The Role of Zuo Jin Wan in Modulating the Tumor Microenvironment of Colorectal Cancer

Introduction: Traditional Chinese medicine (TCM) can modulate the immune function of tumor patients in various ways. Zuojin Wan (ZJW, a 6:1 ratio of Huanglian and Wuzhuyu) can modulate the microenvironment of ulcerative colitis, but its role in regulating the CRC microenvironment remains unclear. Exploring the role of ZJW in CRC immunomodulation may improve the antitumor effect of existing immunotherapeutic strategies. Material and Methods: The active compounds of each herb in ZJW were obtained from the HIT2.0 database with literature evidence. Single-cell RNA sequencing data of CRC were obtained from published studies (PMID: 32451460, 32103181, and 32561858). Pathway enrichment was analyzed using the reactome database, and intergenic correlation analysis was performed using the corrplot R software package. ZJW-regulated gene expression was verified by RT-qPCR. Results: Huanglian and Wuzhu contain 19 and 4 compounds, respectively. Huang Lian targets 146 proteins, and Wu Zhu Yu targets 28 proteins based on evidence from the literature. ZJW regulates a range of biological processes associated with immune function, including cytokine signaling and Toll-Like Receptor 4 (TLR4) cascade. ZJW regulates malignant CRC cells, immune cells (including T-cells, B-cells, mast cells, NK/NKT cells, and myeloid cells), and other non-immune cells (including endothelial cells, enteric glial cells, and pericytes). We confirmed that ZJW significantly downregulated the expression of TIMP1 and MTDH. Conclusions: ZJW regulates a range of cells in the CRC microenvironment, including malignant CRC, immune cells, and stromal cells. In CRC cell lines, downregulation of TIMP1 and MTDH by ZJW may play an important role in the immunomodulation in CRC.