DDX1 facilitates lenvatinib resistance in hepatocellular carcinoma through regulating ephrin-A3 and activating the Wnt/β-catenin signaling pathway

Background Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Lenvatinib is a common first-line treatment for advanced HCC. However, resistance to lenvatinib is the greatest challenge limiting its clinical application. Currently, the molecular mechanisms of resistance remain poorly understood. Methods The expression of DDX1 and Ephrin-A3 in lenvatinib-resistant HCC cells was identified via RNA-seq and Western blotting. Bioinformatic analyses were applied to explore its expression and prognostic role. The biological role of DDX1 was evaluated via CCK8, EdU, flow cytometry analyses and xenograft tumor model. The regulation between DDX1 and Ephrin-A3 was determined by mass spectrometry, coimmunoprecipitation, RNA Immunoprecipitation, and RNA stability assay. Results We successfully established lenvatinib-resistant HCC cells. The results of RNA-seq showed DDX1 and Ephrin-A3 were significantly increased in lenvatinib-resistant HCC cells compared to parental cell. The DDX1 expression in HCC tissues is positively associated with worse prognosis. DDX1 knockdown increased the sensitivity of cells to lenvatinib by inhibiting proliferation and promoting Apoptosis in vitro and in vivo. Conversely, overexpression of DDX1 exhibited the opposite regulation. Moreover, DDX1 bound to Ephrin-A3 and regulated its expression levels. The effects of DDX1 overexpression on cell proliferation, Apoptosis, and lenvatinib resistance were significantly blocked by Ephrin-A3 knockdown. Mechanistically, DDX1 promotes lenvatinib resistance in HCC by regulating Ephrin-A3 mRNA stability and activating the Wnt/β-catenin pathway. Conclusion: The increased DDX1 expression in HCC cells promotes lenvatinib resistance via regulating Ephrin-A3 mRNA stability and activating the Wnt/β-catenin pathway, indicating that targeting DDX1 may be an important strategy for overcoming lenvatinib resistance.

DDX1; Ephrin-A3; Hepatocellular carcinoma; Lenvatinib resistance; Wnt/β-catenin pathway.