Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P10721 (c-kit)
 6,575 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A novel fibroblast-dependent human immature megakaryoblastic leukemia cell line (M-MOK) was established from the bone marrow of a girl with acute megakaryoblastic leukemia, and its growth was determined to be completely dependent on the presence of human embryonic lung-derived fibroblasts, HEL-O. Adhesive interaction between M-MOK and HEL-O was crucial for viability; once HEL-O was removed from the culture, mortality was total within a few days. On HEL-O cells, M-MOK could be passaged for more than 2 years. With regard to surface marker profile, the established cells were positive for CD11a, CD13, CD18, CD33, CD34, CD41b, CD42b, CD54, and c-kit antigens, but negative for HLA class II antigen and glycophorin. Histochemically, the cells were negative for myeloperoxidase, nonspecific esterase, and naphthol ASD chloroacetate esterase staining. Electron-microscope examination revealed the cells to be negative for platelet peroxidase (PPO). After induction of differentiation by a phorbol ester, however, the cells were demonstrated to be positive for PPO with a morphological change to megakaryocytes. From these results, M-MOK was considered to represent an immature cell line of megakaryocyte lineage. Studies of the mechanisms sustaining the HEL-O-dependent continuous in vitro growth of M-MOK cells revealed the following results: (1) M-MOK could grow even when separated from HEL-O by a nucleopore membrane; (2) conditioned medium (CM) from HEL-O supported the growth of M-MOK for more than 1 month without feeder cells; (3) the growth of M-MOK on HEL-O or CM supplement was nearly entirely inhibited by anti-GM-CSF (1 microgram/mL); (4) GM-CSF mRNA was detected in HEL-O cells; and (5) HEL-O was found to secrete GM-CSF into the culture medium. Taken together, the growth of M-MOK might therefore be driven by a soluble factor, that is, GM-CSF secreted from HEL-O cells. The presence of HEL-O, however, inhibited anti-GM-CSF-induced M-MOK death. Co-culture of M-MOK and HEL-O cells thus offers a useful experimental model for analysis of interactions between hematopoietic stem cells and stromal cells.
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PMID:Establishment and characterization of a novel human immature megakaryoblastic leukemia cell line, M-MOK, dependent on fibroblasts for its viability. 758 86

After immunizing mice with a human megakaryoblastic leukemia cell line, M-MOK, we obtained two monoclonal antibodies which recognize the human c-kit receptor. The monoclonal antibodies, designated MTK1 and MTK2, were found to specifically recognize Balb/3T3 cells transfected with human c-kit cDNA and not parent Balb/3T3 cells while showing different immunological, biochemical and biological behaviors. Both allowed visualization of the 140 kDa c-kit protein by Western blot analysis, but MTK1 detected only positive band with non-reducing conditions for sodium dodecyl sulfate-polyacrylamide gel electrophoresis. MTK1 partially inhibited the stem cell factor (SCF) induced proliferation of M-MOK cells, whereas, MTK2 was without effect. MTK1 also inhibited the bone marrow derived colony forming unit granulocyte/macrophage (CFU-GM) formed by granulocyte-macrophage colony stimulating factor (GM-CSF) and SCF. Not only anti-CD34 antibodies (HPCA-1) but also MTK1 could be shown to concentrate bone marrow CFU-GM and burst forming unit erythroid (BFU-E) effectively. The presently described monoclonal antibodies may therefore be useful for functional analysis of the ligand binding domain of the human c-kit receptor, as well as for further classification of hematopoietic stem cells in addition to the CD34 positive cells.
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PMID:Isolation and characterization of two monoclonal antibodies that recognize different epitopes of the human c-kit receptor. 872