Pirfenidone induces translocation of sirt1 to nucleus and deacetylation of histone 3 slows down the development of fibrosis and tumorigenicity in a experimental model of hepatocarcinoma.

Abstract

Introduction and objectives: Hepatocellular carcinoma (HCC) is the most common liver neoplasm worldwide. Pro-inflammatory and pro-fibrogenic processes are key in tumor development. On the other hand, Pirfenidone (PFD) has anti-inflammatory and antifibrogenic properties useful to counteract hepatocarcinogenesis; however, the effects of this drug on SIRT1, and histone H3 regulation in this disease are unknown.The objective this work is evaluate PFD effects on SIRT1 translocation, and histone H3 lysines 9 and 14 (H3K9 and H3K14) deacetylation in an experimental model of HCC. Materials and Patients: Fischer-344 rats were divided into three groups: CTL: control group, HCC: group damaged with diethylnitrosamine (DEN), 50 mg/kg and 2-aminofluorene (2AAF), 25 mg/kg/p.o. HCC/PFD group: damage group and with PFD (300 mg/kg/day) for 16 weeks. Histological and molecular analyzes were performed evaluating patterns of protein acetylation, fibrosis, and malignancy. Results: Normal liver architecture is disturbed by dysplastic nodules formation surrounded by extracellular matrix and fibrosis, also an increase in cells with anaplasia and steatotic foci was observed in liver tissues of HCC group. PFD administration was effective to prevent these changes. Immunohistochemistry reveals an overexpression of GPC3 and α-SMA in damage group, which is correlated with malignant degeneration, these responses was prevented by PFD too. Finally, western blots evidence a SIRT1 overexpression in nuclear fraction of PFD group, triggering H3K9 and H3K14 deacetylation, in addition, a decrease in p300 acetylase expression in nuclear fractions. Notably, c-Myc was reduced and p53 increased significantly. Conclusions: PFD treatment reduces fibrotic and malignant patterns development. Likewise, PFD induces SIRT1 expression and nuclear translocation, and H3K9 and H3K14 deacetylation, decompacting chromatin and possibly increasing tumor suppressor genes expression for example c-MYC. These results demonstrate for the first time the capability of PFD to regulate epigenetic hallmarks on histones.