Gambogenic Acid Suppresses Malignant Progression of Non-Small Cell Lung Cancer via GCH1-Mediated Ferroptosis

<b>Introduction:</b> Non-small cell lung cancer (NSCLC) is a lethal type of lung cancer (LC) with a 5-year survival rate of 19%. Because drug resistance typically develops following chemotherapy, radiotherapy, and immunotherapy, a novel NSCLC therapeutic strategy is urgently demanded. Gambogenic acid (GNA), a major bioactive ingredient isolated from gamboge, has multipotent antitumor effects, although activity against NSCLC is unknown. <b>Methods:</b> CCK8, ethynyl deoxyuridine (EdU), the plate colony formation assay, and the transwell and wound healing (WH) assay were used to study the effect of GNA on the proliferation and migration ability of NSCLC. Flow cytometry was used to detect apoptosis and the cell cycle. Proteomic analysis and LiP-SMap were used to detect the downstream target of GNA. Ferroptosis inhibitor ferrostatin-1 was used to detect the effect of GNA on NSCLC ferroptosis. Overexpressing GCH1 was used for a rescue experiment. Subcutaneous tumor and pulmonary metastasis in a mouse model were used to study the effect of GNA on NSCLC growth and metastasis. <b>Results:</b> The results of the present study showed that GNA inhibited the proliferation and migration of NSCLC cells in a dose- and time-dependent manner, which arrested the cell cycle in the G0/G1 phase. In vivo data revealed that GNA inhibited tumor growth and lung metastasis. Proteomic analysis found that GNA significantly inhibited the expression of GTP cyclohydrolase 1 (GCH1). LiP-SMap analysis showed that GNA interacted with ILE248 and ARG249 of GCH1. GCH1 overexpression had a similar role to the ferroptosis inhibitor ferrostatin-1 and restored cell proliferation and migration after GNA treatment. Also, GNA promoted reactive oxygen species (ROS) accumulation, which reduced mitochondrial membrane potential. GCH1 overexpression or ferrostatin-1 treatment reversed GNA regulation of ROS accumulation and mitochondrial membrane potential inhibition. <b>Conclusions:</b> Taken together, these findings confirmed that GNA suppressed the malignant progression of NSCLC by inducing GCH1-mediated ferroptosis.