Germline mutations of the CBL gene define a new genetic syndrome with predisposition to juvenile myelomonocytic leukaemia.

Background: CBL missense mutations have recently been associated with juvenile myelomonocytic leukaemia (JMML), an aggressive myeloproliferative and myelodysplastic neoplasm of early childhood characterised by excessive macrophage/monocyte proliferation. CBL, an E3 ubiquitin ligase and a multi-adaptor protein, controls proliferative signalling networks by downregulating the growth factor receptor signalling cascades in various cell types.

Methods And Results: CBL mutations were screened in 65 patients with JMML.

Interlaboratory development and validation of a HRM method applied to the detection of JAK2 exon 12 mutations in polycythemia vera patients.

Background: Myeloproliferative disorders are characterized by clonal expansion of normal mature blood cells. Acquired mutations giving rise to constitutive activation of the JAK2 tyrosine kinase has been shown to be present in the majority of patients. Since the demonstration that the V617F mutation in the exon 14 of the JAK2 gene is present in about 90% of patients with Polycythemia Vera (PV), the detection of this mutation has become a key tool for the diagnosis of these patients.

High molecular response rate of polycythemia vera patients treated with pegylated interferon alpha-2a.

V617F JAK2 mutation is a reliable molecular marker of polycythemia vera (PV), potentially useful to monitor the effect of treatments in this disease. In a phase 2 study of pegylated (peg) IFN-alpha-2a in PV, we performed prospective sequential quantitative evaluation of the percentage of mutated JAK2 allele (%V617F) by real-time polymerase chain reaction (PCR). The %V617F decreased in 24 (89%) of 27 treated patients, from a mean of 49% to a mean of 27% (mean decrease of 44%; P < .

Overcoming bacterial DNA contamination in real-time PCR and RT-PCR reactions for LacZ detection in cell therapy monitoring.

Since the introduction of the polymerase chain reaction the presence of contaminating bacterial DNA in the Taq polymerase preparations has hampered the use of this technique in microbiology. Lately, this inconvenience has equally impeded gene quantification in the field of cell or gene therapy, where bacterial genes such as LacZ are often used as tags to detect vectors or cells after their injection in the recipient organism. Several means to overcome the DNA contamination of Taq Polymerase have been reported with variable degrees of decontamination efficiency and alteration of the PCR reaction.

Temporal patterns of bone marrow cell differentiation following transplantation in doxorubicin-induced cardiomyopathy.

Objective: Recent studies have suggested benefits of bone marrow cell transplantation for the regeneration of ischemic cardiac tissue. To extend the potential of cell transplantation, we assessed this treatment in a mouse model of acute nonischemic doxorubicin-induced cardiomyopathy.

Methods: To allow detection of engrafted cells, we used transgenic mice expressing the nuclear-located LacZ under the control of either desmin or vimentin promoters, which identify muscle lineage and mesenchymal cells, respectively.

Functional G-CSF pathways in t(8;21) leukemic cells allow for differentiation induction and degradation of AML1-ETO.

Introduction: Efficacy of differentiating agents requires that their specific cellular targets are still expressed and functional in the leukemic cells. One hypothesis to target sensitive cells is to select leukemic clones which harbor disrupted transcription factors. CBFalpha and CBFbeta are core-binding proteins which have been identified as transcription regulators of hematopoietic genes and shown to be altered in numerous leukemias.

In vitro all-trans retinoic acid sensitivity of acute promyelocytic leukemia blasts: a novel indicator of poor patient outcome.

Acute promyelocytic leukemia (APL) blasts possess a unique sensitivity to the differentiating effects of all-trans retinoic acid (ATRA). Multicenter trials confirm that the combination of differentiation and cytotoxic therapy prolongs survival in APL patients. However relapses still occur, and exquisite adaptation of therapy to prognostic factors is essential to aim at a possible cure of the disease.

All trans retinoic acid abrogates spontaneous monocytic growth in juvenile chronic myelomonocytic leukaemia.

Introduction: All trans retinoic acid, the active metabolite of vitamin A, exerts profound effects on cell differentiation. On normal myeloid progenitors, retinoids switch the differentiation program of granulo-macrophagic progenitors towards the granulocytic lineage and consequently reduce CFU-M colony formation. Bone marrow and peripheral blood mononuclear cells from children with Juvenile Chronic Myelomonocytic Leukaemia show typical spontaneous monocytic growth.

G-CSF activates STAT pathways in Kasumi-1 myeloid leukemic cells with the t(8; 21) translocation: basis for potential therapeutic efficacy.

In an attempt to find new agents that promote differentiation and have therapeutic potential in acute myeloid leukemias, we have studied the effect of recombinant human granulocyte colony stimulating factor (rhG-CSF) on the Kasumi-1 AML2 t(8; 21) cell line. Upon incubation with rhG-CSF (0.2-2000 ng/ml), Kasumi-1 cells showed a peak of cell growth, with a subsequent decrease of cell survival after 4 days of culture.

Chronic myelomonocytic leukemia: from biology to therapy.

Chronic myelomonocytic leukemia represents a distinct myelodysplastic syndrome in which an excess of monocytes is observed both in the blood and bone marrow of the patients. Whereas diagnosis is relatively easy, therapeutic design and efficacy is difficult and no treatment has to date provided complete or significant partial response. In vitro data suggest that the growth and differentiation of myelomonocytic progenitors may be altered inasmuch as monocytic or granulo-macrophagic colonies show spontaneous growth.

All-trans retinoic acid in adult chronic myelomonocytic leukemia: results of a pilot study.

Retinoids can inhibit the spontaneous in vitro growth of CFU-GM observed in juvenile chronic myeloid leukemia (JCML) and, when administered in vivo, have shown some clinical benefit in this disease. Because adult chronic myelomonocytic leukemia (CMML) has many features in common with JCML, we treated 10 cases of advanced adult CMML with ATRA (45 mg/m2/day). Five of them were also tested in vitro.

Characterization of nuclear retinoic acid binding activity in sensitive leukemic cell lines: cell specific uptake of ATRA and RAR alpha protein modulation.

The diverse effects of all-trans retinoic acid (ATRA) on growth, differentiation and homeostasis of vertebrate organisms are mediated by three distinct isoforms of retinoic acid receptors (RARs). Although it is not known to what extent each RAR contributes to the different effects of ATRA, several studies have demonstrated that ATRA induced granulocytic differentiation in human myeloid leukemic cell lines is mediated by RAR alpha. In this study, we investigated ATRA binding affinity of the endogenous nuclear receptors of HL-60 and NB4 leukemic cells.

Retinoid acid supports granulocytic but not erythroid differentiation of myeloid progenitors in normal bone marrow cells.

In the new context of the use of retinoic acid (RA) therapy as an inducer of leukemic differentiation and a selective inhibitor of human myeloid leukemia cell growth, we undertook to explore the potential physiological role of retinoids on the proliferation and differentiation of normal bone marrow myeloid progenitors. The effects of continuous exposure of all-trans-RA, its naturally occurring isomer, 13-cis-RA, and its metabolite 4-oxo-all-trans-RA were studied on the growth of normal human bone marrow cells in soft agar, directly and after liquid culture. Retinoids enhanced the total number of granulocytic colony and macrocluster formation in the presence of exogenous colony-stimulating factor (n = 9).