Comprehensive Analysis of the Expression Profiles of Long Non-Coding RNAs with Associated ceRNA Network Involved in the Colon Cancer Staging and Progression

Long non-coding RNAs (lncRNAs) act as competing endogenous RNAs (ceRNAs) to compete with microRNAs (miRNAs) in cancer occurrence and development. However, the differential expression of RNAs and their ceRNA network during the development of colon cancer (CC) remains unclear. This study was aimed at comprehensive analysis of the lncRNAs and their ceRNA networks associated with CC. Whole transcriptome sequencing was performed on colorectal and adjacent normal tissues at different pathological stages. Forty-nine lncRNAs were differently expressed between the CC tissues and their adjacent normal tissues at all stages. Aberrant expression of lncRNA CDKN2B-AS1 and lncRNA MIR4435-2HG was confirmed by TCGA database. Moreover, 14 lncRNAs were differentially expressed between early and advance stages of the tumor tissues, and 117 miRNAs were specifically expressed in stage III & IV. Weighted gene co-expression network analysis of 17105 differently expressed mRNAs revealed that the mRNAs shown in module pink, midnight blue, black, and light cyan were related to TNM and pathological stage, and that these mRNAs were enriched in cancer related functions and pathways. As DElncRNA showed a trend of change similar to that of the DEmRNA and opposite to that of DEmiRNA, ceRNA network was constructed with 3 DEmiRNAs, 5 DElncRNAs, and 130 DEmRNAs. Real time PCR revealed that expression of MEG3 was decreased in the tumor tissues belonging to stage III and IV as compared to that in stage I. Moreover, hsa-miR-324-5p was upregulated, while FGFR3, PLCB4, and IKBKB were downregulated in the tumor tissues as compared to that in the adjacent normal tissues. Thus, this study revealed differentially expressed lncRNA between different stages of CC as well as suggested that lncRNA CDKN2B-AS1, MIR4435-2HG, and MEG3 may act as diagnostic biomarkers for the development of CC.