Abstract
Homeobox transcription factors are developmentally regulated genes that play crucial roles in tissue patterning. Homeobox C6 (HOXC6) is overexpressed in prostate cancers and correlated with cancer progression, but the downstream targets of HOXC6 are largely unknown. We have performed genome-wide localization analysis to identify promoters bound by HOXC6 in prostate cancer cells. This analysis identified 468 reproducibly bound promoters whose associated genes are involved in functions such as cell proliferation and apoptosis. We have complemented these data with expression profiling of prostates from mice with homozygous disruption of the Hoxc6 gene to identify 31 direct regulatory target genes of HOXC6. We show that HOXC6 directly regulates expression of bone morphogenic protein 7, fibroblast growth factor receptor 2, insulin-like growth factor binding protein 3, and platelet-derived growth factor receptor alpha (PDGFRA) in prostate cells and indirectly influences the Notch and Wnt signaling pathways in vivo. We further show that inhibition of PDGFRA reduces proliferation of prostate cancer cells, and that overexpression of HOXC6 can overcome the effects of PDGFRA inhibition. HOXC6 regulates genes with both oncogenic and tumor suppressor activities as well as several genes such as CD44 that are important for prostate branching morphogenesis and metastasis to the bone microenvironment.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Animals
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Apoptosis / genetics
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Bone Morphogenetic Protein 7
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Bone Morphogenetic Proteins / biosynthesis
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Bone Morphogenetic Proteins / genetics
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CARD Signaling Adaptor Proteins / genetics
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Cell Growth Processes / genetics
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Cell Line, Tumor
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Core Binding Factor Alpha 2 Subunit / biosynthesis
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Core Binding Factor Alpha 2 Subunit / genetics
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Gene Expression Profiling
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Gene Expression Regulation, Neoplastic
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Genome, Human
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Homeodomain Proteins / genetics*
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Humans
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Insulin-Like Growth Factor Binding Protein 3
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Insulin-Like Growth Factor Binding Proteins / genetics
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Male
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Mice
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Mice, Knockout
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Neoplasm Proteins / genetics
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Nuclear Proteins / genetics
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Promoter Regions, Genetic
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Prostatic Neoplasms / genetics*
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Prostatic Neoplasms / metabolism
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Prostatic Neoplasms / pathology
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Receptor, Fibroblast Growth Factor, Type 2 / biosynthesis
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Receptor, Fibroblast Growth Factor, Type 2 / genetics
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Receptor, Platelet-Derived Growth Factor alpha / antagonists & inhibitors
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Receptor, Platelet-Derived Growth Factor alpha / biosynthesis
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Receptor, Platelet-Derived Growth Factor alpha / genetics
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Transcription, Genetic*
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Transforming Growth Factor beta / biosynthesis
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Transforming Growth Factor beta / genetics
Substances
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BMP7 protein, human
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Bone Morphogenetic Protein 7
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Bone Morphogenetic Proteins
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CARD Signaling Adaptor Proteins
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CARD8 protein, human
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Core Binding Factor Alpha 2 Subunit
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HOXC6 protein, human
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Homeodomain Proteins
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IGFBP3 protein, human
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Insulin-Like Growth Factor Binding Protein 3
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Insulin-Like Growth Factor Binding Proteins
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Neoplasm Proteins
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Nuclear Proteins
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TARP
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Transforming Growth Factor beta
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Receptor, Fibroblast Growth Factor, Type 2
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Receptor, Platelet-Derived Growth Factor alpha