Exploring the immunological mechanism of Houttuynia cordata in the treatment of colorectal cancer through combined network pharmacology and experimental validation.

To explore the potential mechanisms of Houttuynia cordata in the treatment of CRC using network pharmacology combined with experimental validation. The major active components of Houttuynia cordata were identified using the TCMSP database, and their related targets were mined. CRC-related target genes were obtained through the Genecards and OMIM databases. The R software Ven Diagram package was used for visualization of the intersection of drug and disease targets. The intersection target genes were subjected to GO function enrichment and KEGG pathway enrichment analysis using the R software clusterProfiler package. A "Drug - active component - target - Disease" network was constructed and analyzed using Cytoscape software. Intersection target genes were uploaded to the STRING database, and the resultant data were imported into Cytoscape software to construct a PPI network and filter core target genes. Expression analysis, diagnostic efficacy, and survival analysis were used to demonstrate the function and clinical value of the core target genes. The correlation between core genes in CRC samples and immune cell infiltration was analyzed using the R software and ssGSVA algorithm. Molecular docking validation of core active components with core target genes was performed using AutodockVina 1.2.2 software. Finally, the effects of quercetin and kaempferol, core active components of Houttuynia cordata, on the growth of HCT116 cells and the regulation of core target genes were validated through CCK8 assay, flow cytometry, and RT-qPCR. Seven effective active components and 147 component-related targets were selected, along with 3806 CRC-related target genes. GO analysis mainly involved biological processes such as epithelial cell proliferation, with KEGG pathway analysis focusing on pathways including AGE-RAGE signaling. Quercetin and kaempferol were identified as two core components, with IL1B, MMP9, CXCL8, and IL6 as four core target genes. Immune infiltration analysis showed that IL1B, MMP9, CXCL8, and IL6 primarily exert anti-CRC effects by promoting neutrophil activity. Molecular docking results indicated stable binding capacities of quercetin and kaempferol with IL1B, MMP9, CXCL8, and IL6. Experimental validation showed that quercetin and kaempferol could inhibit the viability of HCT116 cells in a dose-dependent manner, promote apoptosis, and downregulate the expression of IL1B, MMP9, CXCL8, and IL6 genes. Houttuynia cordata may exert therapeutic effects on CRC by modulating the immune microenvironment and anti-inflammatory responses, providing new research directions and theoretical guidance for the treatment of CRC with Houttuynia cordata.