GSE158933
Colonization of distant organs by mechanosensitive tumor cells via generation of stable circulating homotypic clusters
Mechanisms governing cancer metastasis remain poorly understood. Once disseminated tumor cells (DTCs) arrive at a metastatic organ, they remain there, latent, and become seeds of metastasis. However, the clonal composition of DTCs in a latent state remains unclear. Here, we applied high-resolution DNA barcode tracking to a mouse model that recapitulated the metastatic dormancy of head and neck squamous cell carcinoma (HNSCC). We found that clones that had abundant circulating tumor cells (CTCs) but were rare in the primary site dominated DTCs. We obtained a specific subclone that dominated CTCs and subsequent DTCs in lungs and bone marrow. Despite no notable features under static conditions, this clone significantly generated stable cell aggregates that were resistant to anoikis in suspension culture under fluid shear stress conditions. Even as a heterogeneous population, this clone generated almost monoclonal CTC clusters. Via transcriptome analyses, we identified E-cadherin to be indispensable but not sufficient for such stable cell-cell adhesion. Instead, our data indicated that mutual regulation of cortical actin-myosin dynamics according to mechanostress in the cells within each aggregate governed stable adhesion. Furthermore, the gene expression signature of the mechanosensitive clone, which originated clustered CTCs, was associated with locoregional and metastatic recurrence in patients with HNSCC. These results reveal that intrinsically mechanosensitive rare clones in the parental population dominantly colonize distant sites via homotypic CTC cluster formation. This novel clonal selection mechanism based on intrinsic tumor cell mechanosensitivity may lead to promising cancer therapies. Overall design: Analyze global gene expression in 3 different clones by comparing its gene expression.