MicroRNA-876-5p inhibits epithelial-mesenchymal transition and metastasis of hepatocellular carcinoma by targeting BCL6 corepressor like 1

Our previous study has reported that BCL6 corepressor like 1 (BCORL1) plays an oncogenic role in hepatocellular carcinoma (HCC) via promoting epithelial-mesenchymal transition (EMT) and tumor metastasis. However, the regulation of BCORL1 mediated by microRNAs (miRNAs) remains poorly known. The analysis of our clinical samples indicated that BCORL1 expression was markedly higher in HCC tissues than that in tumor-adjacent normal tissues. The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets revealed that high BCORL1 expression associated with high tumor grade, advanced tumor stage and poor survival of HCC patients. miR-875-5p expression was down-regulated and negatively correlated with BCORL1 mRNA expression in HCC tissues. Furthermore, miR-876-5p inversely regulated BCORL1 abundance in HCC cells by directly targeting the 3′-untranslated region (3′-UTR) of BCORL1. Ectopic expression of miR-876-5p suppressed cell migration and invasion in both HCCLM3 and MHCC97H cells. In accordance, miR-876-5p knockdown promoted the metastatic behaviors of Hep3B cells. Mechanistically, miR-876-5p suppressed the EMT progression of HCC cells. HCC tissues with high miR-876-5p level showed a higher E-cadherin staining compared to cases with low miR-876-5p level. Moreover, the repression of cell metastasis mediated by miR-876-5p was rescued by BCORL1 restoration in HCCLM3 cells. Notably, low miR-876-5p expression associated with venous infiltration, high tumor grade and advanced tumor stage. HCC patients with low miR-876-5p expression had a significant poorer overall survival and disease-free survival. To conclude, miR-876-5p inhibits EMT progression, migration and invasion of HCC cells by targeting BCORL1. Therefore, miR-876-5p/BCORL1 axis may represent as a novel therapeutic target for HCC treatment.