Long noncoding RNA DDX11-AS1 induced by YY1 accelerates colorectal cancer progression through targeting miR-873/CLDN7 axis.

Increasing studies have confirmed long non-coding RNAs (lncRNAs) as novel regulators in tumorigenesis. LncRNA DDX11 antisense RNA 1 (DDX11-AS1) has been found to be abnormally expressed in several tumors. In this work, we aimed to evaluate its expressions and functions in colorectal cancer (CRC). The Cancer Genome Atlas (TCGA) datasets were used for the identification of dysregulated lncRNA in CRC. The levels of DDX11-AS1 were determined in tumor tissues and cell lines by Real Time-Polymerase Chain Reaction (RT-PCR). The clinical significance of DDX11-AS1 in CRC patients was analyzed using Chi-square test and Kaplan-Meier analysis. Functional assays for the exploration of DDX11-AS1 and miR-873 were performed using a series of cells experiment. ChIP assay and luciferase reporter assays were used to explore the mechanism of actions of DDX11-AS1 in CRC cells. We identified DDX11-AS1 as a new CRC-related lncRNA whose levels were distinctly up-regulated in CRC specimens and cell lines, partly induced by YY1. Clinical explorations suggested that increased expressions of DDX11-AS1 in CRC were positively associated with lymph nodes metastasis and TNM stage and had a distinct influence on the overall survival. Further multivariate assays indicated that DDX11-AS1 was an independent prognostic parameter implying a poorer clinical outcome for patients with CRC. Functional assays revealed that the knockdown of DDX11-AS1 suppressed the proliferation, migration, and invasion of CRC cells, and stimulate apoptosis. Mechanistic studies showed that the up-regulation of DDX11-AS1 competitively bound to miR-873 prevented CLDN7 from miRNAs-mediated degradations, thus facilitated the CRC progress. Further rescue assays were carried out to achieve confirmation. Our present findings may enhance our understanding of the pathogenesis of CRC and revealed DDX11-AS11 as a potential therapeutic target for CRC.