ARHGEF39 Targeted by E2F1 Fosters Hepatocellular Carcinoma Metastasis by Mediating Fatty Acid Metabolism.

ABSTRACT

BACKGROUND: Hepatocellular carcinoma (HCC) stands as the prevailing manifestation of primary liver cancer. Previous studies have implicated ARHGEF39 in various cancer progression processes, but its impact on HCC metastasis remains unclear. METHODS: Bioinformatics analysis and qRT-PCR were employed to test ARHGEF39 expression in HCC tissues and cells, identified enriched pathways associated with ARHGEF39, and investigated its regulatory relationship with E2F1. The impact of ARHGEF39 overexpression or knockdown on cellular phenotypes in HCC was assessed through the implementation of CCK-8 and Transwell assays. Accumulation of neutral lipids was determined by BODIPY 493/503 staining, while levels of triglycerides and phospholipids were measured using specific assay kits. Expression of E-cadherin, Vimentin, MMP-2, MMP-9, and FASN were analyzed by Western blot. The interaction between ARHGEF39 and E2F1 was validated through ChIP and dual-luciferase reporter assays. RESULTS: Our study demonstrated upregulated expression of both ARHGEF39 and E2F1 in HCC, with ARHGEF39 being associated with fatty acid metabolism (FAM) pathways. Additionally, ARHGEF39 was identified as a downstream target gene of E2F1. Cell-based experiments unmasked that high expression of ARHGEF39 mediated the promotion of HCC cell viability, migration, and invasion via enhanced FAM. Moreover, rescue assays demonstrated that the promotion of HCC cell metastasis by high ARHGEF39 expression was attenuated upon treatment with Orlistat. Conversely, the knockdown of E2F1 suppressed HCC cell metastasis and FAM, while the upregulation of ARHGEF39 counteracted the repressive effects of E2F1 downregulation on the metastatic potential of HCC cells. CONCLUSION: Our findings confirmed the critical role of ARHGEF39 in HCC metastasis and unmasked potential molecular mechanisms through which ARHGEF39 fostered HCC metastasis via FAM, providing a theoretical basis for exploring novel molecular markers and preventive strategies for HCC metastasis.