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Early nuclear events in lymphocyte proliferation. The role of DNA strand break repair and ADP ribosylation.

The previously reported extensive DNA strand breakage in resting murine splenic lymphocytes is not an artifact of the extraction or assay procedure. The benzamide inhibitors of poly(ADP ribose) synthetase (pADPRS), such as 5-methoxybenzamide (MBA), had been shown to block the strand break repair occurring within 2 h of activation of splenic lymphocytes by the mitogen concanavalin A (conA); the inhibitors also blocked early events in proliferation, such as blast formation, as well as entry into S phase. Inhibitors of pADPRS blocked lymphocyte proliferation by inhibiting the activity of this enzyme, rather than by non-specific effects. Aphidicolin, an inhibitor of alpha-polymerase, also prevented DNA strand break repair in conA-stimulated cells but, unlike MBA, did not prevent blast formation. DNA strand breaks accumulated in the presence of MBA at the same linear rate (300-400/h) in both resting and conA-treated cells. We and others had hypothesized that this accumulation was due to a continuous production of strand breaks in lymphocytes, leading to their accumulation in presence of repair inhibitors. However, incubation of the cells with aphidicolin at concentrations that inhibited repair did not result in any increase in strand breaks. The hypothesis of continuous cycling of breaks is incorrect; accumulation of breaks was due to some indirect effect of MBA, such as a possible disinhibition of an ADP-ribosylation-sensitive endonuclease described in other cell types. All of the early stages of lymphocyte proliferation, including blast transformation (but not DNA synthesis) require ADP ribosylation. Repair of DNA strand breaks is not a precondition for blast formation, though experiments involving the combined effects of MBA and aphidicolin showed that repair of the breaks is essential in order for the cells to replicate their DNA. Our data are consistent with a model suggesting that DNA strand breaks introduced into differentiated cells act as an additional safety-catch mechanism that restrains them from replicating their genetic material but not from undergoing the early stages of proliferation.

Adenosine Diphosphate Ribose↗

[Antileukemic drug--a selective inhibitor of BCR-ABL tyrosine kynase, imatinib(STI571)].

Chronic myeloid leukemia (CML) is a clonal hematopoietic stem cell disorder characterized by Philadelphia chromosome and resultant production of the constitutively activated BCR-ABL tyrosine kinase. Imatinib (STI571), selective inhibitor of the ABL-tyrosine kinase, inhibits the activity of BCR-ABL tyrosine kinase. A phase I and II study of STI571 showed remarkable cytogenetic effect in patients with interferon-refractory CML, offering new hope for therapy for CML. It will, however, require long-term follow-up data from phase II and III clinical studies to validate the effect of STI571 on survival. As therapy for CML improves, monitoring minimal residual disease will be important.

Animals↗

Central nervous system relapse in two patients with chronic myelogenous leukemia in myeloid blastic phase on imatinib mesylate therapy.

We report two patients with Philadelphia (Ph) chromosome positive chronic myelogenous leukemia (CML) in myeloid blastic phase that developed central nervous system disease while on imatinib mesylate therapy. Patient 1 presented with CML in myeloid blastic phase and responded to imatinib, cytarabine, and idarubicin-based treatment achieving complete cytogenetic remission in the marrow, but developed myeloid blasts in his cerebrospinal fluid (CSF) during treatment. Patient 2 developed CML myeloid blastic phase after initially being in hematologic and cytogenetic remission with imatinib treatment. He represented with an extramedullary mass at the base of his skull and CSF involvement. Both patients were treated with intrathecal chemotherapy and received craniospinal irradiation to clear the spinal fluid of disease. Both patients have undergone related allogeneic stem cell transplant and are in complete hematologic remission; one is in complete cytogenetic remission, the other is too early to evaluate. Central nervous system involvement with myeloid blasts is previously unreported for patients with CML in blastic phase on imatinib and warrants cautious observation and vigilance in these patients.

Adolescent↗

[A new drug in the therapy of chronic myeloid leukemia: ST1571].

The therapy of chronic myeloid leukemia, characterized by the presence of the Philadelphia chromosome in the clonal hematopoietic stem cells, has changed dramatically in the last years with the development of a specific inhibitor of the BCR-ABL tyrosine kinase: tyrosine kinase inhibitor imatinib mesylate (formerly STI571, [Glivec]). Glivec selectively blocks cellular proliferation and induces apoptosis in Philadelphia chromosome-positive (Ph+) cells harbouring the Bcr-Abl tyrosine kinase. Clinical development of imatinib mesylate began with 3 large, multicenter, phase II trials. The majority (88%) of interferon-alpha-resistant or intolerant patients in chronic-phase CML, achieved a complete hematologic response to imatinib mesylate. More importantly, approximately half of the patients achieved a major cytogenetic response, a result historically associated with improved survival. Furthermore, 21% of patients in accelerated-phase CML and 13.5% of patients in blastic-phase CML (patient populations with typically poor prognosis before the advent of imatinib mesylate) achieved major cytogenetic responses.

Antineoplastic Agents↗

[Tumor progression in chronic lympholeukemia].

Tumor progression associated with chronic lympholeukemia is an extreme rarity. The clinico-morphological types of malignant transformation include Richter's syndrome marked by a dramatic increase of the size of one or several lymph nodes, spleen, appearance of extranodal tumors, fever, the signs of intoxication, frequent reduction in the blood leukocyte count or hemogram normalization. Biopsy specimens of neoplasms show cells uncommon to the typical version of chronic lympholeukemia (blasts, histiocytes, and so forth). In rarely occurring "prolymphocytoid" transformation in the phase of marked progression of CLL as shown by the hemogram, the myelogram demonstrates a great number of prolymphocytes of the monoclonal origin with small lymphocytes of the chronic phase. During transformation according to the lymphoblastic type (two case reports described in the literature), the blasts showed the phenotype of small lymphocytes. Early diagnosis of tumor progression in CLL requires that the treatment be carried out according to the protocols for lymphosarcomas.

Adult↗

Fibrinogen survival and fibrinopeptide A in acute leukemia.

BACKGROUND. Hypofibrinogenemia and increased fibrin(ogen) degradation products in acute leukemia have been attributed to intravascular thrombin generation triggered by leukemic cells. However, the strict relationship between fibrinogen catabolism and turnover of fibrinopeptide A (FPA), which is a sensitive and specific marker of thrombin activity, has not been evaluated in acute leukemia (AL) with or without disseminated intravascular coagulation (DIC) to see whether mechanisms other than thrombin activity could be responsible for fibrinogen consumption. We report here the 125I-fibrinogen kinetics and FPA measurements in 19 patients with AL, 6 of them with DIC. METHODS AND RESULTS. Radiolabelled fibrinogen kinetics were studied in all the patients concomitantly with the start of chemotherapy. Fibrinopeptide A was measured by a radioimmunoassay at time of diagnosis and during chemotherapy. The kinetics of disappearance of radiolabelled fibrinogen where biphasic, with a rapid phase in the first 1-3 days of chemotherapy and a subsequent slow phase associated with the reduction or disappearance of blast cells. Patients with DIC had a significantly shorter half-life and turnover than patients without DIC. The latter group had significant shortening of these parameters in comparison to normal subjects. The thrombin-dependent catabolic rate of fibrinogen, calculated from the mean level of FPA during the first phase of disappearance curve and by assuming 2 moles of FPA generated per mole of fibrinogen, was similar in patients without DIC and in normal subjects, whereas patients with DIC had a significantly higher catabolic rate, even though the increase was not sufficient to account for all the turnover of fibrinogen. No relationship was observed between fibrinogen turnover and FPA turnover.

Acute Disease↗

Acute leukemia with mediastinal mass, lymphadenopathy, and monocytic precursor cells.

Cell marker analysis with monoclonal antibodies (MoAb) as well as differentiation studies with the chemical inducer TPA were used to identify a population of apparently lymphoid cells as monocytic precursor cells in a patient with acute leukemia. The initial manifestation of the disease with mediastinal mass and lymphadenopathy was followed by the appearance of small lymphocyte-like blast cells in bone marrow (BM) and peripheral blood (PB). Although a lymph node biopsy revealed an infiltration with monoblasts, the leukemic cells in BM and PB were not classifiable. However, when the patient relapsed after chemotherapy with large monoblasts and again with morphologically lymphoid blast cells, the latter could be classified by treatment with TPA. After incubation with the inducer (12-48 hr) the cells became positive with the MoAB VIM-D5, showed a strong reaction with alpha-naphthyl-acetate-esterase and developed macrophage like morphology, as well as phagocytic properties. During the terminal phase of the disease, small, lymphocyte-like blast cells predominated. These cells could be classified by a panel of MoABs. They expressed myeloid determinants (VIM-D5, VIM-2, MY 9, VIM-12, VIM-13) but showed no reactivity with MoABs specific for lymphocytic cells.

Adult↗

Allogeneic bone-marrow transplantation for chronic myelogenous leukaemia.

In 117 patients with chronic myelogenous leukaemia (CML) treatment with a combination of high-dose chemoradiotherapy plus transplantation of allogeneic bone-marrow from HLA-identical, mixed-lymphocyte-culture-identical siblings resulted in an actuarial probability of 3-year survival of 63 +/- 16% (95% confidence interval) for 39 patients transplanted in chronic phases; 36 +/- 14% for 56 transplanted in accelerated phase; and 12 +/- 15% for 22 transplanted during blast crisis. Irrespective of disease status at the time of transplantation, and in contrast to chemotherapy, a plateau-effect was observed in the survival curves starting 14 to 19 months after transplantation. The actuarial probability of recurrent or persistent leukaemia at 3 years was 7 +/- 9% for patients transplanted in chronic phase, 41 +/- 19% for accelerated phase, and 41 +/- 39% for blastic phase. All relapses occurred within 18 months of transplantation. This study demonstrates that long-term disease-free survival in CML can be achieved with bone-marrow transplantation. Best results were obtained in patients transplanted during chronic phase of the disease.

Adolescent↗

Translocations (4p+; 6q-) and (12q-; Xp+) in blastic phase of a Ph1-positive chronic myeloid leukemia.

This paper reports a 28-year-old woman with Philadelphia chromosome (Ph1)-positive chronic myeloid leukemia (CML) who developed two marrow cell lines during the blastic phase: one with the translocation (12;X) (q 11;p22) and the other with the translocation (4;6) (p 16;q 25). The literature on involvement of chromosomes 12 and X in translocations and the appearance of 6 q- aberration in CML is summarized. The relationship between the 6 q-aberration and the blast cells with lymphoid appearance in the plastic phase of CML is discussed.

Adult↗

[Immunophenotypes on blast cells of chronic myelogenous leukemia].

Immunophenotypes of chronic myelogenous leukemia(CML) in chronic phase and in blastic crisis were reviewed. CML cells in chronic phase show a relatively mature immunophenotypes, such as CD13, CD33, CD15, and MPO, but not positive for CD34, CD117, TdT, and HLA-DR. When a CML transforms into blastic crisis, the blast cells demonstrate an immature myeloid(acute myelogenous leukemia(AML)-like) phenotypes in 60-70% of cases. The blast cells which have myeloid markers show CD13, CD33, MPO. In contrast to de novo AML, these myeloid blast cells often express megakaryocytic, erythroid markers or natural killer cell markers, and in some of the cases, the myeloid blast cells have complex phenotypes, with co-expression of markers from two or three lineages. The blast cells, in 25-30% of cases, demonstrate lymphoid blast phenotype characteristics similar to acute lymphoblastic leukemia(ALL), common ALL, or pre-B-ALL. In 60-80% of cases, the lymphoid blast cells co-express myeloid phenotype, fulfilling the criteria of biphenotypic leukemia.

Blast Crisis↗

Genomewide screening of DNA copy number changes in chronic myelogenous leukemia with the use of high-resolution array-based comparative genomic hybridization.

Chronic myelogenous leukemia (CML) evolves from an indolent chronic phase (CP) characterized by the Philadelphia chromosome. Without effective therapy, it progresses to an accelerated phase (AP) and eventually to a fatal blast crisis (BC). To identify the genes involved in stage progression in CML, we performed a genomewide screening of DNA copy number changes in a total of 55 CML patients in different stages with the use of the high-resolution array-based comparative genomic hybridization (array CGH) technique. We constructed Human 1M arrays that contained 3,151 bacterial artificial chromosome (BAC) DNAs, allowing for an average resolution of 1.0 Mb across the entire genome. In addition to common chromosomal abnormalities, array CGH analysis unveiled a number of novel copy number changes. These alterations included losses in 2q26.2-q37.3, 5q23.1-q23.3, 5q31.2-q32, 7p21.3-p11.2, 7q31.1-q31.33, 8pter-p12(p11.2), 9p, and 22q13.1-q13.31 and gains in 3q26.2-q29, 6p22.3, 7p15.2-p14.3, 8p12, 8p21.3, 8p23.2, 8q24.13-q24.21, 9q, 19p13.2-p12, and 22q13.1-q13.32 and occurred at a higher frequency in AP and BC. Minimal copy number changes affecting even a single BAC locus were also identified. Our data suggests that at least a proportion of CML patients carry still-unknown cryptic genomic alterations that could affect a gene or genes of importance in the disease progression of CML. This article contains Supplementary Material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.

Adult↗

Immunoglobulin gene organisation and expression in haemopoietic stem cell leukaemia.

We have analysed the organisation and expression of mu genes in the granulocytic phase and in the lymphoid and myeloid blast crises of Philadelphia chromosome (Ph1) chronic granulocytic leukaemia (CGL), a leukaemia which is known to arise in multipotential stem cells. We find that mu chain gene rearrangement occurs exclusively in lymphoid blast crisis leading in some, but not all, cases to the synthesis of small amounts of cytoplasmic mu chains characteristic of early pre-B lymphocytes. In Southern blots, only one or two rearranged mu chain genes are seen, suggesting that a clonal event leading to blast crisis can occur in a committed B cell precursor rather than in the multipotential stem cell precursor, in which the Ph1 chromosome originated. The pattern of mu gene rearrangement observed in Ph1 CGL blast crisis is compared with that in normal B cells, other B lineage malignancies, myeloid leukaemias and T cell leukaemias.

B-Lymphocytes↗

Detection of the BCR/ABL fusion gene in chronic myeloid leukemia by RNA polymerase chain reaction.

The bcr/abl fusion gene in 20 patients with chronic myeloid leukemia (CML) was detected by RNA polymerase chain reaction, which used mRNA as the starting material to generate cDNA with reverse transcriptase followed by PCR amplification (RNA/PCR). Amplification of a sequence spanning the bcr/abl junction region was achieved by using peripheral blood cells as the source of mRNA from all 20 patients with CML, including 3 cases of Ph (-) CML, and cell line K562 was derived from patients with CML. No amplification was seen when mononuclear cells from 3 normal individuals, 2 patients with lymphoma and cell line HL-60 were used. The presence or absence of bcr exon 3 in the fusion mRNA was determined by the size of the amplified fragments. Of the 20 CML patients, 15 showed only the 165-bp amplified band (indicating retention of bcr exon 3), one showed only the 90-bp amplified band, and 4 showed both 165-bp and 90-bp bands. Both bands were seen more frequently in blast crisis than in remission and chronic phase.

Adolescent↗

Lymphocyte subpopulations transformation studies in an experimental model of intestinal and hepatic amoebiasis.

The lymphocyte subpopulations in peripheral blood and blast transformation were studied on days 0, 3, 7, 11, 15, 20 and 35 after infection in progesterone-treated guinea-pigs which had been experimentally infected with Entamoeba histolytica by intracaecal inoculation. In animals with intestinal infection, lowered T cell numbers and blast transformation were seen during the acute phase with a subsequent tendency to recover. In guinea-pigs with hepatic amoebiasis, both these parameters were significantly depressed throughout the period of study with no tendency to recovery. In progesterone-treated and sham-operated animals, a less marked depression of T cells, was observed. The B cell population did not vary greatly in either group. This study has thus shown that in hepatic amoebiasis there is highly significant depression in both number and function of T cells in comparison to intestinal amoebiasis.

Animals↗

Alkaline phosphatase activity is expressed only in B lymphocytes committed to proliferation.

Alkaline phosphatase (APase) activity was measured in murine splenic lymphocytes stimulated with the T lymphocyte mitogens phytohemagglutinin (PHA) and Concanavalin A (Con A) and the B lymphocyte mitogens lipopolysaccharide (LPS) and anti-immunoglobulin (anti-Ig). APase activity was found to be enhanced specifically in mitogen-stimulated B lymphocytes, but not in T lymphocytes. This enhancement starts around 8 h after stimulation with a mitogen. With soluble anti-Ig it was observed that the B cells enter G1 phase as assessed by RNA synthesis and blast transformation. However, these cells fail to synthesize DNA and also do not show any increase in APase activity. When the same anti-Ig coupled to Sepharose was used as a stimulator, cells synthesized DNA and also showed significant increase in APase activity. When hydroxyurea was added, the enhancement in APase activity by the mitogen was not diminished although the cells failed to synthesize DNA. These observations indicate that APase activity is enhanced only in activated B cells committed to proliferation.

Alkaline Phosphatase↗

High incidence of a second BCR-ABL fusion in chronic myeloid leukemia revealed by interphase cytogenetic analysis on blood and bone marrow smears.

The t(9;22)(q34;q11) is the single most common chromosomal abnormality in leukemias. Recently, dual-color fluorescence in situ hybridization (FISH) protocols for the detection of the BCR-ABL fusion, which is the molecular counterpart of this translocation, have been described. In the present study, we analyzed blood or bone marrow smears of 46 patients (34 with chronic myeloid leukemia [CML] and 12 with acute lymphoblastic leukemia [ALL]) for the presence of a BCR-ABL fusion. On these clinical routine samples, hybridization was performed with high efficiency and the BCR-ABL fusion was detected reliably. This series includes one case with a Philadelphia chromosome (Ph) on banding analysis and negative reverse transcriptase polymerase chain reaction (RT-PCR) results. Surprisingly, in 13 of the 34 CML patients (4 of 17 patients with chronic phase and 9 of 17 patients with blast crisis), and in 1 of the 12 ALL patients, an additional BCR-ABL fusion was diagnosed in 4% to 72.5% of interphase cells. In 10 of these 14 patients, banding data are available; only in two cases was the additional Ph detected by metaphase analysis. The data from this interphase cytogenetic analysis indicate that an additional Ph occurs more frequently than would be assumed based on banding analysis.

Adult↗

Acute myeloid leukemia cell lines MOLM-17 and MOLM-18 derived from patient with advanced myelodysplastic syndromes.

The two acute myelomonocytic leukemia sister cell lines MOLM-17 and MOLM-18 and the Epstein-Barr-virus positive non-malignant B-lymphoblastoid cell lines (B-LCLs) B422 and B423 were established from the bone marrow sample of a 60-year-old Japanese male in the advanced leukemic phase of refractory anemia with excess of blasts, a subtype of myelodysplastic syndromes (MDS). MOLM-17/-18 are proliferatively responsive to the growth factors present in the culture supernatant of the 5637 cell line. The B-LCLs are constitutively growth factor-independent. MOLM-17 and B422 were established at eight months after the initial diagnosis, while MOLM-18 and B423 were derived from a sample one month later. Immunophenotyping of the first leukemia sample revealed a mixed lineage leukemia immunophenotype with positivity for terminal deoxynucleotidyl transferase (TdT), CD13 and CD19; the second sample revealed solely myeloid characteristics with positivity for CD13, CD41 and CD61, whereas TdT was negative. MOLM-17/-18 showed immunomarker profiles typical of the myelomonocytic lineage. The karyotype analysis of MOLM-17/-18 revealed various non-random numerical and structural abnormalities including del(5)(q?), -7, der(11)add(11)(p11.2)add(11)(q23), add(17)(p11.2), add(18)(p11.2), -20, -22 as common aberrations. Treatment with tumor necrosis factor-alpha induced pronounced cellular differentiation of both cell lines into macrophage-like cells. The overall profile of MOLM-17/-18 based on their extensive immunological, cytogenetic and functional characterization suggests that these cell lines together with the paired B-LCLs B422 and B423 may represent scientifically significant in vitro models which could facilitate investigations into the pathobiology of MDS.

Cell Line, Tumor↗

A novel abl protein expressed in Philadelphia chromosome positive acute lymphoblastic leukaemia.

The Philadelphia (Ph) chromosome breakpoints in chronic myelocytic leukaemia are clustered on chromosome 22 band q11 in a 5.8-kilobase (kb) region designated bcr. The c-abl protooncogene is translocated from chromosome 9 band q34 into bcr and the biochemical consequence of this molecular rearrangement is the production of an abnormal fusion protein bcr-abl p210 with enhanced protein-tyrosine kinase activity compared to the normal p145 c-abl protein. The Ph chromosome translocation is also seen in some acute lymphoblastic leukaemias with B-cell precursor phenotypes some of which have bcr rearrangement (bcr+) and some do not (bcr-). We present evidence that the Ph+, bcr- leukaemias are associated with a novel p190 abl kinase. We propose that acute lymphoblastic leukaemias that are bcr+, p210+ are probably lymphoid blast crises following a clinically silent chronic phase of chronic myelocytic leukaemia arising in multipotential stem cells whereas bcr-, p190+ cases are de novo acute lymphoblastic leukaemias arising in more restricted precursors.

Adolescent↗