L-741626 inhibits hepatocellular carcinoma progression by targeting Ref-1 to suppress MAPK/ERK signalling pathway activity.

Hepatocellular carcinoma (HCC) is a common and challenging malignancy of the digestive tract. Unfortunately, patients with advanced HCC frequently experience limited long-term benefits from current treatments, highlighting the critical need for innovative therapeutic agents. The discovery and development of new small-molecule compounds that target tumours have become crucial aspects of cancer research. In this study, we report on L-741626, a compound that has significant inhibitory effects on HCC. Both in vivo and in vitro experiments confirmed that L-741626 inhibited the growth of HCC by suppressing the MAPK/ERK signalling pathway. Molecular docking simulations and drug affinity responsive target stability assays further identified redox Factor 1 (Ref-1) as a target of L-741626. Ref-1 is overexpressed in HCC and is correlated with poor prognosis and high stage. Further studies demonstrated that Ref-1 interacts with CRAF, a crucial component of the MAPK/ERK signalling pathway. Knockdown of Ref-1 in HCC cells led to inhibition of the MAPK/ERK pathway. Sorafenib is a well-established targeted therapy for the treatment of HCC, with its primary antitumor mechanism being the inhibition of the MAPK/ERK signalling pathway. However, the presence of tumor stem cells is a key factor contributing to resistance to sorafenib. Our study demonstrates that L-741626 can suppress tumor stemness in HCC. The combination of L-741626 and sorafenib significantly enhances the sensitivity of HCC, resulting in increased tumoricidal effects. Our findings reveal a novel pharmacological effect of L-741626, which inhibits MAPK/ERK signalling activity in HCC by targeting Ref-1. Furthermore, L-741626 exhibits a synergistic effect when combined with sorafenib, suggesting a new potential approach for HCC treatment.