M2 macrophage facilitated angiogenesis in cutaneous squamous cell carcinoma via circ_TNFRSF21/miR-3619-5p/ROCK axis.

In recent years, the role of circular RNA in cancer cells has been studied broadly; however, the functional significance of circular RNA in the regulation of the tumor microenvironment (TME) is not fully understood. In this study, we aimed to reveal the role of circ_TNFRSF21 in M2 macrophage-induced cutaneous squamous cell carcinoma (cSCC) angiogenesis. Quantitative polymerase chain reaction and Western blotting were performed to determine the levels of the indicated genes. Direct binding between circ_TNFRSF21 and miR-3619-5p, miR-3619-5p, and ROCK2 was verified by dual-luciferase activity. The migration and invasion of human umbilical vein endothelial cells were evaluated by wound healing and transwell assays. Tube formation was performed to detect in vitro angiogenesis. Circ_TNFRSF21 and ROCK2 were upregulated in cSCC tissue, while miR-3619-5p was downregulated. Circ_TNFRSF21 negatively regulated the expression of miR-3619-5p, while miR-3619-5p negatively regulated the expression of ROCK2. miR-3619-5p suppressed tube formation by inhibiting ROCK signaling. M2 macrophages facilitated tube formation via the circ_TNFRSF21/miR-3619-5p/ROCK2 axis. Our present study revealed that circ_TNFRSF21 was elevated in M2 macrophages and mediated M2 macrophage-induced tube formation in vitro.