CircRNA ZNF609 promotes angiogenesis in nasopharyngeal carcinoma by regulating miR-145/STMN1 axis.

Nasopharyngeal carcinoma (NPC) is the most common type of human malignant tumor in the head and neck, and tumor angiogenesis is essential for its development. Here, we showed that the circRNA ZNF609/microRNA (miR)-145/Stathmin 1 (STMN1) axis regulated angiogenesis in NPC.Circ-ZNF609, miR-145, and STMN1 expression in NPC cells and NPC samples were examined using qRT-PCR. The protein levels of STMN1, VEGFR1, and VEGFR2 were evaluated using western blotting. VEGF level was determined by ELISA. The proliferation of NPC cells and HUVECs was examined using a CCK-8 assay. Transwell assays and wound-healing assays were applied to assess the migration of NPC cells and HUVECs, respectively. Angiogenesis of HUVECs was evaluated by an angiogenesis assay. In addition, a dual-luciferase reporter assay and RNA pull-down assays were employed to verify the binding relationship between circ-ZNF609 and miR-145 as well as between miR-145 and STMN1. Here, we showed that circ-ZNF609 and STMN1 expression was increased, while miR-145 expression was decreased in NPC cells and NPC samples. Circ-ZNF609 may negatively regulate miR-145 expression by acting as a ceRNA. Silencing circ-ZNF609 suppressed cell proliferation, migration, and angiogenesis in NPC, while knockdown of miR-145 reversed these effects. In addition, we found that STMN1 was the downstream target of miR-145. MiR-145 overexpression suppressed cell proliferation, migration, and angiogenesis in NPC, which was abolished by STMN1 overexpression. Our data suggested that circ-ZNF609 promotes cell proliferation, migration, and angiogenesis in NPC by upregulating the expression of STMN1 by sponging miR-145 in NPC.