Myeloid progenitor cells lacking p53 exhibit delayed up-regulation of Puma and prolonged survival after cytokine deprivation.
Loss of p53-dependent apoptosis contributes to the development of hematologic malignancies and failure to respond to treatment. Proapoptotic Bcl-2 family member Puma is essential for apoptosis in HoxB8-immortalized interleukin-3 (IL-3)-dependent myeloid cell lines (FDM cells) provoked by IL-3 deprivation. p53 and FoxO3a can transcriptionally regulate Puma. To investigate which transcriptional regulator is responsible for IL-3 deprivation-induced Puma expression and apoptosis, we generated wild-type (WT), p53(-/-), and FoxO3a(-/-) FDM cells and found that p53(-/-) but not FoxO3a(-/-) cells were protected against IL-3 withdrawal. Loss of p21(cip/waf), which is critical for p53-mediated cell-cycle arrest, afforded no protection against IL-3 deprivation. A survival advantage was also observed in untransformed p53(-/-) hematopoietic progenitor cells cultured in the presence or absence of cytokines. In response to IL-3 deprivation, increased Puma protein levels in p53(-/-) cells were substantially delayed compared with WT cells. Increased p53 transcriptional activity was detected after cytokine deprivation. This was substantially less than that induced by DNA damage and associated not with increased p53 protein levels but with loss of the p53 regulator, MDM2. Thus, we conclude that p53 protein is activated after IL-3 deprivation by loss of MDM2. Activated p53 transcriptionally up-regulates Puma, which initiates apoptosis.
Jabbour
Anissa M
AM
Children's Cancer Centre, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC, Australia. anissa.jabbour@mcri.edu.au
Daunt
Carmel P
CP
Green
Benjamin D
BD
Vogel
Sandra
S
Gordon
Lavinia
L
Lee
Rachel S
RS
Silke
Natasha
N
Pearson
Richard B
RB
Vandenberg
Cassandra J
CJ
Kelly
Priscilla N
PN
Nutt
Stephen L
SL
Strasser
Andreas
A
Borner
Christoph
C
Ekert
Paul G
PG
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000235:genetics; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects / Q000235:genetics; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000235:genetics / Q000378:metabolism; D017353:Gene Deletion; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007377:Interleukin-3 / Q000378:metabolism* / Q000494:pharmacology; D051379:Mice; D023461:Myeloid Progenitor Cells / Q000166:cytology / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D051736:Proto-Oncogene Proteins c-mdm2 / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000096:biosynthesis* / Q000235:genetics; D015854:Up-Regulation
D051017:Apoptosis Regulatory Proteins; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; C474033:FoxO3 protein, mouse; D018398:Homeodomain Proteins; C095822:Hoxb8 protein, mouse; D007377:Interleukin-3; C488588:PUMA protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C497207:Mdm2 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2