title: c-MYC delays prometaphase by direct transactivation of MAD2 and BubR1: identification of mechanisms underlying c-MYC-induced DNA damage and chromosomal instability.
abstract: Here we show that the human BubR1 and MAD2 genes, which encode inhibitors of the anaphase promoting complex (APC/C), are directly activated by the oncogenic transcription factor c-MYC via E-box sequences in their first introns. In colorectal cancer biopsies elevated expression of c-MYC correlated with increased MAD2 levels. Activation of a conditional c-MYC allele delayed progression through mitosis in pro-metaphase in a MAD2- and BubR1-dependent manner. A fraction of the daughter cells derived from extended mitotic events underwent synchronous apoptosis, which was in part mediated by BubR1. Furthermore, c-MYC activation resulted in CIN (chromosomal instability) in the diploid MIN (microsatellite instability) cell line DLD-1 and further enhanced CIN in the aneuploid CIN-line MCF7. Unexpectedly, c-MYC-induced CIN was independent of c-MYC-induced BubR1/MAD2 expression and mitotic delay. Therefore, c-MYC-induced CIN may be caused be alternative pathways. We observed that activation of c-MYC induced DNA double-strand breaks, as evidenced by formation of gamma-H2AX foci, which colocalized with foci of active DNA replication. Furthermore, c-MYC activation resulted in mitotic chromosomes exhibiting DNA damage. Therefore, oncogenic deregulation of c-MYC prevents repair of replication-stress induced DNA lesions in the G(2)-phase. We suggest that the c-MYC-mediated persistence of DNA lesions throughout mitosis leads to chromosomal missegregation and underlies c-MYC-induced CIN. The effects of deregulated c-MYC on progression through mitosis described here may have important implications for the origin of chromosomal instability in many tumor types and the sensitivity towards cancer therapeutic agents targeting DNA or the mitotic spindle.
authors.affiliation: Molecular Oncology, Max-Planck-Institute of Biochemistry, Martinsried, Germany.
authors.forename: Antje
authors.initials: A
authors.lastname: Menssen
authors.forename: Alexey
authors.initials: A
authors.lastname: Epanchintsev
authors.forename: Dmitri
authors.initials: D
authors.lastname: Lodygin
authors.forename: Nousin
authors.initials: N
authors.lastname: Rezaei
authors.forename: Peter
authors.initials: P
authors.lastname: Jung
authors.forename: Berlinda
authors.initials: B
authors.lastname: Verdoodt
authors.forename: Joachim
authors.initials: J
authors.lastname: Diebold
authors.forename: Heiko
authors.initials: H
authors.lastname: Hermeking
mesh_terms: D000705:Anaphase / Q000235:genetics / Q000502:physiology; D017209:Apoptosis / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D045744:Cell Line, Tumor; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D043171:Chromosomal Instability; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage; D024721:E-Box Elements; D005047:Etoposide / Q000378:metabolism; D016259:Genes, myc; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007438:Introns / Q000235:genetics; D064246:Mad2 Proteins; D008938:Mitosis / Q000235:genetics; D049468:Prometaphase; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015533:Transcriptional Activation
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; C468783:H2AX protein, human; D006657:Histones; C577697:MAD2L1 protein, human; C489427:MYC protein, human; D064246:Mad2 Proteins; D016271:Proto-Oncogene Proteins c-myc; D012097:Repressor Proteins; D005047:Etoposide; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases