Mechanism of Hepatocellular Carcinoma Exosome-Derived Circular RNA Circ_0001649 in Regulating Release of Matrix Metalloproteinase 9 in Fibroblasts and Promoting Metastasis of Hepatocellular Carcinoma

Abstract

To investigate the effects of hepatocellular carcinoma cell-derived circ_0001649-mediated regulation of intercellular communication on the progression of hepatocellular carcinoma and their mechanisms is the main objective of the study. Immunohistochemical staining was used to detect the expression level of matrix metalloproteinase 9 in tumour and paracancer tissues. The expression levels of matrix metalloproteinase 9 messenger RNA, circ_0001649 and micro RNA-331-3p were measured by real-time fluorescence quantitative polymerase chain reaction. In vivo transfer models were established. Bagg Albino/c nude mice were injected subcutaneously with human hepatocellular carcinoma cell lines, Hep3B cell suspension, Hep3B cells stably shows overexpressing circ_0001649 and knockdown circ_0001649, respectively. The expression level of circ_0001649 in serum exosomes from hepatocellular carcinoma was significantly correlated with the expression level of matrix metalloproteinase 9 protein in tissues compared to serum exosomes from non-cancerous populations (p<0.05). Bioinformatics software was used to predict the target of circ_0001649 and micro RNA-331-3p and the 3’-untranslated region of micro RNA-331-3p binding site of matrix metalloproteinase 9 messenger RNA. There was no significant change in matrix metalloproteinase 9 protein expression when circ_0001649 and miR-331-3p were either up-regulated or down-regulated. In vivo experiments showed that the expression levels of circ_0001649 content and matrix metalloproteinase 9 proteins were reduced in the tumour of circ_0001649-knockdown group, while the expression levels of circ_0001649 content and matrix metalloproteinase 9 protein were significantly increased in the tumour of circ_0001649-over expression group. Circ_0001649 in hepatocellular carcinoma cell exosomes translocate to cancer-associated fibroblast and promoted matrix metalloproteinase 9 expressions and thus promote tumor metastasis through adsorption of micro RNA-331-3p.