Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Stroma-supported long-term cultures (LTC) of chronic myeloid leukemia (CML) progenitor cells have previously revealed differences between normal and malignant stem cells with respect to their maintenance and adhesive properties. Using the cobblestone area forming cell (CAFC) assay and LTC, we have examined the frequencies of stem cell subsets, their ability for long-term progenitor cell production and the relative frequencies of malignant and normal progenitor cells before and after a 5-6 week culture period. Cells were obtained from bone marrow (BM) and peripheral blood (PB) samples of patients in chronic phase CML. CD34-enriched cells were sorted by FACS on the basis of CD34 and CD38 expression and overlaid on confluent stromal layers of murine FBMD-1 cells. The presence of the bcr/abl chimeric gene was detected by fluorescent in situ hybridization (FISH) using differently labelled bcr and abl-specific probes. In the CD34pos/CD38pos subset of CML-PB, representing 64-95% of CD34pos cells, CAFC frequencies at week 1 (wk-1) were much higher than those of CAFC wk-5 (1.10(4)/10(5) cells vs 1.10(3)/10(5)). In contrast, in the CD34pos/CD38neg subset, representing 2-3% of CD34pos cells, the frequency of CAFC wk-1 was only 1.10(2)/10(5) cells, but a high CAFC frequency (10(3)-10(4)/10(5)) was detected after 5 weeks of culture. CAFC frequencies in the CD34pos subset obtained from CML-BM were 10- to 100-fold lower than those from CML-PB, but displayed a similar distribution over CD38pos, CD38dim and CD38neg cells. Analysis of the percentage of Philadelphia chromosome-positive (Ph+) and Ph- cells by FISH on freshly sorted cells revealed that normal cells were not enriched in any CD34pos/CD38 subset. In addition, Ph- as well as Ph+ cells were maintained with similar efficiency throughout 5 week LTC. These results demonstrate that immature normal and malignant stem cells in CML have a comparable distribution on the basis of CD34 and CD38 expression. The ability to maintain immature normal and malignant hemopoietic cells with similar efficiency in LTC provides a model enabling a direct comparison of differential effects of cytokines or drugs on either normal or malignant immature stem cells in CML.
Leukemia 1997 Jan
PMID:Efficient long-term maintenance of chronic myeloid leukemic cobblestone area forming cells on a murine stromal cell line. 900 28

We have previously shown by reverse transcriptase-PCR (rtPCR) that CML CD34+ HLA-DR- cells are enriched for BCR/ABL(-) hematopoietic progenitor cells (HPC) while leukemic HPC reside predominately within CML CD34+ HLA-DR+ cells. We investigated whether the 30/35 kDa fragment of fibronectin (FN) could be used to enhance retroviral-mediated gene transfer (RMGT) in chronic phase CML marrow HPC. CML CD34+ HLA-DR- and CD34+ HLA-DR+ cells were transduced with vector supernate containing the neomycin resistance gene on plates coated with either FN or bovine serum albumin (BSA) as control, then assayed for transduced HPC in progenitor cell assays in the presence or absence of G418. Transduction efficiency of CML CD34+ HLA-DR- cells over BSA ranged from 0.09 to 7.2% (mean 3.3 +/- 1.5%), while that over FN plates ranged from 3.8 to 23% (mean 11.0 +/- 4.5%) (n = 4). Transduction efficiencies of CML CD34+ HLA-DR+ cells ranged from 0.4 to 9.8% (mean 3.7 +/- 1.7%) and 6.0 to 26% (mean 17.3 +/- 4.5%) (n = 5) over BSA and FN, respectively. rtPCR analysis for BCR/ABL mRNA of individual G418-resistant HPC generated from CD34+ HLA-DR- cells revealed that normal BCR/ABL(-) HPC were successfully transduced under these experimental conditions. These results demonstrate the feasibility of transducing normal CML primitive HPC, and illustrate the potential clinical use of FN in the setting of gene therapy for CML, as well as other diseases.
Leukemia 1997 Jan
PMID:The 30/35 kDa chymotryptic fragment of fibronectin enhances retroviral-mediated gene transfer in purified chronic myelogenous leukemia bone marrow progenitors. 900 33

Although Chronic Myeloid Leukaemia (CML) can be treated successfully with allogeneic bone marrow transplantation (BMT), leukaemia relapse remains a significant clinical problem. Molecular monitoring of the post transplant marrow can be useful in predicting relapse particularly in CML patients where the Philadelphia chromosome or its molecular counterpart, the BCR-ABL fusion messenger RNA can be used as a leukaemia specific marker of minimal residual disease (MRD). We have investigated chimaerism (using polymerase chain reaction of short tandem repeat sequences (STR-PCR)) and MRD status (using reverse transcriptase PCR of the BCR-ABL fusion mRNA) in a serial fashion in 18 patients who were in clinical and haematological remission post allogeneic BMT for chronic phase CML. Eleven patients exhibited complete donor chimaerism with no evidence of minimal residual disease. Five patients had transient or low level stable MC. Late MC and MRD was observed in two patients who relapsed > 6 years after T cell depleted BMT for CML. Thus STR-PCR is an appropriate screening test in the post transplant setting for CML patients, but those patients exhibiting mixed haemopoietic chimaerism should also be monitored using a leukaemia specific sensitive molecular assay.
Leukemia 1997 Apr
PMID:Donor chimaerism is a strong indicator of disease free survival following bone marrow transplantation for chronic myeloid leukaemia. 920 41

Thirty-two adults (median age 36 years) with leukemia (15 AML, eight CML, six ALL, three CLL) persisting or relapsing 1-40 months (median 4) after allogeneic BMT (20 matched siblings, eight unrelated, four family mismatch) underwent immunotherapy to elicit GVHD. This comprised one or more of: infusion of donor cells (n = 22), stopping cyclosporine (n = 14), and administration of interferon-alpha2b (n = 15) or interleukin-2 (n = 4). Eight acute leukemia patients received chemotherapy as well. The time from relapse to immunotherapy was 0-1344 days (median 4). Acute and/or chronic GVHD developed in 17 patients. Response was not evaluable in three patients due to early toxic death. There was no response in 10 patients, whereas 19 showed objective response. Nine patients died due to toxicity and 10 due to progressive disease. Thirteen patients are alive 4-58 months (median 14) after immunotherapy; 12 in remission (five AML, four chronic phase CML, one ALL, one accelerated phase CML, one CLL) and one with progressive disease (accelerated phase CML). Eleven of 13 patients who are alive had GVHD compared with six of 19 who died (P = 0.005, Fisher's exact test). We conclude that with the exception of CML in myeloid blast crisis, immunotherapy is active in most types of acute and chronic leukemia relapsing after allogeneic BMT. It is associated with considerable toxicity. Clinically obvious GVHD, especially chronic GVHD, results in a higher probability of survival.
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PMID:Induction of graft-versus-host disease as immunotherapy of leukemia relapsing after allogeneic transplantation: single-center experience of 32 adult patients. 924 16

Chronic myeloid leukaemia (CML) can be treated successfully with allogeneic bone marrow transplantation (BMT) leading to long-term disease-free survival. Leukemia relapse, however, remains a significant clinical problem. Relapse following BMT presumably results from the expansion of small numbers of recipient leukaemic cells which have survived the conditioning therapy. In order to define patients who are at a high risk of leukaemia relapse, a variety of techniques have been employed to detect persistence of host haemopoiesis (mixed chimaerism, MC) or residual leukaemia (minimal residual disease, MRD). However, the precise relationship between the detection of MC and MRD post-BMT is unknown. We have investigated chimaerism and MRD status in 22 patients who were in clinical and haematological remission post-allogeneic BMT for chronic phase CML. Chimaerism was assessed using short tandem repeat PCR (STR-PCR) while BCR-ABL mRNA detection using reverse transcriptase polymerase chain reaction (RT-PCR) was performed to detect the presence of MRD. Seventeen patients received unmanipulated marrow (non-TCD) while in five patients a T cell-depleted transplant (TCD) was performed as additional GVHD prophylaxis. Chimaerism was evaluated in 18 patients (14 non-TCD, four TCD). Mixed chimaerism was an uncommon finding in recipients of unmanipulated BMT (21%) when compared to TCD BMT (100%). No evidence of MRD, as identified using the BCR-ABL mRNA RT-PCR assay, was detected in those patients who were donor chimaeras. Early and transient MC and MRD was detected in four patients (two non-TCD, two TCD) who have subsequently converted to a donor profile. One patient has stable low-level MC but remains MRD negative 4 years post-BMT. Late MC and MRD was observed in two patients who relapsed >6 years after TCD BMT for CML. We conclude that mixed chimaerism is a rare event in recipients of unmanipulated BMT and that donor chimaerism as detected by STR-PCR assay is consistent with disease-free survival and identifies patients with a low risk of leukaemic relapse post-BMT for CML.
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PMID:Persistent donor chimaerism is consistent with disease-free survival following BMT for chronic myeloid leukaemia. 925 92

The 9;22 chromosomal translocation characteristic of CML results in a fused bcr/abl gene and an abnormal fusion protein, p210bcr/abl. Relative to normal c-abl, p210bc1/abl has elevated tyrosine kinase activity that is essential for its transforming activity. We recently reported a prominent 62 kDa GAP-associated P-tyr protein and five additional consistent but less prominent P-tyr proteins as well as five more minor P-tyr proteins that are constitutively tyrosine phosphorylated in primary primitive lineage negative (lin-) chronic phase CML blasts but not in comparable primary lin- normal blasts. The GAP-associated p62 protein has now been purified, sequenced and its gene has been cloned; it is a previously unidentified protein and is currently being characterized. In analyzing P-tyr proteins in primary lin- normal blasts in response to various hematopoietic cytokines, we found a striking similarity in the tyrosine phosphorylation of four major and three minor proteins after stimulation with c-kit ligand (KL) and the P-tyr proteins that are constitutively phosphorylated in primary primitive lin- chronic phase CML blasts. Other cytokines tested (ie GM-CSF, G-CSF, IL-3, FLT3 ligand, TPO, EPO) were much less active or stimulated phosphorylation of other proteins. KL/c-kit and bcr/abl have some similar activities including enhancing survival and expansion of hematopoietic progenitor cells, probably acting primarily on early progenitors at the time of lineage commitment rather than on self-renewing stem cells. Activation of growth factor receptors promote a cascade of protein phosphorylations that can ultimately result in a wide range of cellular responses. Sustained activation of discrete signaling pathways in some types of cells results in differentiation, whereas transient activation instead causes a proliferative response; in other cell types, the converse is true. It may be postulated that stem cells and primitive progenitors are at a particularly susceptible stage of development that renders them especially responsive to sustained bcr/abl-induced phorphorylation of a number of signaling proteins that are components of critical regulatory pathways, including c-kit. The affected pathways control and coordinate multiple diverse cell processes including proliferation, differentiation, maturation and apoptosis, processes that are normally tightly regulated and integrated. Perturbation of these key pathways in primitive progenitors would be expected to seriously disrupt orderly hematopoiesis and could also explain the multiple subtle pleiotropic biological abnormalities characteristically observed in later maturing CML compartments that we have collectively designated 'discordant maturation'. The true situation is undoubtedly very complex and involves interaction of multiple cytokines and signaling pathways that we are now trying to define. Constitutive downstream activation of critical pathways in susceptible early progenitors that normally require KL or other factors for activation could explain most if not all features of the disease.
Leukemia 1997 Sep
PMID:New understanding of the pathogenesis of CML: a prototype of early neoplasia. 952 44

Philadelphia chromosome-positive (Ph+) hemopoietic cells predominate in patients with chronic myeloid leukemia (CML) in chronic phase, but some Ph presumably normal stem cells persist in most patients. Ph cells are relatively frequent, compared to mature cell populations, in primitive hemopoietic cell populations from CML patients. We have purified CD34+ cells from chronic phase CML blood and separated them into two fractions on the basis of adherence or non-adherence to tissue culture plastic. We also separated CD34+ CML cell populations into HLA-DR(hi) and HLA-DR(lo) fractions and CD38(hi) and CD38(lo) fractions by flow cytometry. The CD34+ cells that adhered to plastic were predominantly CD33-, CD38- and HLA(-)-DR; cells with these phenotypic properties were significantly rarer in the CD34+ non-adherent cell population (P = 0.008-0.02). Expression of p210 BCR/ABL mRNA by adherent, non-adherent, HLA-DR(hi) and HLA-DR(lo)CD34+ cell subpopulations was demonstrated by RT-PCR. Using fluorescence in situ hybridization (FISH) in conjunction with BCR and ABL probes we detected Ph+ and Ph- cells in both adherent and non-adherent CD34+ cell fractions of 15/15 patients studied and in the HLA-DR(lo) or CD38(lo) sorted CD34+ cell fractions. The concentration of Ph- cells in the adherent CD34+ cell fraction was three-fold higher than in the non-adherent fraction (P = 0.001). Ph- adherent cells were detected in untreated CML patients and as late as 6 years after diagnosis of CML in patients treated with hydroxyurea (HU) or interferon-alpha (IFN-alpha). We conclude that whilst appreciable numbers of Ph- primitive hemopoietic progenitors are present in the circulation in untreated patients and also in treated patients in late chronic phase, the majority of cells expressing CD34 but not CD33, CD38 or HLA-DR antigens, are part of the CML clone.
Leukemia 1997 Sep
PMID:BCR/ABL-negative progenitors are enriched in the adherent fraction of CD34+ cells circulating in the blood of chronic phase chronic myeloid leukemia patients. 930 2

The aim of this study was to investigate the influence of interferon-alpha (IFN-alpha) on bone marrow fibrosis associated with chronic myelogenous leukemia (CML). Eighty-two bone marrow biopsies from 41 patients in chronic phase CML were stained with Snook's reticulin stain for argyrophilic fibers. Grading of reticulin fibrosis (scale of 1 to 4) was according to the quantity and pattern of distribution of reticulin. The interval between biopsies was a median of 25 months (range 12 to 40 months). Patients had been treated with IFN-alpha for at least 12 months, were still on IFN-alpha therapy during the study, and had achieved at least a complete hematological response. Before the start of IFN-alpha therapy, reticulin fibrosis was grade 1-2 in 23 patients (56%) and grade 3-4 in 18 (44%). During IFN-alpha therapy, reticulin fibrosis in bone marrow did not worsen or was reduced in 33 patients (80%) and increased by one grade in eight patients (20%). Only five patients (12%) with limited fibrosis (grade 1-2) before start of IFN-alpha therapy showed an increase towards significant fibrosis (grade 3-4), while eight of the 18 patients (44%) with grade 3-4 fibrosis achieved a decrease of fiber content in bone marrow. In summary, IFN-alpha was not associated with an enhancing effect on myelofibrosis in patients with CML and may have prevented increasing fibrosis in patients who respond to therapy.
Leukemia 1998 Jan
PMID:Effect of interferon-alpha therapy on bone marrow fibrosis in chronic myelogenous leukemia. 943 22

Twenty-seven patients above 40 years of age (range 40-55) with leukaemia underwent transplantation with haematopoietic stem cells from HLA-A, -B and -DR identical unrelated donors. They were compared to 69 younger patients, median age 23. In the older group, the diagnoses were acute myeloid leukaemia (AML) five, acute lymphoblastic leukaemia (ALL) three and chronic myeloid leukaemia (CML) 19. The corresponding figures in the younger patients were 21, 27 and 21, respectively. Conditioning consisted of cyclophosphamide (120 mg/kg) combined with 10 Gy total body irradiation. Immunosuppression was ATG or OKT3 for 5 days before transplantation and methotrexate combined with cyclosporin A. The probabilities of grades II-IV acute graft-versus-host disease (GVHD) were 23 and 21%, and the cumulative incidences of chronic GVHD were 64 and 50% in the older and younger patient cohorts, respectively. Overall, 3-year transplant-related mortality rates were 46% in patients > or =40 years of age and 32% in patients <40 years of age (P = 0.16). Three-year patient survival rates were 54 and 46% in the two groups, respectively. In patients with chronic phase CML, the corresponding figures were 67 and 68%, respectively. We conclude that patients above 40 years of age should be considered for transplantation with marrow from unrelated donors.
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PMID:Transplantation with unrelated bone marrow in leukaemic patients above 40 years of age. 948 93

CML, characterized by the BCR/ABL gene rearrangement has been more extensively studied than any other malignancy. Over the last decade, significant progress has been made in our understanding of BCR-ABL-induced alterations in intracellular signaling. Unfortunately, we still only poorly understand the correlation between the clinical symptoms of chronic phase CML and the BCR-ABL oncoprotein. This is in part due to lack of a good in vivo animal model of chronic phase CML. In vivo and in vitro studies from the Clarkson group, recently reviewed in this journal (Leukemia 1997; 11: 1404-1428), have significantly enhanced our understanding of the pathophysiology of CML. However, further characterization of the effect of the BCR-ABL oncoprotein on signal molecules involved with cell differentiation, cell proliferation, cell survival and cell adhesion in primary Ph+ CML progenitors or in vivo models of CML will be needed to provide a full understanding of the pathophysiology of chronic phase CML.
Leukemia 1998 Feb
PMID:Chronic myelogenous leukemia: too much or too little growth, or both? 930 92


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