MicroRNA let-7c-5p Alleviates in Hepatocellular Carcinoma by Targeting Enhancer of Zeste Homolog 2: An study intersecting bioinformatic analysis and validated experiments

Objectives. Enhancer of zeste homolog 2 (EZH2) gene has a prognostic role in hepatocellular carcinoma (HCC). This study aimed to identify the role of microRNAs (miRNAs) let-7c-5p by targeting EZH2 in HCC. Methods. We downloaded gene and miRNA RNA-seq data from The Cancer Genome Atlas (TCGA) database. Differences in EZH2 expression between different groups were analyzed and the association of EZH2 expression with HCC prognosis was detected using Cox regression analysis. The miRNA-EZH2-pathway network was constructed. Dual-luciferase reporter assay was performed to detect the hsa-let-7c-5p-EZH2. Cell proliferation, migration, invasion, and apoptosis were detected by CCK-8, Wound healing, Transwell, and Flow cytometry, respectively. RT-qPCR and Western blot were used to detect the expression of let-7c-5p and EZH2. Results. EZH2 was upregulated in HCC tumors (P < 0.0001). Cox regression analysis showed that TCGA HCC patients with high EZH2 expression levels showed a short survival time (HR = 1.677, 95% CI 1.316-2.137; P < 0.0001). Seven miRNAs were negatively correlated with EZH2 expression and were significantly downregulated in HCC tumor samples (P < 0.0001), in which hsa-let-7c-5p was associated with prognosis in HCC (HR = 0.849 95% CI 0.739-0.975; P = 0.021). We identified 14 immune cells that showed significant differences in EZH2 high- and low- expression groups. Additionally, let-7c-5p inhibited HCC cell proliferation, migration, and invasion and reversed the promoted effects of EZH2 on HCC cell malignant characteristics. Conclusions. hsa-let-7c-5p-EZH2 significantly suppressed HCC malignant characteristics, which can be used for HCC prognosis.