lncRNAs ITFG2-AS1 and MMP25-AS1 have significant high-expression in gastric cancer patients as the potential diagnostic biomarkers: integrated bioinformatics and experimental investigation

Background The third most frequent cause of cancer-related death is gastric cancer (GC). Recent studies have reported that non-coding RNAs (ncRNAs) seem to play a crucial role in many tumors. Due to their extraordinary stability, long non-coding RNAs (LncRNAs) have the potential to be employed as biomarkers to identify the presence and prognosis of GC. In this study, we performed an integrated bioinformatics and experimental approach to evaluate the expression and interaction of two novel lncRNAs in the GC samples. Methods Bioinformatics analyses was performed to demonstrate the lncRNA expression profile of gastric cancer patients. Microarray data analysis was executed by R Studio, using affy and limma packages. Validation of gene expression analysis was carried out by ENCORI online database. Pathway enrichment analysis was conducted using enrichr and Reactome. Protein interaction analysis was performed by STRING. LncRNA interaction analysis was carried out by lncRRIsearch. RT-qPCR experiment was implemented for validation. Using Receiver operating characteristic (ROC), correlation, and t-tests, the biomarker potential of selected lncRNAs, co-expression of selected lncRNAs, and the differences in the expression level of GC samples have been investigated, based on qRT-PCR experiment. Results Microarray analysis revealed that ITFG2-AS1 (logFC: 2.25, adj. P. Val: 0.00029) and lncRNA MMP25-AS1 (logFC: 2.25, adj. P. Val: 0.0026) have a significant high-expression in GC samples. RT-qPCR experiments validate the up-regulation of MMP25-AS1 and ITFG2-AS1. Based on the ROC test, ITFG2-AS1 could be a significant diagnostic biomarker of GC (AUC: 0.7225, p-value: 0.0161). ITFG2-AS1 and MMP25-AS1 have a significant co-expression in human GC samples (r: 0.9086, p-value < 0.0001). ITFG2-AS1 and MMP25-AS1 regulate the RPGR expression level of RPGR gene. RPGR is a crucial gene in the “Cilium Assembly signaling pathway”. The expression level of ITFG2-AS1 has a non-significant negative correlation with the survival rate of GC patients. Conclusion ITFG2-AS1 and MMP25-AS1 could be considered as the two potential diagnostic GC biomarkers with significant low expression in tumor samples.