Effect of human osteopontin on proliferation, transmigration and expression of MMP-2 and MMP-9 in osteosarcoma cells. To explore the effect of human osteopontin (hOPN) on the proliferation, transmigration and expression of matrix metallproteinase-2 (MMP-2) and matrix metallproteinase-9 (MMP-9) in osteosarcoma (OS) cells in vitro.The prokaryotic-expression vector of hOPN was produced. hOPN was then subcloned into E. coli BL21 (DE3) cells and purified with ProBond trade mark Columns. The proliferation, cell cycle and the expression of cyclin A in OS cells were investigated by using MTT assay, flow cytometry and Western blot respectively. The transmigration of OS cells was checked by using transwell cell culture chamber. The micro-pore-filter-membrane system was used to study the chemiotaxis of hOPN to OS cells. The levels of total protein were examined according to Coomassie Brilliant Blue manuals. The expression of MMP-2 and MMP-9 were evaluated by detecting the volume of degradation of gelatin on SDS-PAGE gel.The prokaryotic-expression vector of hOPN and purified hOPN protein were achieved hOPN promoted OS cells proliferation in a dose-dependent manner, and stimulated cyclin A expression in OS cells to accelerate cell division cycle. hOPN facilitated the trans-membrane migration of OS cells. hOPN also enhanced the secretion of MMP-2 and MMP-9 in OS cells.hOPN could stimulate cyclin A expression in OS cells. hOPN has chemiotaxis to OS cells and increases their transmigration. hOPN enhances the secretion of MMP-2 and MMP-9 in OS cells.