Desmosomal proteins of DSC2 and PKP1 promote cancer cells survival and metastasis by increasing cluster formation in circulatory system.

To study how cancer cells can withstand fluid shear stress (SS), we isolated SS-resistant breast and lung cancer cells using a microfluidic circulatory system. These SS-resistant cells showed higher abilities to form clusters, survive in circulation, and metastasize in mice. These SS-resistant cells expressed 4.2- to 5.3-fold more desmocollin-2 (DSC2) and plakophilin-1 (PKP1) proteins. The high expression of DSC2 and PKP1 facilitated cancer cells to form clusters in circulation, and also activated PI3K/AKT/Bcl-2–mediated pathway to increase cell survival. The high levels of DSC2 and PKP1 are also important for maintaining high expression of vimentin, which stimulates fibronectin/integrin β1/FAK/Src/MEK/ERK/ZEB1–mediated metastasis. Moreover, higher levels of DSC2 and PKP1 were detected in tumor samples from patients with breast and lung cancer, and their high expression was correlated with lower overall survival and worse disease progression. DSC2 and PKP1 may serve as new biomarkers for detecting and targeting metastatic circulating tumor cells.