Uncontrolled　cell　proliferation　and　metastasis　are　the　two　well-known　manifestations　of　melanoma.　We　hypothesized　that　metapristone,　a　potential　cancer　metastatic　chemopreventive　agent　derived　from　mifepristone　(RU486),　had　a　dual　function　to　fight　cancer.　In　the　present　study,　our　findings　clearly　demonstrated　that　metapristone　had　modest　cytostatic　effect　in　melanoma　cells.　Metapristone　inhibited　cell　viability　and　induced　both　early　and　late　apoptosis　in　B16F10　and　A375　cells　in　a　time-　and　concentrate-dependent　manner.　Metapristone-treatment　caused　the　cell　arrest　at　the　G0/G1　stage,　and　the　inhibition　of　colony　formation　in　B16F10　cells.　Western　blot　analysis　further　revealed　that　metapristone　treatment　elicited　a　decline　of　Akt　and　ERK　phosphorylation　and　Bcl-2,　and　facilitated　expression　of　total　P53　and　Bax　in　A375　cells.　In　addition,　cell　migration　and　invasion　were　significantly　suppressed　by　metapristone　through　down-regulating　the　expression　of　MMP-2,　MMP-9,　N-cadherin　and　vimentin,　whereas　up-regulating　E-cadherin　expression.　Notably,　metapristone　exhibited　anti-metastatic　activity　in　melanoma　B16F10　cells　in　vivo.　Our　results　reveal　metapristone,　having　the　dual　function　of　anti-proliferation　and　anti-migration　for　melanoma　cell　lines,　may　be　a　useful　chemopreventive　agent　to　reduce　the　risk　of　melanoma　cancer　metastasis.　©　2017