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Longterm effects of cyclophosphamide on granulocyte colony formation in patients with rheumatoid arthritis.

Longterm cytotoxic therapy, particularly with alkylating agents, is frequently associated with the development of second neoplasms, particularly acute myeloid leukemia. Twelve patients with classic, progressive rheumatoid arthritis (RA), treated with a cytotoxic agent, cyclophosphamide, from 1969 to 1974 at the University of Colorado Health Sciences Center were reassessed for current status of the granulocytic system. Bone marrow biopsies were investigated histologically and the number of granulocyte precursor cells judged using colony forming cells in culture (CFU-C). Control bone marrow biopsies were done on 8 patients with classic, progressive RA who had not taken cyclophosphamide as well as 16 healthy controls. Colony forming cell numbers in patients with RA who had been treated with cyclophosphamide were significantly lower compared to patients with RA who had not received cyclophosphamide and normal controls. These data suggest that cyclophosphamide may cause suppression of the hematopoietic system that does not totally recover even after long periods of time.

Aged↗

EFA (9-beta-D-erythrofuranosyladenine) is an effective salvage agent for methylthioadenosine phosphorylase-selective therapy of T-cell acute lymphoblastic leukemia with L-alanosine.

The deficiency of methylthioadenosine phosphorylase (MTAP) in T-cell acute lymphoblastic leukemia (T-ALL) and other cancers, while constitutively expressed in normal cells, allows for selective therapy using L-alanosine, an inhibitor of de novo AMP synthesis. We demonstrate that MTAP- T-ALL cells obtained at relapse are as sensitive to L-alanosine toxicity as diagnosis samples. The therapeutic index of L-alanosine can be increased by the use of a MTAP substrate, which protects MTAP+ normal cells. Since MTAP substrates MTA and 5'deoxyadenosine are prone to toxicities associated with adenosine, we synthesized and evaluated a potentially nontoxic MTAP substrate, 9-beta-D-erythrofuranosyladenine (EFA). The cytotoxicity of EFA to hematopoietic progenitors erythroid burst-forming units (BFU-Es) and granulocyte-macrophage colony-forming units (CFU-GMs) was at least 26- to 41-fold less than that of MTA. In addition, EFA selectively rescued MTAP+ MOLT-4 cells from L-alanosine toxicity at 25 microM with negligible toxicity even at 100 microM. As for MTA, significant, albeit incomplete, rescue was achieved at 12.5 microM, but higher concentrations were toxic. EFA at 20 microM or less rescued primary MTAP+ T-ALL cells and normal lymphocytes from L-alanosine toxicity. Collectively, these data indicate that EFA is an effective agent for salvaging MTAP+ cells from L-alanosine toxicity and is superior to MTA due to lower cytotoxicity.

Adenine↗

p120 nucleolar-proliferating antigen is a direct target of G-CSF signaling during myeloid differentiation.

Granulocyte-colony stimulating factor (G-CSF) is an essential cytokine, which contributes to proliferation and differentiation of granulocyte precursor cells in the bone marrow. Despite recent progress in understanding G-CSF signaling events, the mechanisms that underlie the distinct spectrum of biological functions attributed to G-CSF-mediated gene expression remain unclear. Previous studies have identified a number of genes, which are up-regulated in G-CSF-stimulated myeloid precursor cells. In this study, we sought to identify additional target genes of G-CSF-mediated proliferation and/or differentiation. cDNA representational difference analysis was used with the 32Dcl3 cell line as a model system to isolate genes, which are up-regulated in an immediate-early manner upon G-CSF stimualtion. We isolated p120 nucleolar-proliferation antigen (NOL1), a highly conserved, nucleolar-specific, RNA-binding protein of unknown function, and confirmed its expression by Northern blot analysis in 4-h, G-CSF-induced 32Dcl3 cells. Isolation of a mouse p120 genomic clone revealed the presence of a signal tranducer and activator of transcription (STAT)-binding site in the first intron of the gene. We demonstrate the importance of STAT3 and STAT5 in mediating the G-CSF response with respect to p120 expression by transient transfection analysis, oligonucleotide pull-down assays, and the loss of p120 expression in the bone marrow of mice lacking normal STAT3 signaling. In addition, overexpression of p120 in G-CSF-induced 32D cells revealed normal, morphologic maturation and growth characteristics but loss of lactoferrin expression, a marker of normal neutrophil maturation, suggesting that inappropriate expression of the p120 gene can result in aberrant neutrophil maturation.

Animals↗

Multiple signaling pathways induced by granulocyte colony-stimulating factor involving activation of JAKs, STAT5, and/or STAT3 are required for regulation of three distinct classes of immediate early genes.

Granulocyte colony-stimulating factor (G-CSF) is the major regulator of proliferation and differentiation of neutrophilic granulocyte precursor cells. G-CSF activates multiple signaling molecules, including the JAK1 and JAK2 kinases and the STAT transcription factors. To investigate G-CSF signaling events regulated by the JAK-STAT pathway, we have generated UT7-epo cells stably expressing either wild-type (wt) G-CSF receptor or a series of C-terminal deletion mutants. Gel mobility shift and immunoprecipitation/Western analysis showed that STAT5 is rapidly activated by G-CSF in cells expressing the wt G-CSF receptor, in addition to the previously reported STAT3 and STAT1. Mutants lacking any tyrosine residues in the cytoplasmic domain maintain their ability to activate STAT5 and STAT1 but cannot activate STAT3, implying that STAT5 and STAT1 activation does not require receptor tyrosine phosphorylation. We also observed significant changes in the ratio of STAT1:STAT3:STAT5 activated by various G-CSF receptor C-terminal deletion mutants. These mutant receptors were further used to investigate the role of JAKs and STATs in G-CSF-mediated responses in these cells. We found that JAK activation correlates with G-CSF-induced cell proliferation, whereas STAT activation is not required. We have also identified three classes of G-CSF immediate early genes, whose activation correlates with the activation of distinct JAK-STAT pathways. Our data show that, whereas c-fos is regulated through a pathway independent of STAT activation, oncostatin M, IRF-1, and egr-1 are regulated by an STAT5-dependent pathway and fibrinogen is regulated by an STAT3-dependent pathway. In conclusion, our results suggest that G-CSF regulates its complex biologic activities by selectively activating distinct early response genes through different JAK-STAT signaling molecules.

Animals↗

Isovaleric acidemia with promyelocytic myeloproliferative syndrome.

Isovaleric acidemia, an autosomal recessive disorder, is due to isovaleryl-coenzyme A dehydrogenase deficiency and is one of the branched-chain aminoacidopathies. Isovaleric acidemia may present in the neonatal period with an acute episode of severe metabolic acidosis, ketosis, and vomiting and may lead to coma and death in the first 2 months of life. This report concerns an infant who presented at 10 days of age because of lethargy, poor feeding, hypothermia, cholestasis, and thrombocytopenia, leukopenia, and profound pancytopenia. Death occurred at 19 days of age. Autopsy showed mild fatty change in the liver and extramedullary hematopoiesis, generalized Escherichia coli sepsis, and myelodysplasia of the bone marrow with arrest of the myeloid series at the promyelocytic stage. The appearance resembled promyelocytic leukemia, but the diagnostic 15:17 translocation was not present. The maturation arrest in granulopoiesis in isovaleric acidemia appears to be most likely due to a direct metabolic effect on granulocyte precursor cells.

Amino Acid Metabolism, Inborn Errors↗

Expression of AML1-ETO in human myelomonocytic cells selectively inhibits granulocytic differentiation and promotes their self-renewal.

The t(8;21) translocation is one of the most frequent translocations in acute myeloid leukaemia (AML), giving rise to the AML1-ETO fusion protein (or RUNX1-CBF2T1). This abnormality is associated with myelocytic leukaemia with dysplastic granulopoiesis. Here, we demonstrate that when expressed in a normal human (CD34(+)) progenitor population, AML1-ETO selectively inhibits granulocyte colony formation but not monocyte colony formation. In bulk liquid culture, we found that though AML1-ETO transiently inhibited the proliferation of CD34(+) cells, it promoted long-term growth of myeloid cells for more than 80 days, suggesting that differentiation was inhibited. In support of this, cultures expressing AML1-ETO demonstrated enhanced retention of colony-forming capacity. Phenotypic examination of AML1-ETO cultures revealed a defect in granulocytic differentiation in terms of retention of CD34(+) cells within the culture and delayed CD11b upregulation. Morphologically, granulocyte terminal differentiation in AML1-ETO-expressing cells was inhibited by 83+/-5%, giving rise to a build-up of early to intermediate granulocytes that exhibited a number of morphological features associated with t(8;21) leukaemias. In contrast, AML1-ETO had little or no effect on monocytic differentiation. Taken together, these results suggest that expression of AML1-ETO selectively inhibits the differentiation of granulocytic cells and promoted extensive self-renewal, supporting a causal role for t(8;21) translocations in leukaemogenesis.

Antigens, CD34↗

[Myelosarcoma as the primary manifestation of acute myeloid leukemia].

Myelosarcoma ("Granulocytic sarcoma", "Chloroma") is an extramedullary tumor composed of granulocytic precursor cells and related to myelogenous leukemia. If the tumor precedes acute leukemia diagnosis is difficult and requires special diagnostic techniques. This is documented by the presented 7.5 years old girl with primary myelosarcoma. In spite of early and intensive chemotherapy and radiation the sarcoma soon was followed by acute myelogenous leukemia with skin infiltrations. Cytogenetic classifications may in future lead to the development of a differentiated therapy of myelosarcoma.

Antineoplastic Combined Chemotherapy Protocols↗

Intra-cytoplasmic crystalline inclusions in acute myeloid leukemia: a rare event.

Unusual intracytoplasmic crystal-like inclusions within granulocytic precursor cells from a patient with acute myeloid leukemia (AML) are described. Based upon their cytochemical and immunochemical properties, the possible composition and origin of these inclusions are discussed. They represent a rare event in leukemic cell metabolism since, to our knowledge, only 1 case with identical characteristics has previously been reported.

Aged↗

Multiple granulocytic sarcoma during complete hematologic remission of acute nonlymphoid leukemia.

In this report we describe a case of granulocytic sarcoma (GS) developing in a patient after 66 months in complete remission of acute nonlymphoid leukemia. The granulocytic precursor cell proliferation arose simultaneously in two extramedullary sites (testis and small bowel), without evidence of bone marrow relapse. The intensive systemic chemotherapy with high-dose ARA-C allowed a clinical remission, lasting 8 months. GS eventually recurred as extramedullary multi-site disease (abdominal lymph nodes, central nervous system involvement), once again unassociated with blood and bone marrow relapse. Both, at onset and in relapse, special staining techniques on tissue sections (chloroacetate esterase) and immunohistochemical typing with monoclonal antibodies were necessary for a correct diagnosis. We discuss the relationship between systemic leukemia and the GS which showed a metastasizing tumor-like behavior.

Humans↗

Recurring chromosomal abnormalities in leukemia in PML-RARA transgenic mice parallel human acute promyelocytic leukemia.

Acute promyelocytic leukemia (APL) is characterized by the t(15;17)(q22;q11.2), which results in the PML-RARA fusion gene. In previous studies, we demonstrated that expression of a human PML-RARA complementary DNA in murine granulocyte precursor cells initiated the development of leukemia. However, leukemogenesis by PML-RARA required additional genetic alterations. To identify genetic changes that cooperate with PML-RARA in leukemogenesis, we performed spectral karyotyping analysis of myeloid leukemias from hMRP8-PML-RARA mice (11 cases) and from mice coexpressing PML-RARA and BCL2 (8 cases). Clonal abnormalities were detected in 18 of 19 cases (95%). Recurring numerical abnormalities identified in these murine leukemias included +15 (15 cases, 79%); loss of a sex chromosome (12 cases, 63%); +8 (10 cases, 53%); +10 (9 cases, 47%); +4, +7, or +14 (8 cases each, 42%); +16 (7 cases, 37%); and +6 (5 cases, 26%). In a series of 965 patients with APL, we identified secondary abnormalities in 368 (38%). The most common recurring abnormalities were +8 or partial trisomy of 8q (120 patients, 12.4%) and ider(17) t(15;17) (42 patients, 4.4%). The critical consequence of +8 in human leukemias appears to be the gain of 8q24, which is syntenic to mouse 15. Thus, our results suggest that PML-RARA-initiated murine leukemia is associated with a defined spectrum of genetic changes, and that these secondary mutations recapitulate, in part, the cytogenetic abnormalities found in human APL.

Animals↗

Isolated granulocytic sarcoma: report of a case and review of the literature.

Granulocytic sarcoma (GS) is an extramedullary tumor composed of granulocytic precursor cells. The tumor usually develops during the course of myelogenous leukemia or myeloproliferative disorders and may represent the initial manifestation of leukemia. Rarely, GS is recognized as an isolated tumor without any evidence of leukemia. However, in such cases, leukemia generally develops within 1 to 2 years of the diagnosis of GS. We are reporting a case of a 45-year-old woman who was diagnosed as having an isolated GS of the right breast in August 1980. She was treated with a partial mastectomy followed by 1 year of combination chemotherapy as used in the cases of acute myeloblastic leukemia and has remained free of disease to the present time. That is, she has not developed leukemia or recurrence of GS for 64 months. Based on this experience and on the review of the literature, we recommend that all cases of GS be treated with combination chemotherapy as in cases of acute myeloblastic leukemias.

Adult↗

Myeloid sarcoma of both kidneys, the brain, and multiple bones in a nonleukemic child.

A myeloid sarcoma (MS) is an extramedullary tumor consisting of primitive granulocytic precursor cells. Although most such tumors have been reported in patients with acute myelogenous leukemia, MS is rarely recognized as an isolated tumor without any evidence of leukemia. However, in such cases, the initial diagnosis of MS can be difficult, so initial misdiagnosis rates of up to 75% have been reported. This report describes an unusual case of MS in a 3-year 5-month-old girl presenting as bilateral renal enlargements, and brain masses, with multiple bone involvements, but no hematological abnormalities.

Bone Neoplasms↗

[Experimental study on xue-bao capsules against injury of radiation or cyclophosphamide in mice].

OBJECTIVE: To explore the effects of xue-bao capsules on injury of radio-or chemo-therapy in mice, in order to provide rationale behind clinical trials. METHOD: xue-xu (deficiency of blood) model in mice was induced by radiation or cyclophosphamide. Leucocyte (WBC), erythrocyte (RBC), hemoglobin (Hb) and platelet (Pt) in peripheral blood as well as CFU-E and CFU-Gm in bone marrow were counted. RESULT: CFU-E and CFU-Gm in normal mice were promoted by this drug. The reduction of WBC, RBC and Hb in peripheral blood as well as CFU-E and CFU-Gm in bone marrow owing to the 3.5 Gy of 60Co radiation were antagonized by the drug. It had also antagonized cyclophosphamide induced the reduction of WBC, RBC and Pt in peripheral blood. CONCLUSION: xue-bao capsules has the effects against the adverse reactions of radio-or-chemo-therapy.

Animals↗

[Is hypereosinophilic syndrome a potentially malignant condition?].

The existence of eosinophilic leukemia (EL) has been controversial since it was first described. Recently, some authors have suggested that EL is part of a spectrum of eosinophilic diseases termed hypereosinophilic syndrome (HS). EL diagnosis is very difficult, especially if abnormal chromosome are not present, because HS comprises multiple disease entities of unclear etiology with the common features of prolonged eosinophilia of undetectable cause and organ system dysfunction. We present a case of HS whose findings are consistent with a leukemic process. For two years the patient showed only sharp hypereosinophilia; his clinical course was then marked by signs and symptoms of granulocytic sarcoma (GS), an extramedullary tumor composed of granulocytic precursor cells. GS as a complication of EL was described and in some cases the diagnosis of leukemia was made only on the basis of the GS complication. The formation of eosinophilic GS also suggests a diagnosis of LE in our case of HS. Finally, we always consider HS as a potential malignant disease.

Diagnosis, Differential↗