Bufalin Inhibits Tumorigenesis and SREBP-1-Mediated Lipogenesis in Hepatocellular Carcinoma via Modulating the ATP1A1/CA2 Axis

Altered lipid metabolism is a hallmark of hepatocellular carcinoma (HCC), a common malignancy with a dismal prognosis against which there is a lack of effective therapeutic strategies. Bufalin, a classical Na[Formula: see text]-K[Formula: see text]-ATPase (NKA) inhibitor, shows a potent antitumor effect against HCC. However, the role of bufalin in regulating lipid metabolism-related pathways of HCC remains unclear. In this study, we examined the interaction between bufalin and its target molecule, ATP1A1/CA2, in vitro and in vivo and explored the intersected downstream pathways in silico. A multi-omics analysis of transcriptomics and metabolomics was employed to screen for potential action targets. The results were verified and correlated with the downstream lipid de novo synthesis pathway and the bufalin/ATP1A1/CA2 axis. We found that bufalin suppressed the ATP1A1/CA2 ratio in the treated HCC cells and showed a negative correlation with bufalin drug sensitivity. Functionally, ATP1A1 overexpression and CA2 down-regulation inhibited the bufalin-suppressed HCC proliferation and metastasis. Furthermore, down-regulation of CA2 induced epithelial-mesenchymal transition and bufalin resistance in HCC cells by up-regulating ATP1A1. Mechanistically, lipid metabolism-related signaling pathways were enriched in low ATP1A1 and high CA2 expression subgroups in GSEA. The multi-omics analysis also showed that bufalin was closely related to lipid metabolism. We demonstrated that bufalin inhibits lipogenesis and tumorigenesis by down-regulating SREBP-1/FASN/ACLY via modulating the ATP1A1/CA2 axis in HCC.