Endothelial cells response to mechanosensors activation is modulated by tumor microenvironment

Tumor microenvironment is a rich source of mechanical triggers acting on endothelial cells. In response, they experience mechanosensing and mechanotransduction. Mechanosensing regulates key angiogenic processes like cell adhesion, morphology, migration, and proliferation. Endothelial cells sense mechanical cues mainly thanks to mechanosensitive ion channels as TRP and Piezo channels (Piezo1, TRPV4 and TRPA1), and transmit them intracellularly through mechanotransduction pathways. By mimicking in vitro TME with the conditioned medium approach, I investigated whether the influence of cancer cells could modulate endothelial cells mechanosensors biological activity. Conditioning negatively affected cell viability but tended to promote both cell adhesion and migration. Piezo1 activation resulted in the reduction of cell adhesion and in the slowdown of migration. TRPA1 mirrored Piezo1 trend but with a more robust effect. TRPV4 activation promoted superficially adhesion and migration of only the conditioned cells. By combining Piezo1 and TRPV4 activation outcomes changed. In all cases conditioning affected significantly endothelial cells response to mechanosensor activation by attenuating or reversing channel effect. Treatment with mechanosensors activators caused actin cytoskeleton remodelling and reorganization and altered focal adhesion dynamics, specifically leading to their clustering. Main candidates for mechanotransduction pathways resulted to be the Yap and FAK paths. In conclusion, conditioning managed to exert influence on endothelial cell response and mechanosensors activity, probably by causing their early opening or by predisposing them to the activation. Piezo1, TRPV4 and TRPA1 resulted to be interesting potential targets for actual studies in tumor angiogenesis, also from a vasculature normalization perspective.