Identification of a molecular signature predictive of sensitivity to differentiation induction in acute myeloid leukemia.

Acute myeloid leukemia (AML) blasts are immature committed myeloid cells unable to spontaneously undergo terminal maturation, and characterized by heterogeneous sensitivity to natural differentiation inducers. Here, we show a molecular signature predicting the resistance or sensitivity of six myeloid cell lines to differentiation induced in vitro with retinoic acid or vitamin D. The identified signature was further validated by TaqMan assay for the prediction of response to an in vitro differentiation assay performed on 28 freshly isolated AML blast populations. The TaqMan assay successfully predicts the in vitro resistance or responsiveness of AML blasts to differentiation inducers. Furthermore, performing a meta-analysis of publicly available microarray data sets, we also show the accuracy of our prediction on known phenotypes and suggest that our signature could become useful for the identification of patients eligible for new therapeutic strategies.

Gene expression profile of Vitamin D3 treated HL60 cells shows an incomplete molecular phenotypic conversion to monocytes.

By high density oligonucleotide microarrays we have studied the expression profile of proliferating and VD treated HL60 cells and the molecular phenotype of VD monocytes and that of CD14+ peripheral monocytes has been compared. The results indicate that important changes in functional categories of the differentially expressed genes underlie the differentiation transition from myeloblasts to monocytes. This differential gene expression pattern leads to an increased expression of mRNAs involved in surface and external activities since many of the VD induced genes belong to ligand binding, receptors, cell surface antigens, defense/immunity and adhesion molecules functional categories. The results also indicate that the molecular phenotypes of monocytes and VD induced cells diverge for a small but significant set of defense related genes. Particularly, class II MHC genes are not expressed in these cells. Furthermore, the high levels of expression of these genes induced by serum treatment of monocytes are decreased by VD.

Effect of L-arginine load on platelet aggregation: a comparison between normotensive and preeclamptic pregnant women.

BACKGROUND: In the present study we hypothesized that a derangement of the L-arginine-nitric oxide system could be involved in the development of the hypercoagulative status found during preeclampsia. In order to verify such hypothesis we have compared the effects of nitric oxide substrate, L-arginine on platelet aggregation. Moreover, we have also measured the L-citrulline plasma levels as a stochiometric metabolite resulting from the conversion L-arginine to nitric oxide. METHODS: Nine preeclamptic women and 11 normotensive pregnant women were enrolled for the study. Subjects were infused with saline and with 30gr of L-arginine. Blood samples were drawn during the saline infusion (30 min), during L-arginine administration (30 min) and 30 min thereafter. ADP and collagen-induced platelet aggregation was studied as per Born with a dual-channel aggregometer (Chrono-Log, Mascia Brunelli, Italy) and L-citrulline was measured by HPLC. RESULTS: In normotensive women the infusion significantly decreased ADP and collagen-induced aggregation after 15 minutes of L-arginine load; whereas no effects were observed in preeclamptic women. Similarly in normotensive but not in preeclamptic women L-arginine load was able to increase L-citrulline plasma levels. CONCLUSIONS: In normotensive women the in vivo L-arginine administration decreases platelet aggregation with an increase of L-citrulline plasma levels. On the contrary, no effects were observed in preeclamptic women. These findings confirm that a hypercoagulative status characterizes preeclampsia and that such phenomenon could be explained by a derangement of the platelet L-arginine-nitric oxide pathway.

The effectiveness and tolerability of epoetin alfa in patients with multiple myeloma refractory to chemotherapy.

Anemia is a frequent complication of multiple myeloma, becoming chronic in patients who are resistant to chemotherapy. This randomized, parallel, controlled multicenter study (71 patients receiving concomitant chemotherapy) evaluated the efficacy and safety of epoetin alfa in improving anemia and eliminating the need for transfusions in multiple myeloma patients refractory to conventional first- or second-line chemotherapy. Forty patients were treated with subcutaneous epoetin alfa (150 IU/kg per dose, increasing to 300 IU/kg per dose, every 3 weeks) for 6 months, and 31 entered a control group. The epoetin alfa group had a significantly (P < or = 0.001) greater percentage of patients (75% vs. 21%) with increases in hemoglobin levels and/or reduced transfusion requirements. In 44 non pre-transfused patients (20 controls, 24 in the epoetin alfa group), the mean increase in hemoglobin was significantly (P < or = 0.0001) greater in the epoetin alfa group (+2.1 vs. -0.2 g/dl). Increases in hematocrit and red blood cells were also significantly (P < or = 0.0001) greater in epoetin alfa-treated patients, with corresponding reductions in transfusion requirement. In the 27 pre-transfused patients (11 controls, 16 in the epoetin alfa group), there was a trend towards reduced transfusional need in epoetin alfa-treated patients. Thus, in patients with multiple myeloma refractory to chemotherapy epoetin alfa is a well-tolerated treatment which improves anemia in non pre-transfused patients and appears to reduce transfusion need in those previously transfused.

Chromosome rearrangements at telomeric level in hematologic disorders.

Following retrospective screening of our karyotype data from 414 consecutive non-childhood, neoplastic, and preneoplastic hematologic diseases, we have isolated 11 cases with alterations involving one or two chromosome termini, including: a) nonclonal telomeric telomeric associations (tas), b) subclonal terminal rearrangements consisting of additional (add) material of unknown origin fused at the end of the chromosome, c) clonal telomere-centromere fusion (t telcen) with pseudodicentric structure. Most of these abnormalities were present in karyotypes with multiple alterations and associated to an evolutive stage of the disease (9 of 94 cases studied in progression, including three of 22 CML studied in blast crisis). The immunophenotype of the cell populations was lymphoid in eight cases, six of which were NHL, and myeloid, erythroid, and undifferentiated in the other three. More data on telomeric abnormalities may clarify whether there is ubiquitous genomic instability of neoplastic cells or an inborn cell lineage predisposition favoring rearrangements involving telomeres.

All-trans-retinoic acid induces simultaneously granulocytic differentiation and expression of inflammatory cytokines in HL-60 cells.

All trans-retinoic acid (ATRA) can induce granulocytic differentiation both in vitro and in vivo, and its activity is mediated by the retinoic acid receptor-alpha (RAR-alpha). In the present study, we evaluated the ability of this inducer in HL-60 cells, to stimulate simultaneously granulocytic differentiation and the expression of the cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-3, IL-6, tumor necrosis factor-alpha (TNF-alpha), and stem cell factor (SCF). The level of expression of these cytokines in ATRA-treated HL-60 cells was compared with that observed in normal and lipopolysaccharide (LPS)-treated peripheral granulocytes. The results indicate that the expression of these cytokines is enhanced during differentiation so that the pattern observed in ATRA-treated HL-60 cells is close to that of LPS-stimulated normal granulocytes. In addition, tetra phorbol acetate (TPA)-treated HL-60 cells express several of the above listed cytokines. It is concluded that ATRA not only induces granulocytic differentiation of HL-60 cells, but also activation of these terminally differentiated cells. The activating cytokine expression in these cells appears related to the progress of the differentiation program induced by ATRA since normal granulocytes do not respond to this inducer by activation of the expression of these genes. Furthermore, the cytokine activation is a specific effect of ATRA, since DMSO does not have any stimulatory effect.

Inhibition of c-fes expression by an antisense oligomer causes apoptosis of HL60 cells induced to granulocytic differentiation.

The c-fes protooncogene is expressed at high levels in the terminal stages of granulocytic differentiation, but so far no definite function has been attributed to the product of this oncogene. To tackle this problem, the c-fes protooncogene expression has been inhibited in HL60 cells, and fresh leukemic promyelocytes of acute promyelocytic leukemia have been induced to differentiate with retinoic acid (RA) and dimethylsulfoxide (DMSO). Inhibition was obtained by incubating the cells with a specific c-fes antisense oligodeoxynucleotide. It was observed that the cells, rather than differentiating, underwent premature cell death showing the morphological and molecular characteristics of apoptosis. This process was inhibited by granulocyte and granulocyte/macrophage colony-stimulating factor, but not by interleukin 3 (IL-3), IL-6, or stem cell factor. Our present results demonstrate that the loss of cell viability that occurs during the in vitro differentiation of myeloid cells, after the complete inhibition of the c-fes gene product and treatment with RA-DMSO, is due to activation of programmed cell death. It is concluded that a possible role of the c-fes gene product is to exert an antiapoptotic effect during granulocytic differentiation.

Overexpression of c-kit in a leukemic cell population carrying a trisomy 4 and its relationship with the proliferative capacity.

The expression of c-kit and its ligand, the stem cell factor (SCF), was studied in five cases of acute myeloid leukemia. One of these had a trisomy of chromosome 4, where the c-kit oncogene is located. In this case, the c-kit oncogene was overexpressed, but matched by a low expression of its ligand, SCF. The molecular evaluation of the growth rate by c-myc and the histone H3 expression indicated that the growth fraction of this cell population was very low. In one of the other leukemic cell populations studied, characterized by a low expression of c-kit and an elevated expression of the SCF, the growth fraction was also very low. Our results suggest that at least for some receptor oncogenes, the simple overexpression cannot be taken as an indication that the oncogene is involved in the deregulation of cell proliferation.

[Noma in a patient with acute leukemia allergic to penicillin]. / Noma in paziente con leucemia acuta allergica alla penicillina.

Noma has virtually disappeared from Europe, but is still found in certain parts of Africa, South America and Asia. In our case the etiologic agent was Pseudomonas aeruginosa sensitive to antibiotic therapy that we used (pefloxacin and netilmicin). Another characteristic aspect of our case is the rapid infaust evolution. In this report will be discuss the pathogenesis and the reason of the failure of the antibiotic therapy especially in immunodeficiency patients.

Expression of interleukins 1, 3, 6, stem cell factor and their receptors in acute leukemia blast cells and in normal peripheral lymphocytes and monocytes.

Reverse transcriptase-polymerase chain reaction amplification (RT-PCR) and Southern blot analysis were used to evaluate ligand and receptor expression of interleukin 1 alpha (IL-1 alpha), interleukin 3 (IL-3), interleukin 6 (IL-6) and stem cell factor (SCF) in peripheral blood lymphocytes and monocytes and in several acute leukemia blast cell populations. Resting peripheral lymphocytes and monocytes expressed both ligand and receptor of the four cytokines at considerable levels. The leukemic blast cells of the M1-M4 phenotypes are characterized by almost complete lack of expression of IL-1 alpha, IL-3 and IL-6 and the constant and usually high expression of SCF. On the other hand, these myeloid blast cells express generally high levels of the four cytokine receptors. The data suggest that the regulation of the expression of IL-1 alpha, IL-3 and IL-6, at least in our limited number of leukemic cell populations studied, is independent of that of SCF. The results indicate that, at least in most of the leukemic myeloid blasts cells, the expression of SCF and its receptor, the c-kit oncogene, may permit an autocrine regulation of cell cycling.

bcl-2 gene expression in hematopoietic cell differentiation.

Nonrandom translocations with breakpoint at band q21 on chromosome 18 might cause bcl-2 gene deregulation and might contribute to neoplastic transformation in human lymphomas. As the pattern of expression of bcl-2 in hematopoietic cells is still unclear, we have measured the level of the corresponding messenger RNA (mRNA) in a variety of myeloid and lymphoid cell malignancies not usually associated with the t(14;18) translocation. Molecular genetic analysis showed that bcl-2 was rearranged in only 2 of 77 patients: one was affected by hairy cell leukemia and one by diffuse small cleaved cell lymphoma with peripheral blood invasion. Although in rare cases of myeloid leukemia fairly high levels can be found, the expression of bcl-2 appears to be typical of certain lymphoid malignancies. High levels of bcl-2 mRNA had been found, previously, in established pre-B-cell lines. However, in fresh specimens, the peak level of bcl-2 expression shifts to a more differentiated cell type, represented by the long-living B lymphocytes that are found in most cases of chronic lymphocytic leukemia. bcl-2 gene product might have a role in prolonging cell survival and, even in the absence of translocations, might contribute to some of the biologic features that are typical of this disorder.

[Efficacy of erythropoietin in anemia of patients with immuno-lymphoproliferative disease]. / Efficacia dell'eritropoietina nell'anemia dei pazienti con malattie immuno-linfoproliferative.

Anemia is a common complication of lymphoproliferative syndromes. The exact pathogenic mechanism of this anemia is unclear. Many patients require progressive and persistent blood transfusions. We treated 10 patients (8 with multiple myeloma, 1 with non Hodgkin Lymphoma, 1 with chronic lymphocytic leukemia) by administering low doses of recombinant human erythropoietin (60 U/kg 3 times a week s.c.). All patients presented anemia with hemoglobin levels less than 10 gr/dl; renal function was not impaired (serum creatinine levels less than 1.2 mg/dl or creatinine clearance greater than 60 ml/min). A response was defined as an increase of hemoglobin level of at least 2 gr/dl or stop of red-cell transfusion within the first 3 months of treatment. Nine patients (90%) responded to treatment with a significant increase in the hemoglobin concentration. Two patients presented a cerebral stroke not correlated with erythropoietin administration.

Sinus histiocytosis with massive lymphadenopathy.

To date, the morphological aspects of sinus histiocytosis with massive lymphadenopathy (SHML) have been fully described. The disease is characterized by an enlargement of lymph nodes in which the sinuses are dilated and infiltrated by histiocytes, often phagocytosing lymphocytes. Even if the prognosis is usually benign and not requiring therapy, several fatal cases have been reported. The etiology is still obscure and the biology is not yet completely clear. Recent immunophenotypical studies suggest that histiocytes may belong to the T-zone associated histiocyte lineage. They may be cytologically homogeneous, but can express different antigenic patterns according to their stage of differentiation. Cytogenetic and molecular aspects of the disease have only been sporadically investigated. In order to better understand the pathogenesis of SHML, which seems to be a disorder lying in between the fields of infections, immunological disease and neoplasia, it is considered very useful to systematically employ a variety of immunophenotypical, cytogenetic and molecular techniques to study the disease, particularly in cases which are clinically atypical or with a more aggressive evolution.