PML/RARalpha, a fusion protein in acute promyelocytic leukemia, prevents growth factor withdrawal-induced apoptosis in TF-1 cells.
A unique mRNA produced by the t(15;17) (q22-24;q11-21) translocation in the leukemic cells of acute promyelocytic leukemia patients encodes a chimeric protein, PML/RARalpha, which is formed by the fusion of the retinoic acid receptor alpha (RARalpha) and the promyelocytic locus gene (PML). This translocation is often the only visible karyotypic aberration present which is detected in almost 100% of acute promyelocytic leukemia patients. As an initial step to study the role of PML/RARalpha in leukemogenesis, we attempted to express the fusion protein in hematopoietic cells through retrovirus-mediated gene transfer of the retroviral vector, pGPRCHT, which contains the PML/RARalpha cDNA. Transduction of the PML/RARalpha cDNA fragment used in this vector, which extends from the position 31 bp to the position 2638 bp in a transcription unit driven by the Moloney murine sarcoma virus LTR, was found to abrogate the growth factor dependence of TF-1 cells. In addition, introduction of PML/RARalpha into TF-1 cells can protect these cells from the apoptosis usually induced in TF-1 cells by growth factor withdrawal, as measured by three assays for apoptosis: morphology, DNA ladder formation, and end labeling of nicked DNA with fluorescent-conjugated nucleotide precursors followed by a fluorescence-activated cell sorting assay. These data suggest that the PML/RARalpha fusion protein may inhibit programmed cell death in myeloid cells.
Fu
S
S
Department of Hematology, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA.
Consoli
U
U
Hanania
E G
EG
Zu
Z
Z
Claxton
D F
DF
Andreeff
M
M
Deisseroth
A B
AB
D017209:Apoptosis / Q000502:physiology*; D002455:Cell Division / Q000187:drug effects; D002874:Chromosome Mapping; D002884:Chromosomes, Human, Pair 15; D002886:Chromosomes, Human, Pair 17; D005822:Genetic Vectors; D006133:Growth Substances / Q000494:pharmacology / Q000502:physiology; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics*; D008954:Models, Biological; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism*; D015514:Oncogene Proteins, Fusion / Q000235:genetics* / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012190:Retroviridae; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection; D014178:Translocation, Genetic; D014407:Tumor Cells, Cultured
D006133:Growth Substances; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011993:Recombinant Fusion Proteins; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein