Abstract
HMGA2 gene amplification and overexpression in human prolactinomas and the development of pituitary adenomas in HMGA2 transgenic mice showed that HMGA2 plays a crucial role in pituitary tumorigenesis. We have explored the pRB/E2F1 pathway to investigate the mechanism by which HMGA2 acts. Here we show that HMGA2 interacts with pRB and induces E2F1 activity in mouse pituitary adenomas by displacing HDAC1 from the pRB/E2F1 complex-a process that results in E2F1 acetylation. We found that loss of E2F1 function (obtained by mating HMGA2 and E2F1(-/-) mice) suppressed pituitary tumorigenesis in HMGA2 mice. Thus, HMGA2-mediated E2F1 activation is a crucial event in the onset of these tumors in transgenic mice and probably also in human prolactinomas.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Acetylation
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Animals
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Cell Line
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Cell Proliferation
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Cell Transformation, Neoplastic
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DNA / metabolism
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E2F1 Transcription Factor / genetics
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E2F1 Transcription Factor / physiology*
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Enzyme Activation
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HMGA2 Protein / biosynthesis
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HMGA2 Protein / genetics
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HMGA2 Protein / physiology*
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Histone Deacetylase 1
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Histone Deacetylases / metabolism
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Histones / metabolism
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Humans
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Mice
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Mice, Knockout
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Mice, Mutant Strains
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Mice, Transgenic
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Pituitary Neoplasms / metabolism*
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Pituitary Neoplasms / pathology
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Promoter Regions, Genetic
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Protein Binding
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Response Elements
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Retinoblastoma Protein / metabolism
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Signal Transduction
Substances
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E2F1 Transcription Factor
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E2f1 protein, mouse
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HMGA2 Protein
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Histones
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Retinoblastoma Protein
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DNA
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Hdac1 protein, mouse
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Histone Deacetylase 1
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Histone Deacetylases