Akkermansia muciniphila attenuates apatinib resistance in hepatocellular carcinoma through NF-κB-mediated reprogramming of tumor-associated macrophages.

BACKGROUND: Hepatocellular carcinoma (HCC) remains among the most lethal malignancies worldwide, and acquired resistance to targeted therapy limits durable clinical benefit. Apatinib, a selective vascular endothelial growth factor receptor-2 inhibitor, is used in advanced HCC, but the contribution of the gut microbiota to Apatinib resistance remains incompletely defined. This study aimed to determine whether gut microbiota dysbiosis, particularly loss of Akkermansia muciniphila (Akk), contributes to an Apatinib-resistant HCC phenotype and to evaluate whether Akk-derived factors modulate macrophage NF-κB signaling. METHODS: A Hepa1-6 syngeneic subcutaneous HCC model was established in C57BL/6 mice. The apatinib-resistant phenotype was operationally defined by continued tumor growth under apatinib pressure together with an ex vivo right shift in the half-maximal inhibitory concentration (IC50) determined using the Cell Counting Kit-8 (CCK-8) assay. Fecal microbiota were analyzed by 16S ribosomal RNA (16S rRNA) gene sequencing, Akk abundance was validated by quantitative polymerase chain reaction, and inferred microbial functional potential was explored using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States 2. Macrophage polarization, tumor-level NF-κB signaling, live Akk oral supplementation, and bone marrow-derived macrophage (BMDM) responses to Akk supernatant or pasteurized Akk were assessed. RESULTS: Apatinib-resistant mice showed gut dysbiosis characterized by reduced microbial diversity, distinct beta-diversity clustering, and marked depletion of Akk. Resistant tumors exhibited reduced M1-like and increased M2-like macrophage fractions, together with lower phosphorylation of p65 and IκBα in whole-tumor lysates. Oral live Akk administration restored intestinal Akk abundance, reduced tumor volume and weight, re-established M1-like macrophage polarization, and reactivated tumor-level NF-κB signaling. In BMDMs exposed to apatinib-resistant Hepa1-6-conditioned medium, Akk supernatant and pasteurized Akk partially restored NF-κB phosphorylation and attenuated M2-like transcriptional skewing. CONCLUSIONS: Akk depletion accompanies an apatinib-resistant HCC phenotype and Akk-centered microbial modulation may help counteract resistance by reshaping macrophage-associated antitumor immunity. These findings support further validation of Akk-derived signals in community-level microbiome models and clinically relevant HCC settings.