Circular RNA circARPP21 Acts as a Sponge of miR-543 to Suppress Hepatocellular Carcinoma by Regulating LIFR

Background: A large body of evidence has shown that circular RNAs (circRNAs) play a significant role in the progression of some malignant cancers, including hepatocellular carcinoma (HCC). However, the complex mechanism of circRNAs in hepatocellular carcinoma has not been clarified.

Methods: We identified circRNAs by microarray analysis and quantitative real-time polymerase chain reaction (RT-qPCR). We also carried out bioinformatics analysis, luciferase reporter assays, and RNA pull-down assays to define the relationship between microRNA (miR)-543 and circARPP21. Through silencing and overexpression of circARPP21, we investigated the effects of circARPP21 on proliferation, migration, and invasion abilities of HCC cells in vitro and in vivo.

Results: In this study, we found that a novel circRNA, circARPP21 (hsa_circ_0123629), exerts a strong effect on HCC progression. Reduced expression of circARPP21 in HCC patients is correlated with larger tumor size, higher tug-lymph node metastasis (TNM) stage, and poor prognosis as indicated by elevated levels of alpha-fetoprotein (AFP). Conversely, higher expression of circARPP21 can increase leukemia inhibitory factor receptor (LIFR) expression by sponging miR-543. Finally, overexpression of miR-543 can reverse the anti-proliferation and anti-metastasis effects of circARPP21.

Conclusion: The circARPP21/miR-543/LIFR axis suppresses the proliferation, invasion, and migration of hepatocellular carcinoma cells. In addition, circARPP21 can serve as a biomarker in HCC, thus offering a potential new approach to HCC therapy.