Modeling T-cell acute lymphoblastic leukemia induced by the SCL and LMO1 oncogenes.
Deciphering molecular events required for full transformation of normal cells into cancer cells remains a challenge. In T-cell acute lymphoblastic leukemia (T-ALL), the genes encoding the TAL1/SCL and LMO1/2 transcription factors are recurring targets of chromosomal translocations, whereas NOTCH1 is activated in >50% of samples. Here we show that the SCL and LMO1 oncogenes collaborate to expand primitive thymocyte progenitors and inhibit later stages of differentiation. Together with pre-T-cell antigen receptor (pre-TCR) signaling, these oncogenes provide a favorable context for the acquisition of activating Notch1 mutations and the emergence of self-renewing leukemia-initiating cells in T-ALL. All tumor cells harness identical and specific Notch1 mutations and Tcrbeta clonal signature, indicative of clonal dominance and concurring with the observation that Notch1 gain of function confers a selective advantage to SCL-LMO1 transgenic thymocytes. Accordingly, a hyperactive Notch1 allele accelerates leukemia onset induced by SCL-LMO1 and bypasses the requirement for pre-TCR signaling. Finally, the time to leukemia induced by the three transgenes corresponds to the time required for clonal expansion from a single leukemic stem cell, suggesting that SCL, LMO1, and Notch1 gain of function, together with an active pre-TCR, might represent the minimum set of complementing events for the transformation of susceptible thymocytes.
Institute of Research in Immunology and Cancer, University of Montreal, Montréal, Québec H3C3J7, Canada.
Mathieu
M
Tremblay
Cédric S
CS
Tremblay
Sabine
S
Herblot
Peter D
PD
Aplan
Josée
J
Hébert
Claude
C
Perreault
Trang
T
Hoang
D000818:Animals; D017951:Antigen Presentation / Q000502:physiology; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D017252:CD3 Complex / Q000235:genetics / Q000378:metabolism; D049109:Cell Proliferation; D002478:Cells, Cultured; D015972:Gene Expression Regulation, Neoplastic; D060588:LIM Domain Proteins; D008285:Major Histocompatibility Complex / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000378:metabolism / Q000473:pathology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D013601:T-Lymphocytes / Q000378:metabolism / Q000473:pathology*; D013950:Thymus Gland / Q000166:cytology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D051792:Basic Helix-Loop-Helix Proteins; D017252:CD3 Complex; D060588:LIM Domain Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D051881:Receptor, Notch1; D000073942:T-Cell Acute Lymphocytic Leukemia Protein 1; D014157:Transcription Factors; C513044:Lmo1 protein, mouse; C497762:Notch1 protein, mouse; C489366:Tal1 protein, mouse