p16Ink4a or p19Arf loss contributes to Tal1-induced leukemogenesis in mice.
Analysis of the INK4A/ARF locus in human T-ALL patients revealed frequent deletions in exon 2, the exon common to both p16(INK4A) and p14(ARF). Other studies have described selective deletion of exon 1beta of p14(ARF) or methylation of the p16(INK4A) promoter. Therefore, it is unclear from these studies whether loss of p16(INK4A) and/or p14(ARF) contributes to the development of T-ALL. To elucidate the relative contribution of the ink4a/arf locus to T-cell leukemogenesis, we mated our tal1 transgenic mice to ink4a/arf-/-, p16(ink4a)-/-, and p19(arf)-/- mice and generated tal1/ink4a/arf+/-, tal1/p16(ink4a)+/-, and tal1/p19(arf)+/- mice. Each of these mice developed T-cell leukemia rapidly, indicating that loss of either p16(ink4a) or p19(arf) cooperates with Tal1 to induce leukemia in mice. Preleukemic studies reveal that Tal1 expression stimulates entry into the cell cycle and thymocyte apoptosis in vivo. Interestingly, mice expressing a DNA-binding mutant of Tal1 do not exhibit increases in S phase cells. The S phase induction is accompanied by an increase in thymocyte apoptosis in tal1 transgenic mice. Whereas apoptosis is reduced to wild-type levels in tal1/ink4a/arf-/- mice, S phase induction remains unaffected. Thus, Tal1 stimulates cell cycle entry independent of the ink4a/arf locus, but its ability to induce apoptosis is Ink4a/Arf-dependent.
Shank-Calvo
J A
JA
Department of Cancer Biology, University of Massachusetts Medical School, Worcester, 01650, USA.
Draheim
K
K
Bhasin
M
M
Kelliher
M A
MA
D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D000951:Antigens, Neoplasm / Q000032:analysis; D017209:Apoptosis / Q000235:genetics; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D002453:Cell Cycle / Q000235:genetics; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000172:deficiency / Q000502:physiology*; D004247:DNA / Q000378:metabolism; D005091:Exons / Q000235:genetics; D017353:Gene Deletion; D005786:Gene Expression Regulation; D015973:Gene Expression Regulation, Leukemic; D019942:Genes, p16; D006023:Glycoproteins / Q000502:physiology; D016130:Immunophenotyping; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D009363:Neoplasm Proteins / Q000235:genetics / Q000502:physiology; D011289:Preleukemia / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D051881:Receptor, Notch1 / Q000502:physiology; D016196:S Phase / Q000235:genetics; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D016176:T-Lymphocyte Subsets / Q000473:pathology; D014157:Transcription Factors / Q000502:physiology; D025803:Tumor Suppressor Protein p14ARF / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051153:Wnt Proteins / Q000502:physiology
D015703:Antigens, CD; D000951:Antigens, Neoplasm; D051792:Basic Helix-Loop-Helix Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004247:DNA; D006023:Glycoproteins; D009363:Neoplasm Proteins; D011518:Proto-Oncogene Proteins; D051881:Receptor, Notch1; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; D025803:Tumor Suppressor Protein p14ARF; D051153:Wnt Proteins; C417743:Cdkn2a protein, mouse; C497762:Notch1 protein, mouse; C489366:Tal1 protein, mouse; C468567:Wnt5b protein, mouse