RESUMO
Kinase signaling fuels growth of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Yet its role in leukemia initiation is unclear and has not been shown in primary human hematopoietic cells. We previously described activating mutations in interleukin-7 receptor alpha (IL7RA) in poor-prognosis "ph-like" BCP-ALL. Here we show that expression of activated mutant IL7RA in human CD34+ hematopoietic stem and progenitor cells induces a preleukemic state in transplanted immunodeficient NOD/LtSz-scid IL2Rγnull mice, characterized by persistence of self-renewing Pro-B cells with non-productive V(D)J gene rearrangements. Preleukemic CD34+CD10highCD19+ cells evolve into BCP-ALL with spontaneously acquired Cyclin Dependent Kinase Inhibitor 2 A (CDKN2A) deletions, as commonly observed in primary human BCP-ALL. CRISPR mediated gene silencing of CDKN2A in primary human CD34+ cells transduced with activated IL7RA results in robust development of BCP-ALLs in-vivo. Thus, we demonstrate that constitutive activation of IL7RA can initiate preleukemia in primary human hematopoietic progenitors and cooperates with CDKN2A silencing in progression into BCP-ALL.
Assuntos
Subunidade alfa de Receptor de Interleucina-7/imunologia , Leucemia-Linfoma Linfoblástico de Células Precursoras B/imunologia , Células Precursoras de Linfócitos B/imunologia , Transdução de Sinais/imunologia , Animais , Antígenos CD34/genética , Antígenos CD34/imunologia , Antígenos CD34/metabolismo , Sequência de Bases , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor p16 de Quinase Dependente de Ciclina/imunologia , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Expressão Gênica/imunologia , Humanos , Subunidade alfa de Receptor de Interleucina-7/genética , Subunidade alfa de Receptor de Interleucina-7/metabolismo , Camundongos Endogâmicos NOD , Camundongos Knockout , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/metabolismo , Células Precursoras de Linfócitos B/metabolismo , RNA-Seq/métodos , Receptores de Citocinas/genética , Receptores de Citocinas/imunologia , Receptores de Citocinas/metabolismo , Transdução de Sinais/genética , Análise de Célula Única/métodos , Transplante HeterólogoRESUMO
Comparison of intratumor genetic heterogeneity in cancer at diagnosis and relapse suggests that chemotherapy induces bottleneck selection of subclonal genotypes. However, evolutionary events subsequent to chemotherapy could also explain changes in clonal dominance seen at relapse. We, therefore, investigated the mechanisms of selection in childhood B-cell precursor acute lymphoblastic leukemia (BCP-ALL) during induction chemotherapy where maximal cytoreduction occurs. To distinguish stochastic versus deterministic events, individual leukemias were transplanted into multiple xenografts and chemotherapy administered. Analyses of the immediate post-treatment leukemic residuum at single-cell resolution revealed that chemotherapy has little impact on genetic heterogeneity. Rather, it acts on extensive, previously unappreciated, transcriptional and epigenetic heterogeneity in BCP-ALL, dramatically reducing the spectrum of cell states represented, leaving a genetically polyclonal but phenotypically uniform population with hallmark signatures relating to developmental stage, cell cycle and metabolism. Hence, canalization of cell state accounts for a significant component of bottleneck selection during induction chemotherapy.
Assuntos
Linfoma de Burkitt , Leucemia-Linfoma Linfoblástico de Células Precursoras , Linfoma de Burkitt/tratamento farmacológico , Ciclo Celular , Humanos , Quimioterapia de Indução , Leucemia-Linfoma Linfoblástico de Células Precursoras/tratamento farmacológico , RecidivaRESUMO
ETV6-RUNX1 is associated with childhood acute B-lymphoblastic leukemia (cALL) functioning as a first-hit mutation that initiates a clinically silent pre-leukemia in utero. Because lineage commitment hierarchies differ between embryo and adult, and the impact of oncogenes is cell-context dependent, we hypothesized that the childhood affiliation of ETV6-RUNX1 cALL reflects its origins in a progenitor unique to embryonic life. We characterize the first emerging B cells in first-trimester human embryos, identifying a developmentally restricted CD19-IL-7R+ progenitor compartment, which transitions from a myeloid to lymphoid program during ontogeny. This developmental series is recapitulated in differentiating human pluripotent stem cells (hPSCs), thereby providing a model for the initiation of cALL. Genome-engineered hPSCs expressing ETV6-RUNX1 from the endogenous ETV6 locus show expansion of the CD19-IL-7R+ compartment, show a partial block in B lineage commitment, and produce proB cells with aberrant myeloid gene expression signatures and potential: features (collectively) consistent with a pre-leukemic state.
Assuntos
Linfócitos B/patologia , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Desenvolvimento Embrionário , Regulação Leucêmica da Expressão Gênica , Células-Tronco Pluripotentes Induzidas/patologia , Células Mieloides/patologia , Proteínas de Fusão Oncogênica/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Doença Aguda , Linfócitos B/metabolismo , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Feminino , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Modelos Biológicos , Células Mieloides/metabolismo , Proteínas de Fusão Oncogênica/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras/metabolismo , Gravidez , Primeiro Trimestre da Gravidez , Receptores de Interleucina-7 , TranscriptomaRESUMO
Tumor relapse is associated with dismal prognosis, but responsible biological principles remain incompletely understood. To isolate and characterize relapse-inducing cells, we used genetic engineering and proliferation-sensitive dyes in patient-derived xenografts of acute lymphoblastic leukemia (ALL). We identified a rare subpopulation that resembled relapse-inducing cells with combined properties of long-term dormancy, treatment resistance, and stemness. Single-cell and bulk expression profiling revealed their similarity to primary ALL cells isolated from pediatric and adult patients at minimal residual disease (MRD). Therapeutically adverse characteristics were reversible, as resistant, dormant cells became sensitive to treatment and started proliferating when dissociated from the in vivo environment. Our data suggest that ALL patients might profit from therapeutic strategies that release MRD cells from the niche.