The Role And Mechanism Of PCSK6 In Proliferation,Invasion And Metastasis Of Gastric Cancer Cells

Objective:To investigate the expression of PCSK6 in human GC tissues and cell and explore its relationship with clinical and pathological features and study the potential role of PCSK6 protein in human GC proliferation,invasion and metastasis and its potential molecular mechanisms.Methods:The mRNA and protein levels of PCSK6 in 103 specimens of GC tissues and cell lines were tested by qRT-PCR and IHC staining.The association between PCSK6 expression and clinicopathological variables was assessed subsequently.CCK8,the plate colony formation assay,trans-well assay,The wound-healing assay were used to study the function of PCSK6 in the tumor proliferation,migration and invasion.To further verified the effect of PCSK6 in tumor proliferation and metastasis on GC cell through transplanted tumor model and pulmonary metastasis model of human GC in the nude mice.Detected the expression of tumor metastasis-related proteins TGF-? 1 and E-cadherin in 103 cases of gastric cancer tissues by IHC,and analyzed the correlation of PCSK6 expression with TGF-? 1 and E-cadherin expression.Western blot and ELISA kit were used to explore the mechanism of the PCSK6 participating in the malignant biological process of GC.Results:1.The PCSK6 expression was significantly higer in GC tissues compared to corresponding ANT and significantly associated with tumor size,lymph node metastasis and TNM stage.PCSK6 mRNA and protein were higer expression in 8 GC cell lines than GES-1.2.PCSK6 silencing retarded GC cell proliferation and growth and inhibited GC cell migration and invasion.PCSK6 over-expression promoted GC cell proliferation,growth,migration and invasion3?Transplanted tumor model and pulmonary metastasis model of human GC in the nude was constructed successfully.The weight and voume of transplanted tumor of nude mice between treated group and control group were significant difference.The results of pulmonary metastasis model of human GC in the nude between treated group and control group were also significant difference.The Kaplan-Meier survival curves showed that mice injected with PCSK6 over-expression cells had lower survival rates than those injected with PCSK6-vector cells.4?The results of IHC assay showed that PCSK6 expression in 103 cases of GC tissues had positive significant correlation with TGF-? 1(r=0.217,P<0.05),but negative significant correlation with E-cadherin(r=-0.307,P<0.05).TGF-? 1 expression in GC tissues had also negative significant correlation with E-cadherin(r=-0.324,P<0.01).5?The results of western blot and ELISA kit were shown that PCSK6 silencing decreased the expression level of TGF-? 1 while PCSK6 over-expression increased the expression level of TGF-? 1.PCSK6 silencing inhibited the expression of p-AKT,N-cadherin,Vimentin,MMP2,MMP9,and promoted the expression of P21 and E-cadherin.Conversely,PCSK6 over-expression promoted the expression of p-AKT,N-cadherin,Vimentin,MMP2,MMP9,and inhibited the expression of P21 and E-cadherin.Conclusion:1?PCSK6 is up-regulated in GC tissues and GC cells and significantly associated with tumor size,lymph node metastasis and TNM stage.2?PCSK6 promotes GC cell proliferation,migration and invasion.In addition,PCSK6 may promote proliferation partly via activation of the PI3K/AKT/P21 signaling pathways.Up-regulation of PCSK6 expression induces EMT via TGF-?signaling.The possible molecular mechanism of GC cell metastasis maybe that PCSK6 affects the TGF-? signaling and regulates the expression of its downstream target genes(e.g.MMP2,MMP9,E-cadherin,N-cadherin,Vimentin).