Identification of Active Compounds of Centipeda minima for Potentiating Tumor Immunotherapy in Non‐Small Cell Lung Cancer via FANCD2 ‐ cGAS / STING / IFN ‐I Signaling Axis

ABSTRACT Activation of cGAS/STING/IFN‐I signaling pathway serves as a potential therapeutic strategy to enhance CD8 + T cells infiltration and augment antitumor immunotherapy. The medicinal herb Centipeda minima has been traditionally employed to treat respiratory diseases and cancer; however, whether C. minima and its bioactive constituents can activate CD8 + T cell‐mediated antitumor immunity in non‐small cell lung cancer (NSCLC) remains elusive. In this study, the ethanol extract of C. minima (ECM) significantly enhanced the cytotoxic activity of human peripheral blood mononuclear cell‐derived activated T cells and murine primary CD8 + T cells against NSCLC cells, and promoted CD8 + T cell infiltration in the LLC syngeneic tumor model. RNA‐seq profiling indicated that ECM potentially triggers type‐I interferon (IFN‐I)‐mediated innate immunity in NSCLC. Mechanistically, ECM treatment activated the cGAS/STING pathway in NSCLC cells, as evidenced by increased phosphorylation of TBK1 and IRF3, elevated IFN‐I gene expression, and enhanced CD8 + T cells activity. Notably, ECM markedly downregulated both mitochondrial and nuclear FANCD2 protein levels, which may facilitate cytosolic release of mitochondrial and nuclear DNA, thereby stimulating the cGAS/STING/IFN‐I signaling axis. ECM‐induced FANCD2 downregulation was markedly reversed by the proteasome inhibitor MG‐132. Combination treatment with ECM and anti‐PD‐1 antibody synergistically suppressed tumor growth in the LLC syngeneic model, accompanied by elevated IFN‐I expression and pronounced recruitment of activated CD8 + T cells. Moreover, 3‐ O ‐methylquercetin and several sesquiterpene lactones abundant in ECM were identified to downregulate FANCD2, activate TBK1/IRF3 pathway, and enhance IFN‐I expression in NSCLC cells. Among these active compounds, arnicolide D promoted FANCD2 degradation in a proteasome‐dependent manner, whereas 3‐ O ‐methylquercetin predominantly suppressed FANCD2 gene expression. Collectively, our findings suggest that FANCD2 may serve as a novel therapeutic target for enhancing antitumor innate immunity, and that C. minima along with its active compounds can potentiate antitumor immunotherapy by activating the FANCD2‐cGAS/STING/IFN‐I signaling axis.