Multi-genetic events collaboratively contribute to Pten-null leukaemia stem-cell formation.
Cancer stem cells, which share many common properties and regulatory machineries with normal stem cells, have recently been proposed to be responsible for tumorigenesis and to contribute to cancer resistance. The main challenges in cancer biology are to identify cancer stem cells and to define the molecular events required for transforming normal cells to cancer stem cells. Here we show that Pten deletion in mouse haematopoietic stem cells leads to a myeloproliferative disorder, followed by acute T-lymphoblastic leukaemia (T-ALL). Self-renewable leukaemia stem cells (LSCs) are enriched in the c-Kit(mid)CD3(+)Lin(-) compartment, where unphosphorylated beta-catenin is significantly increased. Conditional ablation of one allele of the beta-catenin gene substantially decreases the incidence and delays the occurrence of T-ALL caused by Pten loss, indicating that activation of the beta-catenin pathway may contribute to the formation or expansion of the LSC population. Moreover, a recurring chromosomal translocation, T(14;15), results in aberrant overexpression of the c-myc oncogene in c-Kit(mid)CD3(+)Lin(-) LSCs and CD3(+) leukaemic blasts, recapitulating a subset of human T-ALL. No alterations in Notch1 signalling are detected in this model, suggesting that Pten inactivation and c-myc overexpression may substitute functionally for Notch1 abnormalities, leading to T-ALL development. Our study indicates that multiple genetic or molecular alterations contribute cooperatively to LSC transformation.
Guo
Wei
W
Department of Molecular and Medical Pharmacology, University of California, Los Angeles, Los Angeles, California 90095, USA.
Lasky
Joseph L
JL
Chang
Chun-Ju
CJ
Mosessian
Sherly
S
Lewis
Xiaoman
X
Xiao
Yun
Y
Yeh
Jennifer E
JE
Chen
James Y
JY
Iruela-Arispe
M Luisa
ML
Varella-Garcia
Marileila
M
Wu
Hong
H
D000818:Animals; D017252:CD3 Complex / Q000378:metabolism; D049109:Cell Proliferation; D033481:Chromosomes, Mammalian / Q000235:genetics; D005260:Female; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000473:pathology; D017404:In Situ Hybridization, Fluorescence; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000473:pathology*; D008297:Male; D051379:Mice; D014411:Neoplastic Stem Cells / Q000378:metabolism* / Q000473:pathology*; D051059:PTEN Phosphohydrolase / Q000172:deficiency* / Q000235:genetics*; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000235:genetics; D014178:Translocation, Genetic; D051176:beta Catenin / Q000378:metabolism
D017252:CD3 Complex; D016271:Proto-Oncogene Proteins c-myc; D011948:Receptors, Antigen, T-Cell; D051176:beta Catenin; D019009:Proto-Oncogene Proteins c-kit; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse