KBM-7, a human myeloid leukemia cell line with double Philadelphia chromosomes lacking normal c-ABL and BCR transcripts.
A human myeloid leukemia cell line, KBM-7, was developed from a patient in the blastic phase of chronic myeloid leukemia (CML). We characterized its morphology, immunophenotype, cytogenetics, and proliferative capacity. Developed in the absence of exogenous lymphokines, KBM-7 in vitro cloning capacity actually decreased when colony-stimulating factors were added. The cells had an aberrant immature myeloid phenotype, a doubling time of 22 h in suspension cultures and a high cloning efficiency in semisolid system (24 +/- 3)%. Early passages contained one near-haploid (predominant) and one hyperdiploid stem line. Gradually the hyperdiploid stem line became predominant, reaching an average of 49 chromosomes per cell. Cells from passage 89 had two Philadelphia chromosomes [t(9;22)(q34;q11)] and lacked normal copies of chromosomes 9 and 22. Detailed molecular characterization of the breakpoint in the t(9;22)(q34;q11) revealed that KBM-7 had the BCR 2/ABL II splice junction. The cells had high protein kinase (p210BCR-ABL) activity and carried two identified variants of an ABL-BCR message. There was no evidence that normal BCR or c-ABL messages were expressed, assessed with the reverse-transcriptase polymerase chain reaction. When KBM-7 cells were heterotransplanted into nude mice without immunosuppressive pretreatment, one of three mice injected with 1 x 10(7) cells and all mice injected with 1 x 10(8) cells developed slowly growing granulocytic sarcomas within 6-8 weeks. These tumors were locally invasive but did not metastasize. We conclude that the KBM-7 cell line will be of value for investigating molecular events underlying neoplastic transformation in CML, in particular for studying the effects of BCR-ABL and ABL-BCR on the proliferation of CML cells in the absence of normal BCR and c-ABL messages.
Andersson
B S
BS
Department of Hematology, University of Texas MD Anderson Cancer Center, Houston 77030, USA.
Collins
V P
VP
Kurzrock
R
R
Larkin
D W
DW
Childs
C
C
Ost
A
A
Cork
A
A
Trujillo
J M
JM
Freireich
E J
EJ
Siciliano
M J
MJ
D000818:Animals; D001483:Base Sequence; D002455:Cell Division; D016044:Fusion Proteins, bcr-abl / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007621:Karyotyping; D007951:Leukemia, Myeloid / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D015513:Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D010677:Philadelphia Chromosome; D011505:Protein-Tyrosine Kinases; D011518:Proto-Oncogene Proteins; D051562:Proto-Oncogene Proteins c-bcr; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; C496613:BCR protein, human; C496614:Bcr protein, mouse; D051562:Proto-Oncogene Proteins c-bcr