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Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adult rat dorsal root ganglion sensory neurons in culture require nerve growth factor for synthesis of substance P and calcitonin gene-related peptide but express vasoactive intestinal peptide independently of nerve growth factor. In contrast, the same neurons from newborn rats do not express detectable vasoactive intestinal polypeptide when cultured with nerve growth factor. To further explore the mechanisms regulating neuropeptide expression in these cells, I compared the effects of nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, ciliary neurotrophic factor and leukaemia inhibitory factor on substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide and somatostatin expression in rat dorsal root ganglion cultures. As with neurons from adult animals, newborn rat sensory neurons required nerve growth factor for synthesis of substance P and calcitonin gene-related peptide. This effect was independent of neuronal survival since most neurons capable of expressing these peptides appeared to survive without added neurotrophic factors. Neurons surviving in the absence of nerve growth factor also expressed vasoactive intestinal polypeptide, suggesting that nerve growth factor suppresses vasoactive intestinal polypeptide expression in immature neurons. However, nerve growth factor withdrawal after eight days' culture failed to cause vasoactive intestinal polypeptide induction which therefore appears to depend on other factors also. Neither ciliary neurotrophic factor nor leukaemia inhibitory factor affected peptide levels when used alone, but both inhibited nerve growth factor-stimulated expression of substance P and calcitonin gene-related peptide in adult rat neurons. They also stimulated vasoactive intestinal polypeptide expression in newborn rat neurons in the presence of nerve growth factor but not to such high levels as those seen under conditions of nerve growth factor deprivation. Neither brain-derived neurotrophic factor nor neurotrophin-3 affected peptide expression significantly. Somatostatin was defected in adult rat neurons, but was unaffected by neurotrophic factors. No somatostatin was detected in newborn rat neurons. These results suggest that in immature animals at least, the increased expression of vasoactive intestinal polypeptide seen in sensory neurons following peripheral nerve injury in vivo, could result from deprivation of target-derived nerve growth factor in combination with increased availability of ciliary neurotrophic factor or leukaemia inhibitory factor from the injured nerve.
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PMID:Neuropeptide expression by newborn and adult rat sensory neurons in culture: effects of nerve growth factor and other neurotrophic factors. 751 8

Osteolysis resulting in extensive bone damage is a major clinical manifestation of patients with multiple myeloma (MM). The mechanisms of bone resorption in MM are incompletely understood. The final pathway is the generation of activated osteoclasts within bone marrow (BM) microenvironment. To investigate the mechanisms of bone resorption in MM we established an experimental system that, including bone marrow (BM) stromal cells and bone slices, closely mimicks in vitro the in vivo BM microenvironment. Peripheral blood mononuclear cells (PBMC) from nine patients with MM, three monoclonal gammopathy of undetermined significance (MGUS), and nine normal controls were cultured in this system. PBMC from patients with aggressive and bone devastating MM gave rise to multi-nucleated cells with the morphology and phenotype of osteoclasts. These cells induced bone resorption in vitro which was inhibited by the addition of calcitonin. No bone resorption was observed in cultures of PBMC from patients with MM and limited bone damage, with MGUS and from normal subjects. These findings indicate that patients with aggressive MM have a population of circulating precursors that develop into functionally active osteoclast-like cells once they come in contact with the BM microenvironment. These cells may contribute to the wide-spread and generalized bone erosion observed in the patients.
Leukemia 1995 Aug
PMID:Osteoclast precursors circulate in the peripheral blood of patients with aggressive multiple myeloma. 764 30

One of the earliest events in the multistep process of malignant transformation is a change in the methylation pattern of certain genes. DNA methylation is usually detected by Southern blotting after restriction digest with methylation-sensitive endonucleases. Calcitonin gene hypermethylation has been described in a variety of human malignancies including lymphomas and leukemias. Here we report a technique based on the semi-quantitative differential polymerase chain reaction (PCR) which is capable of detecting subtle changes in the methylation pattern of the human calcitonin gene. This technique is based on two principles: (i) simultaneous coamplification of the target gene (5'-region of the calcitonin gene) and a reference gene for quantitative purposes; and (ii) simultaneous coamplification of a competitor with identical primer-binding sites as the target gene to control for proper restriction digest. Using this technique, we investigated calcitonin gene methylation in a variety of human cell lines, primary leukemias and normal human blood donors. The data revealed good correlation with standard Southern blotting. Weak calcitonin gene methylation was found in all normal blood donors tested (n = 14). In contrast, strong calcitonin gene methylation was detected in most acute leukemias (five of 10 acute myeloid leukemias (AML); six of seven acute lymphoblastic leukemias (ALL)). These data show that this technique can reliably be used to quantitate gene methylation and indicate that there exists heterogeneity with regard to methylation status in different leukemias, suggesting that hypermethylation of the calcitonin gene may play a role in the transformation process of some, but not all, human leukemias. Furthermore, differential PCR may facilitate determination of calcitonin gene methylation in clinical or archival tumor samples.
Leukemia 1995 May
PMID:Detection of DNA methylation in the calcitonin gene in human leukemias using differential polymerase chain reaction. 776 56

Hypercalcemia in adult T-cell leukemia has been attributed to increased levels of 1,25-dihydroxyvitamin D (1,25(OH)2D), whereas in other types of leukemia, hypercalcemia has been blamed on direct skeletal invasion by malignant cells, ectopic parathyroid hormone (PTH) production or bone-resorbing cytokines. A 51-year-old man was studied who presented with back pain, circulating myeloblasts, and hypercalcemia. The bone marrow revealed acute myeloblastic leukemia. While the ionized calcium concentration was 8.17 mg/dL (normal, 4.73 to 5.21 mg/dL), the levels of PTH, PTH-related peptide, vitamin D, and thyroxine were normal or subnormal. Bone histomorphometry showed a decreased cortical width with intracortical erosion cavities dissecting into the marrow space. In cancellous bone, the osteoid area, osteoblast perimeter, and tetracycline fluorescence were sparse, whereas the osteoclast perimeter was increased. Persistent marrow fat, the general absence of trabecular narrowing, and the prompt response to calcitonin suggest that the osteoclasts caused the hypercalcemia and lytic lesions, rather than pressure atrophy or osteolysis by leukemic infiltration. Osteoclast activation and subsequent hypercalcemia may have been due to a locally produced cytokine, such as interleukin-1 beta or tumor necrosis factor.
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PMID:Case report: hypercalcemia in acute myeloblastic leukemia is caused by osteoclast activation. 812 79

Alterations in DNA methylation appear to be an integral part of the malignant transformation. For example, the p15 region of chromosome 11 with multiple genes related to cell growth regulation exhibits different methylation patterns in the 5' area of the calcitonin A gene in healthy bone marrow cells, and in leukemic cell populations. In this work the methylation status of the 5' area of the calcitonin gene in myeloproliferative disorders (MPD) other than chronic myeloid leukemia (CML) is studied. A total number of 37 patients with polycythemia vera, essential thrombocythemia, or myelofibrosis were studied. A control group of 18 healthy persons and patients with reactive hematologic changes was included. The DNA isolated from peripheral blood or bone marrow cells was digested with the methylation-sensitive HpaII restriction enzyme. A Southern blot was hybridized with a 1.7 kb probe specific to the 5' area of the calcitonin gene. The result was visualized autoradiographically and analyzed with a densitometer. The results have been expressed as ratios between the abnormal and normal autoradiography band intensities, referred to as the calc-value or CALC. An increase in the calc-value signifies increasing methylation. In the control group the calc-value had a mean of 0.274. The myelofibrosis patients exhibited very strong hypermethylation in the calcitonin gene 5' area, with a mean calc-value of 11.1 (median 2.6). The polycythemia vera patients showed considerable variation in their methylation status, with a mean value of 1.52. The essential thrombocythemia patients exhibited weak hypermethylation, with a mean calc-value of 0.58. A correlation between karyotypic abnormalities and hypermethylation was observed. Complicated forms of MPD exhibited higher levels of methylation than the uncomplicated disease forms.
Leukemia 1994 Feb
PMID:Calcitonin gene methylation in chronic myeloproliferative disorders. 830 47

It is well documented that the calcitonin gene area in the short arm of chromosome 11 is hypermethylated in most acute leukemias as well as in chronic lymphatic leukemia. In contrast, the gene is normally methylated during the chronic phase of the chronic myeloid leukemia but turns hypermethylated as the disease escalates. As the methylation of the calcitonin gene correlates with the disease activity in chronic myeloid leukemia, it seemed worthwhile to study the gene methylation in other premalignant hematologic conditions with a potential to terminate in fulminant acute leukemia. We report here on the calcitonin gene methylation in patients with myelodysplastic syndromes (MDS) using a methylation sensitive restriction enzyme HpaII and standard Southern blotting techniques. Bone marrow aspirates from a total of 26 MDS patients were studied. In 24 of these patients, the calcitonin gene was hypermethylated. There was no correlation between the methylation status and the morphological stage of the disease. All six patients with a blast count < 5% had a hypermethylated gene. Of the 19 patients with a blast count > 5%, 17 were hypermethylated only two having normal methylation status of the gene. It appears that the hypermethylation of the calcitonin gene area in the short arm of chromosome 11 may be an early event in the pathogenesis of the myelodysplastic syndromes. The methylation analysis may thus be of value as a diagnostic tool in MDS but an abnormal methylation pattern does not seem to have a direct relation with the degree of blast infiltration.
Leukemia 1993 Feb
PMID:Hypermethylation of the calcitonin gene in the myelodysplastic syndromes. 842 80

Certain osteoclastic markers (multinucleation and tartrate-resistant acid phosphatase) were induced in human leukemia HL-60 cells by treatment with 10(-7) M 1,25-dihydroxy-vitamin D3 [1,25(OH)2D3] for 10 days. However, no formation of pits on a bone substrate by vitamin-treated HL-60 cells was detected. Expression of calcitonin receptors (CTR), another osteoclastic marker, was examined by means of the reverse transcriptase polymerase chain reaction. The human CTR-cDNA (T47D isotype) was amplified from untreated HL-60 cells, but not from cells treated with 1,25(OH)2D3. The CTR mRNA disappeared within 24 h after the treatment. Thus, 1,25(OH)2D3-differentiated HL-60 cells failed to show two intrinsic characteristics of osteoclasts, pit formation on a bone substrate and expression of CTR. We then examined the expression of CTR on established human leukemia cell lines. The CTR mRNA was expressed in myeloblastic ML-1 and promyelocytic HL-60 leukemia cells but not in more mature macrophage-like cell lines, U-937 and THP-1 cells. Neither B cell leukemia BALL-1, T cell leukemia Jurkat, promegakaryoblastic leukemia Meg-J, nor cervix uteri carcinoma HeLa S3 cells amplified the CTR products. The cDNA of BIN67-isotype CTR, that has an additional 16-amino acid insert in the putative first intracellular loop of T47D-type CTR [Kuestner et al. (1994) Mol. Pharmacol. 46, 246-255], was amplified by neither strain tested. It was suggested that the T47D-type CTR is a novel differentiation antigen of immature myeloid lineage cells.
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PMID:Expression of calcitonin receptors on human myeloid leukemia cells. 854 84

Inflammatory processes are mediated by many cellular events involving different cell types (leukocytes, monocytes, stromal cells, etc.). Numerous soluble mediators regulate these reactions, including leukaemia inhibitory factor (LIF), a cytokine which may play an important role in inducing acute-phase protein synthesis by hepatocytes during inflammation. This study was designed to determine the effects of LIF on the human monocyte/macrophage lineage and provide a better definition of its behaviour during systemic inflammation. In-vitro exposure of human long-term bone marrow cultures to recombinant human LIF significantly increased (about two-fold) the number of multinucleated cells (MNC) formed after three weeks of culture. These LIF-induced MNC expressed tartrate-resistant acid phosphatase, and LIF increased this intracellular activity by about 50%. MNC displayed phagocytotic activity but were unable to degrade sperm whale dentin or respond to human calcitonin. They did not possess the main characteristics of osteoclasts and were in fact macrophage polykaryons. Our results demonstrate for the first time that LIF can induce macrophage polykaryon formation from human bone marrow culture, suggesting that this factor not only produces leukocytes but also has a direct influence on the monocyte/macrophage lineage.
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PMID:Upmodulation of multinucleated cell formation in long-term human bone marrow cultures by leukaemia inhibitory factor (LIF). 906 95

Aberrant DNA methylation can occur early in neoplastic transformation and may lead to the development of cancer. We describe the alterations of methylation patterns at the DNA sequence level which occurred in the 5' region of the calcitonin gene in lymphoblasts from 14 pediatric patients with acute lymphoblastic leukemia (ALL). The DNA methylation status of 25 CpG sites was determined by sequence analysis after bisulfite treatment of the DNA. This method showed that 13 out of 14 patients had increased numbers of methylated CpG sites in the calcitonin gene region at initial diagnosis when compared to control DNA from healthy individuals. The 5' region of the calcitonin gene appears to be methylated to a significantly higher degree in T lineage ALL compared to B lineage ALL (P < 0.01). Each of six ALL patients who were investigated at initial diagnosis and at relapse showed alterations in DNA methylation between the two stages. These six cases were also investigated by Southern blot analysis with methylcytosine-sensitive restriction enzymes and this method showed an increase in DNA methylation in only four of the six cases. The DNA sequencing method thus appears to be better suited to assess alterations of DNA methylation than Southern blot analysis. There are marked regional differences in the frequency of methylation of individual CpG sites and in the frequency of alterations between the two stages. Our results show that alterations in DNA methylation continue to occur from the initial stage to the relapse stage of ALL, suggesting that aberrant DNA methylation may play a role in tumor progression.
Leukemia 1997 Jul
PMID:DNA methylation patterns in the calcitonin gene region at first diagnosis and at relapse of acute lymphoblastic leukemia (ALL). 920 77

Hypermethylation in cancer often occurs in CpG islands that span the promoter regions of tumor suppressor genes. However, it is not clear if hypermethylation is limited to single target genes or if multiple genes are simultaneously methylated. To understand the extent of aberrant de novo methylation, we have analyzed the methylation pattern of a number of tumor-related genes in leukemia from the same cohort of patients. We used bisulfite genomic sequencing to characterize the methylation pattern of the CpG islands associated with the calcitonin, estrogen receptor, E-cadherin, p15, p16, Rb, GST-Pi, and HIC1 genes in the bone marrow from 9 normal and 20 patients with acute myeloid leukaemia (AML). All of the normal control samples were essentially unmethylated for each of the eight tumor-related genes studied. In contrast, 19 of 20 (95%) of the AML patients had an abnormal methylation pattern in at least one gene, and 15 of 20 (75%) had abnormal methylation patterns in two or more of the target genes. We conclude that there is a general deregulation of CpG island methylation in leukemia and that hypermethylation is not limited to single genes, but a number of genes are methylated concurrently. Moreover, the subset of genes that are commonly methylated in leukemia appear to be cancer type specific.
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PMID:Concurrent DNA hypermethylation of multiple genes in acute myeloid leukemia. 1044 89


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