e15083 Background: Pharmacotherapy remains a pivotal treatment strategy for patients with advanced hepatocellular carcinoma (HCC). Donafenib, globally the first targeted therapy proven to offer superior survival benefits and safety over sorafenib in a large-scale phase III clinical trial with head-to-head comparison, has been adopted for first-line treatment of advanced HCC. Given the limited basic research on Donafenib both domestically and internationally, and its constrained clinical efficacy, this study aims to explore combination drug therapy for HCC in an attempt to achieve further breakthroughs and enhance the anticancer activity of Donafenib. Methods: A xenograft tumor model in nude mice was established to observe the in vivo antitumor effects of Donafenib. Transcriptomics and proteomics were employed to characterize the gene expression changes in HCC cell lines after Donafenib intervention and to screen for key molecules. A series of assays, including the Cell Counting Kit-8 (CCK8), flow cytometry, scratch assays, Transwell assays, Western blotting, and in vivo tumorigenicity in nude mice, were conducted to determine the impact of the hub gene on the malignant behavior of HCC and to evaluate the combined antitumor effects of the molecular inhibition and Donafenib treatment in HCC. Results: Treatment with Donafenib significantly slowed tumor growth in a nude mouse xenograft model, resulting in a marked reduction in final tumor volumes compared to control subjects. Proteomic analyses post-Donafenib treatment identified FADS2 as the protein with the highest absolute log2 fold change among all differentially expressed proteins in HCC cells. This finding was corroborated by transcriptomic data, which indicated a concurrent downregulation of FADS2 at the mRNA level. Subsequent in vitro and in vivo assays validated the inhibitory effect of FADS2 blockade on the malignant biological behaviors of HCC cells. Importantly, the concomitant administration of Donafenib and the FADS2 inhibitor SC-26196 exhibited a synergistic antitumor action, significantly enhancing therapeutic efficacy in both HCC cell lines and xenografted tumors in nude mice. Conclusions: Combination therapy, a prevalent approach in clinical oncology, has the potential to augment treatment efficacy while simultaneously diminishing toxicity. This study employed an extensive multi-omics approach complemented by a range of both in vitro and in vivo experiments. It revealed that the synergistic use of Donafenib and SC-26196 markedly enhances Donafenib-induced the inhibition of cancer cell growth and metastasis, demonstrating a significant synergistic antitumor effect. These findings from our preclinical investigations may offer a promising new combinational drug regimen for the therapeutic management of HCC patients.