Netrin-1 Promotes The Growth And Metastasis Of Gastric Cancer Through Its Receptor Neogenin

Background:Gastric cancer(GC)is the third leading cancer-related death worldwide.China is one of the highest incidence rates of GC in the world.GC mortality rate ranks third in all malignant tumors and threats to human life and health in our country.The function of Netrin-1 has been extensively studied in nervous system.Netrin-1 can induce neuronal differentiation and promote directional migration of nerve fibers.In recent years,the role of Netrin-1 in the development and progression of tumors has been attracting more and more attention.It was reported that Netrin-1 was highly expressed in many malignant tumors,and was related to tumor growth,invasion,angiogenesis and metastasis.However,the role of Netrin-1 in the development of GC has not been studied.In this study,we analyzed the biological function of Netrin-1 in the development of GC by using clinical specimen analysis.Moreover,cell/animal experiments were used to explore the function of Netrin-1 in GC development.Finally,molecular mechanism of Netrin-1 in GC development was investigated by molecular biology technology.Methods:The relationship between the Netrin-1 expression and GC was analyzed by using RT-PCR and immunohistochemical methods.After knockdown/overexpression Netrin-1 in GC cells by transfection of lentivirus,we analyzed the effect of Netrin-1 on the proliferation,invasion and metastasis abilities of GC by using CCK-8,colony formation,scratch and Transwell test,while xenograft tumors of subcutaneous and tail vein metastatic mice model were used to verify the above research results.Subsequently,we studied the molecular mechanism of Netrin-1 biological function in GC progression.We detected the expression level of Netrin-1 receptors in GC cells,then suppressed the expression level of related receptors by siRNA and analyzed the main receptor.Furthermore,FAK and PI3 K inhibitors were used to analyze whether FAK/PI3K/AKT signaling pathway was the main signaling pathway.Results:We found that the expression level of Netrin-1 was associated with lymph node metastasis and clinical stage in GC.CCK-8 assay and plate colony formation assay showed that Netrin-1 promoted the proliferation of GC cells.Scratch test and Transwell assay showed that Netrin-1 enhanced the migration and invasion abilities of GC cells.Xenograft tumors of mice model showed that the tumor volume and growth curve were reduced in Netrin-1 inhibition group,and the distant metastasis rate in Netrin-1 inhibition group was lower than that in normal control group.The expression level of Netrin-1 receptors was analyzed by RT-PCR,we found that neogenin was the highest expression and Netrin-1 induced proliferation and invasion abilities of GC cells via its receptor neogenin.Western blotting analysis showed that Netrin-1 enhanced the expression level of FAK,AKT and MMP-9.In a word,we demonstrated that FAK/PI3K/AKT signaling pathway mediated Netrin-1 promoting the growth and metastasis of GC.Conclusion:In summary,this study demonstrated that Netrin-1 was highly expressed in GC and its expression positively correlated with lymph node metastasis and clinical stage.Our in vivo and in vitro results showed that Netrin-1 promoted the proliferation,migration and invasion abilities of GC cells.Our study found neogenin was the highest expression level in all Netrin-1 receptors,and Netrin-1 induced proliferation and invasion abilities of GC cells mainly through its receptor neogenin.Moreover,our results showed that FAK/PI3K/AKT signaling pathway mediated Netrin-1 promoting the growth and metastasis of GC.