Single-Cell RNA Sequencing Reveals Shenbai Granule Retards Colorectal Tumorigenesis by Modulating Cholesterol-Induced Ccl22+ DCs and Tregs Crosstalk

Colorectal tumorigenesis generally follows a progressive sequence from adenoma to adenocarcinoma, accompanied by dynamic changes in the tumor microenvironment (TME). Randomized controlled trials have confirmed that Shenbai Granule (SBG), a traditional Chinese medicine formula, is safe and effective for the prevention of recurrent colorectal adenoma. However, the effects and mechanisms of SBG on colorectal tumorigenesis and the TME remain unclear. To investigate this, single-cell RNA sequencing (scRNA-seq) was conducted to reveal the dynamic evolution of the TME. Primary cells were isolated for in vitro validation experiments. The findings demonstrated that SBG reduces both the number and volume of tumors. There was a marked accumulation of Ccl22+ dendritic cells (DCs) and an enhanced interaction between Ccl22+ DCs and CD4+ regulatory T cells (Tregs), which were reversed by the treatment of SBG and its active compound, berberine. Combined treatment with cholesterol and lipopolysaccharide induced characteristic gene expression in Ccl22+ DCs, which may represent a type of “exhausted DCs”. Intraperitoneal injection of the Ccl22+ DCs after SBG treatment eliminated its therapeutic effects. These findings highlight critical crosstalk between Ccl22+ DCs and CD4+ Tregs in colorectal cancer. The multi-component properties of natural products may restore TME homeostasis and offer novel cancer therapy.