Cross-regulation of non-coding RNAs and their correlations with target protein-coding genes in CRC pathobiology

Illuminating the correlations between non-coding RNAs and protein-coding genes are of great interest to understand more about the molecular mechanisms that drive malignant transformation and understanding such correlations will enable development of more specific and efficient targeted therapeutics. Accordingly, in this comprehensive meta-analysis study, we tried to determine correlations between long non-coding RNA (lncRNA), microRNA (miRNA) and messenger RNA (mRNA) molecules that are involved in the pathogenesis of colorectal cancer (CRC). For the present study, current colorectal cancer studies published until 20 August 2017 and associated with the lncRNA-miRNA-mRNA interactions was included. The current literature search was done online in Pubmed, Embase and Web of Science databases. These databases have been screened with three keywords; "lncRNA", "miRNA" and "colorectal cancer". As a result, colorectal neoplasia differentially expressed (CRNDE) was determined to be consistently up-regulated in CRC tissues and inversely associated with miR-181a-5p. Also, CRNDE expression was significantly associated with lymph node metastasis (p = 0.032). Additionally, a significant association was determined between CRC and survival time in the OS analysis of FER1L4, TUSC7, UCC and lincRNA-ROR. More importantly, there was a negative correlation between lncRNA-miRNA expressions (p = 0.001). Particularly, CRNDE/miR-181a-5p, FER1L4/miR-106a-5p, TUSC7/miR-211, UCC/miR-143 and lincRNA-ROR/miR-145 was negatively correlated. In addition, there was a significant positive correlation between GAPLINC/CD44 and TUSC7/CDK6 in CRC tissues (p = 0.000). Overall analysis showed that lncRNAs and mRNAs, which are targets of the same miRNA, have positive interactions. In addition, miRNAs were shown to have negative correlations with target lncRNA/mRNA.