Elevated TFPI is a prognostic factor in hepatocellular carcinoma: Putative role of miR-7-5p and miR-1236-3p

Background: Primary liver cancer is the third leading cause of cancer related deaths worldwide, and the disease is associated with high incidence rate of thrombosis. Studies indicate that Tissue Factor Pathway Inhibitor (TFPI) plays a role in cancer development. We aimed to study its expression, clinical role and regulation by micro RNAs (miRNAs) in hepatocellular carcinoma (HCC). Methods: Publically available datasets were used for clinical analysis of TFPI and miRNAs expression by web analysis tools. miRNA mimics targeting TFPI alpha 3'untranslated region (UTR) were selected from target prediction programs and verified by luciferase reporter assay. In vitro effects of miRNAs overexpression in HCC cell lines on TFPI expression and cell proliferation and apoptosis were analysed. Results: TFPI expression was significantly increased in HCC tumours compared to normal tissue. Low TFPI tumour expression was associated with better survival probability. Four candidate miRNAs were selected from the target prediction programs. miR-7-5p and miR-1236-3p were validated in HepG2 and Huh7 cells to reduce TFPI mRNA and protein levels following overexpression. Furthermore, miR-7-5p and miR-12363p reduced TFPI alpha-3'UTR-controlled luciferase activity. The two validated miRNAs inhibited proliferation of HepG2 cells, and had clinical significance in HCC. Conclusions: TFPI was increased in HCC tumours compared to normal tissue and high TFPI expression was associated with an unfavorable outcome in HCC patients. miR-7-5p and miR-1236-3p were identified as novel regulators of TFPI in vitro.