Therapy-related myelodysplasia or acute myeloid leukemia (t-MDS/AML) is a lethal complication of cancer treatment. Although t-MDS/AML development is associated with known genotoxic exposures, its pathogenesis is not well understood and methods to predict risk of development of t-MDS/AML in individual cancer survivors are not available. We performed microarray analysis of gene expression in samples from patients who developed t-MDS/AML after autologous hematopoietic cell transplantation (aHCT) for Hodgkin lymphoma (HL) or non-Hodgkin lymphoma (NHL) and controls that did not develop t-MDS/AML after aHCT. CD34+ progenitor cells from peripheral blood stem cell (PBSC) samples obtained pre-aHCT from t-MDS/AML cases and matched controls, and bone marrow (BM) samples obtained at time of development of t-MDS/AML, were studied. Significant differences in gene expression were seen in PBSC obtained pre-aHCT from patients who subsequently developed t-MDS/AML compared to controls. Genetic alterations in pre-aHCT samples were related to mitochondrial function, protein synthesis, metabolic regulation and hematopoietic regulation. Progression to overt t-MDS/AML was associated with additional alterations in DNA repair and DNA-damage checkpoint genes. Altered gene expression in PBSC samples were validated in an independent group of patients. An optimal 63-gene PBSC classifier derived from the training set accurately distinguished patients who did or did not develop t-MDS/AML in the independent test set. These results indicate that genetic programs associated with t-MDS/AML are perturbed long before disease onset, and can accurately identify those at risk of developing this complication.
Altered hematopoietic cell gene expression precedes development of therapy-related myelodysplasia/acute myeloid leukemia and identifies patients at risk.
Disease, SubjectView Samples
The primary aim of this study was to evaluate the changes in hepatocyte gene expression under short-term hypoxic conditions in wild type and HIF-1a null cultures. To this end, hypoxia treated cultures were subjected to incubation with 1% O2/5% CO2/94% N2 at 37 C for eight hours prior to RNA isolation. Duplicate normoxic controls were established from separate animals wherein cultures were untreated and treated with Adbgal. Biological triplicates of wild type and HIF-1a null cultures were placed under hypoxic conditions and subsequently processed for microarray analysis. A total of 10 microarray hybridizations were performed.
In vitro liver tissue model established from transgenic mice: role of HIF-1alpha on hypoxic gene expression.
No sample metadata fieldsView Samples
Using a CML mouse model, we identified differences in gene expression between leukemic compared with non-leukemic LTHSC, including increased expression of the thrombopoietin (THPO) receptor MPL. LTHSC expressing high levels of MPL showed enhanced JAK/STAT signaling and proliferation in response to THPO in vitro, and increased leukemogenic capacity in vivo compared to LTHSC with low MPL expression. Although both G0 and S-phase subpopulations were increased in MPL expressing LTHSC, LSC capacity was restricted to quiescent cells. Inhibition of MPL expression in CML LTHSC resulted in reduced THPO-induced JAK/STAT signaling and leukemogenic potential. Similar observations were made with LTHSC from CML patients. MPL expressing LTHSC demonstrated reduced sensitivity to BCR-ABL TKI treatment but demonstrated increased sensitivity to JAK inhibitors. Our studies identify MPL expression levels as a key determinant of heterogeneous leukemia-initiating capacity and drug sensitivity of CML LTHSC, and suggest that MPL-expressing CML stem cells are critical targets for therapy. Overall design: To evaluate heterogeneity in LSC potential, donor LTHSC from SCL-tTA/BCR-ABL mice (200 cells/mouse) were transplanted into a cohort of congenic FVBN mice. Recipient mice were followed for engraftment of donor CML cells and development of CML. LTHSCs were isolated from leukemic and non-leukemic recipient mice and global gene expression was analyzed using RNA-Seq.
Heterogeneity of leukemia-initiating capacity of chronic myelogenous leukemia stem cells.
Specimen part, SubjectView Samples
In this study, we have explored microarray-based differential gene expression profile in mouse lung tissue 8 h after inducing polymicrobial sepsis and the effect of preprotachykinin-A (PPTA) gene deletion. A range of genes differentially expressed (> 2-fold) in microarray analysis was assessed, PPTA-knockout septic mice with their respective sham controls.
Substance P in polymicrobial sepsis: molecular fingerprint of lung injury in preprotachykinin-A-/- mice.
Specimen part, TreatmentView Samples
This study examines the innate immune response of human pluripotent stem cell derived airway epithelium. Immune challenge was performed with TNF-alpha or bacterial lipopolysaccharide (LPS)
Innate immune response of human pluripotent stem cell-derived airway epithelium.
Specimen part, TreatmentView Samples
Human pluripotent stem cells (hPSC) generate hematopoietic progenitor cells (HPC), but fail to engraft xenograft models, which is a hallmark feature of adult/somatic hematopoietic stem cells (HSC) from human donors. Progress to derive hPSC-derived HSCs has relied on cell autonomous approaches that force expression of transcription factors (TF), however the role of bone marrow (BM) niche remains poorly understood. Here, we quantified a failure of hPSC-HPCs to survive even in the first 24 h upon transplantation into the BM. Across several hPSC-HPC differentiation methodologies, we identified the lack of CXCR4 expression and network function. Ectopic CXCR4 conferred CXCL12-dependent signaling of hPSC-HPCs in biochemical assays and increased migration/chemotaxis and progenitor capacity, as well as survival and proliferation following transplantation in vivo. In addition, hPSC-HPCs forced to express CXCR4 demonstrated a transcriptional shift toward somatic HPCs, but this approach failed to produce long-term HSC engraftment. Our results reveal that independent of differentiation methods, networks involving CXCR4 should be targeted to generate HSCs with in vivo function from hPSCs.
CXCL12/CXCR4 Signaling Enhances Human PSC-Derived Hematopoietic Progenitor Function and Overcomes Early In Vivo Transplantation Failure.
Specimen partView Samples
Tyrosine kinase inhibitors (TKI) are highly effective in treatment of chronic myeloid leukemia (CML) but do not eliminate leukemia stem cells (LSC), which remain a potential source of relapse. TKI treatment effectively inhibits BCR-ABL kinase activity in CML LSC, suggesting that additional kinase-independent mechanisms contribute to LSC preservation. We investigated whether signals from the bone marrow (BM) microenvironment protect CML LSC from TKI treatment. Coculture with human BM mesenchymal stromal cells (MSC) significantly inhibited apoptosis and preserved CML stem/progenitor cells following TKI exposure, maintaining colony forming ability and engraftment potential in immunodeficient mice. We found that the N-Cadherin receptor plays an important role in MSC-mediated protection of CML progenitors from TKI. N-Cadherin-mediated adhesion to MSC was associated with increased cytoplasmic N-Cadherin--catenin complex formation, as well as enhanced -catenin nuclear translocation and transcriptional activity. Increased exogenous Wnt-mediated -catenin signaling played an important role in MSC-mediated protection of CML progenitors from TKI treatment. Our results reveal a close interplay between N-Cadherin and the Wnt--catenin pathway in protecting CML LSC during TKI treatment. Importantly, these results reveal novel mechanisms of resistance of CML LSC to TKI treatment, and suggest new targets for treatment designed to eradicate residual LSC in CML patients.
Microenvironmental protection of CML stem and progenitor cells from tyrosine kinase inhibitors through N-cadherin and Wnt-β-catenin signaling.
Specimen partView Samples
Comparison of gene expression signatures in hESC-derived gastrointestinal precursors, enterospheres and primary human tissues to determine lineage and cell type identity.
Functional Enterospheres Derived In Vitro from Human Pluripotent Stem Cells.
Specimen part, Cell lineView Samples
To investigate the effects of BCL11B on T-cell differentiation, we performed gain of function studies in cells with a T-lineage differentiation arrest, namely T-ALL cells. Gene expression profiling by RNA-Seq demonstrated that BCL11B overexpression induced transcriptional changes consistent with T-cell differentiation as early as 72 hours after transduction, indicating a rapid regulatory effect of BCL11B on the T-lineage transcriptional program and supporting an important role for BCL11B in human T-cell differentiation. Overall design: T-ALL cells were transduced with a BCL11B-GFP expression vector (overexpressing cells) or an empty GFP vector (control cells). GFP+ cells were isolated by fluorescence activation cell sorting (FACS) at 72 hours post transduction and analyzed by RNA-Seq to determine the effect of BCL11B on the transcriptome of T-ALL cells.
The T-ALL related gene BCL11B regulates the initial stages of human T-cell differentiation.
microRNAs play crucial roles in the early development of an organism. However the regulation of transcription through the action of microRNAs during the initial embyonic development has not been studied.
miR-34 is maternally inherited in Drosophila melanogaster and Danio rerio.
Specimen partView Samples