FOXO6 specifically promotes Rac1 overactivation drives Hepatocellular Carcinoma migration and Early Recurrence: FOXO6 as a novel Therapeutic Target for Liver Cancer

Background Rac1 activation is a common occurrence in various tumors and is often associated with poor prognosis, underscoring the potential therapeutic value of targeting the Rac1 pathway. Therefore, selectively inhibiting the heightened Rac1 activity in tumor cells may represent an innovative approach to cancer treatment. Methods Techniques included siRNA-mediated gene silencing, luciferase reporter assays for promoter activity, Western blotting, qRT-PCR, and chromatin immunoprecipitation (ChIP) to validate FOXO6-Rac1 interactions. Migration assays assessed cellular motility, while Kaplan-Meier survival analysis correlated FOXO6 expression with HCC recurrence. Mutagenesis of promoter regions and phosphorylation/ localization studies clarified regulatory mechanisms. Results We found the increase in Rac1 expression contributes to heightened Rac1 activity and enhanced migration of HCC cells. Notably, our investigations identified FOXO6, rather than HIF-1α, Smad7, miR-142-3p, or miR-137, as the mediator of Rac1 expression. FOXO6 exhibits transcriptional activation and correlates with the early recurrence of HCC following hepatectomy. The transcriptional activation of the Rac1 gene hinges on a FOXO-binding sequence in the Rac1 gene promoter. FOXO6 was found to directly bind to this sequence both in vitro and in vivo . Ultimately, Rac1 operates downstream of the FOXO6-dependent pro-migration signaling cascade. Our findings illuminate the direct role of FOXO6 in mediating the upregulation of Rac1 expression and activity in HCC cells. Conclusion This discovery unveils a differentially activated FOXO6/Rac1 pathway in liver cancer, thereby positioning FOXO6 as a potential therapeutic target for liver cancer treatment, offering the prospect of mitigating excessive side effects.