The miR-199a-5p/HIF1alpha dual-regulatory axis participates in hypoxia-induced aggressive phenotypes of oral squamous cell carcinoma (OSCC) cells.

BACKGROUND: The late-stage diagnosis and distant metastasis of oral squamous cell carcinoma (OSCC) remain a huge challenge to clinical treatment for OSCC. During the past decades, targeting glycolysis-inducing factors becomes an attractive new strategy in OSCC therapies. METHODS: OSCC cells were stimulated with hypoxia or transfected with agomir-199a-5p, antagomir-199a-5p, and siRNA for HIF1A, cell proliferation was detected by CCK-8 assay; HIF1alpha, GLUT1, HK2 and LDHA expression levels were examined with western blot; miR-199 expression was determined with RT-PCR; cell migratory and invasive abilities were examined using wound healing and transwell assays; the lactate and glucose in culture medium were also determined. Luciferase assay or CHIP assay was applied for confirm the binding between miR-199a-5p and HIF1A 3'UTR, or between HIF1alpha and miR-199a promoter. RESULTS: HIF1alpha showed to be abnormally up-regulated, and miR-199a-5p showed to be abnormally down-regulated within OSCC under hypoxia. Hypoxia considerably enhanced OSCC cell proliferation, glycolysis, migratory ability, and invasive ability. MiR-199a-5p bound to HIF1A 3'-UTR and suppressed HIF1A expression; HIF1alpha targeted miR-199a-5p promoter region and downregulated miR-199a-5p expression. Under hypoxia, miR-199a-5p overexpression significantly repressed HIF1alpha up-regulation inresponse to hypoxia, OSCC cell proliferation, glycolysis, migratory ability, and invasive ability. CONCLUSION: miR-199a-5p and HIF1alpha form a dual-regulatory axis in OSCC cells; the miR-199a-5p/HIF1alpha dual-regulatory axis contributes to hypoxia-induced aggressive OSCC phenotypes.