miR-589-5p inhibits MAP3K8 and suppresses CD90+ cancer stem cells in hepatocellular carcinoma

Background: cancer stem cells (cscs) are important in the tumorigenesis and progression of hepatocellular carcinoma (hcc). micrornas (mirnas) play crucial roles regulating cd133+ and epcam+ cscs in hcc,although it is unclear whether mirnas regulate cd90+ cscs in hcc. methods: the mirna profiles of cd90+ and cd90- hcc cells were analyzed using a mirna microarray and quantitative real-time pcr (qrt-pcr). csc characteristics were examined by qrt-pcr and western blot of pluripotency-associated genes,clone and sphere formation assay,transwell migration assay,and nude mice tumorigenicity assay. mir-589-5p mimic transfection was used to overexpress mir-589-5p in vitro. the cd90 and mir-589-5p expressions of hcc samples were detected by immunohistochemistry and qrt-pcr,respectively. results: mir-589-5p and mir-33b-5p were down-regulated in cd90+ cells. overexpression of mir-589-5p suppressed cd90+ csc characteristics such as oct4,sox2 and nanog expression,a high likelihood of forming cell spheres,high invasiveness and high tumorigenicity. luciferase reporter assays demonstrated that mir-589-5p directly binds to the 3ˈ-untranslated region of mitogen-activated protein kinase kinase kinase 8 (map3k8) mrna,and exogenous mir-589-5p down-regulated map3k8 expression. in addition,sirna inhibition of map3k8 also suppressed cd90+ csc characteristics,even in the absence of mir-589-5p overexpression. in hcc tissues,mir-589-5p expression was inversely correlated with cd90 expression,and high cd90 expression and low mir-589-5p expression were positively correlated with vascular invasion and recurrence and significantly decreased disease-free and overall survival by clinical analysis. conclusion: in hcc,mir-589-5p down-regulates the stemness characteristics of cd90+ cscs in part by silencing map3k8. cd90 and mir-589-5p expression predict hcc outcomes and might be novel molecular targets for hcc treatment. © 2016 the author(s).