Matrix metalloproteinase-9 expression in gastric cancer and construction of the gastric cancer cell line with silenced matrix metalloproteinase-9 gene

Objective To investigate the roles of matrix metalloproteinase-9 (MMP-9) in gastric cancer development,to construct MMP-9 short hairpin RNA (shRNA) expression plasmids and to establish the gastric cancer cell line with silenced MMP-9 gene expression.Methods The expression level of MMP9 in 46 fresh specimens was detected by using immunohistochemistry.Three oligonucleotides which silenced MMP-9 gene expression were synthesized chemically and inserted into shRNA expression vector pGenesil to construct MMP-9 shRNA plasmids.Immunofluorescence,gelatin zymography and reverse transcription-polymerase chain reaction (RT-PCR) were applied to detect the MMP-9 silencing efficiency.The MMP-9 knockdown plasmid that had a high efficiency in silencing MMP-9 gene expression was chosen and transfected into BGC823 to establish the cell line with silenced MMP-9 gene expression.Results MMP-9 protein was expressed in 46 cases of gastric cancers,and strong expression was found in 57％ (26/46) of the gastric cancers.A shRNA expression plasmid with markedly silenced MMP-9 gene was screened out.BGC823 cell line with silenced MMP-9 gene was successfully constructed.Conclusion MMP-9 may play an important role in gastric cancer development,migration and invasion. Key words: Matrix metalloproteinase-9 ;  RNA interference ;  Stomach neoplasm