Long non-coding RNA FBXL19-AS1 plays oncogenic role in colorectal cancer by sponging miR-203

Long non-coding RNAs (lncRNAs) have emerged as critical regulators of the progression of human cancers, including colorectal cancer (CRC). The study of genome-wide lncRNA expression patterns in metastatic CRC could provide novel mechanism underlying CRC carcinogenesis. In here, we determined the lncRNA expression profiles correlating to CRC with or without lymph node metastasis (LNM) based on microarray analysis. We found that 2439 lncRNAs and 1654 mRNAs were differentially expressed in metastatic CRC relative to primary CRC. Among these dysregulated lncRNAs, FBXL19-AS1 was the most significantly upregulated lncRNA in metastatic tumors. Functionally, knockdown of FBXL19-AS1 played tumor-suppressive effects by inhibiting cell proliferation, migration and invasion in vitro and tumor growth and metastasis in vivo. Overexpression of FBXL19-AS1 was markedly correlated with TNM stage and LNM in CRC. Bioinformatics analysis predicted that miR-203 was potentially targeted by FBXL19-AS1, which was confirmed by dual-luciferase reporter assay. Pearson's correlation analysis showed that miR-203 expression was negatively related to FBXL19-AS1 in tumor tissues. Finally, miR-203 inhibition abrogated the effect of FBXL19-AS1 knockdown on the proliferation and invasion of LoVo cells. Our results reveal the cancer-promoting effect of FBXL19-AS1, acting as a molecular sponge in negatively modulating miR-203, which might provide a new insight for understanding of CRC development.