Leukemia with distinct phenotypes in transgenic mice expressing PML/RAR alpha, PLZF/RAR alpha or NPM/RAR alpha.
Recurrent chromosomal translocations involving the RAR alpha locus on chromosome 17 are the hallmark of acute promyelocytic leukemia (APL). The RAR alpha gene fuses to variable partners (PML, PLZF, NPM, NuMA and STAT5B: X genes) leading to the expression of APL-specific fusion proteins with identical RAR alpha moieties. To analyse whether the variable X moiety could affect the activity of the fusion protein in vivo, we generated and characterized, on a comparative basis, NPM/RAR alpha transgenic mice (TM) in which the fusion gene is expressed under the control of a human Cathepsin G (hCG) minigene. We compared the features of the leukemia observed in these TM with those in hCG-PML/RAR alpha and hCG-PLZF/RAR alpha TM. In all three transgenic models, leukemia developed after a variably long latency, with variable penetrance. However, the three leukemias displayed distinct cytomorphological features. hCG-NPM/RAR alpha leukemic cells resembled monoblasts. This phenotype contrasts with what was observed in the hCG-PML/RAR alpha TM model in which the leukemic phase was characterized by the proliferation of promyelocytic blasts. Similarly, hCG-PLZF/RAR alpha TM displayed a different phenotype where terminally differentiated myeloid cells predominated. Importantly, the NPM/RAR alpha oncoprotein was found to localize in the nucleolus, unlike PML/RAR alpha and PLZF/RAR alpha, thus possibly interfering with the normal function of NPM. Similarly to what was observed in human APL patients, we found that NPM/RAR alpha and PML/RAR alpha, but not PLZF/RAR alpha leukemia, was responsive to all-trans retinoic acid (ATRA) or As2O3 treatments. Taken together, our results underscore the critical relevance of the X moiety in dictating the biology of the disease and the activity of the APL fusion oncoprotein.
Rego
E M
EM
Cancer Biology and Genetics Program, Department of Pathology, Memorial Sloan-Kettering Cancer Center, Sloan Kettering Institute, New York, NY 10021, USA.
Ruggero
D
D
Tribioli
C
C
Cattoretti
G
G
Kogan
S
S
Redner
R L
RL
Pandolfi
P P
PP
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D056649:Cathepsin G; D002403:Cathepsins / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D002471:Cell Transformation, Neoplastic; D004268:DNA-Binding Proteins / Q000235:genetics*; D050939:Gene Fusion; D006801:Humans; D051741:Kruppel-Like Transcription Factors; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D009363:Neoplasm Proteins / Q000235:genetics*; D009687:Nuclear Proteins / Q000235:genetics*; D010641:Phenotype; D000071156:Promyelocytic Leukemia Protein; D000075722:Promyelocytic Leukemia Zinc Finger Protein; D018168:Receptors, Retinoic Acid / Q000235:genetics*; D000072482:Retinoic Acid Receptor alpha; D012697:Serine Endopeptidases / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics*; D014178:Translocation, Genetic; D014212:Tretinoin / Q000494:pharmacology; D025521:Tumor Suppressor Proteins / Q000235:genetics*
D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D051741:Kruppel-Like Transcription Factors; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C513293:Pml protein, mouse; D000071156:Promyelocytic Leukemia Protein; D000075722:Promyelocytic Leukemia Zinc Finger Protein; C000607071:RARA protein, human; C000607072:Rara protein, mouse; D018168:Receptors, Retinoic Acid; D000072482:Retinoic Acid Receptor alpha; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C513267:Zbtb16 protein, mouse; C070576:PML protein, human; C092037:ZBTB16 protein, human; D014212:Tretinoin; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; C534096:Ctsg protein, mouse