Long Non-coding RNA LINC01268 Promotes EMT And Invasion And Metastasis Of Gastric Cancer Cell Via PI3K/Akt Signaling Pathway

Objective:The role and regulatory mechanism of long non-coding RNA in tumorigenesis and development of tumor is a hot spot,which needs to be further clarified.The purpose of this study is to investigate the relationship between the expression level of LncRNA LINC01268 in gastric cancer(GC)and the clinicopathological features of patients with GC,its potential significance in the diagnosis and prognosis evaluation of GC,and to further explore the molecular mechanisms involved in regulating EMT and invasion and metastasis of GC.Method:(1)Differentially expressed LncRNA LINC01268 was screened by microarray analysis.RT-qPCR was used to detect the expression level of LINC01268 in 62 GC tissues and paired adjacent normal tissues(ANTs),as well as GC cell lines and normal gastric mucosal epithelial cell line.(2)Combined with data of clinicopathological,the relationship between the expression changes of LINC01268 and the clinicopathological characteristics of GC patients was analyzed.(3)The expression levels of LINC01268 in plasma of 31 GC patients and 19 healthy people were detected by RT-qPCR,and the ROC curve was constructed to evaluate its value of diagnosis.(4)According to the data of telephone follow-up,Kaplan-Meier method was used to draw the survival curve and to explore the relationship between the expression level of LINC01268 and prognosis of patients,and to evaluate its value in prognosis judgment of GC patients.(5)Co-expressed genes of LINC01268 were screened by the online analysis tool circlncRNAnet.The expression levels of co-expressed genes in GC tissues were detected by RT-qPCR,and their correlations with expression of LINC01268 in GC and evaluation of prognosis were respectively analyzed by the databases of starBase and Kaplan-Meier Plotter.(6)In vitro cell experiments,the expression of LINC01268 was knockdown by RNAi technology,and the changes of invasion and migration ability of GC cell lines were observed by Transwell and wound healing test.Meanwhile,the expression changes of MARCKS,PI3K/Akt signaling pathway and EMT-related molecules were analyzed.Result:(1)Compared with ANTs and normal gastric mucosal epithelial cell line,the expression level of LINC01268 was significantly up-regulated in GC tissues and GC cell lines.(2)The expression level of LINC01268 was significantly correlated with lymph node metastasis,TNM stage and differentiation degree of cancer tissues in patients with GC.(3)The expression level of LINC01268 was an independent factor affecting the metastasis of GC.(4)The expression level of LINC01268 in plasma of GC patients was significantly up-regulated.The sensitivity,specificity and AUC of LINC01268 in plasma for the diagnosis of GC were respectively 67.74%,94.74%and 0.840,which had certain diagnostic value.(5)The expression level of LINC01268 may be related to the poor prognosis of patients with GC,and the prognosis of patients with high expression level was even worse.(6)The mRNA and protein levels of MARCKS in GC tissues were higher than those in ANTs.In the co-expressed genes MARCKS and HDAC2,MARCKS and LINC01268 showed more obvious positive correlations in many aspects,so it was speculated that MARCKS may be the target regulatory gene of LINC01268.(7)After knocking down the expression level of LINC01268,the expression level of MARCKS also decreased,and invasion and migration abilities of GC cell lines were weakened.(8)After knocking down the expression level of LINC01268,the expression levels of PI3K,Akt,CDH2,Vimentin and MMP9 in GC cell lines also decreased,suggesting that the PI3K/Akt signaling pathway and EMT process were inhibited.Conclusion:(1)The expression of LINC01268 is up-regulated in GC,which is significantly correlated with lymph node metastasis,worse TNM stage and poor differentiation of cancer tissues.Meanwhile,the expression level of LINC01268 may be associated with poor prognosis in GC patients,and the prognosis of patients with high expression level is even worse.(2)Compared with the healthy population,the expression level of LINC01268 in plasma of GC patients is increased,which has certain potential clinical application value for the diagnosis and prognosis assessment and monitoring of GC.(3)Knocking down the expression of LINC01268 can significantly inhibit the EMT and invasion and metastasis of GC cell lines,which suggests that LINC01268 plays an important role in the invasion and metastasis of GC.It is most likely that upregulated expression of LINC01268 promotes the up-regulation and activation of MARCKS expression,thereby activating the PI3K/Akt signaling pathway,promotes the occurrence of EMT in GC cell lines,and ultimately promotes the invasion and metastasis of GC.