DKN-01 Suppresses Gastric Cancer Progression Through Activating cGAS-STING Pathway to Block Macrophage M2 Polarization.

Dickkopf-1 (DKK1) is a secretory antagonist that can bind with the Wnt coreceptor to desensitize cells to canonical Wnt ligands. DKN-01 is a specific antibody targeting secreted DKK1, which has been investigated as a monotherapy or combination therapy for various malignant tumors, including gastric cancer (GC). Tumor-associated macrophages (TAMs) with high plasticity usually present M2 phenotype, which can promote tumor progression. The aim of this study was to investigate the effect of DKN-01 on macrophage polarization in GC and the underlying molecular mechanism. To ascertain the effect of DKN-01 on GC tumor growth, we established a tumor-bearing mouse model and found that DKN-01 treatment suppressed tumor growth efficiently. Through RNA-seq and pathway enrichment analysis, we identified that the differentially expressed genes after DKN-01 treatment are associated with tumor immune-related pathways. Macrophage polarization was assessed using immunohistochemistry and quantitative real-time polymerase chain reaction. DKN-01 and knockdown of DKK1 promoted M1 polarization and inhibited M2 polarization of macrophages, while DKK1 overexpression got the opposite results. Moreover, DKN-01 activated the cGAS/STING pathway, while the inactivation of cGAS-STING pathway using RU.521 reversed the inhibition of tumor growth in vivo and macrophage M2 polarization caused by DKN-01. This study reveals that DKN-01 suppresses GC tumor growth through activating cGAS-STING pathway to block macrophage M2 polarization.