BCR/ABL modulates protein phosphorylation associated with the etoposide-induced DNA damage response.
BCR/ABL expression is the key characteristic of chronic myeloid leukaemia (CML). The progression of CML is associated with genomic instability. Systematic analysis of DNA damage signalling in the presence of BCR/ABL thus offers opportunities to identify mechanisms of leukaemic progression. We therefore undertook a quantitative phosphoproteomics study to test whether BCR/ABL expression could globally affect the response to genotoxic stress signalling. Etoposide-induced DNA damage was chosen and the concentration and time of exposure determined such that apoptosis was not associated with the study. More than 1100 phosphoentities were identified. BCR/ABL was shown to significantly alter the response to etoposide in many cases. These include sites on MDC1, a key component of DNA repair, and Hemogen. Hemogen is a transcriptional target of HOXB4 and GATA1, two transcription factors involved in haemopoietic development, and is overexpressed in acute myeloid leukaemia. To validate Hemogen phosphorylation, absolute quantification using an isotopomeric standard and selected reaction monitoring was performed. This revealed a strong correlation with isobaric tagging data and offering quantification at about 10 fmol per million cells. Furthermore we found that multiple protein phosphorylation changes mediated by BCR/ABL were connected to the increased activation of NFκB, a key survival transcription factor, after etoposide exposure.
Stem Cell and Leukaemia Proteomics Laboratory, Manchester Academic Health, Science Centre, The University of Manchester, Wolfson Molecular Imaging, Centre, 27 Palatine Road, Withington, Manchester, M20 3LJ, UK.
François
F
Griaud
Andrew J K
AJ
Williamson
Samuel
S
Taylor
David N
DN
Potier
Elaine
E
Spooncer
Andrew
A
Pierce
Anthony D
AD
Whetton
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D004249:DNA Damage; D005047:Etoposide / Q000494:pharmacology*; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism*; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000401:mortality* / Q000473:pathology; D051379:Mice; D009687:Nuclear Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*
D000972:Antineoplastic Agents, Phytogenic; C486660:Hemgn protein, mouse; D009687:Nuclear Proteins; D005047:Etoposide; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl