ACTIVATED JAK-STAT SIGNALING COOPERATES WITH HOXA9 AND DRIVES LEUKEMIA DEVELOPMENT
(Abstract release date: 05/19/16)
EHA Library. de Bock C. 06/12/16; 135295; S801
Dr. Charles de Bock
Contributions
Contributions
Abstract
Abstract: S801
Type: Oral Presentation
Presentation during EHA21: On Sunday, June 12, 2016 from 08:45 - 09:00
Location: Hall C11
Background
The JAK-STAT signaling pathway is critical for the normal development and proliferation of hematopoietic cells. Mutations in JAK1 or JAK3 occur within ~20% of T-cell acute lymphoblastic leukemia (T-ALL) cases and have also been described in other malignancies. We have previously shown that JAK3 mutations are able to transform hematopoietic cells in vitro and cause long latency T-ALL in a mouse model.
Aims
To determine mutations which are significantly associated with ectopic activation of the JAK-STAT signaling pathway and determine whether they cooperate in leukemia development in vivo.
Methods
Targeted-resequencing of 115 genes across 155 diagnostic T-ALL samples and qPCR on patient derived xenograft (PDX) samples was used to evaluate candidate genes significantly associated with mutations within the JAK-STAT5 pathway. Oncogenic cooperation and transformation to cytokine independent growth was evaluated using primary hematopoietic progenitor cells ex vivo. In vivo leukemia cooperation was assayed using a modified bone marrow transplant assay using either wild type or CD4-Cre donor mice in conjunction with either a retroviral vector for constitutive expression in all hematopoietic lineages or a novel antiparallel lox66/71 retroviral vector for restricted expression within developing T-cells.
Results
Mutations in JAK3 were found to frequently co-occur with HOXA cluster rearrangement and our qPCR analysis of PDX samples identified HOXA9 as the most upregulated HOXA gene in cases with mutant JAK3. Constitutive expression of the JAK3(M511I) mutant together with HOXA9 transformed murine hematopoietic progenitors to cytokine independent growth ex vivo, while JAK3 mutant or HOXA9 alone did not transform cells ex vivo. To model the possible cooperation of JAK3(M511I) and HOXA9 in vivo we initially used the bone marrow transplant model with constitutive expression of JAK3(M511I) and HOXA9. This led to the rapid development of a mixed myeloid-lymphoid leukemia in vivo (median survival = 82 days) compared to JAK3(M511I) alone (median survival = 164 days) or HOXA9 alone (no disease). To study the cooperation during T-ALL development specifically, we modified the bone marrow transplant model by using a novel inducible retroviral vector in combination with CD2-Cre or CD4-Cre donor bone marrow cells so that JAK3(M511I) and HOXA9 expression is delayed to lymphoid progenitors or T-cells. All models confirmed a clear cooperation between JAK3(M511I) and HOXA9, and ChIP-seq, ATAC-seq, and RNA-seq on the leukemic cells confirmed cooperation at the transcriptional level between STAT5 (downstream of JAK3) and HOXA9
Conclusion
JAK3 mutations and ectopic expression of HOXA9 cooperate to transform hematopoietic cells and cause rapid leukemia development in vivo.
Session topic: ALL Biology - Transcriptional dysregulation
Keyword(s): HOXa9, Mouse model, T-ALL
Type: Oral Presentation
Presentation during EHA21: On Sunday, June 12, 2016 from 08:45 - 09:00
Location: Hall C11
Background
The JAK-STAT signaling pathway is critical for the normal development and proliferation of hematopoietic cells. Mutations in JAK1 or JAK3 occur within ~20% of T-cell acute lymphoblastic leukemia (T-ALL) cases and have also been described in other malignancies. We have previously shown that JAK3 mutations are able to transform hematopoietic cells in vitro and cause long latency T-ALL in a mouse model.
Aims
To determine mutations which are significantly associated with ectopic activation of the JAK-STAT signaling pathway and determine whether they cooperate in leukemia development in vivo.
Methods
Targeted-resequencing of 115 genes across 155 diagnostic T-ALL samples and qPCR on patient derived xenograft (PDX) samples was used to evaluate candidate genes significantly associated with mutations within the JAK-STAT5 pathway. Oncogenic cooperation and transformation to cytokine independent growth was evaluated using primary hematopoietic progenitor cells ex vivo. In vivo leukemia cooperation was assayed using a modified bone marrow transplant assay using either wild type or CD4-Cre donor mice in conjunction with either a retroviral vector for constitutive expression in all hematopoietic lineages or a novel antiparallel lox66/71 retroviral vector for restricted expression within developing T-cells.
Results
Mutations in JAK3 were found to frequently co-occur with HOXA cluster rearrangement and our qPCR analysis of PDX samples identified HOXA9 as the most upregulated HOXA gene in cases with mutant JAK3. Constitutive expression of the JAK3(M511I) mutant together with HOXA9 transformed murine hematopoietic progenitors to cytokine independent growth ex vivo, while JAK3 mutant or HOXA9 alone did not transform cells ex vivo. To model the possible cooperation of JAK3(M511I) and HOXA9 in vivo we initially used the bone marrow transplant model with constitutive expression of JAK3(M511I) and HOXA9. This led to the rapid development of a mixed myeloid-lymphoid leukemia in vivo (median survival = 82 days) compared to JAK3(M511I) alone (median survival = 164 days) or HOXA9 alone (no disease). To study the cooperation during T-ALL development specifically, we modified the bone marrow transplant model by using a novel inducible retroviral vector in combination with CD2-Cre or CD4-Cre donor bone marrow cells so that JAK3(M511I) and HOXA9 expression is delayed to lymphoid progenitors or T-cells. All models confirmed a clear cooperation between JAK3(M511I) and HOXA9, and ChIP-seq, ATAC-seq, and RNA-seq on the leukemic cells confirmed cooperation at the transcriptional level between STAT5 (downstream of JAK3) and HOXA9
Conclusion
JAK3 mutations and ectopic expression of HOXA9 cooperate to transform hematopoietic cells and cause rapid leukemia development in vivo.
Session topic: ALL Biology - Transcriptional dysregulation
Keyword(s): HOXa9, Mouse model, T-ALL
Abstract: S801
Type: Oral Presentation
Presentation during EHA21: On Sunday, June 12, 2016 from 08:45 - 09:00
Location: Hall C11
Background
The JAK-STAT signaling pathway is critical for the normal development and proliferation of hematopoietic cells. Mutations in JAK1 or JAK3 occur within ~20% of T-cell acute lymphoblastic leukemia (T-ALL) cases and have also been described in other malignancies. We have previously shown that JAK3 mutations are able to transform hematopoietic cells in vitro and cause long latency T-ALL in a mouse model.
Aims
To determine mutations which are significantly associated with ectopic activation of the JAK-STAT signaling pathway and determine whether they cooperate in leukemia development in vivo.
Methods
Targeted-resequencing of 115 genes across 155 diagnostic T-ALL samples and qPCR on patient derived xenograft (PDX) samples was used to evaluate candidate genes significantly associated with mutations within the JAK-STAT5 pathway. Oncogenic cooperation and transformation to cytokine independent growth was evaluated using primary hematopoietic progenitor cells ex vivo. In vivo leukemia cooperation was assayed using a modified bone marrow transplant assay using either wild type or CD4-Cre donor mice in conjunction with either a retroviral vector for constitutive expression in all hematopoietic lineages or a novel antiparallel lox66/71 retroviral vector for restricted expression within developing T-cells.
Results
Mutations in JAK3 were found to frequently co-occur with HOXA cluster rearrangement and our qPCR analysis of PDX samples identified HOXA9 as the most upregulated HOXA gene in cases with mutant JAK3. Constitutive expression of the JAK3(M511I) mutant together with HOXA9 transformed murine hematopoietic progenitors to cytokine independent growth ex vivo, while JAK3 mutant or HOXA9 alone did not transform cells ex vivo. To model the possible cooperation of JAK3(M511I) and HOXA9 in vivo we initially used the bone marrow transplant model with constitutive expression of JAK3(M511I) and HOXA9. This led to the rapid development of a mixed myeloid-lymphoid leukemia in vivo (median survival = 82 days) compared to JAK3(M511I) alone (median survival = 164 days) or HOXA9 alone (no disease). To study the cooperation during T-ALL development specifically, we modified the bone marrow transplant model by using a novel inducible retroviral vector in combination with CD2-Cre or CD4-Cre donor bone marrow cells so that JAK3(M511I) and HOXA9 expression is delayed to lymphoid progenitors or T-cells. All models confirmed a clear cooperation between JAK3(M511I) and HOXA9, and ChIP-seq, ATAC-seq, and RNA-seq on the leukemic cells confirmed cooperation at the transcriptional level between STAT5 (downstream of JAK3) and HOXA9
Conclusion
JAK3 mutations and ectopic expression of HOXA9 cooperate to transform hematopoietic cells and cause rapid leukemia development in vivo.
Session topic: ALL Biology - Transcriptional dysregulation
Keyword(s): HOXa9, Mouse model, T-ALL
Type: Oral Presentation
Presentation during EHA21: On Sunday, June 12, 2016 from 08:45 - 09:00
Location: Hall C11
Background
The JAK-STAT signaling pathway is critical for the normal development and proliferation of hematopoietic cells. Mutations in JAK1 or JAK3 occur within ~20% of T-cell acute lymphoblastic leukemia (T-ALL) cases and have also been described in other malignancies. We have previously shown that JAK3 mutations are able to transform hematopoietic cells in vitro and cause long latency T-ALL in a mouse model.
Aims
To determine mutations which are significantly associated with ectopic activation of the JAK-STAT signaling pathway and determine whether they cooperate in leukemia development in vivo.
Methods
Targeted-resequencing of 115 genes across 155 diagnostic T-ALL samples and qPCR on patient derived xenograft (PDX) samples was used to evaluate candidate genes significantly associated with mutations within the JAK-STAT5 pathway. Oncogenic cooperation and transformation to cytokine independent growth was evaluated using primary hematopoietic progenitor cells ex vivo. In vivo leukemia cooperation was assayed using a modified bone marrow transplant assay using either wild type or CD4-Cre donor mice in conjunction with either a retroviral vector for constitutive expression in all hematopoietic lineages or a novel antiparallel lox66/71 retroviral vector for restricted expression within developing T-cells.
Results
Mutations in JAK3 were found to frequently co-occur with HOXA cluster rearrangement and our qPCR analysis of PDX samples identified HOXA9 as the most upregulated HOXA gene in cases with mutant JAK3. Constitutive expression of the JAK3(M511I) mutant together with HOXA9 transformed murine hematopoietic progenitors to cytokine independent growth ex vivo, while JAK3 mutant or HOXA9 alone did not transform cells ex vivo. To model the possible cooperation of JAK3(M511I) and HOXA9 in vivo we initially used the bone marrow transplant model with constitutive expression of JAK3(M511I) and HOXA9. This led to the rapid development of a mixed myeloid-lymphoid leukemia in vivo (median survival = 82 days) compared to JAK3(M511I) alone (median survival = 164 days) or HOXA9 alone (no disease). To study the cooperation during T-ALL development specifically, we modified the bone marrow transplant model by using a novel inducible retroviral vector in combination with CD2-Cre or CD4-Cre donor bone marrow cells so that JAK3(M511I) and HOXA9 expression is delayed to lymphoid progenitors or T-cells. All models confirmed a clear cooperation between JAK3(M511I) and HOXA9, and ChIP-seq, ATAC-seq, and RNA-seq on the leukemic cells confirmed cooperation at the transcriptional level between STAT5 (downstream of JAK3) and HOXA9
Conclusion
JAK3 mutations and ectopic expression of HOXA9 cooperate to transform hematopoietic cells and cause rapid leukemia development in vivo.
Session topic: ALL Biology - Transcriptional dysregulation
Keyword(s): HOXa9, Mouse model, T-ALL
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