Tumor-resident intracellular microbiota promotes metastatic colonization in breast cancer

• DOI: 10.1016/j.cell.2022.02.027
• Publication Date: 2022-04-07T14:35:59Z
• Authors: Aikun Fu; Bingqing Yao; Tingting Dong; Yongyi Chen; Jia Yao; Yu Liu; Hang Li; Huiru Bai; Xiaoqin Liu; Yue Zhang; Chunhui Wang; Yajing Guo; Nan Li; Shang Cai
• Keywords: 0301 basic medicine; 0303 health sciences; Lung Neoplasms; Microbiota; Breast Neoplasms; Neoplastic Cells, Circulating; 3. Good health; Mice; 03 medical and health sciences; Cell Line, Tumor; Animals; Humans; Female; Neoplasm Metastasis

Tumor-resident intracellular microbiota is an emerging tumor component that has been documented for a variety of cancer types with unclear biological functions. Here, we explored the functional significance of these intratumor bacteria, primarily using a murine spontaneous breast-tumor model MMTV-PyMT. We found that depletion of intratumor bacteria significantly reduced lung metastasis without affecting primary tumor growth. During metastatic colonization, intratumor bacteria carried by circulating tumor cells promoted host-cell survival by enhancing resistance to fluid shear stress by reorganizing actin cytoskeleton. We further showed that intratumor administration of selected bacteria strains isolated from tumor-resident microbiota promoted metastasis in two murine tumor models with significantly different levels of metastasis potential. Our findings suggest that tumor-resident microbiota, albeit at low biomass, play an important role in promoting cancer metastasis, intervention of which might therefore be worth exploring for advancing oncology care.