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D’Souza AM, Jiang Y, Cast A, Valanejad L, Wright M, Lewis K, Kumbaji M, Shah S, Smithrud D, Karns R, Shin S, Timchenko N. Gankyrin Promotes Tumor-Suppressor Protein Degradation to Drive Hepatocyte Proliferation. Cell Mol Gastroenterol Hepatol 2018; 6:239-255. [PMID: 30109252 PMCID: PMC6083020 DOI: 10.1016/j.jcmgh.2018.05.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 05/18/2018] [Indexed: 12/19/2022]
Abstract
Background & Aims Uncontrolled liver proliferation is a key characteristic of liver cancer; however, the mechanisms by which this occurs are not well understood. Elucidation of these mechanisms is necessary for the development of better therapy. The oncogene Gankyrin (Gank) is overexpressed in both hepatocellular carcinoma and hepatoblastoma. The aim of this work was to determine the role of Gank in liver proliferation and elucidate the mechanism by which Gank promotes liver proliferation. Methods We generated Gank liver-specific knock-out (GLKO) mice and examined liver biology and proliferation after surgical resection and liver injury. Results Global profiling of gene expression in GLKO mice showed significant changes in pathways involved in liver cancer and proliferation. Investigations of liver proliferation after partial hepatectomy and CCl4 treatment showed that GLKO mice have dramatically inhibited proliferation of hepatocytes at early stages after surgery and injury. In control LoxP mice, liver proliferation was characterized by Gank-mediated reduction of tumor-suppressor proteins (TSPs). The failure of GLKO hepatocytes to proliferate is associated with a lack of down-regulation of these proteins. Surprisingly, we found that hepatic progenitor cells of GLKO mice start proliferation at later stages and restore the original size of the liver at 14 days after partial hepatectomy. To examine the proliferative activities of Gank in cancer cells, we used a small molecule, cjoc42, to inhibit interactions of Gank with the 26S proteasome. These studies showed that Gank triggers degradation of TSPs and that cjoc42-mediated inhibition of Gank increases levels of TSPs and inhibits proliferation of cancer cells. Conclusions These studies show that Gank promotes hepatocyte proliferation by elimination of TSPs. This work provides background for the development of Gank-mediated therapy for the treatment of liver cancer. RNA sequencing data can be accessed in the NCBI Gene Expression Omnibus: GSE104395.
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Key Words
- 2D, 2-dimensional
- BrdU, bromodeoxyuridine
- C/EBP, CCAAT/enhancer binding protein
- CUGBP1, CUG triplet repeat binding protein 1
- Cancer
- Co-IP, co-immunoprecipitation
- DEN, diethylnitrosamine
- FXR, farnesoid X receptor
- GLKO, Gankyrin liver-specific knock-out
- Gank, Gankyrin
- HCC, hepatocellular carcinoma
- HNF4α, hepatocyte nuclear factor 4α
- LKO, liver-specific knock-out
- Liver
- Opn, osteopontin
- PCNA, proliferating cell nuclear antigen
- PH, partial hepatectomy
- Progenitor Cells
- Proliferation
- RT-PCR, reverse-transcriptase polymerase chain reaction
- Rb, retinoblastoma
- TSP, tumor-suppressor protein
- Tumor-Suppressor Proteins
- UPS, ubiquitin proteasome system
- WT, wild-type
- cDNA, complementary DNA
- mRNA, messenger RNA
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Affiliation(s)
- Amber M. D’Souza
- Department of Oncology, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Yanjun Jiang
- Huffington Center on Aging, Baylor College of Medicine, Houston, Texas
| | - Ashley Cast
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Leila Valanejad
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Mary Wright
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Kyle Lewis
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Meenasri Kumbaji
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Sheeniza Shah
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | - David Smithrud
- Department of Chemistry, University of Cincinnati, Cincinnati, Ohio
| | - Rebekah Karns
- Department of Gastroenterology, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Soona Shin
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Nikolai Timchenko
- Department of Surgery, Hepatology and Nutrition, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
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