| Gastric cancer is the most common malignant tumor of alimentary tract and the mortality rate accounts the second in total carcinomas,seriously threatens the health of humans.Early diagnosis and early treatment is very important to improve the prognosis of patients,shorten the course and reduce the mortality rate.The only potentially curative treatment for gastric cancer is complete resection.However,despite aggressive surgical intervention,more than 50% of patients undergoing radical resection will experience disease recurrence,usually in the form of metastatic disease.At present,the occurrence of gastric cancer development and metastasis of mechanism is not clear,to some extent,limits the development of gastric cancer therapy.Therefore,to investigate the mechanism of gastric cancer metastasis and to find effective gene therapy targets become a research hotspot in the field of gastric cancer.ADAMs is a kind of zinc dependent or secreted proteins across the membrane.They play a very important role in biological processes.ADAM17 becomes one of the most pop research fields in the ADAMs.ADAM17 is also termed TACE.It can hydrolysis on the cell membrane of tumor necrosis factor,at the same time make a variety of epidermal growth factor receptor ligands activation,activate the related signal channel and biological functions.Accumulating reports have shown that ADAM17 plays a critical role in human diseases,particular cancer.Objective: To explore the expression level of ADAM17 in gastric cancer and its role in the invasion and metastasis of gastric cancer cells and the underlying mechanism,which might provide new strategy for gastric cancer treatment.Methods: 1.We analyzed the ADAM17 expression in MGC803,MKN45,HGC27 and BGC823 cells using real-time PCR and western blot.2.We constructed plasmids sh-ADAM17 and pRK5M-ADAM17 to identify the role of ADAM17 in the development of gastric cancer,and then we examined the effect of sh-ADAM17 and pRK5M-ADAM17 at both protein and mRNA levels.3.To investigate the effect of ADAM17 on cell growth in gastric carcinoma cells,we first used the CCK8 assay to determine the growth curves.To further confirm the effect of ADAM17 on proliferation of gastric carcinoma cells,we evaluated their ability of colony formation in the above mentioned cells.4.Wound healing assay and transwell migration assay were conducted to evaluate the migration abilities.5.The protein levels of EMT related protein were examined by Western blot,and the levels of MMP2 and MMP9 were detected by real-time PCR and Western blot.6.Expression level of TGF-β/Smad pathway related protein was examined by Western blot.Results: 1.We found that ADAM17 expression,at both mRNA and protein levels,was higher in MGC803 and MKN45 cells than that in HGC27 and BGC823 cells.2.In this study,we confirm that ADAM17 promotes proliferation,migration and invasion in gastric carcinoma cells.3.ADAM17 knockdown conduced to down-regulation of MMP-2 and MMP-9 at both mRNA and protein levels in MGC803 and MKN45 cells,while ADAM17 overexpression up-regulated the expression of MMP-2 and MMP-9 in BGC823 andHGC27 cells.4.Silencing ADAM17 induces epithelial markers E-cadherin expression and downregulates expression of mesenchymal markers including N-cadherin,vimentin and snail in MGC803 and MKN45 cells,whereas ADAM17 overexpression reverses these changes in BGC823 and HGC27.5.The expressions of TGF-β and its downstream signaling molecules p-Smad2 and p-Smad3 in MGC803-shADAM17 and MKN45-shADAM17 cells were decreased significantly.Expectedly,ADAM17 overexpression also reverses these changes in BGC823 and HGC27.Conclusions: 1.ADAM17 promotes the abilities of proliferation,migration and invasion in gastric cancer cells.2.ADAM17 promotes EMT probably via TGF-β/Smad signaling pathway in gastric cancer. |
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