Mechanism of Qingjie Fuzheng Granules in inhibiting colitis associated colorectal cancer by regulating TLR4 and IL-4R mediated macrophage polarization.

Background: Qingjie Fuzheng Granules (QFG), a herbal formula, has been employed as an adjuvant therapy for colitis-associated colorectal cancer (CAC), yet the underlying mechanisms by which QFG operates remain unclear.

Objective: The aim of this study is to investigate whether the potential mechanism of QFG against CAC is associated with macrophage polarization.

Methods: Non-targeted metabolomics and molecular docking assessed potential compounds of QFG to interact with targets associated with macrophage polarization. A model of AOM/DSS-induced CAC mice was established to analyze the effects of QFG on macrophage polarization using flow cytometry and immunohistochemical staining. In vitro experiments involved models of Ana-1 macrophages, either induced by varying QFG concentrations or with MD2 knockdown, to analyze M1-like phenotype. Meanwhile, M2-like macrophages models induced by IL-4 or culture supernatant of CT26 cells were utilized to assess the effects of QFG on M2-like macrophages. Finally, the mRNA expression of M1-like phenotype related to TLR4 pathways and the protein expression in IL-4R-mediated pathways were analyzed using RT-qPCR and Western blot, respectively.

Results: Molecular docking confirmed the presence of binding sites between the ingredients of QFG and IL-4R or TLR4/MD2 receptor complex. QFG could induce a shift in macrophages towards an M1-like phenotype while inhibiting an M2-like phenotype in the colon with CAC mice and Ana-1 macrophages. QFG resulted in the upregulation of iNOS, IL-6, IL-1β, and TNF-α mRNA expression, which could be counteracted by TAK242, SR11302, INH14, PDTC, and LY294002, or by the knockdown of MD2. Meanwhile, QFG inhibited IL-4R-induced phosphorylation of STAT 6 and Akt.

Conclusions: Various monomer components within QFG can bind to MD2 or IL-4R, respectively, thereby inducing macrophages towards an M1-like phenotype through TLR4-mediated NF-κB, MAPK, and PI3K/Akt pathway activation, or inhibiting macrophages towards an M2-like phenotype via IL-4R-mediated JAKs pathway inhibition, ultimately exerting an inhibitory effect on the occurrence and development of CAC.