Objective     To investigate the inhibition effect

in vitro

of mucin gene MUC2 antisense oligodeoxynucleotide (ASODN) on its gene expression and proteolytic enzyme on gastric cancer cell line.       Methods     Phosphorothioated MUC2 ASODN were synthesized and transfected to SGC7901 cells mediated by lipofectin. MUC2 mRNA and MUC2 protein expressed on SGC7901 cells was detected by RT-PCR and immun

ohistochemical method. The inhibitory effects of ASODN on proteolytic enzyme

such as cathepsin D

MMP-2 and MMP-9 protein were detected by immunohistochemical staining. The cell cycle and apoptosis were determined by flow cytometry (FCM).        Results     The inhibition effects peaked at 48th hour after transfection

and the inhibition rate reached 55% when the concentration of ASODN was 0.5 μmol/L. The number of the cells treated with MUC2 ASODN was decreased as compared to the control cells. MUC2 ASODN transfection could inhibit the transition period of S phase to G

2

/M phase

and G

2

/M did not change much. The apoptosis rate was about 4.38%. As compared with blank control group

MUC2 ASODN could significantly inhibit MUC2 mRNA expression of SGC7901 cells. ASODN could downregulate the expression levels of MUC2 protein

MMP-2 and cathepsin D protein.      Conclusion     MUC2 ASODN transfection could specifically inhibit SGC7901 cells by downregulating the expression levels of proteolytic enzyme.