Using two independently derived murine BXH2 cell lines, Ara-C resistant derivatives were developed by exposure to increasing concentrations of Ara-C. Microarray analysis comparing the Ara-C resistant cells to their Ara-C sensitive parental cell lines identified potential genes involved in Ara-C resistance.
Deoxycytidine kinase is downregulated in Ara-C-resistant acute myeloid leukemia murine cell lines.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
NRASG12V oncogene facilitates self-renewal in a murine model of acute myelogenous leukemia.
Specimen part
View SamplesThe pathways by which oncogenes, such as MLL-AF9, initiate transformation and leukemia in humans and mice are incompletely defined. In a study of target cells and oncogene dosage, we found that Mll-AF9, when under endogenous regulatory control, efficiently transformed LSK (Lin- Sca1+ c-kit+) stem cells while committed granulocyte-monocyte progenitors (GMPs) were transformation-resistant and did not cause leukemia. Mll-AF9 was expressed at higher levels in hematopoietic stem (HSC) than GMP cells. Mll- AF9 gene dosage effects were directly shown in experiments where GMPs were efficiently transformed by the high dosage of Mll-AF9 resulting from retroviral transduction. Mll-AF9 up-regulated expression of 196 genes in both LSK and progenitor cells, but to higher levels in LSKs than in committed myeloid progenitors.
Malignant transformation initiated by Mll-AF9: gene dosage and critical target cells.
No sample metadata fields
View SamplesThe transcription factor STAT5 plays a critical role in B cell acute lymphoblastic leukemia (B-ALL). How STAT5 mediates this effect is unclear. Here we demonstrate that STAT5 activation cooperates with defects in the pre-BCR signaling components encoded by Blnk, Btk, Prkcb, Nfkb1, and Ikzf1 to initiate B-ALL. STAT5 antagonizes NF-B and IKAROS by opposing regulation of shared target genes. STAT5 binding was enriched at super-enhancers, which were associated with an opposing network of transcription factors, including PAX5, EBF1, PU.1, IRF4, and IKAROS. Patients with high ratios of active STAT5 to NF-B or IKAROS have more aggressive disease. Our studies illustrate that an imbalance of two opposing transcriptional programs drive B-ALL, and suggest that restoring the balance of these pathways may inhibit B-ALL.
Antagonism of B cell enhancer networks by STAT5 drives leukemia and poor patient survival.
No sample metadata fields
View SamplesSTAT5 is critical for differentiation, proliferation and survival of progenitor B cells suggesting a possible role in Acute Lymphoblastic Leukemia (ALL). Herein, we show increased expression of activated STAT5 in ALL patients, which correlates with treatment outcome. Mutations in Ebf1 and Pax5, genes critical for B cell development have also been identified in human ALL. To determine whether mutations in Ebf1 or Pax5 synergize with STAT5 activation to induce ALL we crossed mice expressing a constitutively active form of STAT5 (Stat5b-CA) with mice heterozygous for Ebf1 or Pax5. Haploinsufficiency of either Pax5 or Ebf1 synergized with Stat5b-CA to rapidly induce ALL in 100% of the mice. The leukemic cells displayed reduced expression of both Pax5 and Ebf1 but this had little affect on most EBF1 or PAX5 target genes. However, a subset of these genes was deregulated and included a large percentage of potential tumor suppressor genes and oncogenes. Further, most of these genes appear to be jointly regulated by both EBF1 and PAX5. Our findings suggest a model whereby small perturbations in a self-reinforcing network of transcription factors critical for B cell development, specifically PAX5 and EBF1, cooperate with STAT5 activation to initiate ALL.
Ebf1 or Pax5 haploinsufficiency synergizes with STAT5 activation to initiate acute lymphoblastic leukemia.
No sample metadata fields
View SamplesMutant RAS oncoproteins activate signaling molecules that drive oncogenesis in multiple human tumors including acute myelogenous leukemia (AML). However, the specific function of these pathways in AML is unclear. To elucidate the downstream functions of activated NRAS in AML, we employed a murine model of AML harboring Mll-AF9 and NRASG12V. We found that NRASG12V enforced leukemia self-renewal gene expression signatures and was required to maintain an MLL-AF9 and MYB-dependent gene expression program. In a multiplexed analysis of RAS-dependent signaling intermediates, the leukemia stem cell compartment was preferentially sensitive to RAS withdrawal. Use of RAS-pathway inhibitors showed that NRASG12V maintained leukemia self-renewal through mTOR and MEK pathway activation, implicating these pathways as potential targets for cancer stem cell-specific therapies.
No associated publication
Specimen part
View SamplesLeukemias with MLL-rearrangements are characterized by high expression of the homeo box gene MEIS1. In these studies, we knocked down Meis1 expression by shRNA lentivirus transduction in murine Mll-AF9 leukemia cells. Meis1 knockdown resulted in decreased proliferation and survival of murine Mll-AF9 leukemia cells. We also observed reduced clonogenic capacity and increased monocytic differentiation. The establishment of leukemia in transplant recipients was significantly delayed by Meis1 knockdown. Gene expression profiling of cells transduced with Meis1 shRNA showed reduced expression of genes associated with cell cycle entry and progression. shRNA mediated knockdown of MEIS1 in human MLL-fusion gene leukemia cell lines resulted in reduced cell growth. These results show that MEIS1 expression is important for MLL-rearranged leukemias and suggest that MEIS1 promotes cell cycle entry. Targeting MEIS1 may have therapeutic potential for treating leukemias expressing this transcription factor.
A role for MEIS1 in MLL-fusion gene leukemia.
No sample metadata fields
View SamplesImmunosurveillance of secondary lymphoid organs (SLO) is performed by central memory T cells that recirculate through blood. Resident memory T cells (TRM) remain parked in nonlymphoid tissues and often stably express CD69. We recently identified TRM within SLO, and this study addresses knowledge gaps in their origin and phenotype. Parabiosis of dirty mice revealed that CD69 expression is insufficient to infer stable residence. Using selective depletion strategies, parabiosis, imaging, tissue grafting, and photoactivatable T cells, we report that restimulation of TRM within the skin or mucosa results in a substantial increase in TRM that patrol all regions of draining lymph nodes. SLO TRM were derived from nonlymphoid tissue residents. Transcriptional profiling and flow cytometry revealed a refined phenotype shared between both nonlymphoid and SLO TRM. These data demonstrate the nonlymphoid origin of SLO TRM and suggest vaccination strategies by which memory CD8 T cell immunosurveillance can be regionalized to specific lymph nodes.
T Cells in Nonlymphoid Tissues Give Rise to Lymph-Node-Resident Memory T Cells.
Specimen part
View SamplesDmrt1 (doublesex and mab-3 related transcription factor 1) is a conserved transcriptional regulator of male differentiation required for testicular development in vertebrates. This study examines the result of conditional removal of Dmrt1 from Sertoli cells in P28 testis tissue.
DMRT1 prevents female reprogramming in the postnatal mammalian testis.
Sex, Specimen part
View SamplesDmrt1 (doublesex and mab-3 related transcription factor 1) is a conserved transcriptional regulator of male differentiation required for testicular development in vertebrates. In mice of the 129Sv strain, loss of Dmrt1 causes a high incidence of teratomas. Mutant 129Sv germ cells undergo apparently normal differentiation up to embryonic day 13.5 (E13.5), but some cells fail to arrest mitosis and ectopically express pluripotency markers. Expression analysis and chromatin immunoprecipitation identified DMRT1 target genes whose misexpression may underly teratoma formation.
The DM domain protein DMRT1 is a dose-sensitive regulator of fetal germ cell proliferation and pluripotency.
Specimen part
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