P-21 FIBROSIS DEVELOPMENT AND MALIGNANCIES ARE DELAYED BY PIRFENIDONE WHILE INCREASING SIRT1 NUCLEAR TRANSLOCATION AND HISTONE 3 DEACETYLATIONS IN A HEPATOCARCINOMA MODEL

Introduction and Objectives

Hepatocellular carcinoma (HCC) is the most common liver neoplasm worldwide. Pro-inflammatory and pro-fibrogenic processes are fundamental in tumor development. On the other hand, Pirfenidone (PFD) has anti-inflammatory and antifibrogenic properties useful to counteract hepatocarcinogenesis; however, effects of this drug on SIRT1, and epigenetic regulations in this type of damage are unknown. The aimed of this study is to evaluate PDF effects on SIRT1 translocation, and deacetylation of histone H3 lysines 9 and 14 (H3K9 and H3K14) in a HCC model.

Materials and Methods

Male Fischer-344 rats (n=18) were divided into three groups: CTL: control group, HCC: damage group, rats weekly administrated with diethylnitrosamine (DEN,50mg/kg/i.p.) and 2-aminofluorene (2AAF, 25mg/kg/p.o.) for 16 weeks. HCC/PFD group of rats administrated with DEN and 2AAF plus PFD (300mg/kg/day/p.o.). Tumor development and fibrosis markers were analyzed histologically. In addition, expression of SIRT1 deacetylase, p300 acetylase, H3 and H3K9 and H3K14 acetylated were analyzed by western blot.

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 was effective in preventing these changes. Immunohistochemistry revealed an overexpression of GPC3 and -SMA in damage group, which correlates with malignant degeneration; these responses were also prevented by PFD. Finally, western blots evidenced an overexpression of SIRT1 in nuclear fraction of PFD group, triggering H3K9 and H3K14 deacetylation, in addition, a decrease in p300 acetylase expression in nuclear fractions was noted. Noteworthy, c-Myc was decreased.

Conclusions

PFD reduces fibrotic and malignant patterns development. Likewise, PFD induces SIRT1 expression and nuclear translocation along with H3K9 and H3K14 deacetylation, compacting chromatin and possibly down expression of oncogenes. These results demonstrate the capability of PFD to regulate epigenetic hallmarks on histones.