UMLS:C0023473 - FACTA Search

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Query: UMLS:C0023473 (chronic myeloid leukemia)
18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The peripheral blood of chronic myeloid leukemia (CML) patients with chronic-phase disease and elevated white blood cell (WBC) counts typically contains markedly increased numbers of a variety of neoplastic pluripotent and lineage-restricted hematopoietic progenitors. These include cells detected in standard colony assays as well as their more primitive precursors. The latter are referred to as long-term culture-initiating cells (LTC-IC) because of their ability to generate clonogenic cell progeny detectable after a minimum of 5 weeks incubation on competent fibroblast feeder layers. In this study, we have investigated a number of the properties of the LTC-IC and clonogenic cells present in the blood of such CML patients with high WBC counts. This included an analysis of the light scattering properties of these progenitors, as well as their expression of CD34 and HLA-DR, Rhodamine-123 staining, and in vitro sensitivity to 4-hydroperoxycyclophosphamide. In the case of LTC-IC, the production of different types of lineage-restricted and multipotent progeny was also analyzed. Most of the circulating LTC-IC and clonogenic cells in the CML patients studied (on average approximately 70% and approximately 90%, respectively) showed features of proliferating or activated cells. This is in marked contrast to the majority of progenitors in the blood of normal individuals and most of the LTC-IC in normal marrow, all of which exhibit a phenotype expected of quiescent cells. Interestingly, a significant proportion of the circulating clonogenic cells and LTC-IC in the CML samples studied (on average approximately 10% and approximately 30%, respectively) appeared to be phenotypically similar to normal circulating progenitors, although their absolute numbers were indicative of a neoplastic origin. Both phenotypes of circulating CML clonogenic cells and LTC-IC could be obtained at approximately 10% to 20% purity by differential multiparameter sorting. These findings suggest that expansion of the Philadelphia chromosome-positive clone at the level of the earliest types of hematopoietic cells results from the activation of mechanisms that enable some, but not all, signals that block the cycling of normal stem cells to be bypassed or overcome. In addition, they provide strategies for purifying these primitive leukemic cells that should facilitate further analysis of the mechanisms underlying their abnormal proliferative behavior.
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PMID:Phenotypic heterogeneity of primitive leukemic hematopoietic cells in patients with chronic myeloid leukemia. 138 87

In this report we describe a quantitative in vitro assay for the most primitive type of leukemic precursors yet defined in patients with chronic myeloid leukemia (CML). This assay is based on the recently described "long-term culture-initiating cell" (LTC-IC) assay for primitive normal human hematopoietic cells. Such cells, when cocultured with competent fibroblast feeder layers, give rise after a minimum of 5 weeks to multiple single and multilineage clonogenic progenitors detectable in secondary semisolid assay cultures. Similar cultures initiated by seeding a highly enriched source of leukemic cells from patients onto normal feeders showed the clonogenic cell output after 5 weeks to be linearly related to the input innoculum over a wide range down to limiting numbers of input cells, thus allowing absolute frequencies of leukemic LTC-ICs to be determined using standard limiting dilution analysis techniques. Leukemic LTC-IC concentrations in CML marrow were found to be decreased, on average to less than 10% of the normal LTC-IC concentration in normal marrow, but were greatly increased (up to greater than 10(5) times) in CML blood. Assessment of the number of clonogenic cells produced per leukemic LTC-IC by comparison to normal blood or marrow LTC-IC values showed this function to be unchanged in leukemic LTC-ICs [i.e., 3.1 +/- 0.4 clonogenic cells per CML LTC-IC (mean +/- SEM, n = 6) versus 3.7 +/- 1.2 (n = 3) and 4.3 +/- 0.4 (n = 5), respectively, for normal blood and marrow LTC-ICs]. In contrast, leukemic LTC-IC maintenance in LTC proved to be highly defective by comparison to normal LTC-IC of either blood or marrow origin. Thus, when cells from primary LTC were subcultured into secondary LTC-IC assays, leukemic LTC-IC rapidly declined (greater than 30-fold) within the first 10 days of culture, whereas normal LTC-IC numbers remained unchanged during this period. These findings illustrate how self-maintenance and differentiation events in primitive human hematopoietic cells can be differentially modulated by an oncogenic process and provide a framework for further studies of their manipulation, analysis, and therapeutic exploitation.
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PMID:Rapid decline of chronic myeloid leukemic cells in long-term culture due to a defect at the leukemic stem cell level. 163 Nov 7

Leukotriene (LT) formation was studied in ionophore A23187-stimulated white blood cell (WBC) preparations from patients with chronic myelogenous leukaemia (CML; n = 14), polycythaemia vera (PV; n = 10) and two control groups consisting of patients with non-malignant inflammatory disease (n = 4) and normal healthy donors (n = 25). The synthesized products were identified and quantitated using high-performance liquid chromatography combined with computerized UV-spectroscopy. White blood cell preparations from the CML patients produced more LTC4 (40.2 +/- 7.9 pmol/10(6) WBC, mean +/- SEM) than WBC from the healthy donors (9.0 +/- 1.8), P less than 0.0005. In contrast, the formation of LTB4 was normal and there was no increase in the total leukotriene synthesis (the sum of LTC4, LTB4, 20-OH-LTB4 and the delta 6-trans-isomers of LTB4). The ratio between leukotrienes C4 and B4 was strongly elevated in the CML group; 1.67 +/- 0.25 v. 0.37 +/- 0.07 in the controls, P less than 0.0005. No significant correlation was observed between the levels of LTC4 and the number of known LTC4 producing cells (such as monocytes, eosinophils and basophils) in the CML WBC preparations. In contrast, a correlation was found between the sum of neutrophilic granulocytes and metamyelocytes in these suspensions and the amount of LTB4 formed; r = 0.600, P less than 0.05. A number of other laboratory or clinical variables of the CML patients (including total white blood cell and platelet counts, differential counts, previous cytotoxic treatment, time from diagnosis, time from last treatment, post study survival and age) did not significantly correlate with the formation of leukotrienes. No abnormality in the production of LTB4 or LTC4 was observed in granulocyte and WBC preparations from the patients with polycythaemia vera and non-malignant inflammatory disease, respectively. The results indicate a selectively increased LTC4 producing capacity in CML.
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PMID:Elevated white blood cell synthesis of leukotriene C4 in chronic myelogenous leukaemia but not in polycythaemia vera. 211 Apr 64

The production of leukotrienes (LT) in peripheral blood leukocyte preparations from 9 patients with chronic myelogenous leukemia (CML) and 9 healthy controls was studied. Leukotriene generation was stimulated by the calcium ionophore A 23187 (1 mumol). Lipoxygenase products were separated and identified using a high performance liquid chromatography (HPLC) technique and computerized spectrophotometry. Leukotriene C4 (LTC4) was formed in significantly larger amounts by cells from the CML patients than cells from the controls; 14.4 +/- 4.3 pmol per 10(6) nucleated cells (mean +/- SE) and 4.0 +/- 1.2 pmol respectively (p less than 0.05). Seven of the 9 patients but none of the controls synthesized equal or higher amounts of LTC4 than LTB4. A highly significant difference in mean values of LTC4/(LTB4 + 20-OH-LTB4) ratios was observed; CML 0.69 +/- 0.08 versus controls 0.12 +/- 0.02, p less than 0.001. These findings suggest an increased LTC4 synthase activity in CML cells. In earlier studies we have found a decreased 12-lipoxygenase activity in CML bone marrow cells.
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PMID:Increased leukotriene C4 production in chronic myelogenous leukemia. 285 46

CD44 is a widely expressed, multifunctional, cell-surface glycoprotein that has been implicated in the regulation of normal hematopoiesis. In addition, expression of particular isoforms of CD44 has been associated with malignant transformation and/or the acquisition of metastatic potential. In this study, we used two recently developed monoclonal anti-CD44 antibodies, one reactive with an epitope shared by many CD44 isoforms and the other with an epitope unique to CD44 isoforms containing amino acids encoded by the alternatively spliced exon v10, to compare the expression of CD44 on primitive hematopoietic cells from the marrow of normal individuals and their neoplastic counterparts present in the peripheral blood of patients with chronic myeloid leukemia (CML). Multiparameter fluorescence-activated cell sorter (FACS) analysis and cell sorting studies showed that CD44 is normally expressed at high to very high levels on both long-term culture-initiating cells (LTC-IC) and granulopoietic colony-forming cells (granulocyte-macrophage colony-forming units [CFU-GM]). In contrast, primitive erythropoietic progenitors (burst-forming units-erythroid [BFU-E]) in normal marrow were more homogeneous in their expression of CD44, and very few (less than 5%) showed the very high levels of CD44 seen on 20% to 25% of LTC-IC and CFU-GM. Antibody staining showed the expression of exon v10-containing CD44 isoforms to be restricted to a small subpopulation (4% to 8%) of morphologically recognizable mature (CD34-) myeloid cells within the light-density fraction of normal marrow cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed the presence of two exon v10-containing mRNA species. In CML, a significantly greater proportion of the circulating neoplastic CFU-GM expressed very high levels of CD44, and these CFU-GM were accompanied by an increased number of light density v10+ cells, including some that coexpressed CD34. Nonmalignant hematopoietic progenitors mobilized by prior chemotherapy and growth factor treatment of patients with Hodgkin's disease or acute myeloid leukemia in remission showed no changes in CD44 expression relative to normal marrow progenitors. These results provide evidence of early differentiation-associated changes in CD44 expression during normal hematopoiesis in vivo that may be deregulated in the neoplastic clone of patients with CML.
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PMID:Differentiation-associated changes in CD44 isoform expression during normal hematopoiesis and their alteration in chronic myeloid leukemia. 757 90

The bone marrow microenvironment supports and regulates the proliferation and differentiation of hematopoietic cells. Dysregulated hematopoiesis in chronic myelogenous leukemia (CML) is caused, at least in part, by abnormalities in CML hematopoietic progenitors leading to altered interactions with the marrow microenvironment. The role of the microenvironment itself in CML has not been well characterized. We examined the capacity of CML stroma to support the growth of long-term culture-initiating cells (LTC-IC) obtained from normal and CML marrow. The growth of normal LTC-IC on CML stroma was significantly reduced compared with normal stroma. This did not appear to be related to abnormal production of soluble factors by CML stroma because normal LTC-IC grew equally well in Transwells above CML stroma as in Transwells above normal stroma. In addition, CML and normal stromal supernatants contained similar quantities of both growth-stimulatory (granulocyte colony-stimulating factor (CSF), interleukin-6, stem cell factor, granulocyte-macrophage CSF, and interleukin-1 beta) and growth-inhibitory cytokines (transforming growth factor-beta, macrophage inflammatory protein-1 alpha, and tumor necrosis factor-alpha). The relative proportion of different cell types in CML and normal stroma was similar. However, polymerase chain reaction and fluorescence in situ hybridization studies showed the presence of bcr-abl-positivo cells in CML stroma, which were CD14+ stromal macrophages. To assess the effect of these malignant macrophages on stromal function, CML and normal stromal cells were separated by fluorescence-activated cell sorting into stromal mesenchymal cell (CD14-) and macrophage (CD14+) populations. CML and normal CD14- cells supported the growth of normal LTC-IC equally well. However, the addition of CML macrophages to normal or CML CD14- mesenchymal cells resulted in impaired progenitor support. This finding indicates that the abnormal function of CML bone marrow stroma is related to the presence of malignant macrophages. In contrast to normal LTC-IC, the growth of CML LTC-IC on allogeneic CML stromal layers was not impaired and was significantly better than that of normal LTC-IC cocultured with the same CML stromal layers. These studies demonstrate that, in addition to abnormalities in CML progenitors themselves, abnormalities in the CML marrow microenvironment related to the presence of malignant stromal macrophages may contribute to the selective expansion of leukemic progenitors and suppression of normal hematopoiesis in CML.
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PMID:Abnormal function of the bone marrow microenvironment in chronic myelogenous leukemia: role of malignant stromal macrophages. 778 Jan 47

Recent developments have occurred in the identification and quantitation of a very primitive type of hematopoietic cell (referred to as a long-term culture initiating cell or LTC-IC) using defined long-term culture conditions. These have facilitated investigations of the numbers and properties of both normal and leukemic LTC-IC in patients with chronic myeloid leukemia (CML). Such studies have revealed that the marrow of many chronic phase patients contains a substantial population of normal LTC-IC that are functionally intact albeit suppressed in vivo. Leukemic LTC-IC are typically less numerous in the marrow of these patients but are found in elevated numbers in the peripheral blood which, on average, in total contains more leukemic LTC-IC than the marrow when the WBC count rises above 10(11) per liter. However, a very marked heterogeneity in all of these parameters exists among individual patients. Some of the properties of leukemic LTC-IC are indistinguishable from those of their normal counterparts. Others, particularly those typically associated with an activated state, are altered, although frequently in only 90% (or less) of the leukemic LTC-IC. A more marked disparity between primitive normal and leukemic LTC-IC is seen in terms of their relative abilities to maintain their numbers in vitro. At the level of primitive clonogenic cells, the leukemic population has been shown to exhibit an increased rate of turnover. This appears to be due to an inability of these cells to respond to the cytostatic effects of macrophage inflammatory protein-1 alpha (MIP-1 alpha). These findings provide new insights into the biology of CML and highlight the power of quantitative assays to guide the development of more generally applicable curative therapies.
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PMID:Biological strategies for the selective manipulation of normal and leukemic stem cells. 790 19

Over the past 5 years we have been evaluating the feasibility of using cultured marrow autografts to allow patients with chronic myeloid leukemia (CML) to receive intensive, potentially curative therapy. The rationale for this approach is based on two important findings. The first is that leukemic stem cells (operationally defined as Ph-positive long-term culture-initiating cells, or LTC-IC) are present in the marrow of many CML patients at relatively low levels by comparison to co-existing normal stem cells (i.e., Ph-negative LTC-IC). The second finding is that leukemic LTC-IC are selectively "purged" following their incubation in vitro for 10 days under LTC conditions. As a result, cultured CML marrow preparations show, on average, a 300-fold selection in favour of normal LTC-IC. However, there is considerable variation in the initial normal and leukemic LTC-IC content of marrow samples from different CML patients. Thus in only approximately one third of cases does the number of leukemic LTC-IC in the marrow decrease to undetectable levels within the first 10 days of culture with the number of co-existing normal LTC-IC remaining at or above 1/50th of the average value for normal marrow. We have now transplanted 22 such CML patients with 10 day cultured marrow autografts following their treatment with myeloablative therapy. Fifteen of these patients were in first chronic phase and 7 had more advanced disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Culture purging in leukemia: past, present, and future. 825 7

The present results demonstrate leukotriene and lipoxin synthesis in human bone marrow and link these findings to biological effects in the same tissue. However, the mechanisms behind the described effects on myeloid progenitor cell growth are presently unknown. It is conceivable that both leukotrienes and lipoxins may act through modulation of endogenous cytokine production. However, it should be noted, that these lipoxygenase products totally failed to induce colony growth in the absence of GM-CSF. Moreover, the role of lipoxins in the bone marrow needs to be further clarified, since LXA4 induced both synergistic (with GM-CSF) and antagonistic (with LTC4) effects on progenitor cell growth. A possible pathophysiological role for leukotrienes and lipoxins may be suggested in chronic myelogenous leukemia. Thus, the capacity of hematological cells from CML patients to synthesize LTC4 was significantly increased. In addition, we have recently reported that CML platelets possessed a markedly decreased ability to participate in transcellular synthesis of the potential inhibitors of myelopoiesis, LXA4 and 5(S),12(S)-diHETE (Stenke et al., 1991b). Moreover, the production of these compounds was totally abolished in platelets obtained from CML patients in blastic crisis. Further studies should aim at defining the mechanisms behind the regulatory actions of leukotrienes and lipoxins in normal and leukemic human myelopoiesis.
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PMID:Formation and effects of leukotrienes and lipoxins in human bone marrow. 835 90

We have previously demonstrated that Philadelphia negative (Ph-ve) hemopoietic cells can be collected by leukaphereses after an acute leukemia-like chemotherapy during the early hemopoietic recovery in patients with chronic myeloid leukemia (CML). In this study we have evaluated whether these collections contain very primitive hemopoietic cells defined as 'long-term culture initiating cells' (LTC-IC) and whether these cells belong to the Ph-positive or Ph-negative population. Twenty-eight out of 76 cytaphereses collected in 15 patients with CML proved to contain Ph-ve cells only (six patients), 21 showed only Ph+ve cells (five patients), and 27 a mixture of Ph+ve and Ph-ve cells (four patients). In cytaphereses containing Ph-ve cells only, we found variable numbers of LTC-ICs, more consistently when we mobilized patients in the first 3 months from diagnosis. In three cases cytogenetic analysis on LTC-ICs and CFU-GM confirmed results obtained on fresh samples. Ph-positive collections were devoid of LTC-ICs except for 2/21 samples. However, their cytogenetic analysis revealed a small number of Ph-negative progenitors. LTC-ICs were randomly detected in mixed (Ph+ve and Ph-ve) collections. In conclusion these data indicate that, in a consistent proportion of chronic myeloid leukemia patients, intensive chemotherapy is able to recruit Ph-ve LTC-ICs in to the peripheral blood. Moreover these data provide the biological basis for developing autografting programs with Ph-negative cells.
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PMID:Very primitive hemopoietic cells (LTC-IC) are present in Philadelphia negative cytaphereses collected during early recovery after chemotherapy for chronic myeloid leukemia (CML). 852 71

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