Project description:We examined gene expression profiling in long-term chronic myelogenous leukemia (CML) stem cells isolated from Gdpd3+/+ and Gdpd3-/- CML mouse model by RNA sequence.
Project description:Chronic myelogenous leukemia (CML) is a malignant stem cell disease characterized by a reciprocal translocation between chromosome 9 and 22. The selective bcr-abl tyrosine-kinase inhibitor Imatinib has become the therapy of choice for patients with newly diagnosed CML including those previously considered candidates for allogeneic haematopoietic stem cell transplantation. The tyrosine-kinase inhibitor Nilotinib is a derivate of Imatinib with higher potency. To examine the molecular and functional effects of Nilotinib and Imatinib in chronic myelogenous leukemia, we performed gene expression and functional analyses in K562 cells following treatment with the two tyrosine kinase inhibitors.
Project description:We show the molecular and functional characterization of a novel population of lineage-negative CD34-negative (Lin- CD34-) hematopoietic stem cells (HSCs) from chronic myelogenous leukemia (CML) patients at diagnosis. Molecular caryotyping and quantitative analysis of BCR/ABL transcript demonstrated that about one third of CD34- was leukemic. CML CD34- cells showed kinetic quiescence and limited clonogenic capacity. However, stroma-dependent cultures and cytokines induced CD34 expression on some HSCs, cell cycling, acquisition of clonogenic activity and increased expression of BCR/ABL transcript. CML CD34- cells showed an engraftment rate in immunodeficient mice similar to that of CD34+ cells. Gene expression profiling revealed the down-regulation of cell cycle arrest genes together with genes involved in antigen presentation and processing, while the expression of angiogenic factors was strongly up-regulated when compared to normal counterparts. Flow cytometry analysis confirmed the significant down-regulation of HLA class I and II molecules in CML CD34-cells. Increasing doses of imatinib mesilate (IM) did not affect fusion transcript levels, BCR-ABL kinase activity and the clonogenic efficiency of CML CD34- cells as compared to leukemic CD34+cells. Thus, we identified in CML a novel CD34- leukemic stem cell subset with peculiar molecular and functional characteristics which may be a potential target for CML therapeutics.
Project description:We show the molecular and functional characterization of a novel population of lineage-negative CD34-negative (Lin- CD34-) hematopoietic stem cells (HSCs) from chronic myelogenous leukemia (CML) patients at diagnosis. Molecular caryotyping and quantitative analysis of BCR/ABL transcript demonstrated that about one third of CD34- was leukemic. CML CD34- cells showed kinetic quiescence and limited clonogenic capacity. However, stroma-dependent cultures and cytokines induced CD34 expression on some HSCs, cell cycling, acquisition of clonogenic activity and increased expression of BCR/ABL transcript. CML CD34- cells showed an engraftment rate in immunodeficient mice similar to that of CD34+ cells. Gene expression profiling revealed the down-regulation of cell cycle arrest genes together with genes involved in antigen presentation and processing, while the expression of angiogenic factors was strongly up-regulated when compared to normal counterparts. Flow cytometry analysis confirmed the significant down-regulation of HLA class I and II molecules in CML CD34-cells. Increasing doses of imatinib mesilate (IM) did not affect fusion transcript levels, BCR-ABL kinase activity and the clonogenic efficiency of CML CD34- cells as compared to leukemic CD34+cells. Thus, we identified in CML a novel CD34- leukemic stem cell subset with peculiar molecular and functional characteristics which may be a potential target for CML therapeutics. Leukemic cells were obtained from 12 chronic phase Ph+ CML patients at diagnosis and before treatment. Normal samples were leukapheresis products from 12 healthy stem cell donors receiving recombinant human granulocyte colony-stimulating factor (G-CSF; Lenograstim, Sanofi-Aventis, Milan, Italy). The protocol was approved by the ethical committee of the University Hospital and each patient/donor gave written informed consent. Hemopoietic stem/progenitor cell purification and phenotypic analyses were performed as previously described (Lemoli et al, Br J Haematol, 2003; Lemoli RM et al., Blood, 1997). Aliquots of sorted Lin-CD34-, Lin-CD34+ and Lin+CD34+ were reanalyzed by FacScan (Becton Dickinson, Franklin Lakes, NJ) to assess their purities. Total cellular RNA was extracted from 0.5x105 cells of each sample using RNeasy Micro kit (Qiagen, Valencia, CA) following the protocol supplied by the manufacturer. Disposable RNA chips (Agilent RNA 6000 Nano LabChip kit, Agilent Technologies, Waldbrunn, Germany) were used to determine the concentration and purity/integrity of RNA samples using Agilent 2100 Bioanalyzer. RNAs originating from 12 normal donors or from 12 CML patients were pooled in order to obtain at least 2 mg per sample. One-cycle target labeling assays, as well as the Affymetrix Human HG-U95Av2 GeneChip arrays hybridization, staining, and scanning, were performed, using Affymetrix standard protocols (Affymetrix, Santa Clara,CA).
Project description:Tyrosine kinase inhibitors (TKI) are highly effective in treating chronic myelogenous leukemia (CML), but primitive, quiescent CML stem cells persist as a source for recurrence. The effects of TKI treatment on CML stem cell metabolism, and the role of metabolic reprogramming in CML stem cell persistence after TKI treatment are not clear. Here we show that TKI treatment in a CML mouse model leads to acute inhibition of aerobic glycolysis, glutaminolysis, TCA cycle and oxidative phosphorylation (OXPHOS) in CML progenitor cells, but that these pathways are restored with continued TKI treatment. Single cell analysis reveals that primitive CML stem cell subpopulations characterized by lower OXPHOS, glycolysis, nucleotide metabolism, and MYC gene signatures are enriched after TKI treatment. TKI treatment initially results in broad inhibition of energy metabolism gene signatures, but continued treatment leads to metabolic reprogramming in persistent stem cells, with enhanced OXPHOS and MYC gene signatures. TKI treatment enhanced HIF-1 activity in quiescent CML stem cells, and addition of a HIF-1 inhibitor significantly depleted CML stem cells in TKI-treated mice. Our results identify mechanisms of metabolic adaptation in CML stem cells following TKI treatment, which can be targeted to deplete persistent quiescent CML stem cells.
Project description:This is a class prediction experiment, where the class is the response status to imatinib (also called Gleevec), a drug used to treat patients with chronic myelogenous leukemia (CML). There are two data sets, a training set (from Leipzig, 8 Responders and 5 Non-Responders) and a validation set (from Mannheim, 8 Responders and 7 Non-Responders). The objective is to identify differentially regulated genes between CML patients who respond and those who do not respond to imatinib and confirm the results in the validation data set. The samples from blood or bone marrow of CML patients were hybridized to Affymetrix HG-U95Av2 chip and RMA was used to generate the normalized signal values. Keywords = chronic myelogenous leukemia Keywords = imatinib Keywords = cytogenetic responses Keywords = Gleevec Keywords = Affymetrix Keywords: other
Project description:Chronic myelogenous leukemia (CML) is a malignant stem cell disease characterized by a reciprocal translocation between chromosome 9 and 22. The selective bcr-abl tyrosine-kinase inhibitor Imatinib has become the therapy of choice for patients with newly diagnosed CML including those previously considered candidates for allogeneic haematopoietic stem cell transplantation. The tyrosine-kinase inhibitor Nilotinib is a derivate of Imatinib with higher potency. To examine the molecular and functional effects of Nilotinib and Imatinib in chronic myelogenous leukemia, we performed gene expression and functional analyses in K562 cells following treatment with the two tyrosine kinase inhibitors. Experiment Overall Design: Affymetrix U133A 2.0 microarrays were used to examine the gene expression profile of K562 cells after in vitro treatment with Imatinib (0.5 µM) or Nilotinib (0.05 µM) for 24 hours. Gene expression data of the treated cells were compared with data of untreated cells.
Project description:Leukemia stem cells (LSC) in chronic myelogenous leukemia (CML) resist elimination with tyrosine kinase inhibitors (TKI) and persist as a source of disease recurrence. LSC populations are heterogeneous, but the most primitive, drug-resistant subsets are not well characterized. Previous studies indicate that variable cell-surface expression of the c-Kit receptor identifies heterogeneous hematopoietic stem cells (HSC) populations. We found that c-Kit expression is reduced on CML LSC compared to normal HSC. Long-term engraftment and leukemia generation capacity was restricted to low c-Kit expressing (c-KitLow) LSC, which showed increased quiescence and inflammatory gene signatures expression. The c-Kit ligand, stem cell factor (SCF), expanded normal HSC but drove maturation of CML LSC. The proportion of c-Kitlow LT-HSC was increased with TKI treatment. Supplementary SCF treatment enhanced elimination of committed but not primitive CML LT-HSC in TKI-treated mice. Low c-Kit expression identifies primitive, treatment-resistant LSC subpopulations with distinct regulatory characteristics, that are critical therapeutic targets.
Project description:Heteronemin is a sesterterpene first isolated from Hyrtios Erecta in 1976. In this study we decided to investigate the anti-cancer and anti-inflammatory potential of this marine natural compound at the transcriptomic level in chronic myelogenous K562 leukemia cells. Our results suggest that this sesterterpene has an impact on cell cycle, apoptosis, the MAP kinase signalling pathway and the NF-kappaB transcription factor.
Project description:Heteronemin is a sesterterpene first isolated from Hyrtios Erecta in 1976. In this study we decided to investigate the anti-cancer and anti-inflammatory potential of this marine natural compound at the transcriptomic level in chronic myelogenous K562 leukemia cells. Our results suggest that this sesterterpene has an impact on cell cycle, apoptosis, the MAP kinase signalling pathway and the NF-kappaB transcription factor. We used four experimental conditions : untreated cells, cells treated with heteronemin, cells treated with TNFalpha and cells co-treated with TNFalpha and heteronemin. Experiments were performed in three biological replicates including two technical replicates. Technical replicates were hybridized as dye-swaps. Dye-swap between replicates 1 and 2, 3 and 4, 5 and 6, respectively.