miR-221-3p regulates hepatocellular carcinoma cell proliferation, migration and invasion via targeting LIFR.

Abstract Introduction and Objectives Hepatocellular carcinoma (HCC) is one of the most common and fatal cancers in the world. This study aims to investigate the mechanism by which miR-221-3p regulates HCC cell proliferation, migration and invasion, so as to provide a new idea for targeted therapy towards HCC. Materials and Methods Expression quantification data including mature miRNA and mRNA were accessed from TCGA-LIHC dataset, and matched clinical information was obtained as well, which helped identify the miRNA of interest. Thereafter, effect of the miRNA on HCC cell biological functions was assessed with a series of in vitro experiments, such as qRT-PCR, MTT, wound healing assay and Transwell. To gain more insight into the mechanism of the miRNA in HCC, bioinformatics method was conducted to predict downstream target gene. The potential targeting relationship between the miRNA and the predicted mRNA was validated by dual-luciferase reporter assay. Western blot was performed to test protein expression. Results MiR-221-3p identified by differential expression analysis was found to be significantly elevated in HCC tissue. Overexpressing miR-221-3p noticeably enhanced HCC cell proliferative, migratory and invasive abilities. Leukemia inhibitory factor receptor (LIFR), confirmed as a downstream target of miR-221-3p in HCC by dual-luciferase reporter assay, was poorly expressed in HCC tissue and cells. Additionally, the expression of LIFR was decreased following the targeted binding between miR-221-3p and LIFR 3’-UTR, while increasing the expression of LIFR attenuated the promoting effect of miR-221-3p on HCC cells. Conclusion MiR-221-3p is an oncogene in HCC cells, and it exerts its role in HCC cell viability and motility via targeting LIFR.