Long Non-coding RNA Lnc-LEFTY1 Promotes Intrahepatic Cholangiocarcinoma Invasion By Acting As Competing Endogenous RNA To Regulate Notch1

Objective: To identify differentially expressed genes that may play pivotal roles in the pathogenesis and progression of intrahepatic cholangiocarcinoma(ICC),we performed LncRNA and mRNA microarray based on four pairs of ICC and para-cancerous tissues.In this study,we found the expression of LncLEFTY1 was significantly up-regulated in ICC,which was selected for further research of its biological function and molecular mechanism.Moreover,we conducted bioinformatic analysis of ICC LncRNA microarray published in open acess databases to find common differentially expressed genes.Methods:(1)We used a variety of analytical methods to establish LncRNAmRNAs regulatory network of ICC,then screened differentially expressed genes and identified four candidate LncRNAs that met our criteria.(2)The expression of Lnc-LEFTY1 in 45 pairs of tissues and correlation with clinical data were analyzed.Through molecular biology techniques and predictive websites,we explored and demonstrated the in vitro function of Lnc-LEFTY1 as a competing endogenous RNA(ce RNA)to regulate downstream target gene.(3)By using bioinformatics methods such as KEGG,we analyzed two different public LncRNA microarray datasets related to ICC in GEO database.Results:(1)Compared with adjacent normal tissues,we found that LncRNA expression profile of ICC was significantly different,suggesting that LncRNA may play pivotal role in pathogenesis and progression of ICC.The differentially expressed genes are strongly linked to the biological behaviors of tumor cells such as oxidative stress,proliferation and metastasis.Whole-transcriptome analysis indicated that the five most relevant signaling pathways associated with ICC are ERBB,JAK / STAT,MAPK,VEGF and WNT.(2)Lnc-LEFTY1 was highly expressed in clinical tissues and cell lines of intrahepatic cholangiocarcinoma,and significantly inhibited the invasion ability of cholangiocarcinoma cells when being interference with si RNA.By competitively binding endogenous mi R-433-3p,Lnc-LEFTY1 regulated the expression of downstream Notch1 protein,thereby promoting tumor cell invasion.(3)By analyzing the two datasets,we found five differentially expressed genes with the same regulation pattern: MMP11,TGFB2,DNAH14,FOSB and HBB.Further co-expression network analysis showed that most regulatory networks can participate in cellular metabolism process.Conclusion: Long non-coding RNA Lnc-LEFTY1 promotes intrahepatic cholangiocarcinoma invasion by acting as a ce RNA to regulate Notch1 expression in vitro.Lnc-LEFTY1/mi R-433-3p/Notch1 signaling pathway may play important role in the invasion of ICC,which may be a potential target for this malignancy.Co-expression network analysis results suggested that the differential gene involved in cellular metabolism may be vital to the pathogenesis and development of intrahepatic cholangiocarcinoma.