Circ_0000972 Inhibits Hepatocellular Carcinoma Cell Stemness by Targeting miR-96-5p/PFN1.

Previous study has identified circRNAs as an important factor in cancer stem cells (CSCs) progression, which contributes to tumor initiation and progression. This study aspired to uncover the mechanisms of circ_0000972 on hepatocellular carcinoma (HCC) CSCs. RT-qPCR was utilized to quantify circ_0000972, miR-96-5p, and profilin 1(PFN1) expression in HCC tissues and cells. To evaluate the in vivo functions of circ_0000972, HCC cells with circ_0000972 overexpression were utilized to establish xenograft model through subcutaneous injection. The cell colony and sphere formation assays were adopted to evaluate the impact of circ_0000972 on the stemness characteristics of HCC cells. Additionally, the interaction between circ_0000972, miR-96-5p, and PFN1 was determined through bioinformatics analysis, dual-luciferase reporter assays, and rescue experiments. Circ_0000972 and PFN1 expression was significantly downregulated in HCC tissues and cells, while miR-96-5p exhibited an increased expression level. The overexpression of circ_0000972 was observed to inhibit the cell colony, sphere formation, and EMT of HCC CSCs. In xenograft model, circ_0000972 overexpression restrained the tumor volume and weight. Mechanistically, circ_0000972 stimulated PFN1 expression through the inhibition of miR-96-5p. More importantly, circ_0000972 overexpression could promote PFN1 expression and inhibit the stemness of HCC CSCs. Interestingly, the effect of circ_0000972 overexpression on such progresses was reversed by PFN1 silencing. This study elucidates that circ_0000972, an antitumor factor, sponges miR-96-5p to inhibit oncogenic cellular process in HCC by mediating PFN1 expression.