CONICET | Buscador de Institutos y Recursos Humanos

Cirrhosis is characterized by an excessive accumulation of extracellular matrix components including hyaluronic acid (HA) and is widely considered a pre-neoplastic condition for hepatocellular carcinoma (HCC). 4-methylumbelliferone (4MU) is an inhibitor of HA synthesis and has anti-cancer activity in an orthotopic HCC model with underlying fibrosis. Our aim was to explore the effects of HA inhibition by 4MU orally administered on tumour microenvironment. Hepa129 tumour cells were inoculated orthotopically in C3H/HeJ male mice with fibrosis induced by thioacetamide. Mice were orally treated with 4MU. The effects of 4MU on angiogenesis were evaluated by immunostaining of CD31 and quantification of proangiogenic factors (VEGF, IL-6, CXCL12). IL-6 was also quantified in Hepa129 cells in vitro after treatment with 4MU. Migration of endothelial cells and tube formation were also analyzed. As a result, 4MU treatment decreases tumour growth and increased animal survival. Systemic levels of VEGF were significantly inhibited in 4MU treated mice. Expression of CD31 was reduced after 4MU therapy in liver parenchyma in comparison with control group. In addition, mRNA expression and protein levels of IL-6 and VEGF were inhibited both in tumour tissue and in non-tumoral liver parenchyma. Interestingly, IL-6 production was dramatically reduced in Kupffer cells isolated from 4MU-treated mice, and in Hepa129 cells in vitro. Besides, 4MU was able to inhibit endothelial cell migration and tube formation. In conclusion, 4MU has antitumour activity in vivo and its mechanisms of action involve an inhibition of angiogenesis and IL-6 production. 4MU is an orally available molecule with potential for HCC treatment.

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