circ_LRIG3 contributes to the progression of hepatocellular carcinoma by elevating RNF38 via sponging miR-449a.

ABSTRACT

Circular RNAs (circRNAs) play crucial roles in multiple cancers, including hepatocellular carcinoma (HCC). However, the effects and molecular mechanisms of circ_LRIG3 in HCC remain barely unknown. qRT-PCR assay was employed to detect the levels of circ_LRIG3, LRIG3, miR-449a and ring finger protein 38 (RNF38). RNase R assay and Actinomycin D assay were performed to analyze the characteristics of circ_LRIG3. Colony formation assay and MTT assay were used to evaluate cell proliferation. Flow cytometry analysis and transwell assay were adopted for cell apoptosis and metastasis, respectively. Western blot assay was carried out for the protein levels of Ki67, Snail, E-cadherin, RNF38, Smad2/3 and p-Smad2/3. Murine xenograft model assay was used to explore the role of circ_LRIG3 in vivo. circ_LRIG3 expression was upregulated in HCC tissues and cells. Knockdown of circ_LRIG3 suppressed proliferation, migration and invasion and facilitated cell apoptosis in HCC cells in vitro and blocked tumor growth of HCC in vivo. RNF38 overexpression reversed the effects of circ_LRIG3 knockdown on the malignant behaviors of HCC cells. Moreover, circ_LRIG3 could sponge miR-449a to positively modulate RNF38 expression in HCC cells. circ_LRIG3 knockdown inhibited the progression of HCC cells by sponging miR-449a. In addition, circ_LRIG3 silencing might inhibit the Smad2/3 pathway. circ_LRIG3 facilitated HCC progression by modulation of miR-449a/LRIG3 axis, which might provide a novel method for HCC therapy.