SCL, LMO1 and Notch1 Reprogram Thymocytes ...
Document type :
Compte-rendu et recension critique d'ouvrage
Title :
SCL, LMO1 and Notch1 Reprogram Thymocytes into Self-Renewing Cells
Author(s) :
Gerby, Bastien [Auteur]
Centre de Recherches en Cancérologie de Toulouse [CRCT]
Tremblay, Cédric [Auteur]
Institut de Recherche en Immunologie et en Cancérologie [UdeM-Montréal] [IRIC]
Tremblay, Mathieu [Auteur]
Rojas-Sutterlin, Shanti [Auteur]
Herblot, Sabine [Auteur]
Hébert, Josée [Auteur]
Sauvageau, Guy [Auteur]
Lemieux, Sebastien [Auteur]
Institut de Recherche en Immunologie et en Cancérologie [UdeM-Montréal] [IRIC]
Lecuyer, Eric [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Veiga, Diogo [Auteur]
Hoang, Trang [Auteur]
Centre de Recherches en Cancérologie de Toulouse [CRCT]
Tremblay, Cédric [Auteur]
Institut de Recherche en Immunologie et en Cancérologie [UdeM-Montréal] [IRIC]
Tremblay, Mathieu [Auteur]
Rojas-Sutterlin, Shanti [Auteur]
Herblot, Sabine [Auteur]
Hébert, Josée [Auteur]
Sauvageau, Guy [Auteur]
Lemieux, Sebastien [Auteur]
Institut de Recherche en Immunologie et en Cancérologie [UdeM-Montréal] [IRIC]
Lecuyer, Eric [Auteur]
Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 [LOG]
Veiga, Diogo [Auteur]
Hoang, Trang [Auteur]
Journal title :
PLoS Genetics
Pages :
e1004768
Publisher :
Public Library of Science
Publication date :
2014-12-18
ISSN :
1553-7390
HAL domain(s) :
Sciences du Vivant [q-bio]
Sciences du Vivant [q-bio]/Cancer
Sciences du Vivant [q-bio]/Cancer
English abstract : [en]
The molecular determinants that render specific populations of normal cells susceptible to oncogenic reprogramming into self-renewing cancer stem cells are poorly understood. Here, we exploit T-cell acute lymphoblastic ...
Show more >The molecular determinants that render specific populations of normal cells susceptible to oncogenic reprogramming into self-renewing cancer stem cells are poorly understood. Here, we exploit T-cell acute lymphoblastic leukemia (T-ALL) as a model to define the critical initiating events in this disease. First, thymocytes that are reprogrammed by the SCL and LMO1 oncogenic transcription factors into self-renewing pre-leukemic stem cells (pre-LSCs) remain non-malignant, as evidenced by their capacities to generate functional T cells. Second, we provide strong genetic evidence that SCL directly interacts with LMO1 to activate the transcription of a self-renewal program coordinated by LYL1. Moreover, LYL1 can substitute for SCL to reprogram thymocytes in concert with LMO1. In contrast, inhibition of E2A was not sufficient to substitute for SCL, indicating that thymocyte reprogramming requires transcription activation by SCL-LMO1. Third, only a specific subset of normal thymic cells, known as DN3 thymocytes, is susceptible to reprogramming. This is because physiological NOTCH1 signals are highest in DN3 cells compared to other thymocyte subsets. Consistent with this, overexpression of a ligand-independent hyperactive NOTCH1 allele in all immature thymocytes is sufficient to sensitize them to SCL-LMO1, thereby increasing the pool of self-renewing cells. Surprisingly, hyperactive NOTCH1 cannot reprogram thymocytes on its own, despite the fact that NOTCH1 is activated by gain of function mutations in more than 55% of TALL cases. Rather, elevating NOTCH1 triggers a parallel pathway involving Hes1 and Myc that dramatically enhances the activity of SCL-LMO1 We conclude that the acquisition of self-renewal and the genesis of pre-LSCs from thymocytes with a finite lifespan represent a critical first event in TALL. Finally, LYL1 and LMO1 or LMO2 are co-expressed in most human TALL samples, except the cortical T subtype. We therefore anticipate that the self-renewal network described here may be relevant to a majority of human TALL .Show less >
Show more >The molecular determinants that render specific populations of normal cells susceptible to oncogenic reprogramming into self-renewing cancer stem cells are poorly understood. Here, we exploit T-cell acute lymphoblastic leukemia (T-ALL) as a model to define the critical initiating events in this disease. First, thymocytes that are reprogrammed by the SCL and LMO1 oncogenic transcription factors into self-renewing pre-leukemic stem cells (pre-LSCs) remain non-malignant, as evidenced by their capacities to generate functional T cells. Second, we provide strong genetic evidence that SCL directly interacts with LMO1 to activate the transcription of a self-renewal program coordinated by LYL1. Moreover, LYL1 can substitute for SCL to reprogram thymocytes in concert with LMO1. In contrast, inhibition of E2A was not sufficient to substitute for SCL, indicating that thymocyte reprogramming requires transcription activation by SCL-LMO1. Third, only a specific subset of normal thymic cells, known as DN3 thymocytes, is susceptible to reprogramming. This is because physiological NOTCH1 signals are highest in DN3 cells compared to other thymocyte subsets. Consistent with this, overexpression of a ligand-independent hyperactive NOTCH1 allele in all immature thymocytes is sufficient to sensitize them to SCL-LMO1, thereby increasing the pool of self-renewing cells. Surprisingly, hyperactive NOTCH1 cannot reprogram thymocytes on its own, despite the fact that NOTCH1 is activated by gain of function mutations in more than 55% of TALL cases. Rather, elevating NOTCH1 triggers a parallel pathway involving Hes1 and Myc that dramatically enhances the activity of SCL-LMO1 We conclude that the acquisition of self-renewal and the genesis of pre-LSCs from thymocytes with a finite lifespan represent a critical first event in TALL. Finally, LYL1 and LMO1 or LMO2 are co-expressed in most human TALL samples, except the cortical T subtype. We therefore anticipate that the self-renewal network described here may be relevant to a majority of human TALL .Show less >
Language :
Anglais
Popular science :
Non
Source :
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