IDDF2018-ABS-0125 Overexpression of LNCRNA LINC00460 affects cell proliferation and apoptosis by regulating KLF2 and CUL4A expression in colorectal cancer

Abstract

Background Emerging evidence has proven that long noncoding RNAs (lncRNAs) play important roles in human colorectal cancer (CRC) biology, while few lncRNAs have been characterised in CRC. Therefore, the functional significance of lncRNAs in the malignant progression of CRC still needs to be further explored. Methods By utilising publicly available lncRNAs expression profiling data and other publicly available lncRNAs expression profiling data, we screened out LINC00460, whose expression is significantly increased in CRC. The quantitative reverse transcriptase PCR (qRT-PCR) was used to analyse the expression of LINC00460 in 60 CRC tissues and correspond adjacent normal tissues and four CRC cell lines. Gain and loss of function approaches were used to investigate the biological role of LINC00460 both in vitro and in vivo. Bioinformatics analysis followed by qRT-PCR was performed to identify the putative targets of LINC00460, which were further verified by RNA immunoprecipitation (RIP), Chromatin immunoprecipitation (ChIP), Luciferase reporter assays, rescue experiments and western blotting assays. Results We found a novel lncRNA, LINC00460, whose expression was significantly over-expressed in all three publicly available microarray data. Consistently, qRT-PCR results also verified that LINC00460 was over-expressed in CRC tissues and cells. Furthermore, high LINC00460 expression levels in CRC specimens were correlated with larger tumour size, advanced tumour stage, lymph node metastasis and shorter overall survival. In vitro and in vivo assays of LINC00460 alterations revealed a complexly integrated phenotype affecting cell growth and apoptosis. Mechanistically, LINC00460 repressed kruppel like factor 2 (KLF2) transcription by binding to the enhancer of zeste homolog 2 (EZH2). LINC00460 also functioned as a molecular sponge for miR-149–5 p, antagonising its ability to repress cullin 4A (CUL4A) protein translation. Conclusions Taken together, our findings support a model in which the LINC00460/EZH2/KLF2 and LINC00460/miR-149–5 p/CUL4A crosstalk serve as critical effectors in CRC tumorigenesis and progression, suggesting new therapeutic directions in colorectal cancer.