Integrated analysis of long non-coding RNAs in human colorectal cancer

Accumulating evidence highlights the role of long non-coding RNAs (lncRNAs) in tumors. However, the genome-wide expression and roles of lncRNAs in colorectal cancer (CRC) remain unknown. Here, we systematically examined the global gene expressions in primary and synchronous liver metastases CRC tissue, in which thousands of aberrantly expressed lncRNAs were characterized. Co-expression analysis revealed that some lncRNAs correlated to their neighboring mRNAs in expression levels, whereas others formed networks with protein-coding genes in trans. We observed H3K4me3 was enriched at expressed lncRNA transcription start sites (TSSs) and correlated to dysregulated lncRNAs. Furthermore, we identified primary and metastasis tumor linked lncRNA signatures positively correlated with poor-prognosis gene set. Finally, functional experiments demonstrated two candidate lncRNAs were required for proliferation and migration of CRC cells. In summary, we provided a new framework for lncRNA associated clinical prognosis evaluation and target selection of gene therapy in CRC.