Combination therapy with Nifuroxazide and Lenvatinib exerts superior anti-hepatocellular carcinoma effect by enhancing the anti-tumor immune response.

BACKGROUND: Lenvatinib is a first-line multi-target tyrosine kinase inhibitor for hepatocellular carcinoma (HCC) that exerts anti-angiogenic effects by blocking VEGF signaling. However, its clinical efficacy is often compromised by adaptive resistance. Nifuroxazide, an anti-diarrheal agent, has been identified by our group as a potent inhibitor of PD-L1 expression in HCC. OBJECTIVE: This study aimed to evaluate the therapeutic potential and underlying molecular mechanisms of nifuroxazide combined with lenvatinib against HCC. METHODS: In vitro, HCC cell proliferation, colony formation, and migration were assessed, and Western blot was used to detect p-STAT3, STAT3, PD-L1, and VEGF levels. In vivo, antitumor efficacy was evaluated in mouse xenograft models. Tumor tissues were analyzed by immunohistochemistry, TUNEL, and H&E staining, while flow cytometry was used to measure CD4+ and CD8+ T-cell proportions in the tumor microenvironment, peripheral blood, and spleen. RESULTS: The combination synergistically inhibited HCC cell proliferation and migration, and downregulated PD-L1, p-STAT3, and VEGF expression. It also markedly suppressed tumor growth, induced apoptosis, and enhanced CD4+ and CD8+ T-cell infiltration and distribution. CONCLUSIONS: Nifuroxazide potentiates lenvatinib-induced antitumor activity by regulating the STAT3/PD-L1 axis and enhancing antitumor immune responses. This combination provides a promising therapeutic strategy for HCC.