Inhibition of PDGF, TGF-β, and Abl signaling and reduction of liver fibrosis by the small molecule Bcr-Abl tyrosine kinase antagonist Nilotinib.
OBJECTIVE
Nilotinib is a novel tyrosine kinase inhibitor of Bcr-Abl and other kinases. In this study, we have examined its activity as an anti-fibrotic agent.


METHODS
The in vitro effect of Nilotinib on rat and human HSCs was assessed using proliferation assays and Western blotting. The in vivo antifibrotic efficacy of Nilotinib was assessed in mice with liver fibrosis induced by CCl(4) and bile duct ligation (BDL).


RESULTS
Nilotinib inhibited proliferation, migration, and actin filament formation, as well as the expression of α-SMA and collagen in activated HSCs. Nilotinib induced apoptosis of HSCs, which was correlated with reduced bcl-2 expression, increased p53 expression, cleavage of PARP, as well as increased expression of PPARγ and TRAIL-R. Nilotinib also induced cell cycle arrest, accompanied by increased expression of p27 and downregulation of cyclin D1. Interestingly, Nilotinib not only inhibited activation of PDGFR, but also TGFRII through Src. Nilotinib significantly inhibited PDGF and TGFβ-simulated phosphorylation of ERK and Akt. Furthermore, PDGF- and TGFβ-activated phosphorylated form(s) of Abl in human HSCs were inhibited by Nilotinib. In vivo, Nilotinib reduced collagen deposition and α-SMA expression in CCl(4) and BDL-induced fibrosis. These beneficial effects were associated with suppressed expression of procollagen-(I), TIMP-1, CD31, CD34, VEGF, and VEGFR. Nilotinib could induce HSC undergoing apoptosis in vivo, which was correlated with downregulation of bcl-2. We also observed reduced expression of phosphorylated ERK, Akt, and Abl in the Nilotinib-treated CCl(4) and BDL livers. In addition to its antifibrotic activity, the drug was hepatoprotective and reduced the elevations of ALT and AST after CCl(4) and BDL.


CONCLUSIONS
These studies uncover a novel role of Bcr-Abl activity in treatment of liver fibrosis through multiple mechanisms and indicate that Nilotinib represents a potentially effective antifibrotic agent.
Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China; Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, The Shenzhen Graduate School of Peking University, Shenzhen 518055, China. Electronic address: yuqing_liu@hotmail.com.
Yuqing
Y
Liu
Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
Zhuo
Z
Wang
Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
Shu Qin
SQ
Kwong
Department of Biochemistry, The University of Hong Kong, Hong Kong, China.
Eric Lik Hang
ELH
Lui
Division of Liver Diseases, Mount Sinai School of Medicine, New York, NY, USA.
Scott L
SL
Friedman
Clinical Medical Research Center, The Second Clinic Medicine College, Shenzhen People's Hospital, Jinan University, Shenzhen 518020, China.
Fu Rong
FR
Li
Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
Reni Wing Chi
RWC
Lam
Clinical Medical Research Center, The Second Clinic Medicine College, Shenzhen People's Hospital, Jinan University, Shenzhen 518020, China.
Guo Chao
GC
Zhang
Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, The Shenzhen Graduate School of Peking University, Shenzhen 518055, China.
Hui
H
Zhang
Department of Applied Biology & Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China; Laboratory of Chemical Genomics, School of Chemical Biology and Biotechnology, The Shenzhen Graduate School of Peking University, Shenzhen 518055, China. Electronic address: bctaoye@inet.polyu.edu.hk.
Tao
T
Ye
D000199:Actins / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001652:Bile Ducts; D002251:Carbon Tetrachloride; D049109:Cell Proliferation / Q000187:drug effects; D003094:Collagen / Q000378:metabolism; D059585:G1 Phase Cell Cycle Checkpoints / Q000187:drug effects; D016313:Genes, abl / Q000187:drug effects*; D055166:Hepatic Stellate Cells / Q000187:drug effects / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008026:Ligation; D008103:Liver Cirrhosis / Q000139:chemically induced / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D047495:PPAR gamma / Q000378:metabolism; D010982:Platelet-Derived Growth Factor / Q000187:drug effects*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011743:Pyrimidines / Q000494:pharmacology*; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D016212:Transforming Growth Factor beta / Q000187:drug effects*
D000199:Actins; D002251:Carbon Tetrachloride; D003094:Collagen; D047495:PPAR gamma; D010982:Platelet-Derived Growth Factor; D011505:Protein-Tyrosine Kinases; D011743:Pyrimidines; D053220:Receptors, TNF-Related Apoptosis-Inducing Ligand; D016212:Transforming Growth Factor beta; C498862:Acta2 protein, rat; C498826:nilotinib