Cancer Cells Resist Mechanical Destruction in Circulation via RhoA/Actomyosin-Dependent Mechano-Adaptation

Abstract

Summary: During metastasis, cancer cells are exposed to potentially destructive hemodynamic forces including fluid shear stress (FSS) while en route to distant sites. However, prior work indicates that cancer cells are more resistant to brief pulses of high-level FSS in vitro relative to non-transformed epithelial cells. Herein, we identify a mechano-adaptive mechanism of FSS resistance in cancer cells. Our findings demonstrate that cancer cells activate RhoA in response to FSS, which protects them from FSS-induced plasma membrane damage. We show that cancer cells freshly isolated from mouse and human tumors are resistant to FSS, that formin and myosin II activity protects circulating tumor cells (CTCs) from destruction, and that short-term inhibition of myosin II delays metastasis in mouse models. Collectively, our data indicate that viable CTCs actively resist destruction by hemodynamic forces and are likely to be more mechanically robust than is commonly thought. : Moose et al. show that cancer cells exhibit a mechano-adaptive response to fluid shear stress through activation of the RhoA-actomyosin signaling axis. Utilizing in vivo models, they extend these findings to demonstrate that this axis maintains intravascular survival of circulating tumor cells (CTCs) that contributes to the development of metastasis. Keywords: fluid shear stress, circulating tumor cells, metastasis, RhoA, myosin II, formin