ObjectiveTo explore the effects of different concentrations of oleic acid on human osteosarcoma cell lines 143B and HOS， as well as the impacts of the optimal concentration of oleic acid on cellular lipid droplet synthesis and cell functions. MethodsThe 143B and HOS cells were treated with varying concentrations of oleic acid （0， 25， 50， 100， and 200 µmol/L） for 48 hours. Following treatment， oil red O staining and BODIPY staining were performed to determine the optimal concentration. Subsequently， CCK-8 assays and colony formation experiments were conducted to assess the effect of this optimal concentration of oleic acid on the cell proliferation of both cell lines. Transwell migration assays were utilized to evaluate the influence of the optimal concentration on migratory capacity and Transwell invasion assays were utilized to evaluate the invasive ability. Additionally， Western blot analysis was employed to examine the expression levels of epithelial-mesenchymal transition （EMT） markers Epithelial cadherin （E-cadherin） and Neural cadherin （N-cadherin） in response to treatment with the optimal concentration of oleic acid. ResultsTreatment with oleic acid did not induce significant cell death in either 143B or HOS cells； however， an increase in intracellular lipid droplets was observed alongside enhanced proliferation， migration， invasion capabilities as well as EMT transformation potential （P<0.05）. ConclusionOleic acid induces lipid droplet synthesis in osteosarcoma cells which subsequently promotes their proliferation， migration and invasion abilities along with EMT transformation.

Aims HDAC2 gene was cloned into pEGFP-C2 vector to explore the efficiency of the plasmid trans-fection in renal fibroblasts COS-7 cells to identify the expression of both mRNA and protein levels and to ob-serve the distribution of the protein. Methods The HDAC2 cDNA was amlified by PCR and cut with the double enzyme Xho I and BamH I, then inserted into the eukaryotic expression vector pEGFP-C2 with T4 en-zyme. The recombinant vector was verified by PCR, restriction enzymes cut and sequencing identification. Then it was transfected into COS-7 cells and the ex-pression of pEGFP-C2-HDAC2 was monitored by fluo-
rescence microscope and PCR. Results Fragments of HDAC2 could be seen after dealt with double diges-tion, and GFP could also be detected in the transfected COS-7 cells. HDAC2 gene expression could be detec-ted by PCR and Western blot. The fusion expression of pEGFP-C2-HDAC2 could be detected by Western blot. Conclusion Eukaryotic expression vector of HDAC2 has been successfully constructed, the fusion expres-sion of HDAC2 and GFP protein can be detected in COS-7 cells.