The mammalian liver is one of the few adult organs capable of completely regenerating itself in response to injury or two-thirds partial hepatectomy in which terminally differentiated hepatocytes are induced to reenter the cell cycle and undergo DNA replication and mitosis. The proliferative response of differentiated hepatocytes is initiated by the release of growth factors and cytokines that stimulate expression and nuclear translocation of immediate early transcription factors. However, the transcriptional mechanisms mediating hepatocyte entry into S-phase and mitosis are not completely understood. In the previous funding period, we developed transgenic mice in which the Transthyretin promoter functioned to prematurely express the Forkhead Box (Fox) M1B (previously called HFH-11B) transcription factor. Liver regeneration studies with these TG mice demonstrated that premature FoxM1B expression accelerates the onset of hepatocyte proliferation through earlier induction of cell cycle regulatory genes. Furthermore, albumin enhancer/promoter driven Cre recombinase (AIb-Cre) mediated deletion of the FoxM1b fl/fl (LoxP targeted) allele in postnatal hepatocytes resulted in significant reduction in regenerating hepatocyte DNA replication and mitosis. This was associated with increased levels of the cyclin dependent kinase (Cdk) inhibitor p21Cip1 protein and undetectable expression of Cdc25B phosphatase, which is required for Cdk1 activity and entry into mitosis. Our broad, long-term goals are to determine the role of Foxm1b in mediating regenerating hepatocyte proliferation and liver morphogenesis and examine whether Foxm1b is required for development of hepatocellular carcinoma. We propose the following three Specific Aims: (1) To test the hypothesis that deleting the cdk inhibitor p21Cip1 gene and restoring Cdc25B expression will increase hepatocyte proliferation in regenerating AIb-Cre Foxm1b -/- liver. We have shown that deletion of the Foxm1b fl/fl allele in the embryonic liver causes abnormal liver development and embryonic lethality. (2) To further characterize the Foxm1b embryonic liver defect and use of inducible hepatic Cre recombinase to delete the Foxm1b fl/fl allele at various times during liver development to determine the stages of liver development at which Foxm1b function is required. (3) Because Foxm1b is essential for regenerating hepatocyte proliferation, we will test the hypothesis that AIb-Cre Foxm1b -/- hepatocytes are refractory to developing hepatocellular carcinoma in response to a Diethylnitrosamine/Phenobarbital liver tumor induction protocol. ? ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK054687-07
Application #
6858523
Study Section
Special Emphasis Panel (ZRG1-CAMP (05))
Program Officer
Serrano, Jose
Project Start
1999-03-15
Project End
2009-02-28
Budget Start
2005-03-01
Budget End
2006-02-28
Support Year
7
Fiscal Year
2005
Total Cost
$335,451
Indirect Cost
Name
University of Illinois at Chicago
Department
Biochemistry
Type
Schools of Medicine
DUNS #
098987217
City
Chicago
State
IL
Country
United States
Zip Code
60612
Petrovic, Vladimir; Costa, Robert H; Lau, Lester F et al. (2010) Negative regulation of the oncogenic transcription factor FoxM1 by thiazolidinediones and mithramycin. Cancer Biol Ther 9:1008-16
Chen, Yi-Ju; Dominguez-Brauer, Carmen; Wang, Zebin et al. (2009) A conserved phosphorylation site within the forkhead domain of FoxM1B is required for its activation by cyclin-CDK1. J Biol Chem 284:30695-707
Wang, I-Ching; Chen, Yi-Ju; Hughes, Douglas E et al. (2008) FoxM1 regulates transcription of JNK1 to promote the G1/S transition and tumor cell invasiveness. J Biol Chem 283:20770-8
Petrovic, Vladimir; Costa, Robert H; Lau, Lester F et al. (2008) FoxM1 regulates growth factor-induced expression of kinase-interacting stathmin (KIS) to promote cell cycle progression. J Biol Chem 283:453-60
Wang, I-C; Meliton, L; Tretiakova, M et al. (2008) Transgenic expression of the forkhead box M1 transcription factor induces formation of lung tumors. Oncogene 27:4137-49
Park, Hyun Jung; Costa, Robert H; Lau, Lester F et al. (2008) Anaphase-promoting complex/cyclosome-CDH1-mediated proteolysis of the forkhead box M1 transcription factor is critical for regulated entry into S phase. Mol Cell Biol 28:5162-71
Park, H J; Wang, Z; Costa, R H et al. (2008) An N-terminal inhibitory domain modulates activity of FoxM1 during cell cycle. Oncogene 27:1696-704
Brezillon, Nicolas; Lambert-Blot, Martine; Morosan, Serban et al. (2007) Transplanted hepatocytes over-expressing FoxM1B efficiently repopulate chronically injured mouse liver independent of donor age. Mol Ther 15:1710-5
Gusarova, Galina A; Wang, I-Ching; Major, Michael L et al. (2007) A cell-penetrating ARF peptide inhibitor of FoxM1 in mouse hepatocellular carcinoma treatment. J Clin Invest 117:99-111
Kotlo, Kumar; Hughes, Douglas E; Herrera, Victoria L M et al. (2007) Functional polymorphism of the Anpep gene increases promoter activity in the Dahl salt-resistant rat. Hypertension 49:467-72

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