CircFAM114A2 inhibits the progression of hepatocellular carcinoma via miR-630/HHIP axis

Background: Many studies have shown that circular RNAs (circRNAs) are abnormally expressed in various tumor tissues and served as a key regulator in the occurrence and development of cancer. However, in hepatocellular carcinoma (HCC), the molecular mechanism of circRNAs in body fluids remains to be further explored. Methods: The expression levels of genes and proteins were detected by quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting, respectively. Cell counting Kit-8 (CCK-8), 5-Ethynyl-2'-deoxyuridine (EdU), wound healing assay, Transwell assays, flow cytometry, and tumor formation models in nude mice were conducted to investigate the effects of circFAM114A2 on HCC cells both in vitro and in vivo. RNA antisense purification (RAP), dual luciferase reporter assays and rescue assays were carried out to verify the interaction between circFAM114A2, miR-630 and HHIP. Results: CircFAM114A2 was significantly downregulated in HCC tissues and was associated with microvascular invasion and lymph node metastasis of HCC patients. We also observed that circFAM114A2 was lowly expressed in HCC plasma, which may serve as an effective biomarker to screen HCC patients from healthy controls (area under curve (AUC)=0.922). In vitro, circFAM114A2 overexpression significantly blunted HCC cell proliferation, migration, invasion, and promoted apoptosis, whereas circFAM114A2 silencing posed opposite effects. In vivo, circFAM114A2 overexpression inhibited the growth of HCC cells. Mechanistically, circFAM114A2 could increase the expression of the tumor suppressor HHIP via acting as a sponge for miR-630. Conclusions: CircFAM114A2 exerts a tumor suppressor role in HCC through miR-630/HHIP axis, and may be served as a potential diagnostic and therapeutic biomarker for HCC patients.

Automated summary

Many studies have shown that circRNAs play a crucial role in the occurrence and development of cancer, and circFAM114A2 is significantly downregulated in hepatocellular carcinoma (HCC). In this study, it was found that circFAM114A2 is associated with microvascular invasion and lymph node metastasis in HCC patients, and its low expression in HCC plasma could potentially serve as a biomarker for diagnosing HCC. Furthermore, circFAM114A2 acts as a tumor suppressor in HCC through the miR-630/HHIP axis.