ABSTRACT
Objective To observe the expression of estrogen receptors (ERαand ERβ) on gastric cancer cells and evaluate the effect of Tamoxifen(TAM) on the cell proliferation and expression of serine proteinase inhibitor 9(PI9) of gastric cancer cells . Methods PI9 positive expression(MNK45 ,SGC7901)and negative expression (BGC823)of gastric cancer cell lines were from pre‐liminary screened ,the expression of ERα and ERβ detected by immunofluorescence chemical method ,the cell proliferation and ex‐pression of PI9 were tested by CCK8 assay and reverse transcription‐PCR after intervention of TAM .Results ERαprotein expres‐sion was noted in MNK45 and SGC7901 ,ERβwas noted in BGC823 ,but the expression of ERαand ERβwere not appear to be obvi‐ous after the intervention of TAM .Tamoxifen could obviously inhibited cell proliferation of MNK45 and SGC7901 at concentration of 0 .1-100 .0 μmol/L ,the differences were statistically significant compared with negative control group (P<0 .05) ,but showed no dose‐dependent to the proliferation of BGC823 and MNK28 .After treating with TAM ,the expression of PI9 mRNA of SGC7901 (0 .402± 0 .020) and MNK45(0 .359 ± 0 .048) were obviously lower than that in the negatwe control group(P< 0 .05). Conclusion Tamoxifen could significantly inhibit the proliferation of PI9 positive expression than PI9 negative expression of gastric cancer cell lines ,and showed obviously dose‐dependent ,its role in inhibiting proliferation might closely related to immune tolerance improved by PI9 .
ABSTRACT
Serine proteinase inhibitor9(P1-9),a charac-teristic member of serpins,has been identified as the only inhibitor of granzyme B(GrB).Accumulated evidence suggested that PI-9 inhibits GrB-induced apoptosis by blocking DNA fragmentation of target cell.Physiologically,PI-9 could protect cytotoxic lymphocytes from committing autolysis or fratricide,and play an important role in facilitating immunologic tolerance of immune-privileged sites.In addition,evidences in recent years suggest that PI-9 Was also involved in vailous pathologic processes,such as inflammation,trans plantation and immune tolerance of tumor.