microRNA-375 inhibits the malignant behaviors of hepatic carcinoma cells by targeting NCAPG2

Hai-Tao Dai, Shu-Tong Wang, Bin Chen, Ke-Yu Tang, Nan Li, Chun-Yong Wen, Yuan Wan, Gui-Yuan Zhang,  Yong-Hui Huang,  Zhi-Jun Geng

Abstract:

Hepatocellular carcinoma (HCC) is a major cause of cancer-related deaths worldwide. Emerging evidence has revealed the vital functions of microRNAs (miRNAs) in cancer malignant progressions. miR-375 has been verified to serve as an antioncogene in tumorigenesis and a potential therapeutic target in various types of cancer. In this study, we aimed to determine the role of miR-375 in the regulation of chemoresistance and metastasis of HCC. Differentially expressed miR-375 and NCAPG2 were externally validated using expression data from The Cancer Genome Atlas (TCGA) database. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the expression levels of miR-375 in HCC tissues and cell lines. miR-375 mimics and NCAPG2-overexpression were transfected into HepG2 and Huh7 cells to establish miR-375 overexpression models. Cell Counting Kit-8, Transwell, and flow cytometry experiments were conducted to monitor cell proliferation, migration, and apoptosis. The targeting relationship between miR-375 and non-SMC condensin II complex subunit G 2 (NCAPG2) was determined by qRT-PCR, western blot, and luciferase reporter gene assay. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted using Gene Set Enrichment Analysis (GSEA). The pathway enrichment analysis was used to predict the potential pathways for further study. miR-375 was significantly downregulated in HCC tissues and cells compared to adjacent tissue and normal hepatocyte cell line respectively while NCAPG2 was upregulated. The targeting relationship was verified by luciferase reporting assay, and miR-375 could target the 3’UTR of NCAPG2 mRNA and effectively suppress NCAPG2 protein expression. Replenishing of miR-375 significantly repressed HCC cell proliferation and migration, and induced cell apoptosis. Overexpression of NCAPG2 recovered those biological abilities in miR-375 overexpressed cells. Collective data suggested that miR-375 served as a tumor suppressor via regulating NCAPG2. Replenishing of miR-375 or knockout of NCAPG2 could be therapeutically exploited for HCC.