title: An EBF3-mediated transcriptional program that induces cell cycle arrest and apoptosis.
abstract: In a genome-wide screen for putative tumor suppressor genes, the EBF3 locus on the human chromosome 10q26.3 was found to be deleted or methylated in 73% of the examined cases of brain tumors. EBF3 is expressed in normal brain but is silenced in brain tumors. Therefore, it is suggested that EBF3 is a tumor suppressor. However, it remains unknown whether inactivation of EBF3 locus also occurs in other types of tumors and what functions of EBF3 underlie EBF3-mediated tumor suppression. We show here that expression of EBF3 resulted in cell cycle arrest and apoptosis. The expression of cyclin-dependent kinase inhibitors was profoundly affected with early activation and then repression of p21(cip1/waf1) and persistent activation of both p27(kip1) and p57(kip2), whereas genes involved in cell survival and proliferation were suppressed. EBF3 bound directly to p21(cip1/waf1) promoter and regulated transcription from both p21(cip1/waf1) and p27(kip1) promoters in reporter assays. Apoptosis occurred 48 hours after EBF3 expression with caspase-3 activation. Silencing of the EBF3 locus was observed in brain, colorectal, breast, liver, and bone tumor cell lines and its reactivation was achieved on treatment with 5-aza-2'-deoxycytidine and trichostatin A in a significant portion of these tumor cells. Therefore, EBF3 regulates a transcriptional program underlying a putative tumor suppression pathway.
authors.affiliation: Department of Anatomy and Cell Biology, Shands Cancer Center, University of Florida College of Medicine, Gainesville, FL 32611-3633, USA.
authors.forename: Lisa Y
authors.initials: LY
authors.lastname: Zhao
authors.forename: Yuxin
authors.initials: Y
authors.lastname: Niu
authors.forename: Aleixo
authors.initials: A
authors.lastname: Santiago
authors.forename: Jilin
authors.initials: J
authors.lastname: Liu
authors.forename: Sara H
authors.initials: SH
authors.lastname: Albert
authors.forename: Keith D
authors.initials: KD
authors.lastname: Robertson
authors.forename: Daiqing
authors.initials: D
authors.lastname: Liao
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D001932:Brain Neoplasms / Q000235:genetics / Q000473:pathology; D002453:Cell Cycle / Q000235:genetics*; D045744:Cell Line, Tumor; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics; D050760:Cyclin-Dependent Kinase Inhibitor p27; D019175:DNA Methylation; D000077209:Decitabine; D044127:Epigenesis, Genetic; D005260:Female; D017353:Gene Deletion; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D016147:Genes, Tumor Suppressor; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008297:Male; D008869:Microtubule-Associated Proteins / Q000502:physiology*; D009363:Neoplasm Proteins / Q000235:genetics; D009369:Neoplasms / Q000235:genetics* / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics*
chemical_list: C493956:CDKN1A protein, human; C436291:CDKN1B protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D006877:Hydroxamic Acids; D047908:Intracellular Signaling Peptides and Proteins; C403664:MAPRE3 protein, human; D008869:Microtubule-Associated Proteins; D009363:Neoplasm Proteins; D011993:Recombinant Fusion Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; C012589:trichostatin A; D000077209:Decitabine; D001374:Azacitidine