Identification of DJ-1/PARK-7 as a determinant of stroma-dependent and TNF-alpha-induced apoptosis in MDS using mass spectrometry and phosphopeptide analysis.
In patients with myelodysplastic syndromes (MDS), apoptosis in hematopoietic cells is up-regulated in low-grade disease, whereas advanced disease is characterized by apoptosis resistance. We have shown that marrow stroma-derived signals convey sensitivity to tumor-necrosis-factor alpha (TNF-alpha)-mediated apoptosis in otherwise-resistant KG1a myeloid cells and CD34(+) cells from MDS marrow. Here, we used a PhosphoScan proteomic liquid chromatography-mass spectrometry method to identify signals relevant for this effect. The transcription factor DJ-1/PARK-7 (DJ-1) was highly phosphorylated in KG1a cells cultured without stroma but dephosphorylated after stroma coculture, whereas expression of p53 increased significantly, suggesting a stroma contact-dependent effect of DJ-1 on p53. In CD34(+) marrow cells from advanced MDS, expression of DJ-1 was up-regulated, whereas p53 levels were low, resulting in significantly greater DJ-1/p53 ratios than in patients with low-grade MDS (P = .01). DJ-1 levels were correlated with increasing International Prognostic Scoring System scores (P = .006). Increasing DJ-1/p53 ratios were associated with an increased risk of mortality, although the correlation did not reach statistical significance (P = .18). These data suggest that DJ-1/p53 interactions contribute to apoptosis resistance in clonal myeloid cells and may serve as a prognostic marker in patients with MDS.
Marcondes
A Mario
AM
Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
Li
Xiang
X
Gooley
Ted A
TA
Milless
Brian
B
Deeg
H Joachim
HJ
D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D008297:Male; D013058:Mass Spectrometry / Q000379:methods; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D015513:Oncogene Proteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D010748:Phosphopeptides / Q000032:analysis / Q000737:chemistry; D010766:Phosphorylation; D000071617:Protein Deglycase DJ-1; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D012189:Retrospective Studies; D017154:Stromal Cells / Q000378:metabolism / Q000502:physiology*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
D047908:Intracellular Signaling Peptides and Proteins; D015513:Oncogene Proteins; D010748:Phosphopeptides; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; D011505:Protein-Tyrosine Kinases; C105131:PARK7 protein, human; D000071617:Protein Deglycase DJ-1