Silence of lncRNA UCA1 Represses the Growth and Tube Formation of Human Microvascular Endothelial Cells Through miR-195.

Recent studies have suggested that several lncRNAs contribute to the angiogenic function of endothelial cells. Herein, we set out to reveal whether lncRNA UCA1 has functions in endothelial angiogenesis. The expression levels of lncRNA UCA1, miR-195 and CCND1 in human microvascular endothelial HMEC-1 cells were altered by transfection. Subsequently, cell viability, migration, tube formation and apoptosis of HMEC-1 cells were respectively assessed. The cross-talk between lncRNA UCA1, miR-195, CCND1, and MEK/ERK and mTOR signaling pathways were investigated by performing qRT-PCR and Western blotting. Silence of lncRNA UCA1 repressed HMEC-1 cells viability, migration, tube formation, and induced apoptosis. Meanwhile, silence of lncRNA UCA1 significantly up-regulated miR-195 expression. These alterations induced by lncRNA UCA1 were further enhanced by miR-195 overexpression, while were attenuated by miR-195 suppression. Moreover, silence of lncRNA UCA1 deactivated MEK/ERK and mTOR signaling pathways via a miR-195-dependent regulation. And the deactivation of MEK/ERK and mTOR signaling pathways led to a down-regulation of CCND1. This study demonstrates that silence of lncRNA UCA1 largely represses microvascular endothelial cells growth and tube formation. Silence of lncRNA UCA1 exerts its function possibly via up-regulation of miR-195, which in turn inactivates MEK/ERK and mTOR signaling pathways, and ultimately represses CCND1 expression.