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A Rambaldi

Publications and source records attributed to A Rambaldi.

At least 109 records · Page 6Linked to original sources
PubMed1994

Retinoic acid and granulocyte colony-stimulating factor synergistically induce leukocyte alkaline phosphatase in acute promyelocytic leukemia cells.

In this report we show a strong synergistic interaction between granulocyte colony-stimulating factor (G-CSF) and all-trans retinoic acid (ATRA) on the expression of leukocyte alkaline phosphatase (LAP) in freshly isolated acute promyelocytic leukemia (APL) blasts as well as in NB40 and HL-60 cell lines. The strong synergism observed in these cell types was not evident in two acute leukemia cell lines (K562 and GF-D8), in normal granulocytes, and in monocytes. In freshly isolated leukocytes derived from chronic myelogenous leukemia (CML), in the stable phase of the disease, a weaker interaction between ATRA and G-CSF was documented. The cross-talk between the cytokine and the retinoid was studied in detail in NB4, an immortalized APL leukemia cell line, retaining the 15-17 chromosomal translocation involving the retinoic acid receptor type alpha. The treatment of NB4 cells with G-CSF alone or ATRA alone leads to no increase and to minor induction in LAP activity, respectively. If the cells are treated with the two compounds simultaneously, a dramatic elevation of LAP is observed after 4 days. The synergism between G-CSF and ATRA is evident at concentrations of the retinoid between 10(-7) and 10(-5) mol/L and at concentrations of the cytokine between 1 and 10 ng/mL. The simultaneous presence of the two compounds is necessary to obtain maximal increase of LAP activity and the effect is cell density-dependent. Synergism is specific for G-CSF, and it is not observed with other cytokines and functional inducers of the granulocyte. The augmentation of LAP activity is the consequence of an increased transcriptional rate of the liver/bone/kidney-type (L/B/K-type) alkaline phosphatase gene, as determined by Northern blotting and nuclear run-on analysis using specific cDNA probes. Only one of the two possible alternatively spliced forms of L/B/K-type alkaline phosphatase transcript is detected in NB4 cells after stimulation with G-CSF and ATRA. This mRNA form, which is the one observed in normal polymorphonuclear leukocytes, contains the most upstream leader exon. In NB4 cells, ATRA induces G-CSF, alpha, and beta retinoic acid receptor transcripts, whereas G-CSF has minor effects on the expression of these mRNAs.

Alkaline Phosphatase↗
PubMed1994

Dissociation between p93B-myb and p75c-myb expression during the proliferation and differentiation of human myeloid cell lines.

Direct and indirect evidence strongly indicates that the proto-oncogene c-myb plays an important role in the regulation of both the proliferation and differentiation of hematopoietic cells. In addition, recent data suggest that the structurally related B-myb gene is also necessary for the proliferation of these cells. To help understand the relationship between these two related gene products during proliferation and differentiation of myeloid cells, we have studied in parallel the regulated expression of c-myb and B-myb RNAs and proteins in human myeloid cells that were either growth-arrested or induced to differentiate along different pathways. For this purpose, we have produced a polyclonal antibody directed against a fragment of the recombinant B-myb protein. We have thus been able to detect the B-myb protein in human cell lines and have found it to be a 93-kD protein localized in the nucleus. We have chosen two models to study the expression of both c-myb and B-myb mRNAs and proteins during myeloid proliferation and differentiation. One of the models was the HL-60 cell line, which can be induced to differentiate towards the monocytic pathway with either phorbol ester (phorbol myristate acetate) or vitamin D3 and towards the granulocytic pathway with either dimethyl sulfoxide or retinoic acid. In addition, we have studied another recently established human leukemic cell line, called GF-D8, which is strictly dependent on granulocyte-macrophage colony-stimulating factor (GM-CSF) for proliferation. The results show that the expression of B-myb RNA and protein closely correlates with proliferation in all experimental setups studied, whereas the c-myb protein levels do not always do so. We observed that the c-myb protein levels decreased well before the decrease of B-myb protein and of proliferation itself during differentiation toward monocytes. Such a difference was not present during granulocytic differentiation, in which c-myb levels decreased, if anything, later than those of B-myb and proliferation. Most striking was the finding that high levels of c-myb RNA and protein, but not of B-myb, were present in the GF-D8 cell line, even after growth arrest by GM-CSF deprivation. These data suggest that B-myb may function solely in the regulation of cellular proliferation, whereas c-myb has additional functions, for example, in the maintenance of an undifferentiated state.

Cell Differentiation↗
PubMed1994

Polymerase chain reaction (PCR) approach for the evaluation of minimal residual disease in acute leukemia.

Evaluation of minimal residual disease (MRD) in different forms of acute leukemias is an expanding field of experimental hematology. Several strategies and techniques, including cytomorphology, immunophenotype and karyotype, have been applied to evaluate MRD, but molecular biology has provided more sensitive and accurate tools to detect the neoplastic clones. This concise review summarizes some of the technical aspects and pitfalls associated with different molecular approaches such as the analysis of clonospecific DNA sequences in lymphoid malignancies and the demonstration of chimeric genomic products generated by chromosomal translocations. The feasibility, specificity and clinical relevance of all these studies will be briefly discussed.

Acute Disease↗
PubMed1994

Unexpected remission of acute myeloid leukaemia after GM-CSF.

The administration of granulocyte-monocyte colony-stimulating factor (GM-CSF) was associated with complete clinical and haematological response in an adult patient with minimally differentiated acute myeloid leukaemia who presented with pneumonia and moderate neutropenia, but no blast cells in the peripheral blood. The response lasted 9 months. At relapse, a second GM-CSF course resulted in a very good partial remission lasting 5 months, although differences in the kinetics of haemoglobin, neutrophil and platelet recovery were noted. Subsequent recurrences were managed with chemotherapy, a complete remission being obtained twice more and lastly consolidated with myeloablative chemo-radiotherapy supported by a peripheral blood stem cell autograft. This report suggests that GM-CSF should be further investigated as a therapeutic agent in selected cases of AML.

Acute Disease↗
PubMed1994

Expression of GATA-1 mRNA in human myeloid leukemic cells.

Expression of the transcription factor GATA-1, which regulates several erythroid specific genes and possibly also some megakaryocytic genes, has been previously detected in normal erythroblasts, megakaryocytes, and basophils, and in some myeloid cell lines. It has been suggested that GATA-1 may be first expressed in a common progenitor and then further activated during erythroid-megakaryocytic and basophilic differentiation and repressed during myeloid maturation. We investigated GATA-1 mRNA expression in highly purified leukemic blasts representing different lineages and stages of myeloid differentiation and in a recently established leukemic cell line, GF-D8, which exhibits morphological, cytochemical and immunophenotypic characteristics of early myeloid progenitor cells. We found GATA-1 expression in five of five myeloid and in one megakaryocytic blast crisis of CML, in four of six cases of myelomonocytic leukemias (M4 according to FAB classification), in one case of erythroleukemia (M6), whereas lymphoid blast crisis of CML and all other FAB groups were completely negative. In addition, a low level of GATA-1 mRNA was also expressed by the GF-D8 cell line. These data further support the hypothesis that GATA-1 expression may occur not only in erythroid and megakaryocytic progenitors, but also in early myeloid progenitors, and then be further regulated during lineage-specific maturation.

Acute Disease↗
PubMed1994

Cancer procoagulant in the human promyelocytic cell line NB4 and its modulation by all-trans-retinoic acid.

Acute promyelocytic leukemia (APL) cells express different types of procoagulant activity (PCA), including tissue factor (TF), and cancer procoagulant (CP). The aim of this study was to investigate whether the NB4 cell line, the first ever isolated human APL line, with the typical t(15;17) chromosomal balance translocation, possess CP as well as the cells freshly isolated from APL patients. Secondly, since the NB4 line is maturation inducible by all-trans-retinoic acid (ATRA), we wanted to verify whether CP, if present, was affected by ATRA treatment. The NB4 cells were able to shorten the recalcification assay of normal human plasma (total PCA). To distinguish CP in the assay for clotting activity, two criteria were used, the independence from factor VII to trigger blood coagulation and the sensitivity to cysteine proteinase inhibitors. Forty-seven per cent of total PCA of cell extracts was found to be FVII-independent PCA. A similar proportion of FVII-independent activity (42%) was detected in the cell serum-free supernatants. The activity was significantly decreased by cysteine proteinase inhibitors, including HgCl2, lodoacetic acid and Z-Ala-AlaCHN2. Additionally CP was directly identified and quantified by an immunocapture enzyme assay. The mean +/- SD concentration of CP detected by this assay in the NB4 cells, before any treatment, was 1.89 +/- 0.5 microgram/mg protein. Treatment of NB4 cells with 10(-6) M ATRA for 5 days significantly decreased the expression of CP, which became virtually undetectable by the clotting assay, and was 64% less than the untreated control by the immunocapture enzyme assay. This study provides the first evidence that the human promyelocytic cell line NB4 possess CP. The expression of this procoagulant is modulated by ATRA.

Blood Coagulation Factors↗
PubMed1993

Detection of ALL-1/AF4 fusion transcript by reverse transcription-polymerase chain reaction for diagnosis and monitoring of acute leukemias with the t(4;11) translocation.

The chromosomal breakpoints of t(4;11) translocation of acute lymphoblastic leukemia (ALL) have been recently identified at molecular level and shown to involve the AF4 (FEL) gene on chromosome 4 and the ALL-1 (MLL, Hrx) gene on chromosome 11. The ALL-1/AF4 fusion gene is transcribed into a chimeric mRNA. Using primer sets derived from ALL-1 and AF4 cDNAs by reverse transcription-polymerase chain reaction (RT-PCR), we were able to amplify the breakpoint sites of the fusion transcript of all 15 ALL cases with karyotypic or molecular evidence of the t(4;11). DNA fragments of different size were obtained as the consequence of different breakpoints on chromosome 11 and the presence of alternative splicing of ALL-1 exon 8. The feasibility of monitoring the residual cells carrying the t(4;11) in 2 ALL patients with different clinical outcome was evaluated. Overall, the presented results provide evidence that RT-PCR can be used as a rapid method for detecting this chromosomal abnormality and following the patient's response to therapy.

Adolescent↗
PubMed1993

Establishment and characterization of a new granulocyte-macrophage colony-stimulating factor-dependent and interleukin-3-dependent human acute myeloid leukemia cell line (GF-D8).

A novel factor-dependent human myeloid leukemia cell line (GF-D8) was established from the peripheral blood of an 82-year-old man suffering from acute myeloblastic leukemia (AML). By morphology, cytochemical staining, and analysis of surface antigens, GF-D8 cells are myeloblasts of immature progenitor origin. The consensus karyotype is 45, XY, -5, 7q-, inv(7) (q31.2q36), 8q+, +8q+, 11q+, 12p-, -15, -17, + marker. The long-term survival and proliferation of GF-D8 cells is dependent on the presence of either granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 (IL-3). Weak colony growth was observed after exposure of GF-D8 cells to stem cell factor (SCF) but not after exposure to granulocyte-CSF (G-CSF), macrophage-CSF (M-CSF), IL-1 beta, IL-2, IL-5, or tumor necrosis factor-alpha (TNF-alpha). GM-CSF- and IL-3-induced proliferation is dose dependent, with significant growth observed at concentrations as low as 0.1 ng/mL, but the combination of both factors has no synergistic effect. A significant proliferation is induced by GM-CSF and IL-3 even in serum-deprived cultures, although with a slightly decreased efficiency. GF-D8 cells were shown to express specific messenger RNAs for the alpha chains of the GM-CSF and IL-3 receptors as well as for the beta chain, common to both receptors. Interestingly, despite the absence of biologic response to G-CSF, specific transcripts for the G-CSF receptor gene were similarly identified by reverse polymerase chain reaction analysis. GF-D8 cells represent a useful tool for studying chromosome abnormalities of human AML as well as the regulation of myeloid proliferation and differentiation in vitro.

Aged↗
PubMed1993

Transcriptional and post-transcriptional regulation of IL-1 beta, IL-6 and TNF-alpha genes in chronic lymphocytic leukaemia.

The present study was designed to define the mechanisms of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha) gene regulation in chronic lymphocytic leukaemia of B cell origin (B-CLL). By nuclear run-on analysis, all B-CLL cases displayed high levels of nuclear transcription of the IL-6 and TNF-alpha genes, whereas IL-1 beta gene transcription was only barely detectable. Upon in vitro culture for 1 h, B-CLL cells from different patients were substantially heterogeneous in terms of expression of steady state mRNA levels of IL-1 beta, IL-6 and TNF-alpha even though the pattern of nuclear transcription of these cytokines was only marginally affected by in vitro culture. mRNA stability was then examined and cytokine gene transcripts showed a half life of more than 2 h in cultured B-CLL cells and treatment with cycloheximide (CHX) did not affect cytokine transcript levels in B-CLL cells. These results indicate that: steady state levels of each mRNA do not reflect the rate of nuclear transcription of these cytokines in fresh or cultured B-CLL cells, that purification and in vitro culture of leukaemic cells may amplify cytokine gene expression in B-CLL, and that cytokine gene transcripts are relatively stable in B-CLL.

Blotting, Northern↗
PubMed1993

Idarubicin in the initial treatment of adults with acute lymphoblastic leukemia: the effect of drug schedule on outcome.

Fifty two adults (aged 15 to 66 years) with newly diagnosed acute lymphoblastic leukemia (ALL, n = 47) or lymphoid blast phase chronic myelogenous leukemia (Ly-CML, n = 5) were managed with three distinct protocols containing idarubicin at a cumulative dose of 36, 20, and 10 mg/m2, respectively, plus vincristine, L-asparaginase, and prednisolone (IVAP-1, -2, -3). IVAP-1 was highly toxic and gave a low complete remission (CR) rate (7/17, 41%). Nine patients died of complications while severely neutropenic, and one had resistant disease. In contrast, 24 of 28 patients subsequently treated with IVAP-2 achieved a CR (86%, p 0.005), the rate of both hematological and extrahematological toxicity being significantly reduced compared with IVAP-1 (p < 0.05). With IVAP-3, 6/7 patients aged > 60 years achieved CR. IVAP-2 with total idarubicin 20 mg/m2 is a very effective and well tolerated regimen for the initial treatment of adults with ALL.

Adolescent↗
PubMed1993

Clinical and biological effects of erythropoietin treatment of myelodysplastic syndrome.

To evaluate its clinical efficacy as well as its biologic safety, human recombinant Erythropoietin (rh-Epo) was given to 19 patients with myelodysplastic syndromes (MDS) in an open non-randomized study. Among the seventeen evaluable patients only two showed an apparent hematologic response to rh-Epo treatment. In these patients hemoglobin levels increased from a mean pretreatment value of 8.5 and 8.4 g/dl up to 11.7 and 11.3 g/dl respectively and remained relatively stable for several weeks. In one of these patients the transfusion requirement decreased from 4 to 1.5 units per month whereas the other had no transfusion requirement during the whole period of rh-Epo treatment. Interestingly, when the responding patients, after a "wash-out" period of at least ten weeks, received an additional course of rh-Epo results were less impressive. Before treatment the serum level of endogenous Epo was 18 and 110 mU/ml in the two responding patients, whereas a mean value of 532 mU/ml (range 17-2797 mU/ml) was observed in non responders. The treatment of MDS patients with rh-Epo was clinically well tolerated since no relevant side effects were registered. Moreover, no evidence of harmful cytogenetic changes nor activation of myeloid growth factor genes, as determined by Northern blot analysis of GM-CSF and G-CSF gene expression, could be related to rh-Epo treatment. Overall, it appears that administration of rh-Epo is well tolerated but the therapeutic effects appear to be restricted to a minority of patients and a limited period of time.

Aged↗
PubMed1993

Intensive therapy for adult acute lymphoblastic leukemia: preliminary results of the idarubicin/vincristine/L-asparaginase/prednisolone regimen.

Between June 1991 and September 1992, 80 patients with adult acute lymphoblastic leukemia (ALL) (newly diagnosed, n = 68; relapsed or refractory ALL, n = 7; lymphoid blast transformation of Philadelphia chromosome-positive chronic myelogenous leukemia [LT-CML], n = 5) were managed with a combination regimen consisting of idarubicin 36, 20, or 10 mg/m2 plus vincristine, L-asparaginase, and prednisolone (IVAP-1, -2, -3). Three patients with LT-CML and four with relapsing ALL had a complete remission. In the group of newly diagnosed patients aged 15 to 60 years treated with IVAP-1, the complete remission rate was only 44% due to the high incidence of toxic deaths. In contrast, 39 of 44 cases who subsequently received IVAP-2 achieved a complete remission (89%, P = .001), as did 62% of elderly patients who received IVAP-3. Hematologic and nonhematologic toxicity was significantly reduced with IVAP-2 compared with IVAP-1. The use of recombinant human granulocyte colony-stimulating factor in 24 patients was not associated with a reduced duration of granulocytopenia less than 0.5 x 10(9)/L, although there was a lower incidence of documented infections in patients receiving granulocyte colony-stimulating factor than in controls. Post-remission intensification with idarubicin-based courses, high-dose therapy with autologous bone marrow stem cell rescue, and rotational weekly therapy was feasible and its toxicity was manageable. These preliminary findings indicate that IVAP-2 (idarubicin 20 mg/m2) is a highly effective and well-tolerated regimen for remission induction of adult ALL.

Adolescent↗
PubMed1993

Modulation of cell proliferation and cytokine production in AML by recombinant interleukin-1 receptor antagonist.

In Acute Myelogenous Leukemia (AML), Interleukin 1 (IL-1) might sustain autocrine and paracrine loops of leukemic growth. An IL-1 inhibitor has been recently purified and cloned. This molecule binds to the IL-1 receptors but has no IL-1 like activity fulfilling the characteristics of a pure Interleukin-1 receptor antagonist (IL-1ra). We studied the in vitro effect of human recombinant IL-1ra on proliferation of AML blasts. Spontaneous as well as IL-1 stimulated AML proliferation was significantly inhibited by the addition of 50 ng/ml of recombinant IL-1ra in a dose dependent manner. The inhibitory effect of IL-1ra was measurable after 12 hours of culture and reached a plateau at 60 hrs. We found that IL-1ra could compete with IL-1 in binding to specific IL-1 receptors on AML cells. As expected, culture supernatants of unstimulated leukemic samples contained IL-1 beta and GM-CSF activity. The incubation of the same leukemic blasts with IL-1 ra was followed by reduction or disappearance of GM-CSF in culture supernatants whereas the IL-1 beta production was only partially modulated. By Northern blot experiments performed on freshly isolated, uncultured leukemic blasts, we found a constitutive expression of the IL-1 beta gene in 19 of 23 AML cases analyzed. On the contrary, only three of these patients express the IL-1 RA mRNA. All together these results suggest that imbalanced secretion of IL-1 and its natural receptor antagonist could contribute to the unrestricted growth of AML cells.

Cell Division↗
PubMed1992

Molecular evaluation of residual disease as a predictor of relapse in acute promyelocytic leukaemia.

Acute promyelocytic leukaemia (APL) is characterised by a unique fusion transcript, PML/RAR alpha. We tested for this transcript in 35 APL patients who were in apparent remission after various treatments. 11 of 13 patients who tested positive 4 months after achieving remission were in relapse 1-4 months later. All 22 patients who tested negative at 4 months were disease-free after a further 3 months to five years. The test may therefore prove useful in determining the need for additional treatment during clinical remission.

Carrier Proteins↗
PubMed1992

Molecular monitoring of the myl/retinoic acid receptor-alpha fusion gene in acute promyelocytic leukemia by polymerase chain reaction.

The acute promyelocytic leukemia (APL) t(15;17) translocation generates a myl/retinoic acid receptor-alpha (RAR-alpha) chimeric gene that is transcribed as a fusion myl/RAR-alpha messenger RNA. Using primer sets derived from RAR-alpha and myl cDNAs, we were able to amplify the breakpoint sites of the fusion transcripts of all 35 APL RNA samples by reverse polymerase chain reaction (PCR) and nested primer approach of two rounds of amplification. DNA fragments of different size were obtained according to the chromosome 15 breakpoints (intron 3-bcr 3; exon 6-bcr 2; and intron 6-bcr 1). bcr 1 and bcr 3 represent the regions of the myl locus most frequently involved among APL (48.5 and 34.2 of cases, respectively); bcr 3 constitutes 62.5% of cases among M3V as compared with 25.9% of M3 cases. The feasibility of monitoring the APL clone by PCR analysis in five APL patients who received different treatment (chemotherapy, all-trans-retinoic acid or bone marrow transplantation) was evaluated. In five of nine bone marrow samples of patients in complete remission, t(15;17)-positive cells could be detected by PCR analysis. We conclude that PCR amplification of the myl/RAR-alpha junctions represents the easiest and rapid method for diagnosis and monitoring of the APL clone.

Adolescent↗
PubMed1992

Identification of DNA rearrangements at the retinoic acid receptor-alpha (RAR-alpha) locus in all patients with acute promyelocytic leukemia (APL) and mapping of APL breakpoints within the RAR-alpha second intron. Italian Cooperative Study Group "GIMEMA".

Seventy patients with acute promyelocytic leukemia (APL) were characterized at the DNA level using genomic retinoic acid receptor-alpha (RAR-alpha) probes on Southern blot experiments. Sixty-two cases were defined as M3 according to the French-American-British (FAB) criteria, and eight had a diagnosis of microgranular or variant (M3v) APL. The use of two restriction enzymes and three probes exploring the second intron of the RAR-alpha gene allowed us to detect specific abnormal DNA fragments in every case, with clustering of rearrangements within the 20-kb intronic region between RAR-alpha exons II and III. A more detailed mapping of APL breakpoints was performed in 52 cases in which three EcoRI subregions of the RAR-alpha second intron were analyzed with corresponding probes. Comparison of clinical and hematological features in the three subgroups of patients with distinct RAR-alpha breakpoints did not show significant differences regarding age, peripheral blood (PB) counts, presence of coagulopathy, or FAB classification (M3 v M3v). Interestingly, a significant difference was observed in the M/F ratio of the three subgroups, with a higher incidence of rearrangements at the 5' end of the RAR-alpha second intron in female patients, and more frequent 3' breakpoints in males. The results of this study indicate that a unique genomic alteration consistently occurs on the 17q- derivative of the APL specific t(15;17) aberration. Moreover, the clinical relevance of RAR-alpha gene analysis both at diagnosis and in follow-up studies is further emphasized.

Adolescent↗