Exploring The Prognostic Value Of Long Non-coding RNA In Colon Cancer And The Functional Mechanisms Of LINC02257 Based On Bioinformatics Analysis

BackgroundAccording to GLOBOCAN 2020,colorectal cancer was ranked as the fifth leading cause of cancer mortality and the second most common cancer in China^[1],and the trend is still on the rise.A large number of lncRNAs are specifically expressed in tumors and regulate a variety of tumor biological processes.However,the potential functional mechanisms of most lncRNAs remain unclear,which makes lncRNAs promising in the field of tumor research^[2].Benefiting from the rapid development of bioinformatics technology,mining various online database information for application in medical clinical research has emerged as one of the most common means.Objective1.To construct a prognostic risk model for colon cancer consisting of lncRNAs based on TCGA database,and to systematically identify and characterize the established ceRNA network.2.To build a CEA-related ceRNA network,establish the key lncRNA-miRNA-mRNA regulatory axis,and explore its biological mechanism and clinical significance in colon cancer through multi-omics analysis.3.Based on the TCGA database and clinical information and surgical specimens of 40 colon cancer patients collected from the First Affiliated Hospital of Guangxi Medical University,we analyzed and verified the expression of LINC02257 in colon cancer and its correlation with clinicopathological characteristics,and explored its possible biological molecular mechanism.Materials and MethodsObjects of the study:The clinical information data and surgical specimens of 80 patients with colon cancer were collected from the First Affiliated Hospital of Guangxi Medical University;high-throughput transcriptome microarray andRNA sequencing data of colon cancer patients,together with their clinical prognostic data,downloaded from TCGA,GEO and UCSC Xena database.Methods:1.Identify differentially expressed lncRNAs between colon cancer and adjacent tissues were identified,and screen OS related lncRNAs,and then take the intersection of the two gene sets.LASSO regression and multivariate Cox regression were used to construct risk score consisted of eight lncRNAs.Next,verify the ability of risk score to predict the prognosis of colon cancer patients,and analyze its mechanism by establishing ceRNAnetworks.2.Through analyzing TCGA database,we identified differentially expressed lncRNAs,miRNAs,and mRNAs between colon adenocarcinoma and matched normal colon tissues,as well as between CEA high and CEA low expression groups.This is followed by OS-related lncRNAs were obtained.Next,based on the ceRNA hypothesis,multiple databases were used to construct CEA-related ceRNA regulatory networks,and the key LCMT1-AS2/RPS6KA5 regulatory axis was established.Finally,we explored the possible biological mechanism and clinical significance of RPS6KA5 in colon cancer from multi-omics perspective.3.We analyzed the expression of LINC02257 in colon cancer and construct a prognostic model.Then,further investigations were conducted to clarify the mechanism of action on colon cancer,such as enrichment analysis,protein-protein interaction network analysis,correlation analysis between tumor infiltrating immune cells and immune cell gene markers,and prediction of the effect of immunotherapy.Moreover,40 collected clinical specimens verified the expression of LINC02257 and its correlation with clinicopathological factors.Results1.A risk-score model consisting of 8 lncRNAs was constructed,which could predict the clinical outcome and guide clinicians to stratify the risk level of colon cancer patients and develop more reasonable treatment plans.Enrichment analysis was mainly involved in MAPK signaling pathway,miRNAs in cancer,and PI3K-Akt signaling pathway.PPI network analysis yielded 10 key proteins.2.A LCMT1-AS2/miR-454-3p/RPS6KA5 regulatory axis associated with colon cancer prognosis was established,which could help us better learn the intricate interplay of lncRNA-miRNA-mRNA network.The LCMT1-AS2/RPS6KA5 regulatory axis based on the CEA-associated ceRNA network may not only play an important role in colon cancer progression,but be also an important prognostic factor for predicting clinical outcome of colon cancer.3.LINC02257 is notably overexpressed in colon cancer and is positively associated with some advanced clinical-pathological parameters and poor prognosis of colon cancer.RT-q PCR on clinical samples verified the level of LINC02257 expression and its correlation with clinical factors.LINC02257,which may act mainly through the PI3K-Akt signaling pathway,is correlated with immune infiltration and may result in escape from immune recognition.Thus,LINC02257 is a potential prognostic predictive marker and therapeutic target.Conclusion1.The 8-lncRNA-based risk score model served as an independent predictor for the OS and might assist risk stratification of COAD patients,and aid the development of treatment strategies.2.The LCMT1-AS2/RPS6KA5 regulatory axis may be an important prognostic factor and play essential roles in the development of colon cancer.3.LINC02257 is a potential prognostic predictive marker and therapeutic target.