Cytogenetic and molecular analysis of the acute monocytic leukemia cell line THP-1 with an MLL-AF9 translocation.
Cell lines derived from patients with leukemia are used in many molecular biology studies. Here we report the cytogenetic analysis of the THP-1 cell line using G-banding, fluorescence in situ hybridization (FISH), and spectral karyotyping (SKY), and the molecular characterization of the MLL-AF9 rearrangement by RT-PCR. The THP-1 cell line was established from the peripheral blood of a 1-year-old boy with acute monocytic leukemia (AML-M5). THP-1 is near-diploid and consists of two related subclones with a number of aberrations, including the t(9;11), associated with AML M5. The use of FISH allowed us to identify and characterize otherwise hidden cytogenetic rearrangements, which include duplication of the 3' portion of MLL in the derivative 9 chromosome and a deletion of the 5' portion of the AF9 gene involved in the translocation. In addition to confirming the FISH results, SKY allowed for a more precise characterization of the karyotype of THP-1 and allowed us to identify other abnormalities in this cell line, including der(1)t(1;12), der(20)t(1;20), deletions 6p, 12p, and 17p, trisomy 8, and monosomy 10. Sequencing of the RT-PCR product showed a direct in-frame fusion product on the derivative chromosome 11 between exon 6 (exon 9) of MLL and exon 5 of AF9, which is most commonly involved in MLL-AF9 translocations. This study demonstrates that combining different techniques to achieve a more precise characterization of the THP-1 cell line provides important information that will be valuable for understanding the critical events required for leukemogenesis.
Odero
M D
MD
University of Navarra, Pamplona, Navarra, Spain.
Zeleznik-Le
N J
NJ
Chinwalla
V
V
Rowley
J D
JD
D000595:Amino Acid Sequence; D001483:Base Sequence; D002869:Chromosome Aberrations / Q000235:genetics; D002871:Chromosome Banding; D025063:Chromosome Disorders; D002899:Chromosomes, Human, Pair 9 / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D007948:Leukemia, Monocytic, Acute / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D051788:Myeloid-Lymphoid Leukemia Protein; D009687:Nuclear Proteins / Q000235:genetics*; D015514:Oncogene Proteins, Fusion / Q000235:genetics; D011519:Proto-Oncogenes; D014157:Transcription Factors; D014178:Translocation, Genetic / Q000235:genetics*; D014407:Tumor Cells, Cultured
D004268:DNA-Binding Proteins; C497422:KMT2A protein, human; C489901:MLLT3 protein, human; D009687:Nuclear Proteins; D015514:Oncogene Proteins, Fusion; D014157:Transcription Factors; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase