Long non‐coding RNA CRNDE promotes the proliferation, migration and invasion of hepatocellular carcinoma cells through miR‐217/MAPK1 axis

: Hepatocellular carcinoma (HCC) is an invasive malignant tumour and the second major cause of cancer-related deaths over the world. CRNDE and miR-217 are non-coding RNAs which play critical roles in cell growth, proliferation, migration. Mitogen-activated protein kinase 1 (MAPK1) also participates in cancer cell process. Hence, this study aimed at investigating the effect of CRNDE on migration and invasion of HCC and figuring out the role of miR-217 and MAPK1 in this process. The overexpression of CRNDE was demonstrated by a microarray-based lncRNA profiling study. CRNDE expression in HCC was verified by qRT-PCR. MTT assay and BrdU staining were applied to detect cell proliferation level. Transwell assay was utilized to examine cell migration and invasiveness abilities. Wound healing assay was performed for further exploration of cell migration capacity. MiR-217 was predicted by bioinformatics. The dual luciferase reporter assay was performed to corroborate the targeting relationship between CRNDE, miR-217 and MAPK1. MAPK1, the downstream target of miR-217, was predicted using bioinformatics and was further confirmed by qRT-PCR and Western blot. The interaction between CRNDE, miR-217 and MAPK1 was studied by qRT-PCR, Western blot, MTT, BrdU, transwell assay and wound healing assay. CRNDE was up-regulated in HCC tissues and HCC cell lines. The high expression of CRNDE facilitated cell proliferation, migration and invasion, while the inhibited one affected on the contrary. MiR-217, negatively correlated with CRNDE expression, was the target of CRNDE and was more lowly expressed in HCC. With the high expression of miR-217, HCC cell proliferation, migration and invasion were suppressed. MAPK1, the possible target of miR-217, was negatively correlated with miR-217 but positively correlated with CRNDE and had the same effect in HCC formation process as CRNDE. Long non-coding RNA CRNDE promotes the proliferation, migration and invasion of HCC cells through miR-217/MAPK1 axis.