Silibinin induces hepatic stellate cell cycle arrest via enhancing p53/p27 and inhibiting Akt downstream signaling protein expression
Devaraj Ezhilarasan, Jonathan Evraerts, Brice Sid, Pedro Buc Calderon, Sivanesan Karthikeyan, Etienne Sokal and Mustapha Najimi
Brussels, Belgium
Author Affiliations: Institut de Recherche Expérimentale et Clinique (IREC), Laboratory of Pediatric Hepatology and Cell Therapy (Ezhilarasan D, Evraerts J, Sokal E and Najimi M), and Louvain Drug Research Institute, Toxicology and Cancer Biology Research Group, PMNT Unit (Sid B and Calderon PB), Université Catholique de Louvain, 1200, Brussels, Belgium; Facultad de Ciencias de la Salud, Universidad Arturo Prat, Iquique, Chile (Calderon PB); Department of Pharmacology and Environmental Toxicology, Food and Hepatotoxicology Laboratory, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai-600 113, India (Karthikeyan S)
Corresponding Author: Mustapha Najimi, PhD, Institut de Recherche Expérimentale et Clinique (IREC), Laboratory of Pediatric Hepatology and Cell Therapy, Université Catholique de Louvain, Avenue Mounier, 52, Box B1.52.03, 1200, Brussels, Belgium (Tel: +3227645283; Fax: +3227645258; Email: mustapha.najimi@uclouvain.be)
Abstract：BACKGROUND: Proliferation of hepatic stellate cells (HSCs) plays a pivotal role in the progression of liver fibrosis consequent to chronic liver injury. Silibinin, a flavonoid compound, has been shown to possess anti-fibrogenic effects in animal models of liver fibrosis. This was attributed to an inhibition of cell proliferation of activated HSCs. The present study was to gain insight into the molecular pathways involved in silibinin anti-fibrogenic effect.
METHODS: The study was conducted on LX-2 human stellate cells treated with three concentrations of silibinin (10, 50 and 100 μmol/L) for 24 and 96 hours. At the end of the treatment cell viability and proliferation were evaluated. Protein expression of p27, p21, p53, Akt and phosphorylated-Akt was evaluated by Western blotting analysis and Ki-67 protein expression was by immunocytochemistry. Sirtuin activity was evaluated by chemiluminescence based assay.
RESULTS: Silibinin inhibits LX-2 cell proliferation in dose- and time-dependent manner; we showed that silibinin upregulated the protein expressions of p27 and p53. Such regulation was correlated to an inhibition of both downstream Akt and phosphorylated-Akt protein signaling and Ki-67 protein expression. Sirtuin activity also was correlated to silibinin-inhibited proliferation of LX-2 cells.
CONCLUSION: The anti-proliferative effect of silibinin on LX-2 human stellate cells is via the inhibition of the expressions of various cell cycle targets including p27, Akt and sirtuin signaling.
2017, Vol. 16 
