Apatinib triggers ferroptosis in gastric cancer via HDAC1/HIF1α/CA9 signaling axis.

Gastric cancer (GC) poses significant therapeutic challenges due to frequent late-stage diagnosis and limited treatment efficacy. Although Apatinib demonstrates clinical benefits in GC, acquired resistance remains problematic. Ferroptosis induction represents a promising strategy to overcome such resistance. Integrated computational target prediction (SwissTargetPrediction) and ferroptosis suppressor gene screening (FerrDb) identified carbonic anhydrase IX (CA9) as Apatinib's putative target. Functional validation employed EdU, Transwell, sphere-formation, and flow cytometry assays. Ferroptosis markers [Fe²⁺, reactive oxygen species (ROS), ACSL4, and GPX4] were quantified via specific kits and western blotting. Histone deacetylase 1 (HDAC1)/hypoxia inducible factor 1α (HIF1α)/CA9 axis regulation was assessed through overexpression, siRNA knockdown, and immunoprecipitation. Apatinib significantly suppressed GC cell proliferation, migration, and stemness while promoting apoptosis. It induced ferroptosis via Fe²⁺/ROS accumulation and abnormal ACSL4/GPX4 expression. Mechanistically, Apatinib downregulated HDAC1, triggering HIF1α ubiquitination and subsequent CA9 suppression. HDAC1 overexpression reversed Apatinib-induced ferroptosis and antitumor effects, whereas HIF1α knockdown abrogated this rescue. This study elucidates a novel HDAC1/HIF1α/CA9 axis through which Apatinib induces ferroptosis. Targeting this pathway offers translational potential for overcoming Apatinib resistance in GC therapy.