Abstract: Objective:To explore the functions of HDAC4 gene on the biological behaviorsof HOS and U2OS osteosarcoma cells lines whichinhibit HDAC4 gene expression using a small interfering RNA.Methods: The HOS and U2OS cells were transfected with a chemical synthesized small interfering RNA targeting HDAC4; The real time-PCR and Western blot assays were performed to detect the mRNA and protein expression levels of HDAC4 and its downstream genes HIF-1α, respectively; The CCK-8, flow cytometry (FCM), invasion assays were used to identifythe cell proliferation, apoptosis and invasion abilities after the transfection with si-HDAC4, respectively.Results:The q-PCR analysis showed that HDAC4 mRNA expression was down-regulated in HOS and U2OS cellsafter transfected with si-HDAC4 (P<0.01); in addition, the cell proliferation was inhibited and cell apoptosis was induced after suppression of HDAC4. (P<0.05); The cells of HOS and U2OS migrating through themembrane insi-con group and si-HDAC4 group were (146±34), (45±20)and (207±35)、(121±23), (P<0.05), respectively.Western blot showed that the expression of HDAC4 and HIF-1α was significantly reduced. Conclusion:HDAC4si-RNA can inhibit cell proliferation, invasion and induce cell apoptosis in human HOS and U2OSosteosarcoma cells.

Key words: Osteosarcoma, RNA interference, HDAC4