Triptolide enhances lenvatinib sensitivity in hepatocellular carcinoma by regulating CERK-mediated sphingolipid-ferroptosis axis

Hepatocellular carcinoma (HCC) ranks as the third leading cause of cancer-related mortality worldwide. As a first-line targeted agent, the clinical application of lenvatinib (LEN) is constrained by drug resistance. This study elucidated the synergistic antitumor mechanism of the traditional Chinese medicine monomer triptolide (TP) in combination with LEN for HCC therapy. In vitro experiments demonstrated that TP-LEN combination significantly enhanced proliferation inhibition and migration blockade in Hep3B and Huh7 cells, exerting synergistic effects through induction of apoptosis and ferroptosis, characterized by intracellular iron accumulation, elevated reactive oxygen species (ROS) levels, and downregulation of ferroptosis-associated proteins GPX4 and SLC7A11. Mechanistic investigations revealed that TP-LEN combination disrupted sphingolipid metabolism by inhibiting ceramide kinase (CERK), leading to accumulation of ceramide (Cer). CERK overexpression abrogated the antitumor effects of the combination, whereas CERK knockdown potentiated cellular sensitivity. In LEN-resistant cell lines, high CERK expression was correlated with drug resistance, and the CERK inhibitor NVP231 restored sensitivity to LEN. In vivo studies using Huh7 xenograft models showed that TP-LEN combination significantly suppressed tumor growth without causing hepatic or renal dysfunction, accompanied by marked downregulation of CERK, GPX4, and SLC7A11 in tumor tissues. This study confirms that TP enhances LEN sensitivity by targeting the CERK/sphingolipid-ferroptosis axis, providing a novel strategy to overcome HCC resistance.