Tracing the pre-B to immature B cell transition in human leukemia cells reveals a coordinated sequence of primary and secondary IGK gene rearrangement, IGK deletion, and IGL gene rearrangement.
The BCR-ABL1 kinase expressed in acute lymphoblastic leukemia (ALL) drives malignant transformation of pre-B cells and prevents further development. We studied whether inhibition of BCR-ABL1 kinase activity using STI571 can relieve this differentiation block. STI571 treatment of leukemia patients induced expression of the Ig L chain-associated transcription factors IRF4 and SPIB, up-regulation of RAG1 and RAG2, Ckappa and Clambda germline transcription, and rearrangement of Ig kappa L chain (IGK) and Ig lambda L chain (IGL) genes. However, STI571-treated pre-B ALL cells expressed lambda L, but almost no kappa L chains. This could be explained by STI571-induced rearrangement of the kappa-deleting element (KDE), which can delete productively rearranged Vkappa-Jkappa joints. Amplifying double-strand breaks at recombination signal sequences within the IGK, KDE, and IGL loci revealed a coordinated sequence of rearrangement events induced by STI571: recombination of IGK gene segments was already initiated within 1 h after STI571 treatment, followed by KDE-mediated deletion of Vkappa-Jkappa joints 6 h later and, ultimately, IGL gene rearrangement after 12 h. Consistently, up-regulation of Ckappa and Clambda germline transcripts, indicating opening of IGK and IGL loci, was detected after 1 and 6 h for IGK and IGL, respectively. Continued activity of the recombination machinery induced secondary IGK gene rearrangements, which shifted preferential usage of upstream located Jkappa- to downstream Jkappa-gene segments. Thus, inhibition of BCR-ABL1 in pre-B ALL cells 1) recapitulates early B cell development, 2) directly shows that IGK, KDE, and IGL genes are rearranged in sequential order, and 3) provides a model for Ig L chain gene regulation in the human.
Klein
Florian
F
Laboratory for Molecular Stem Cell Biology, Center for Biomedical Research and Institute for Transplantation Diagnostics and Cell Therapeutics, Heinrich-Heine-Universität Düsseldorf, 40225 Düsseldorf, Germany.
Feldhahn
Niklas
N
Mooster
Jana L
JL
Sprangers
Mieke
M
Hofmann
Wolf-Karsten
WK
Wernet
Peter
P
Wartenberg
Maria
M
Müschen
Markus
M
D001402:B-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D001549:Benzamides; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D016044:Fusion Proteins, bcr-abl; D015972:Gene Expression Regulation, Neoplastic; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain / Q000187:drug effects* / Q000235:genetics; D020662:Guanine Nucleotide Exchange Factors / Q000187:drug effects / Q000378:metabolism; D018398:Homeodomain Proteins / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D000068877:Imatinib Mesylate; D007136:Immunoglobulins / Q000235:genetics; D009687:Nuclear Proteins; D010879:Piperazines / Q000627:therapeutic use; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics*; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011743:Pyrimidines / Q000627:therapeutic use; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000187:drug effects* / Q000378:metabolism; D014157:Transcription Factors / Q000187:drug effects / Q000378:metabolism
D001549:Benzamides; C479750:DEF6 protein, human; D017931:DNA Primers; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D018398:Homeodomain Proteins; C014609:IgK; D007136:Immunoglobulins; D009687:Nuclear Proteins; D010879:Piperazines; D047428:Protein Kinase Inhibitors; D011743:Pyrimidines; C499311:RAG2 protein, human; D014157:Transcription Factors; C064655:V(D)J recombination activating protein 2; C064658:RAG-1 protein; C076877:SPIB protein, human; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl