Long non-coding RNA RUNX1-IT1 plays a tumour-suppressive role in colorectal cancer by inhibiting cell proliferation and migration.

Long non-coding RNAs (lncRNAs) have been demonstrated to be involved in the progression of various cancers. In this study, we aim to investigate the role of lncRNA RUNX1-IT1 in the development of colorectal cancer (CRC). The expression levels of lncRNA RUNX1-IT1 were measured using quantitative real-time Polymerase Chain Reaction(qRT-PCR). CCK8 proliferation assay, transwell assay, and flow cytometry were performed to evaluate the effect of lncRNA RUNX1-IT1 on CRC cell proliferation, migration, and apoptosis. The proliferation markers (PCNA, Ki67), apoptosis markers (cleaved-PARP, cleaved-caspase3), and MMP9 are detected by western blotting. Significant down regulation of lncRNA RUNX1-IT1 was measured in CRC tissues and three CRC cell lines (HCT116, HT29, and RKO) compared with paired nontumorous adjacent tissues (P < 0.01) or the normal colonic epithelial cell line FHC (P < 0.05), respectively. Moreover, the proliferative and migration potential of CRC cells were inhibited by overexpressing lncRNA RUNX1-IT1, which could be obviously improved by knocking down lncRNA RUNX1-IT1. The protein levels of PCNA, Ki67, and MMP9 were upregulated by overexpressing lncRNA RUNX1-IT1 and down regulated in si-RUNX1-IT1 cells. Besides, lncRNA RUNX1-IT1 could also promote the apoptosis of CRC cells. In conclusion, lncRNA RUNX1-IT1 is downregulated in CRC and plays a tumour-suppressive role due to the regulatory of cell proliferation, migration, and apoptosis. SIGNIFICANCE OF THE STUDY: We demonstrated that lncRNA RUNX1-IT1 was down regulated both in CRC tissues and cell lines. Besides, lncRNA RUNX1-IT1 could serve as a potential diagnostic biomarker and play a tumour-suppressive role owing to its good diagnostic efficacy and inhibition of CRC cell proliferation and migration.