Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Using the megakaryocytic leukemia cell lines, K-562 and CMK established from a Down's patient with acute megakaryoblastic leukemia, we studied the changes of antigen expression, cytosolic Ca2+ mobilization, thromboxane (TX) A2 formation and gene expression during megakaryocyte differentiation. We found that thrombospondin synthesis and platelet factor (PF)-4 gene expression were specific for mature megakaryoblasts, whereas collagen unresponsiveness and prostaglandin E1-induced Ca2+ mobilization were noted in immature megakaryoblasts alone. This experiment shows that functional and genetic analysis are useful for characterizing the leukemic megakaryoblastic cells. We analyzed the clinical, hematologic and genetic features of 4 patients with M7, and acute megakaryoblastic transformation of CML, MDS and essential thrombocythemia. In two patients, prednisolone and 6-MP were effective in cytoreduction. In 3 patients with increased platelet counts, normal CFU-Meg formation, the megakaryoblasts with platelet production, or the coexistence of immature megakaryoblasts with mature megakaryocytes were observed, thus indicating that some megakaryoblastic leukemia cells still have the capacity of differentiation. One patient had megakaryoblastic cells with PF-4 gene expression. These clinical findings suggest that the megakaryoblastic leukemia could not be characterized as usual leukemia and a more sensitive marker is required to differentiate leukemic megakaryoblasts from normal megakaryoblasts.
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PMID:[Megakaryocytic leukemia cell lines and megakaryocytic leukemia]. 238 Oct 77

The proto-oncogene, c-kit, encodes a transmembrane tyrosine kinase receptor (KIT) and plays an important role in haemopoiesis. We have identified a 95 kD soluble form of KIT (S-KIT) in culture supernatant of human megakaryoblastic cell line, CMK. To study the physiological significance of S-KIT, we have established a sensitive sandwich ELISA system. Serum samples from healthy individuals contained detectable amounts of S-KIT. Next, we determined a total of 220 samples from 134 patients with haemopoietic disorders. A considerable number of patients with acute myeloid leukaemia (AML), especially those with more immature phenotypes (M0, M1 or M2) had elevated levels of serum S-KIT. Those levels decreased to the normal range after effective chemotherapy. In chronic myeloid leukaemia, patients with myeloid blastic crisis showed markedly elevated levels of serum S-KIT. In contrast, S-KIT levels decreased in cases with either acute or chronic lymphoid leukaemia. There was a tendency for patients with severe aplastic anaemia to show decreased levels, but it was not significant. In myelodysplastic syndrome, S-KIT levels appeared to vary by subsets, with higher concentration in more advanced forms of the disease. Although the functional role of S-KIT is not yet elucidated, these results suggest that the serum S-KIT levels may reflect the pathological states of various haematological disorders.
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PMID:Soluble c-kit molecule in serum from healthy individuals and patients with haemopoietic disorders. 757 39

The effects of thrombopoietin (TPO) on cell proliferation and differentiation, and the relation between these effects and the expression of c-mpl on leukemia cells were studied in seven acute myelogeneous leukemia cell lines and seven myelogeneous blast cell preparations from patients with chronic myeloproliferative disorders (CMPDs) and myelodysplastic syndrome (MDS). Among the leukemia cells, five preparations of megakaryoblastic leukemia cells from patients and one megakaryoblastic cell line, CMK 11.5, proliferated in response to TPO in vitro. CMK 11.5 and the blastic cells from one patient diagnosed with MDS with myelofibrosis differentiated with increasing expression of CD41a in response to TPO. However, TPO had no effect on the cells lacking megakaryocytic characteristics. Some patients with CMPD and MDS develop acute transformation with blasts demonstrating megakaryocytic features, and some of these cells show growth in response to TPO. Therefore, in vivo administration of TPO should be considered carefully for patients with CMPD or MDS, since TPO may induce leukemic cell proliferation.
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PMID:Thrombopoietin activates the growth of megakaryoblasts in patients with chronic myeloproliferative disorders and myelodysplastic syndrome. 1077 93

Dlk1 (Pref-1) is a transmembrane and secreted protein, which is a member of the epidermal growth factor-like family, homologous to Notch/Delta/Serrate. We have found by real-time RT-PCR that Dlk1 mRNA levels were high in CD34(+) cells in 10 of 12 MDS samples compared with CD34(+) cells from 11 normals. Also, Dlk1 mRNA was elevated in mononuclear, low density bone marrow cells from 11/38 MDS patients, 5/11 AML M6 and 2/4 AML M7 samples. Furthermore, 5/6 erythroleukemia and 2/2 megakaryocytic leukemia cell lines highly expressed Dlk1 mRNA. Levels of Dlk1 mRNA markedly increased during megakaryocytic differentiation of both CMK megakaryoblasts as well as normal CD34(+) hematopoietic stem cells. High serum levels of Dlk1 occurred in RA (4/10) and essential thrombocythemia (2/10) patients. Functional studies showed that forced expression of Dlk1 enhanced proliferation of K562 cells growing in 1% fetal bovine serum. Analysis of hematopoiesis of Dlk1 knockout mice suggested that Dlk1 contributed to granulocyte, megakaryocyte and B-cell clonogenic growth and was needed for generation of splenic B-cells. In summary, Dlk1 is overexpressed in selected samples of MDS (especially RA and RAEB) and AML (particularly M6, M7), and it appears to be associated with normal development of megakaryocytes and B cells.
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PMID:Dlk1 in normal and abnormal hematopoiesis. 1595 31

Growth factor-independent 1B (GFI1B) is a transcription factor essential for the development and differentiation of erythroid and megakaryocytic lineages. We evaluated the GFI1B expression in erythroleukaemia and megakaryocytic leukaemia, as well as in patients with other subtypes of acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL), chronic myeloid leukaemia (CML), myelodysplastic syndrome (MDS), severe aplastic anaemia (SAA), myelofibrosis with myeloid metaplasia (MMM) and in healthy volunteers. GFI1B expression was increased at least threefold in patients with erythroleukaemia (P < 0.01 compared with controls) and megakaryocytic leukaemia (P < 0.05) as well as in their corresponding leukaemic cell lines HEL, K562, CMK and M-07e. Patients with undifferentiated or monocytic AML, ALL, MMM, MDS and CML had no significantly altered GFI1B expression, whereas GFI1B expression was decreased 10-fold in patients with SAA (P < 0.0001 compared with controls). Silencing GFI1B by transfection with small interfering RNA (siRNA) markedly reduced the proliferation rate in the leukaemic cell lines HEL, K562 and NB4 (P < 0.01). Concomitantly, we observed a two- to threefold increase in the apoptosis rate in these cells after transfection with siRNA towards GFI1B. Our data indicate that GFI1B plays a major role in AML-M6 and AML-M7 and qualifies as a target for anti-leukaemic strategies in these malignancies.
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PMID:Growth factor-independent 1B gene (GFI1B) is overexpressed in erythropoietic and megakaryocytic malignancies and increases their proliferation rate. 1715 8