Constitutive NF-kappab/Rel activation in philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL).
The Bcr-Abl translocation t(9;22)(q34;q11 ) defines a subgroup of ALL patients with a dismal prognosis despite the introduction of intensified induction and consolidation regimen. Although Bcr-Abl induced NF-kappaB/Rel activation has previously been shown, the role of NF-kappaB/Rel in Ph+ leukemia is unclear. Using DNA binding assays, we demonstrate constitutive NF-kappaB/Rel activity in nuclear extracts from Ph+ ALL blasts, whereas Ph- primary blast cells and B-precursor cell lines lack NF-kappaB/Rel activity. NF-kappaB/Rel activity was shown in the ela2 and the b2a2 subtypes. Constitutive NF-kappaB/Rel activity in Ph+ blasts is not due to elevated endogenous IkappaB kinase (IKK) activity as shown by immune complex kinase assays. Since NF-kappaB/Rel is a transcriptional regulator of inhibitors of apoptosis we examined the expression of anti-apoptotic genes known to be induced by NF-kappaB/Rel by real time PCR analysis. We found no induction of TRAFI, TRAF2, cIAPI, cIAP2, XIAP, A20 or Bfl/Al in Ph+ ALL samples as compared to Ph-negative ALL controls. In summary, constitutive NF-kappaB/Rel activation independent of endogenous IKK activation may be a common finding in Ph+ ALL. However, targets of NF-kappaB/Rel mediated transcriptional regulation in this disease remain to be identified.
Munzert
Gerd
G
Abteilung Innere Medizin III, Universität Ulm, Germany. Gerd.Munzert@bc.boehringer-ingelheim.com
Kirchner
Dieter
D
Ottmann
Oliver
O
Bergmann
Lothar
L
Schmid
Roland M
RM
D017209:Apoptosis; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D051858:Forkhead Transcription Factors; D016044:Fusion Proteins, bcr-abl / Q000502:physiology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051550:I-kappa B Kinase; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins; D020572:Oncogene Proteins v-rel / Q000378:metabolism*; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000378:metabolism* / Q000473:pathology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012334:RNA, Neoplasm / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3; D051636:X-Linked Inhibitor of Apoptosis Protein
D004268:DNA-Binding Proteins; C090173:FOXG1 protein, human; D051858:Forkhead Transcription Factors; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D016328:NF-kappa B; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D020572:Oncogene Proteins v-rel; D011506:Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D047990:TNF Receptor-Associated Factor 1; D047992:TNF Receptor-Associated Factor 2; D051636:X-Linked Inhibitor of Apoptosis Protein; C496866:XIAP protein, human; D016044:Fusion Proteins, bcr-abl; D017346:Protein Serine-Threonine Kinases; C496559:CHUK protein, human; D051550:I-kappa B Kinase; C496560:IKBKB protein, human; C496565:IKBKE protein, human; C076529:TNFAIP3 protein, human; D000072598:Tumor Necrosis Factor alpha-Induced Protein 3