Beta-catenin antisense studies in embryonic liver cultures: role in proliferation, apoptosis, and lineage specification.
OBJECTIVE
Wnt/beta-catenin pathway activation occurs during liver growth in hepatoblastomas, hepatocellular cancers, and liver regeneration. The aim of this study was to investigate the role of beta-catenin, a key component of the Wnt pathway, in liver development as well as its normal distribution in developing liver.


METHODS
Embryonic liver cultures and beta-catenin antisense phosphorodiamidate morpholino oligomer (PMO) were used to elucidate the role of beta-catenin in liver development. Livers from embryos at 10 days of gestational development were cultured in the presence of antisense or control PMO for 72 hours and analyzed.


RESULTS
Beta-catenin shows stage-specific localization and distinct distribution compared with known markers in developing liver. A substantial decrease in beta-catenin protein was evident in the organs cultured in the presence of antisense. Beta-catenin inhibition decreased cell proliferation and increased apoptosis in these organ cultures. Presence of antisense resulted in loss of CK19 immunoreactivity of the bipotential stem cells. Beta-catenin inhibition also promoted c-kit immunoreactivity of the hepatocytes.


CONCLUSIONS
We conclude that the PMO antisense to beta-catenin effectively inhibits synthesis of its protein. Beta-catenin modulates cell proliferation and apoptosis in developing liver. It may play a significant role in early biliary lineage commitment of the bipotential stem cells and also seems to be important in hepatocyte maturation.
Monga
Satdarshan P S
SP
Department of Cellular and Molecular Pathology, S421-BST, University of Pittsburgh School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15261, USA. smonga@pitt.edu
Monga
Hardarshan K
HK
Tan
Xinping
X
Mulé
Karen
K
Pediaditakis
Peter
P
Michalopoulos
George K
GK
D000818:Animals; D016375:Antisense Elements (Genetics) / Q000494:pharmacology*; D017209:Apoptosis / Q000502:physiology; D001652:Bile Ducts / Q000196:embryology; D002454:Cell Differentiation / Q000502:physiology; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D016922:Cellular Senescence / Q000502:physiology; D019938:Cyclin D1 / Q000502:physiology; D003598:Cytoskeletal Proteins / Q000037:antagonists & inhibitors / Q000235:genetics*; D004622:Embryo, Mammalian / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D005314:Embryonic and Fetal Development / Q000502:physiology; D022781:Hepatocytes / Q000502:physiology; D008099:Liver / Q000196:embryology*; D051379:Mice; D008813:Mice, Inbred ICR; D009025:Morpholines / Q000494:pharmacology; D060172:Morpholinos; D016271:Proto-Oncogene Proteins c-myc / Q000502:physiology; D015534:Trans-Activators / Q000037:antagonists & inhibitors / Q000235:genetics*; D051176:beta Catenin
D016375:Antisense Elements (Genetics); C495267:CTNNB1 protein, mouse; D003598:Cytoskeletal Proteins; D009025:Morpholines; D060172:Morpholinos; C489428:Myc protein, mouse; D016271:Proto-Oncogene Proteins c-myc; D015534:Trans-Activators; D051176:beta Catenin; D019938:Cyclin D1