The Mechanism Of PRSS1 On The Proliferation Of Gastric Cancer MGC803 Cells

[Objective] Gastric cancer is one of the most common malignancies in China,and its incidence and deaths rank first in the digestive system.In the earlier period of research,the gastric cancer related protein serine protease 1(PRSS1)was screened by quantitative proteomics technology,and it was confirmed that PRSS1 was highly expressed in gastric cancer tissue.This study was to observe the effect of low expression of PRSS1 on the proliferation of gastric cancer MGC803 cells and explore its mechanism.[Methods] 1.Immunohistochemistry and immunocytochemistry were used to detect the expression of PAR-2 protein in gastric cancer tissue microarray and MGC803 cells;2.Fluorescent interference plasmid of pc DNA6.2TM-GW/Em GFP-mi R-PRSS1 was transfect into MGC803 cells to establish MGC803 cells with low expression of PRSS1.The effect of low expression of PRSS1 on the proliferation of gastric cancer cells was observed by MTT colorimetric assay and colony formation assay;3.FSLLRY-NH2(PAR-2 inhibitor)and SLIGKV-NH2(PAR-2 agonist)were used to incubate untreated MGC803 cells and MGC803 cells with low expression of PRSS1,and the effects of PAR-2 activity on the proliferation of MGC803 cells were observed;4.After the change of PRSS1 and PAR-2 expression in MGC803 cells,the phosphorylation of ERK1/2 was detected by Western blot and the role of ERK signaling pathway in the proliferation of MGC803 cells was analyzed.[Results] 1.PAR-2 protein was mainly expressed in gastric cancer cell membrane and cytoplasm.The positive expression rate of PAR-2 protein in normal gastric mucosa tissue,well-differentiated,moderately-differentiated,poorly-differentiated gastric adenocarcinoma tissues and lymph node metastatic carcinoma tissues was 22.03%,75.00%,89.66%,94.23% and 94.34%.The expression of PAR-2 in well-differentiated,moderately-differentiated,poorly-differentiated gastric adenocarcinoma tissues and lymph node metastatic carcinoma tissues was higher than that in normal gastric mucosa tissues(P=0.0418).The expression of PAR-2 in gastric cancer was related to TNM stage(P=0.0001)and lymph node metastasis(P=0.0122).The expression of PAR-2 in MGC803 cells was higher than that in immortalized gastric epithelial GES-1 cells.2.MTT assay showed that the proliferation of MGC803 cells was inhibited after knockdown of PRSS1 and incubation with FSLLRY-NH2(PAR-2 inhibitor)(P<0.05).While after incubation with SLIGKV-NH2(PAR-2 agonist),the inhibition of low expression of PRSS1 on the proliferation of MGC803 cells was restored(P<0.05).3.Clone formation assay revealed that the low expression of PRSS1 and the use of FSLLRY-NH2(PAR-2 inhibitor)inhibited the colony formation ability of MGC803 cells(P<0.001).After incubation with SLIGKV-NH2(PAR-2 agonist),the cloning ability of MGC803 cells with low expression of PRSS1 was restored(P<0.001).4.With the effective knockdown of PRSS1 and the application of FSLLRY-NH2(PAR-2 inhibitor),the level of ERK1/2 phosphorylation in MGC803 cells was decreased(P<0.01),and ERK signaling pathway was inhibited.SLIGKV-NH2(PAR-2 agonist)restored the expression of phosphorylated ERK1/2 in MGC803 cells with low expression of PRSS1(P<0.05).[Conclusions] 1.The high expression of PAR-2 in gastric adenocarcinoma tissues was associated with TNM staging and lymph node metastasis in gastric cancer.2.Low expression of PRSS1 inhibited the activation of ERK signaling pathway by restraining the activation of PAR-2,and inhibited the proliferation of gastric cancer MGC803 cells.