miR-187-3p,　a　novel　cancer-related　microRNA,　was　previously　reported　to　play　promoting　or　suppressive　roles　in　different　malignancies.　However,　the　expression　level,　biological　function,　and　underlying　mechanisms　of　miR-187-3p　in　hepatocellular　carcinoma　(HCC)　remain　unknown.　This　study　demonstrated　that　miR-187-3p　was　significantly　down-regulated　in　HCC　tissues　and　cell　lines,　and　was　associated　with　advanced　TNM　stage　and　metastasis　in　HCC.　Functional　studies　confirmed　that　miR-187-3p　could　inhibit　the　metastasis　of　HCC　both　in　vitro　and　in　vivo.　Moreover,　we　proved　that　miR-187-3p　could　prevent　the　epithelial-mesenchymal　transition　(EMT)　of　HCC　cells.　Mechanically,　S100A4　was　a　direct　downstream　target　of　miR-187-3p,　and　mediated　the　functional　influence　of　miR-187-3p　in　HCC.　Furthermore,　miR-187-3p　and　S100A4　expression　was　evidently　correlated　with　adverse　clinical　features　and　poor　prognosis　of　HCC.　Lastly,　we　showed　that　hypoxia　was　responsible　for　the　significantly　decreased　level　of　miR-187-3p　in　HCC,　and　miR-187-3p　was　involved　in　the　promoting　effects　of　hypoxia　on　the　metastasis　and　EMT　of　HCC　cells.　Taken　together,　miR-187-3p　inhibits　the　metastasis　and　EMT　in　HCC　by　targeting　S100A4.　miR-187-3p　can　serve　as　a　prognostic　indicator　and　a　promising　therapeutic　target　for　HCC　patients.　(C)　2016　Elsevier　Ireland　Ltd.　All　rights　reserved.