Inhibition of Hyaluronic acid synthesis by 4-methylumbelliferone (4MU) reduces fibrosis in a murine model of orthotopic hepatocellular carcinoma (HCC) associated to liver fibrosis.

PICCIONI F; MALVICINI M; RIZZO M; KIPPES N; ATORRASAGASTI C; RODRÍGUEZ A; AMANTE M; FIORE E; BAYO J; AQUINO JB; GARCÍA MG; ALANIZ L; MAZZOLINI G

Petersberg

Conferencia; Conferencia monotemática EASL: Fibrogénesis hepática – mecanismos comunes y órgano-específicos.; 2011

Backgrounds & Aims: Liver fibrogenesis is characterized by an excessive production and deposition of extracellular matrix (ECM) components such as hyaluronic acid (HA), mainly produced by hepatic stellate cells (HSCs) that had transdifferentiated to myofibroblasts. These cells also increase α-smooth muscle actinSMA) expression levels according to degree of their activation state. Cirrhosis is the endstage consequence of liver fibrosis, and is considered a preneoplastic disease being hepatocellular carcinoma (HCC) one of the major complications. The aim of this work was to analyze if inhibition of HA synthesis by the specific inhibitor 4-methylumbelliferone (4-MU) reduced fibrosis development, and as a consequence, tumoral progression of HCC. Methods: We used an orthotopic Hepa129 HCC model established in fibrotic livers induced by thioacetamide. We evaluated 4-MU effects on HSCs (LX2, CFSC-2G) in vitro by proliferation and apoptosis, and on primary cultured hepatocytes by apoptosis and cytotoxicity assays. Fibrogenesis was also analyzed in vivo by Masson’s trichrome and Sirious Red staining for collagen fibres, and immunohistochemistry for α-SMA. Collagen and α-SMA quantification was performed by morphometric analysis. Fibrosis stage was assessed according to Metavir score (no fibrosis F0, cirrhosis F4). Results: 4-MU treatment 2-3-folds reduced number of tumor satellites, reduced proliferation (64% and 24% for CFSC-2G and LX2, respectively for 4MU 0,25 mM) and induced apoptosis (Apoptosis index=28 and 24 for CFSC-2G and LX2, respectively, for 4MU 5mM) of HSCs in vitro while primary cultured hepatocytes remained unaffected (