title: Reciprocal DNA topoisomerase II cleavage events at 5'-TATTA-3' sequences in MLL and AF-9 create homologous single-stranded overhangs that anneal to form der(11) and der(9) genomic breakpoint junctions in treatment-related AML without further processing.
abstract: Few t(9;11) translocations in DNA topoisomerase II inhibitor-related leukemias have been studied in detail and the DNA damage mechanism remains controversial. We characterized the der(11) and der(9) genomic breakpoint junctions in a case of AML following etoposide and doxorubicin. Etoposide-, etoposide metabolite- and doxorubicin-induced DNA topoisomerase II cleavage was examined in normal homologues of the MLL and AF-9 breakpoint sequences using an in vitro assay. Induction of DNA topoisomerase II cleavage complexes in CEM and K562 cell lines was investigated using an in vivo complex of enzyme assay. The translocation occurred between identical 5'-TATTA-3' sequences in MLL intron 8 and AF-9 intron 5 without the gain or loss of bases. The 5'-TATTA-3' sequences were reciprocally cleaved by DNA topoisomerase II in the presence of etoposide, etoposide catechol or etoposide quinone, creating homologous 4-base 5' overhangs that would anneal to form both breakpoint junctions without any processing. der(11) and der(4) translocation breakpoints in a treatment-related ALL at the same site in MLL are consistent with a damage hotspot. Etoposide and both etoposide metabolites induced DNA topoisomerase II cleavage complexes in the hematopoietic cell lines. These results favor the model in which the chromosomal breakage leading to MLL translocations in DNA topoisomerase II inhibitor-related leukemias is a consequence of DNA topoisomerase II cleavage.
authors: Division of Oncology, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
authors: Ryan J
authors: RJ
authors: Whitmarsh
authors: Charles
authors: C
authors: Saginario
authors: Ya
authors: Y
authors: Zhuo
authors: Eva
authors: E
authors: Hilgenfeld
authors: Eric F
authors: EF
authors: Rappaport
authors: Maureen D
authors: MD
authors: Megonigal
authors: Martin
authors: M
authors: Carroll
authors: Mingli
authors: M
authors: Liu
authors: Neil
authors: N
authors: Osheroff
authors: Nai-Kong V
authors: NK
authors: Cheung
authors: Diana J
authors: DJ
authors: Slater
authors: Thomas
authors: T
authors: Ried
authors: Turid
authors: T
authors: Knutsen
authors: Ian A
authors: IA
authors: Blair
authors: Carolyn A
authors: CA
authors: Felix
mesh_terms: D000293:Adolescent; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D051788:Myeloid-Lymphoid Leukemia Protein; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011519:Proto-Oncogenes; D011995:Recombination, Genetic; D014157:Transcription Factors; D014178:Translocation, Genetic
chemical_list: D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; C489901:MLLT3 protein, human; D009687:Nuclear Proteins; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase; D004250:DNA Topoisomerases, Type II