Department of Gastroenterology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, P. R. China.
Institute of Gastroenterology, Zhejiang University, Hangzhou, Zhejiang, P. R. China.
Cancer Commun (Lond). 2023 Sep;43(9):1027-1047. doi: 10.1002/cac2.12469. Epub 2023 Aug 2.
The interplay between gut microbiota and tumor microenvironment (TME) in the pathogenesis of colorectal cancer (CRC) is not well explored. Here, we elucidated the functional role of Bifidobacterium adolescentis (B.a) on CRC and investigated its possible mechanism on the manipulation of cancer-associated fibroblasts (CAFs) in CRC.
Different CRC animal models and various cell line models were established to explore the function of B.a on CRC. The single-cell RNA sequencing (scRNA-seq) or flow cytometry was used to detect the cell subsets in the TME of CRC. Western blot, quantitative real-time polymerase chain reaction (qRT-PCR), or immunofluorescence staining were performed to examine the activation of Wnt signaling and growth arrest specific 1 (GAS1) on CD143 CAFs. Chromatin immunoprecipitation quantitative real-time PCR (CHIP-qPCR) was performed to investigate the regulation of transcription factor 4 (TCF4) on GAS1. Multi-immunofluorescence assay examined the expression level of CD143 and GAS1 on tissue microarray.
We found that B.a abundance was significantly reduced in CRC patients from two independent cohorts and the bacteria database of GMrepo. Supplementation with B.a suppressed Apc spontaneous or AOM/DSS-induced tumorigenesis in mice. scRNA-seq revealed that B.a facilitated a subset of CD143 CAFs by inhibiting the infiltration of Th2 cells, while promoting the TNF-alpha B cells in TME. CD143 CAFs highly expressed GAS1 and exhibited tumor suppressive effect. Mechanistically, GAS1 was activated by the Wnt/β-catenin signaling in CD143 CAFs. B.a abundance was correlated with the expression level of CD143 and GAS1. The level of CD143 CAFs predicted the better survival outcome in CRC patients.
These results highlighted that B.a induced a new subset of CD143 CAFs by Wnt signaling-regulated GAS1 to suppress tumorigenesis and provided a novel therapeutic target for probiotic-based modulation of TME in CRC.
肠道微生物群与肿瘤微环境（TME）在结直肠癌（CRC）发病机制中的相互作用尚未得到充分探索。在这里，我们阐明了双歧杆菌（B.a）对 CRC 的功能作用，并研究了其通过操纵 CRC 中的癌相关成纤维细胞（CAFs）的可能机制。
建立了不同的 CRC 动物模型和各种细胞系模型，以探索 B.a 对 CRC 的作用。单细胞 RNA 测序（scRNA-seq）或流式细胞术用于检测 CRC 中 TME 的细胞亚群。Western blot、定量实时聚合酶链反应（qRT-PCR）或免疫荧光染色用于检测 CD143 CAFs 中 Wnt 信号和生长停滞特异性 1（GAS1）的激活。染色质免疫沉淀定量实时 PCR（CHIP-qPCR）用于研究转录因子 4（TCF4）对 GAS1 的调控。多免疫荧光检测组织微阵列上 CD143 和 GAS1 的表达水平。
我们发现，在两个独立的队列和 GMrepo 的细菌数据库中，CRC 患者的 B.a 丰度显著降低。补充 B.a 可抑制 APC 自发性或 AOM/DSS 诱导的小鼠肿瘤发生。scRNA-seq 显示，B.a 通过抑制 Th2 细胞的浸润，促进 TME 中的 TNF-α B 细胞，促进了一组 CD143 CAFs。CD143 CAFs 高表达 GAS1，并表现出肿瘤抑制作用。机制上，GAS1 在 CD143 CAFs 中被 Wnt/β-catenin 信号激活。B.a 丰度与 CD143 和 GAS1 的表达水平相关。CD143 CAFs 的水平预测 CRC 患者的更好的生存结果。
这些结果强调了 B.a 通过 Wnt 信号调节的 GAS1 诱导新的 CD143 CAFs 来抑制肿瘤发生，并为基于益生菌的 CRC 中 TME 调节提供了新的治疗靶点。
