Project description:Imatinib therapy is first-line treatment for chronic myeloid leukemia (CML), and its failure to target CML progenitor/stem cells may lead to an increased risk of relapse. We report here that fenretinide, a well-tolerated vitamin A derivative, is capable of eradicating primitive CML progenitor/stem cells and significantly enhances the efficacy of imatinib at physiologically achievable concentrations. As tested by colony forming cell assays, formation of various colonies derived primitive CML CD34+ cells was significantly suppressed by fenretinide, particularly with respect to the formation of colonies derived from erythroid progenitors and more primitive CML progenitor/stem cells. Also, fenretinide significantly enhanced the ability of imatinib to suppress the formation of the colonies. Moreover, fenretinide was able to induce apoptosis in primitive CML CD34+ cells while sparing the normal counterparts. In particular, primitive CML CD34+CD38- cells appeared to be most sensitive to fenretinide induced apoptosis. Through transcriptome analysis and molecular validation, we further showed that fenretinide induced apoptosis in CML CD34+ cells was probably mediated by a series of stress responsive events which were likely triggered by elevated levels of intracellular reactive oxygen species. Accordingly, the combination of fenretinide and imatinib may provide a potential solution for overcoming relapse and resistance in CML. Experiment Overall Design: Transcriptome profiles of CML CD34+ cells with and without fenretinide treatment were analyzed using whole genome expression arrays (Affymetrix HG-U133 Plus 2.0) in four CML patients (CML32, CML33, CML34 and CML35, see Table 1). To minimize potential data biases, both treated and untreated cell samples were maintained in culture for 48 hours before hybridization.
Project description:Imatinib, as the first-line agent of chronic myeloid leukemia (CML), is ineffective in eradicating CML stem/progenitor cells, thus unable to prevent late relapse. Here we present data indicating that fenretinide preferentially targets CD34+ CML cells and enhances the efficacy of imatinib in CML. As tested by colony forming cell assays, both number and size of total colonies derived from CD34+ CML cells were significantly reduced by fenretinide, and by combining fenretinide with imatinib. In particular, colonies derived from erythroid progenitors and those derived from more primitive pluripotent progenitor cells were highly sensitive to fenretinide/fenretinide plus immtinib. Further data showed that fenretinide was able to induce apoptosis in CD34+ CML cells which were refractory to imatinib. Through transcriptome analysis and followed by molecular validation, we further showed that apoptosis induced by fenretinide in CD34+ CML cells was mediated by complex mechanisms of stress responses, probably triggered by elevated levels of intracellular reactive oxygen species. Thus, fenretinide combines with imatinib may represent a new strategy for the treatment of CML, in which fenretinide targets primitive CD34+ CML cells whereas imatinib targets leukemic blasts. This strategy may eventually reduce the risk of relapse and probably resistant as well in CML patients.
Project description:Transcriptional profiling of human acute myelogenous leukemia (AML) CD34+ cells treated with 5 μM fenretinide. Two timepoints included are 6h, 12h, covering the apoptosis-induction time window of AML CD34+ cells responsing to the fenretinide treatment. We studied gene expression series in human AML CD34+ cells with or without 5 μM fenretinide treatment by cDNA microarray analysis. Several signal transduction pathways are involve, including stress response, NF-kappaB inhibition and p53 inhibition (p<0.05). These findings indicate fenretinide may represent a promising candidate for targeting AML-initiating cells. 6-condition experiment, untreated AML CD34+ cells vs. fenretinide-treated AML CD34+ cells,including 2 time points, for each point the untreated and 5 μM fenretinide treated, independently grown and harvested. Untreated was used to counteracting the background.
Project description:Transcriptional profiling of human acute myelogenous leukemia (AML) CD34+ cells treated with 5 μM fenretinide. Two timepoints included are 6h, 12h, covering the apoptosis-induction time window of AML CD34+ cells responsing to the fenretinide treatment. We studied gene expression series in human AML CD34+ cells with or without 5 μM fenretinide treatment by cDNA microarray analysis. Several signal transduction pathways are involve, including stress response, NF-kappaB inhibition and p53 inhibition (p<0.05). These findings indicate fenretinide may represent a promising candidate for targeting AML-initiating cells.
Project description:purified CD34+ cells from bone marrow of imatinib-treated patients were compared to those of healthy donors Keywords = CML Keywords = CD34+ cells Keywords = imatinib Keywords: ordered
Project description:Gene expression profiling of immortalized human mesenchymal stem cells with hTERT/E6/E7 transfected MSCs. hTERT may change gene expression in MSCs. Goal was to determine the gene expressions of immortalized MSCs.
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.