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PubMedDate not supplied

Combination treatment of imatinib-sensitive and -resistant BCR-ABL-positive CML cells with imatinib and farnesyltransferase inhibitors.

BACKGROUND: Resistance to imatinib monotherapy frequently emerges in advanced stages of chronic myelogenous leukemia (CML), supporting the rationale for combination drug therapy. In the present study, the activities of the farnesyltransferase inhibitors (FTIs) L744,832 and LB42918, as single agents and in combination with imatinib, were investigated in different imatinib-sensitive and -resistant BCR-ABL-positive CML cells. MATERIALS AND METHODS: Growth inhibition of the cell lines and primary patient cells was assessed by MTT assays and colony-forming cell assays, respectively. Drug interactions were analyzed according to the median-effect method of Chou and Talalay. The determination of apoptotic cell death was performed by annexin V/propidium iodide staining. RESULTS: Combinations of both FTIs with imatinib displayed synergism or sensitization (potentiation) in all the cell lines tested. In primary chronic phase CML cells, additive and synergistic effects were discernible for the combination of imatinib plus L744,832 and imatinib plus LB42918, respectively. Annexin V/propidium iodide staining showed enhancement of imatinib-induced apoptosis with either drug combination, both in imatinib-sensitive and -resistant cells. CONCLUSION: The results indicated the potential of L744,832 and LB42918 as combination agents for CML patients on imatinib treatment.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMedDate not supplied

Long-term culture of chronic myeloid leukemia (CML) bone marrow cells.

BACKGROUND: Clonal Ph1+ hematopoiesis is not allowed to proliferate under a long-term culture system: in 3,4 weeks residual normal (Phl-) hematopoiesis emerges. This culture system has recently been proposed as a method for purging autografts. METHODS: In our study we evaluated for cytogenetic conversion cells harvested from the non-adherent (NA) fraction of LTBMCs from CML patients. Moreover we investigated the effects of prior therapy (busulfan or hydroxyurea) on CML hematopoiesis maintained under long-term culture. RESULTS: Time-course analysis of a large number of metaphases of NA cells from LTBMCs showed that the disappearance of Ph1+ cells is fortuitous. Although most of the analyzed cells were more mature cells, a complete cytogenetic conversion at the level of the early hematopoietic compartment, located within the adherent stromal layers, seems unlikely, at least for the first 3,4 weeks of culture. Thus the possibility exists of reinfusing an indefinite number of Ph1+ progenitor or stem cells, which renders proper evaluation of the clinical benefits of this purging method difficult. Moreover we found that prior chemotherapy (busulfan or hydroxyurea) significantly affected CML hematopoiesis, reducing time-course recovery of clonogenic cells from LTBMCs. CONCLUSIONS: Overall data suggest caution in the reinfusion of bone marrow cells maintained under long-term culture for previously treated CML patients.

Adult↗

PubMed1990

Interstitial insertion of varying amounts of ABL-containing genetic material into chromosome 22 in Ph-negative CML.

We studied the cells from three selected patients with Ph-chromosome-negative chronic myeloid leukemia (CML) by Southern blotting, polymerase chain reaction, and in situ hybridization of informative probes to metaphase chromosomes. All three patients had rearrangement of M-BCR sequences in the BCR gene and expression of one or other of the mRNA species characteristic of Ph-positive CML. Leukemic metaphases studied after trypsin-Giemsa banding were indistinguishable from normal. The ABL probe localized both to chromosome 9 and 22 in each case. A probe containing 3' M-BCR sequences localized only to chromosome 22, and not to chromosome 9 as would be expected in Ph-positive CML. Two new probes that recognize different polymorphic regions distal to the ABL gene on chromosome 9 in normal subjects localized exclusively to chromosome 9 in two patients and to both chromosomes 9 and 22 in one patient. These results show that Ph-negative CML with BCR rearrangement is associated with insertion of a variable quantity of chromosome 9 derived material into chromosome 22q11; there is no evidence for reciprocal translocation of material from chromosome 22 to chromosome 9.

Base Sequence↗

PubMed1990

Use of pulsed field gel electrophoresis to characterize BCR gene involvement in CML patients lacking M-BCR rearrangement.

We studied the pattern of BCR involvement in 52 patients with chronic myeloid leukemia by Southern blotting. Of 33 Philadelphia (Ph)-positive patients, 30 had evidence of M-BCR rearrangement, two cases were difficult to interpret, and one clearly lacked evidence of M-BCR rearrangement. Of 19 Ph-negative patients, nine showed M-BCR rearrangement, nine showed no rearrangement, and one result was uncertain. We selected for more detailed study eight patients (three Ph-positive and five Ph-negative). Two of the Ph-positive patients, whose Southern blots were difficult to interpret, had rearranged bands when the BCR gene was studied by pulsed field gel electrophoresis (PFGE). Results of PFGE studies and in situ hybridization to metaphase chromosomes in the third Ph-positive patient, whose DNA clearly lacked M-BCR rearrangement on Southern analysis, were consistent with a breakpoint on chromosome 22 located 3' of all known exons of the BCR gene. However, mRNA studied with the polymerase chain reaction showed evidence of a classical b2-a2 linkage. The findings in this patient may be explained by an unusual genomic breakpoint downstream of the BCR gene associated with long range splicing that excluded all of the 3' BCR exons. Of the five patients with Ph-negative M-BCR non-rearranged CML studied by PFGE for BCR gene rearrangement, none had evidence of rearranged bands. We conclude that PFGE is a valuable adjunct to standard molecular techniques for the study of atypical cases of CML. Occasional patients with Ph-positive CML have breakpoints outside M-BCR. The BCR gene is probably not involved in patients with Ph-negative, M-BCR non-rearranged CML.

Blotting, Southern↗

PubMed1978

Chromosome analysis of spleen and/or lymph nodes of patients with chronic myeloid leukemia (CML).

Origin and spread of the chromosomally abnormal cells that appear in chronic myeloid leukemia (CML) after transformation are unknown. Spleen and lymph node may be involved. In 16 patients with CML splenectomy and/or adenectomy were performed before or during the blastic crisis of the disease, followed by a chromosomal analysis of the cells from the removed organ. At the same time, the chromosomes of the blood cell and of the bone marrow were also analyzed. Analyses were done with R banding. The results show that an extramedullary clonal development with duplication of the Ph1 chromosome and other features occurred. From a cytogenetic standpoint, acute blastic phase of CML is frequently characterized by an increased number of chromosomes owing to preferential gain of additional chromosomes. This, then, would clearly point to extamedullary acute transition in CML.

Bone Marrow↗

PubMed1989

Cytogenetic and molecular analysis in Philadelphia negative CML.

We studied the clinical, hematologic, cytogenetic and molecular biologic features in four patients with Philadelphia (Ph) negative chronic myeloid leukemia (CML). In all four cases the clinical and hematologic characteristics were indistinguishable from Ph positive CML. Cytogenetic analysis showed a normal karyotype in two patients and chromosomal translocations apparently not affecting chromosome 22 in the other two cases. Southern blot analysis using probes of the bcr region, demonstrated a bcr break-point in all four patients. In situ hybridization with bcr, c-abl, and c-sis probes showed unusual hybridization sites for 5'-bcr and c-abl indicating complex chromosomal rearrangements affecting three different chromosomes in the four patients investigated. Using polymerase chain reaction (PCR) followed by hybridization to oligonucleotide probes specific for the bcr-abl fusion region, the expression of a chimeric bcr-abl mRNA was detected. In these patients we demonstrated that (a) CML with a breakpoint in the bcr region without cytogenetically detectable Ph chromosome is characterized by the same genomic recombination of 5'-bcr and c-abl as CML with standard Ph translocation and (b) unusual localization of 5'-bcr and c-abl sequences caused by complex Ph translocation does not interfere with transcription of the bcr-abl fusion gene.

Adult↗

PubMedDate not supplied

Haematological characteristics of a new membrane oxygenator: the Cobe CML.

The new Cobe CML membrane oxygenator is more compact than other membrane oxygenators and has a combined venous and cardiotomy suction reservoir. Its size makes it as easy to use as a bubble oxygenator. The studies reported here were designed to show whether the excellent haemocompatibility found with other types of membrane oxygenators had ben compromised by the changes introduced in the Cobe CML oxygenator. Platelet number and function (ADP induced aggregation) plasma betathromboglobulin concentration and plasma haemoglobulin concentration were studied in nine patients where the Cobe CML oxygenator had been used and these were compared with ten patients managed with a Shiley S-100 bubble oxygenator. We conclude that the constructional changes of the Cobe CML oxygenator do not affect the haemocompatibility of this type of membrane oxygenator and that it remains significantly better than the Shiley S-100 bubble oxygenator.

Coronary Artery Bypass↗

PubMed1985

HLA regulates postrenal transplant CML nonreactivity.

Previous studies have shown that lymphocytes from renal allografted patients with a good functioning graft display donor-specific cell-mediated lympholysis nonreactivity (CML-NR) in vitro. To define whether the HLA system influences the occurrence of the CML-NR, immunogenetic studies were carried out. Posttransplant lymphocytes derived from CML-NR patients were stimulated in vitro with lymphocytes from unrelated healthy blood donors, who were selected for the presence or absence of kidney donor-specific HLA antigens. The presentation of kidney donor-specific HLA-B (and -C) antigens on the lymphocytes of unrelated blood donors resulted in cytolytic nonresponsiveness, whereas presentation of the kidney donor-specific HLA-A locus antigens on lymphocytes of the unrelated blood donors revealed no cytolytic nonresponsiveness. The results, as displayed by posttransplant lymphocytes of renal allografted patients, demonstrate that the kidney donor HLA-B (and -C) antigens are responsible for the in vitro-observed, donor-specific CML-NR. Consequently, presentation of cells from panel members matched to the kidney donor at the HLA-B locus suppresses the response towards HLA-A locus antigens. The in vitro-observed cytolytic nonresponsiveness appeared not to be due to an absence of specific cytotoxic T lymphocytes, because the nonresponsiveness can be abrogated by addition of exogenous IL 2.

Clone Cells↗

PubMed1980

Philadelphia chromosome (Ph1)-negative chronic myelogenous leukemia (CML): a clonal disease with origin in a multipotent stem cell.

It has been shown with glucose 6-phosphate dehydrogenase (G-6-PD) mosaicism that Ph1-positive chronic myelogenous leukemia (CML) is a clonal disease that involves multipotent hematopoietic stem cells. We now report G-6-PD studies of a 79-yr-old woman with Ph1-negative CML. Equal amounts of B and A-type activities were found in nonhematopoietic tissues, indicating that the patient was heterozygous for G-6-PD. In contrast, only A-type G-6-PD was found in marrow cells, blood erythrocytes, leukocytes, and platelets and in granulocyte-monocyte and eosinophil colonies grown from blood mononuclear cells. Unlike most cases of PH1-positive CML, colony growth in this patient increased during blastic transformation and the colonies contained only immature monocytic cells. The data indicate that in this patient, Ph1-negative CML is similar to the Ph1-positive form of the disease in involvement of multipotent stem cells and probable clonal origin, but the two disorders differ in the rapidity with which they enter blastic transformation and in the pattern of granulocyte-monocyte colony growth at that time.

Aged↗

PubMed1981

Mouse alloantibodies capable of blocking cytotoxic T cell function. III. Studies of the mechanism of blocking of CML by anti-Lyt-2 antibodies.

Attempts were made to analyze the mechanism of action of anti-Lyt-2 antibody in blocking of CML in the absence of complement. Preincubation of killer cells with anti-Lyt-2 antibody followed by washing was found to abrogate the inhibitory effect of the antibody on target cell lysis, whereas an equivalent amount of the antibody present throughout the culture period caused marked inhibition. The failure of pretreatment with anti-Lyt-2 antibody to cause inhibition of CML might be due to rapid turnover of Lyt-2 molecules. Delayed addition of the anti-Lyt-2 antibody to CML cultures decreased the inhibition observed, which indicated that the antibody must be present during early stages of killing in order to exert significant inhibitory effects. The partitioning of CML according to requirements for divalent cations showed that anti-Lyt-2 antibody acts on killer cells during the Mg++-dependent stage of killing. In addition, the antibody was shown to be capable of reversing certain events occurring during this stage. These data are consistent with a role for Lyt-2 molecules during the antigen recognition stage of cell-mediated lysis. However, the exact function of the Lyt-2 molecule remains unknown.

Animals↗

PubMed1982

Identification of human CML target. HLA-B locus (B12) antigen variants defined by CTL generated between B locus-identical (B12) responder-stimulator pairs.

The genetics of human CML targets were studied by seven CTL generated in combinations iun which the responder/stimulator difference was limited to one (or two) HLA-A, -B, or -C antigens. Unstimulated peripheral blood lymphocytes were used as targets. CTL sensitized against antigens A11, Aw31, or B17 lysed all cells bearing the respective target from a large panel of cells from unrelated individuals. Hence, at least one CTL clone was directed against the HLA antigen molecule. However, all CTL also exerted cross-kill to cells not sharing the stimulating HLA antigen. For two CTL, the target of the cross-kill was not clarified. Five CTL were found where the cross-kill was directed against antigen HLA-B12 (Bw44 and Bw45). All these cTL were generated in R/S pairs identical for B locus antigens (Bw44/Bw35 heterozygotes). The individual CTL lysed different parts of the panel of B12-positive target cells. The interpretation is that these CTL detect subtypes of HLA antigens, but alternative possibilities are also considered. Four B12 subtypes are described, tentatively designated as B12-related CML targets. Identification of HLA-B-related CML targets represent CML "typing" of HLA-antigen differences that were not detected serologically. The subtypes can now be tested for their possible functional significance.

B-Lymphocytes↗

PubMed1993

Erythropoiesis in CML--immunomorphometric quantification, PCNA-reactivity, and influence on survival.

An immunohistochemical and morphometric analysis was performed on trephine biopsy specimens in 60 patients with chronic myeloid leukemia (CML) to quantify erythropoiesis and its proliferation capacity and to assess the stainable marrow iron (hemosiderin). For this purpose, an elaborate double-immunostaining technique was applied. This included a monoclonal antibody (PC10) that is directed against proliferating cell nuclear antigen (PCNA), followed by an antibody against glycophorin C (Ret40f), to identify all nucleated erythroid precursor cells. Additionally, morphometric data were derived from immunostaining of megakaryocytes (CD61) and macrophages (PG-M1), including its hemosiderin-laden subpopulation. Finally the determination of argyrophilic (reticulin) fiber density was carried out. In comparison with a control group (15 patients) without any hematologic disorder, in CML patients morphometric evaluation showed a significant reduction in the number of erythroblasts and normoblasts. This feature was associated with a PCNA-labeling index within the normal range and a decreased stainable marrow iron (number of hemosiderin-storaging macrophages). Several parameters were established to exert a predictive value on survival. A worsening of prognosis was associated with a decrease in the number of erythroid precursors (< 460/mm2), a low hemoglobin level (< 10 g/dl), a high megakaryocyte count (> 50 cells/mm2), an increased density of reticulin fibers (> 30 i x 10(2)/mm2) and splenomegaly (> 15 cm below costal margin). Our findings are in keeping with results obtained from in vitro studies of cell proliferation in CML, which is not significantly altered in comparison with the normal bone marrow. Finally, the present data, although derived from a small group of patients, emphasize the impact of histologic variables to be included in one of the major clinical trials on prognosis in CML.

Bone Marrow↗

PubMed1994

Fluorescence in situ hybridization (FISH) detection of trisomy 8 in myeloid cells in chronic myeloid leukemia (CML): a study of archival blood and bone marrow smears.

Patients in accelerated phase or blast crisis of chronic myeloid leukemia (CML) frequently develop clonal cytogenetic abnormalities in addition to the Philadelphia chromosome. Using a DNA probe directed to the centromere of chromosome 8, we performed fluorescence in situ hybridization (FISH) on archival Wright-stained blood and bone marrow smears of seven patients with CML and with a known +8 clone by metaphase cytogenetics to determine the distribution of +8 in interphase cells. All slides had been stored at ambient temperature for 12-26 months. The bone marrow aspirate smears of 21 non-leukemic patients served as controls. Trisomy 8 was demonstrated in all myeloid cell lines including the neutrophils, basophils, eosinophils, monocytes, and erythroid precursors, but not in the lymphocytes. The extra chromosome 8 was present in mature segmented granulocytes as well as more immature precursors. The percentage of +8 cells was highest in specimens from patients with CML in myeloid blast crisis (mean 64%), followed by those in accelerated phase (mean 39%). Three specimens from patients in morphologic chronic phase showed the lowest percentage of +8 cells (mean 13%). One patient was studied twice and showed a substantial expansion of +8 cells with progression from accelerated phase to myeloid blast crisis. Compared to metaphase cytogenetics, the proportion of +8 cells detected by FISH was often lower. We conclude that the acquisition of trisomy 8 in CML occurs in a pluripotent myeloid stem cell apparently incapable of expressing mature lymphoid phenotype, and that morphologic progression of disease is generally associated with an expansion of the +8 component.

Adult↗

PubMed1993

The abnormal p53 proteins expressed in CML cell lines are non-functional.

Inactivation of the tumor suppressor function of the p53 gene is found in association with 20-40% cases of chronic myeloid leukemia (CML) in blast crisis. A common mechanism of p53 inactivation in CML is by complete deletion of one p53 allele in association with a point mutation which produces a mutant p53 protein on the remaining allele. Whether the mutant p53 protein, which is generally expressed at an elevated level, plays any role in the pathogenesis of blastic transformation or in maintaining the neoplastic proliferation, as it does in some solid tumors, is unknown. By using an antisense oligonucleotide approach, we investigated the cellular function of known abnormal forms of p53 protein, both mutant and truncated, expressed in CML cell lines. We found that the introduction of p53 antisense oligonucleotides can specifically inhibit the translation of the p53 mRNA. However, inhibiting p53 expression had no effect on cell proliferation, cell viability, and colony formation. There was no change in cell doubling time when the cells were maintained in serum-free medium (SFM) in the presence of antisense oligonucleotides compared with cells maintained in SFM alone. We conclude that the mutant or truncated p53 proteins expressed in the blast cells of CML have no growth-promoting effect and are not required for cell survival and proliferation. We further speculate that the loss of the tumor suppressor function of p53 might be the only mechanism by which p53 is involved in the transition from chronic phase to blast crisis.

Base Sequence↗

PubMed1993

Unrelated donor and autologous marrow transplant therapy of chronic myelogenous leukemia (CML).

Marrow transplant from an HLA-matched sibling donor can cure CML. Best results are observed when patients are transplanted early in chronic phase. T-lymphocyte depletion of donor marrow can effectively prevent chronic graft versus host disease, but is associated with a high incidence of relapse. Hematologic relapse after marrow transplantation can be treated successfully with alpha-interferon, donor buffy coat cells or second transplant. HLA phenotypically matched and, in some cases, 1 HLA antigen mismatched unrelated donors can also be used successfully for marrow transplantation therapy of CML. Complications include an increased incidence of graft failure and graft vs. host disease. Chronic phase patients transplanted early in the disease course have the best outcome. The development of the National Marrow Donor Program in the United States and a network of donor registries throughout the world as well as the establishment of new techniques for histocompatibility testing will increase the availability of unrelated donors and expedite the donor search process. Autologous marrow transplantation can induce complete hematologic and cytogenetic remissions and may prolong survival when compared with results expected from conventional therapy for CML. Strategies are being developed to obtain benign primitive progenitors suitable for autologous marrow transplantation by positive selection techniques and to develop further post-transplant anti-leukemia cell therapy to use as an adjunct to autologous marrow transplantation for CML.

Bone Marrow Transplantation↗

PubMed1996

Chronic myeloid leukemia of thrombocythemic onset: a CML subtype with distinct hematological and molecular features?

Among 84 consecutive patients with chronic phase Ph-positive chronic myeloid leukemia (CML) who were investigated for the hybrid BCR/ABL mRNA, in six cases (7%) the disease mimicked essential thrombocythemia (ET) at presentation, because of marked thrombocytosis (platelet counts ranging from 1003 x 10(9)/l to 2800 x 10(9)/l) and moderate leukocytosis (WBC counts from 10 x 10(9)/l to 19 x 10(9)/l). At initial examination, four of the six patients showed a few (4-9%) immature myeloid cells in the peripheral blood, and two had blood basophilia. All six patients later developed increasing leukocytosis, and two subsequently died from blast crisis and accelerated CML, respectively. In the overall series, 38 patients (45%) expressed the b2a2 type of BCR/ABL mRNA, and 46 (55%) either the b3a2 or both mRNAs. By contrast, only one of the six patients with CML of thrombocythemic onset expressed the b2a2 mRNA vs five with either b3a2 (n = 4) or both mRNA types (n = 1). The above results, in conjunction with similar data from a few previously published cases, suggest an association between the above form of CML and b3a2 type of BCR/ABL transcript.

Adolescent↗

PubMed1996

[Unclassified chronic myeloproliferative disorder (Ph negative/bcr rearrangement negative CML) with late appearing Philadelphia like chromosome].

A 48-year-old male was diagnosed to be unclassified chronic myeloproliferative disorder (UCMPD)/Ph negative bcr rearrangement negative (Ph-/bcr-) CML by hematological, cytogenetical and DNA analyses (Jpn. J. Clin. Hematol. 33(4): 525-531, 1992). Three years and a half after the diagnosis of UCMPD/Ph-bcr- CML, Ph chromosome was observed in 17 of 20 examined cells. Hematological findings showed a transformation into blast crisis. The late appearing of Ph in a case of UCMPD/Ph1-bcr- CML described here is rare. Southern blot analysis using 3' and 5' bcr probe showed no bcr rearrangement. Analyses of BCR/ABL chimeric RNA by RT-PCR method were negative in both of Major- and Minor BCR/ABL chimeric RNA. In the present case it is speculated that Ph is developed as the result of multistep progression and also speculated that the breakpoint at BCR gene differs from Major- and Minor-bcr in usual Ph+CML and de nove Ph+ ALL. Therefore, it may be reasonable that the present case is understood to be a case with late appearing Ph-like chromosome.

Base Sequence↗

PubMed1998

Survival with bone marrow transplantation versus hydroxyurea or interferon for chronic myelogenous leukemia. The German CML Study Group.

Hydroxyurea, interferon, and HLA-identical sibling bone marrow transplantation are common therapies for chronic myelogenous leukemia (CML) in chronic phase. Which is best is controversial. The purpose of this study was to compare survival of patients with CML receiving HLA-identical sibling transplants versus hydroxyurea or interferon. The transplant cohort included 548 recipients of HLA-identical sibling transplants, reported to the International Bone Marrow Transplant Registry. The nontransplant cohort included 196 patients receiving hydroxyurea (n = 121) or interferon (n = 75) on a randomized trial of the German CML Study Group. Survivals were compared using proportional hazards regression with fixed and time-dependent variables to adjust for patient differences and changing risks over time. For the first 18 months after diagnosis, mortality was higher in the transplant than the nontransplant cohort (relative risk [RR], 5.85; P < .0001). From 18 to 56 months, mortality was similar (RR, 0.80; P = .38). After 56 months, mortality was lower in the transplant cohort (RR, 0.16; P < .0001). Seven-year survival probabilities (95% confidence interval) were 58% (50% to 66%) with transplant and 32% (22% to 41%) with hydroxyurea or interferon. There was a significant survival advantage for hydroxyurea or interferon in the first 4 years after diagnosis and for transplants starting 5.5 years after diagnosis. For transplants done within 1 year of diagnosis, the survival advantage for transplantation began earlier. Survival advantage for transplants was greater and occurred earlier in patients with intermediate- and high-risk prognostic features than in those with low-risk features. This study confirms higher early mortality, but a long-term survival advantage for HLA-identical sibling transplants over hydroxyurea or interferon in CML.

Adolescent↗