JAM-A Regulates The Invasion And Migration Of Non-small Cell Lung Cancer Via The P-JNK/EMT Signaling Pathway

ObjectiveLung cancer is currently one of the fastest growing morbidity and mortality rates and one of the most threatening to the health and life of the population.80% of its dead are non-small-cell lung cancer(NSCLC)patients.Finding the key factors that regulate the progress of NSCLC and revealing the molecular mechanisms that play a regulatory role will help clinical diagnosis and treatment of NSCLC.Junctional adhesion molecule A(JAM-A)is an intercellular adhesion molecule,a type I transmembrane glycoprotein,and belongs to the immunoglobulin superfamily.JAM-A is mainly expressed at the cell junctions of epithelial cells and endothelial cells,and is also widely expressed in a variety of blood cells.In addition,JAM-A is expressed in a variety of tumor tissues,and its regulation of tumor progression appears to be "two-way",which can not only play a role in promoting tumor progression,but also play an inhibitory role.Current research results in this field exist controversy.Previous research by this research group found that the expression of JAM-A in NSCLC tissues was higher than that in adjacent tissues,and was positively related to TNM stage,lymph node metastasis,and poor prognosis.In vitro experiments found that down-regulating JAM-A can regulate Cyclin D1 and CDK4 to inhibit the proliferation of NSCLC cells,but its role and regulatory mechanism in NSCLC migration and invasion need to be studied.The purpose of this study was to find the key downstream signal molecules that JAM-A regulates invasion and metastasis of NSCLC,and to clarify its molecular mechanism.MethodsThe relationship between JAM-A expression and prognosis of patients with lung cancer was analyzed by bioinformatics methods.In NSCLC cell lines H1299 and A549,transfected JAM-A expression vectors up-regulated JAM-A,and transfected shRNA down-regulated JAM-A for subsequent experiments.In order to determine the role of JAM-A in regulating the migration and invasion of NSCLC cells,the migration ability of the cells was tested by scratch tests.The Transwell experiment was divided into the absence of Matrigel and Matrigel at the bottom of the upper chamber,and the absence of Matrigel to test migration ability of cells.Matrigel-layed Tranwell test is used to detect cell invasion ability.Detect the expression of EMT-related proteins E-cadherin,Ncadherin,Snail,and Slug by Western blot,detect the expression of p-JNK,?-catenin,and c-myc which are EMT-related signaling pathways,detect the expression of p-Akt and ?1 integrin which are downstream of JAM-A reported in other tumors.To clarify the mechanism of JAM-A regulates the migration and invasion of NSCLC cells,p-JNK inhibitor SP600125 was added to the overexpressed JAM-A group for rescue experiments.Cell migration and invasion ability was detected by scratch and Transwell.The expression change of E-cadherin and N-cadherin were detected by Western blot.ResultsBioinformatics analysis showed that the survival time of the JAM-A mRNA high expression group was significantly lower than that of the JAM-A mRNA low expression group.Successfully up-regulated JAM-A or down-regulated JAM-A in H1299 and A549 cells.Scratch experiments and Transwell experiments showed that overexpression of JAM-A increased the migration and invasion ability of NSCLC cells,while downregulating the expression of JAM-A,its migration and invasion ability was inhibited,which indicates that JAM-A can promote the migration and invasion of NSCLC cells.Western blot experiments revealed changes of EMT-related proteins,the expression of E-cadherin was negatively correlated with the expression of JAM-A,and the expression of N-cadherin,Snail and Slug was positively correlated with the expression of JAM-A.Through the detection of EMT-related signaling pathways,it was found that p-JNK was activated after over-expression of JAM-A,and the expression of p-JNK decreased after down-regulation of JAM-A.After treatment with p-JNK inhibitor SP600125,JAM-A promoted migration and invasion was rescued,and the expression changes of E-cadherin and N-cadherin caused by overexpression of JAM-A were also rescued after SP600125 treatment,which indicated that JAM-A promote NSCLC migration and invasion by activating p-JNK.Conclusions1.JAM-A promotes NSCLC cell migration and invasion.2.JAM-A induces EMT of NSCLC cells via activation of JNK to promote migration and invasion.