| Objective:In recent years,the critical molecular regulatory role of lncRNAs in tumorigenesis and development has attracted much attention.LncRNAs can be secreted from tumor cells by exosomes into body fluids and play corresponding biological roles.Studies have shown that the lncRNAs in exosomes may be a potential biomarker for the diagnosis and prognosis in various cancers.In this study,we analyzed TCGA database and screened different lncRNAs related to the occurrence of colorectal cancer.We also analyzed their biological effects in vivo and in vitro and detected their expression levels in serum of colorectal cancer(CRC)patients and determined their clinical diagnostic value.Methods:By analyzing the colorectal cancer sequencing data in the TCGA database,we obtained 14 lncRNAs that are low-expressed in colorectal cancer tissues with poor prognosis as our candidates,they are ADAMTS9-AS1,AL36536.1,KCNJ2-AS1,FGF14-AS2,AC129507.2,AC106739.1,MAFTRR,AL109955.1,TRHDE-AS1,AL136368.1,FO393418.1,LINC01571,AP003396.3 and AC 124017.1.Then we extracted the RNA from colorectal cancer tissues.We collected and verified their expression level,finally the lncRNA ADAMTS9-AS1 and AL109955.1 were identified as our research objects.In the next step,we studied their biological function through a series of functional experiments in vitro and in vivo,and predicted the related signal pathways through Gene Ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analysis.Finally,weextracted serum exosomes from 130 pairs of colorectal cancer patients and healthy volunteers and verified them by various methods such as transmission electron microscopy(TEM),immunoblotting(WB),and nano-particle size analysis(NTA).After the exosomes were identified,the exosomal RNA was extracted and the expression level of ADAMTS9-AS1 was detected,and the clinical diagnostic value was determined by combining the correlation of clinical information.Results:A total of 698 samples with RNA-seq data,complete survival information and clinical pathological parameters were obtained from the TCGA database,including 51 normal colorectal tissues.We screened and identified two new lncRNAs,ADAMTS9-AS1 and AL109955.1,which are down-regulated in colorectal cancer tissues and related to the poor prognosis of patients through the R language "DESeq2" software package,single factor Cox regression analysis and Kaplan-Meier survival curve.In vivo and in vitro functional experiments show that ADAMTS9-AS1 can significantly inhibit the Wnt/β-catenin signaling pathway to inhibit cell proliferation and invasion and metastasis.LncRNA AL 109955.1 may inhibit the classic tumor signaling pathways such as Wnt,p53,Notch and Jak-STAT CRC to downregulate cell proliferation and migration ability.Finally,we also found that ADAMTS9-AS1 in exosomes can be used as a potential diagnostic marker for colorectal cancer(AUC=0.835,95%confidence interval=0.777-0.91 1).Conclusion:Our data demonstrated that ADAMTS9-AS1 and AL 109955.1 may play important roles in colorectal cancer by inhibiting oncogenesis and may have potential clinical application value in the prognosis and treatment of colorectal cancer.Finally,exosomal lncRNA-ADAMTS9-AS1 is a promising,novel diagnostic biomarker for colorectal cancer. |
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