Gegen Qinlian Decoction Attenuates Colitis-Associated Colorectal Cancer via Suppressing TLR4 Signaling Pathway Based on Network Pharmacology and In Vivo/In Vitro Experimental Validation

Abstract

Background: Gegen Qinlian Decoction (GQD), is used for intestinal disorders like ulcerative colitis, irritable bowel syndrome, and colorectal cancer. But the precise mechanisms underlying its anti-inflammatory and anti-tumor effects are not fully elucidated. Methods: Use network pharmacology to identify targets and pathways of GQD. In vivo (azoxymethane/dextran sodium sulfate (AOM/DSS)-induced colitis-associated colorectal cancer (CAC) mouse model) and in vitro (lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages) experiments were conducted to explore GQD's anti-inflammatory and anti-tumor effects. We monitored mouse body weight and disease activity index (DAI), and evaluated colon cancer tissues using hematoxylin and eosin staining. Expression of Ki67 and F4/80 was determined by immunohistochemistry analysis. The protein levels of TLR4 signaling pathway were assessed by western blotting analysis. Enzyme-linked immunosorbent assay measured IL-1β, IL-6, and TNF-α levels. Immunofluorescence (IF) staining visualized NF-κB and IRF3 translocation. Results: There were 18, 9, 24 and 77 active ingredients in the four herbs of GQD, respectively, targeting 435, 156, 485 and 691 genes. Through data platform analysis, it was concluded that there were 1104 target genes of GQD and 2022 target genes of CAC. Moreover, there were 99 intersecting genes between GQD and CAC. The core targets of GQD contained NFKB1, IL1B, IL6, TLR4, and TNF, and GQD reduced inflammation by inhibiting the TLR4 signaling pathway. In vivo experiment, GQD increased mouse body weight, lowered DAI scores, while also alleviating histopathological changes in the colon and decreasing the expressions of Ki67 and F4/80 in the AOM/DSS-induced mice. GQD reduced IL-1β, IL-6, and TNF-α levels in the serum and downregulated TLR4, MyD88, and phosphorylation of IκBα, P65, and IRF3 in the colon tissue from AOM/DSS-induced mice. In vitro, GQD suppressed pro-inflammatory cytokines and TLR4 signaling pathway in the LPS-induced RAW264.7 cells, and combined with TAK242, it further reduced the phosphorylation of IκBα, P65. Conclusions: GQD mitigated CAC by inhibiting the TLR4 signaling pathway, offering a potential therapeutic approach for CAC management.