Anlotinib mediates intrinsic drug resistance in hepatoblastoma through the GAD1/GABA pathway.

BACKGROUND

Intrinsic resistance reduces the effectiveness of many anticancer therapies. Anlotinib, a small-molecule multi-targeted tyrosine kinase inhibitor, has shown potential in treating hepatoblastoma. This study investigates the role of γ-aminobutyric acid (GABA) in anlotinib resistance using in vivo and in vitro models.

METHODS

HuH-6 hepatoblastoma cells were implanted into nude mice to assess the effects of anlotinib on tumor growth. Neurotransmitter-targeted metabolomics was performed to analyze neurotransmitter metabolism in xenograft tumor tissues. In vitro, HuH-6 and HepG2 cells were treated with anlotinib to evaluate changes in GABA synthesis, degradation, and associated protein expression.

RESULTS

Anlotinib significantly inhibited HuH-6 tumor growth but was less effective than cisplatin. Neurotransmitter-targeted metabolomics showed tumors treated with anlotinib exhibited increased GABA levels. Anlotinib treatment also upregulated the protein expression of GAD1, a key enzyme in GABA synthesis. In vitro, anlotinib treatment enhanced GABA release and GAD1 expression in hepatoblastoma cells. Exogenous GABA stimulation promoted cell proliferation in vitro and tumor growth in vivo. Notably, GAD1 knockdown enhanced anlotinib's inhibitory effects on hepatoblastoma in vitro and in vivo.

CONCLUSION

Anlotinib induces intrinsic resistance in hepatoblastoma by upregulating GAD1 and increasing GABA accumulation. Targeting GAD1 may enhance anlotinib's therapeutic efficacy and help overcome resistance.

IMPACT

Anlotinib upregulates GAD1 to enhance GABA synthesis, driving intrinsic resistance in hepatoblastoma by activating tumor-promoting GABA signaling in the tumor microenvironment. First identification of the GAD1/GABA axis as a critical mediator of anlotinib resistance, expanding understanding of neurotransmitter-driven drug tolerance in pediatric cancers. GAD1 knockdown synergizes with anlotinib to overcome resistance, establishing a combinatorial strategy to enhance antitumor efficacy in preclinical models. Proposes targeting GABA metabolism to optimize anlotinib-based therapies, addressing unmet needs in refractory hepatoblastoma treatment.