Abstract
Hepatocellular carcinoma (HCC) is a common malignant tumor worldwide with high morbidity and high mortality rates. Previous studies have demonstrated that cytoskeleton regulator RNA (CYTOR) plays critical roles in the tumorigenesis of various types of cancer. The present study aimed to investigate the clinical significance, biological function and molecular mechanism of CYTOR in the progression of HCC. The expression level of CYTOR was determined by reverse transcription quantitative PCR in HCC tissues and cell lines. The biological function of CYTOR was investigated using CCK-8 assay, EdU immunofluorescence, western blotting and TUNEL assay in vitro. A xenograft tumor model and immunohistochemistry were used to validate the role of CYTOR in vivo. The downstream targets of CYTOR and micro-RNA (miR)-125b were confirmed by RNA immunoprecipitation assay and luciferase reporter assays. The results demonstrated that CYTOR was significantly increased in HCC tissues compared with non-tumor tissues and that CYTOR expression was associated with the poor prognosis of patients with HCC. Furthermore, CYTOR silencing could inhibit the proliferation and promote the apoptosis of HCC cells. CYTOR overexpression had the opposite effects. The results from in vivo xenograft demonstrated that CYTOR knockdown suppressed tumor growth. In addition, CYTOR could directly interact with and negatively regulate miR-125b. Furthermore, semaphorin 4C (SEMA4C) was the target of miR-125b and CYTOR regulated SEMA4C expression by modulating miR-125b. Taken together, the findings from the present study demonstrated that CYTOR could promote cell proliferation and tumor growth by sponging miR-125b and upregulating SEMA4C, which suggested that CYTOR may act as a potential therapeutic target in HCC.