Circ_TNFRSF21 promotes cSCC metastasis and M2 macrophage polarization via miR-214-3p/CHI3L1.

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is a highly invasive disease with the potential to metastasize and cause fatality. Therefore, it is crucial to understand the mechanism behind cSCC in order to devise effective strategies to combat this disease. OBJECTIVE: We investigated the function of circ_TNFRSF21/miR-214-3p/CHI3L1 axis in cSCC. METHODS: The features of circ_TNFRSF21 was characterized using Sanger sequencing, and RNase R/actinomycin D treatment. Genes and M1/M2 markers levels were assessed by qRT-PCR and IHC. The proliferation, migration, and invasion of cells were evaluated by CCK-8, colony formation, EdU incorporation, and transwell assays. Tumor growth and metastasis in vivo were evaluated by nude mouse xenograft model. Interactions of circ_TNFRSF21/miR-214-3p and miR-214-3p/CHI3L1 were validated by RNA immunoprecipitation and dual luciferase assay. RESULTS: Circ_TNFRSF21 and CHI3L1 expression were elevated in both human cSCC tissues and cells, whereas miR-214-3p was reduced. Circ_TNFRSF21 silencing or miR-214-3p overexpression suppressed cSCC cell proliferation, migration, invasion, and M2 macrophage polarization. Circ_TNFRSF21 functioned as a sponge for miR-214-3p while miR-214-3p directly targeted CHI3L1. Knockdown of miR-214-3p reversed the effects of circ_TNFRSF21 knockdown on cSCC development, while CHI3L1 upregulation reversed the effects of miR-214-3p overexpression. Furthermore, knockdown of circ_TNFRSF21 inhibited cSCC tumor growth and metastasis in vivo. CONCLUSION: Circ_TNFRSF21 plays a significant role in cSCC progression by enhancing cell proliferation, migration, invasion, and M2 macrophage polarization through inhibiting miR-214-3p and subsequent disinhibition of CHI3L1. These findings deepen our understanding of the molecular mechanism of cSCC and propose the circ_TNFRSF21/miR-214-3p/CHI3L1 axis as promising diagnosis markers or therapeutic targets for cSCC.

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.