3L1 were differentiated by adding IBMX, Dexamethasone, and Insulin (10 μg/ml). After differentiation, ACM was collected. The XTT assay was used to examine the relationship between cell death and ferroptosis by a ferroptosis inducer (Erastin) in high-fat and high-ROS environments.qPCR: To detect the expression of iron transport-related genes.Western Blot: To ascertain protein levels associated with ferroptosis. Mitochondrial assay: Mitochondrial membrane potential (MMP), mitochondrial dynamics-related proteins, and fluorescence mitochondrial tracking and staining. Ferritin, GPX4, IRP2, and ferroportin were upregulated when ACM co-culture with the hepatocytic AML12 cell line, and it also increased the sensitivity of ROS-related cell cytotoxicity, which was related to ferroptosis by the inducer, Erastin, in the high-fat/high-ROS cell environment. However, these results can be suppressed by UAMC3203, a ferroptosis inhibitor. As for the animal model with high-fat and carbon tetrachloride accompanied experiments, the mice had higher weight, Alanine Aminotransferase (ALT) levels, and developed tumors. Their liver sections showed lipid accumulation, histological fibrosis, and iron accumulation in both the WD and WD+CCl4 groups, which corresponds to the IRP1 and IRP2 upregulated in both groups by qPCR result. Our research findings demonstrate that ferroptosis correlates with high-fat and high-ROS-induced hepatocellular damage. The related mitochondria dynamics changes in liver tissue and high-fat and/or high ROS provide evidence for ferroptosis-related hepatic steatosis. We have established the effect of ferroptosis on hepatic steatosis in vivo and in vitro in nonalcoholic steatosis hepatitis (NASH). These results may enable the development of precise health prevention strategies by inhibiting ferroptosis to prevent the occurrence of liver diseases including hepatic steatosis and HCC. Citation Format: Chi-Sheng (Wayne) Chen, Shu-Chi Wang. Investigating the impact of ferroptosis in a high-fat and high-oxidative stress hepatic steatosis environment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7443.