Roles of long noncoding RNAs in colorectal cancer metastasis

Colorectal cancer (CRC) is the 3rd most common malignancies worldwide. Metastasis is responsible for more than 90% CRC patients' death. Long noncoding RNAs (lncRNAs) are an important class of transcribed RNA molecules greater than 200 nucleotides in length. With the development of whole genome sequencing technologies, they have been gained more attention. Accumulating evidences suggest that abnormal expression of lncRNAs in diverse diseases are involved in various biological functions such as proliferation, apoptosis, metastasis and differentiation by acting as epigenetic, splicing, transcriptional or post-transcriptional regulators. Aberrant expression of lncRNAs has also been found in CRC. Besides, recent studies have indicated that lncRNAs play important roles in tumourigenesis and cancer metastasis. They participate in the process of metastasis by activing or inhibiting the metastatic pathways. However, their functions on the development of cancer metastasis are poorly understood. In this review, we highlight the findings of roles for lncRNAs in CRC metastasis and review the metastatic pathways of lncRNAs leading to cancer metastasis in CRC, including escape of apoptosis, epithelial-mesenchymal transition (EMT), angiogenesis and invasion, migration and proliferation. Furthermore, we also discuss the potential clinical application of lncRNAs in CRC as diagnostic markers and therapeutic targets.