miR-18a-5p promotes NPC cell proliferation, invasion, migration, and EMT by targeting SMAD2
Abstract Background Nasopharyngeal carcinoma (NPC) is the most common malignant tumor in the head and neck that is characterized by high local malignant invasion and distant metastasis. miR-18a-5p reportedly plays an important role in tumorigenesis and development. However, little is known about the mechanism underlying miR-18a-5p’s role in NPC. Methods Quantitative real-time PCR was used to detect the expression of miR-18a-5p in NPC tissues and cell lines. MTT assay and plate clone formation assay were used to detect the effect of miR-18a-5p on NPC cell proliferation. Wound healing assays and Transwell assays were used to detect the effect of miR-18a-5p on NPC cell invasion and migration. The expressions of epithelial mesenchymal transition (EMT)-related proteins N-cadherin, Vimentin, and E-cadherin were detected by Western blot. Bioinformatics and dual-luciferase reporter assay were used to detect the targeting interaction between miR-18a-5p and SMAD2. Xenotransplantation and metastasis model were used to detect the effect of miR-18a-5p on NPC growth and metastasis in vivo. Results miR-18a-5p was highly expressed in NPC tissues and cell lines. Overexpression of miR-18a-5p promoted NPC cell proliferation, invasion, migration, and EMT process, whereas inhibition of miR-18a-5p expression led to the opposite results. Results of dual-luciferase reporter assay showed that SMAD2 was the target gene of miR-18a-5p, and SMAD2 could reverse the effect of miR-18a-5p on NPC cell line. Xenotransplantation and metastasis model experiments in nude mice showed that miR-18a-5p promotes NPC growth and metastasis in vivo. Conclusions Targeting SMAD2 downregulated miR-18a-5p expression, thereby promoting NPC cell proliferation, invasion, migration, and EMT.