Fig 2: MiR-146a-5p targets PRSS1 and inhibits MGC803 cell growth and proliferation. (A) MiR-146a-5p expression was significantly decreased in GC cells. (B) PRSS1 mRNA expression was significantly increased in GC cells. (C) The expression level of miR-146a-5p was negatively correlated with PRSS1 mRNA expression as indicated by qRT-PCR. (D-E) The effects of MGC803 cells transfected with miR-146a-5p mimic or miR-146a-5p inhibitor on growth and colony-forming ability were determined by the MTT and colony forming assays. (F-G) Western blot and ICC analyses showed that miR-146a-5p mimic reduced PCNA protein expression while miR-146a-5p inhibitor increased PCNA expression. Data are shown as the means ± SD. *P<0.05, **P<0.01, ***P<0.001; #P<0.05, ###P<0.001.

Fig 3: Expression and clinical significance of PRSS1 in GC. (A) Western blotting was performed to detect the expression of PRSS1, HSP90a/ß, TGM2, SerpinA3 and P180 in purified NGM, AH, GPDAC and LMGAC tissues. (B) PRSS1 was highly expressed in GC cells. (C) Immunohistochemical staining analysis indicated that PRSS1 was highly expressed in tissues. (D) Patients with high expression of PRSS1 had poor overall survival. GC, gastric cancer; SD, standard deviation. Data are shown as the means ± SD. *P<0.05, **P<0.01, ***P<0.001.

Fig 4: Identification of differentially expressed proteins during human gastric mucosal carcinogenesis by proteomics analysis. (A) LCM of purified NGM, AH, GPDAC and LMGAC tissues. (B) MS/MS maps for identifying peptides of PRSS1 and relative quantitative information of PRSS1 expression in four different tissues. (C) A regulatory network of gastric mucosa carcinogenesis-related proteins. LCM, laser capture microdissection; NGM, normal gastric mucosa; AH, atypical hyperplasia; GPDAC, poorly differentiated gastric adenocarcinoma; LMGAC, lymph node metastasis adenocarcinoma.

Fig 5: PRSS1 affects cell proliferation via the PAR-2-activated ERK signaling pathway. (A) The expression of PAR2 protein was analyzed in GC tissues by immunohistochemistry analysis. (B) PAR-2 was highly expressed in MGC803 GC cells compared to GES-1 cells. (C) The effect of PRSS1 knockdown on PAR-2 protein expression in MGC803 cells. (D-E) The effect of FSLLRY-NH2 (PAR-2 inhibitor) and SLIGKV-NH2 (PAR-2 agonist) on the growth and proliferation of MGC803 GC cells was determined by MTT and colony formation assays. (F) Western blotting was performed to detect the expression levels of phosphorylated ERK1/2, PRSS1 and PAR2 in MGC803/miR-PRSS1 cells, MGC803 cells treated with FSLLRY-NH2 (PAR-2 inhibitor), and MGC803/miR-PRSS1 cells treated with SLIGKV-NH2 (PAR-2 agonist). Data are shown as the means ± SD, *P<0.05, **P<0.01, ***P<0.001; #P<0.05, ##P<0.01; ?P<0.05.