title: Silencing of the inhibitor of DNA binding protein 4 (ID4) contributes to the pathogenesis of mouse and human CLL.
abstract: Inhibitor of DNA binding protein 4 (ID4) is a member of the dominant-negative basic helix-loop-helix transcription factor family that lacks DNA binding activity and has tumor suppressor function. ID4 promoter methylation has been reported in acute myeloid leukemia and chronic lymphocytic leukemia (CLL), although the expression, function, and clinical relevance of this gene have not been characterized in either disease. We demonstrate that the promoter of ID4 is consistently methylated to various degrees in CLL cells, and increased promoter methylation in a univariable analysis correlates with shortened patient survival. However, ID4 mRNA and protein expression is uniformly silenced in CLL cells irrespective of the degree of promoter methylation. The crossing of ID4(+/-) mice with Eμ-TCL1 mice triggers a more aggressive murine CLL as measured by lymphocyte count and inferior survival. Hemizygous loss of ID4 in nontransformed TCL1-positive B cells enhances cell proliferation triggered by CpG oligonucleotides and decreases sensitivity to dexamethasone-mediated apoptosis. Collectively, this study confirms the importance of the silencing of ID4 in murine and human CLL pathogenesis.
authors.affiliation: Department of Molecular Virology, Immunology, and Medical Genetics, Human Cancer Genetics Program, the Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA.
authors.forename: Shih-Shih
authors.initials: SS
authors.lastname: Chen
authors.forename: Rainer
authors.initials: R
authors.lastname: Claus
authors.forename: David M
authors.initials: DM
authors.lastname: Lucas
authors.forename: Lianbo
authors.initials: L
authors.lastname: Yu
authors.forename: Jiang
authors.initials: J
authors.lastname: Qian
authors.forename: Amy S
authors.initials: AS
authors.lastname: Ruppert
authors.forename: Derek A
authors.initials: DA
authors.lastname: West
authors.forename: Katie E
authors.initials: KE
authors.lastname: Williams
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Johnson
authors.forename: Fred
authors.initials: F
authors.lastname: Sablitzky
authors.forename: Christoph
authors.initials: C
authors.lastname: Plass
authors.forename: John C
authors.initials: JC
authors.lastname: Byrd
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001402:B-Lymphocytes / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D018899:CpG Islands / Q000235:genetics; D019175:DNA Methylation; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D020869:Gene Expression Profiling; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D057809:HEK293 Cells; D057898:Hemizygote; D006801:Humans; D015151:Immunoblotting; D051796:Inhibitor of Differentiation Proteins / Q000235:genetics* / Q000378:metabolism; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D011401:Promoter Regions, Genetic / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: C490128:ID4 protein, human; D051796:Inhibitor of Differentiation Proteins; D011518:Proto-Oncogene Proteins; C490393:Tcl1 protein, mouse; D003907:Dexamethasone