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)

In the present study, the ability of peripheral blood (PB) progenitor cells to form granulocyte-macrophage (GM) colonies spontaneously in methylcellulose was investigated in healthy controls and patients with myeloproliferative disorders (MPDs). Spontaneous colony formation was observed in only one of the 18 control cases (6%), but in 22 of the 29 MPD patients (76%). The incidence of spontaneous GM colonies correlated both with the number of blast cells and the amount of c-kit positive cells present in the initial sample. Spontaneous GM colony growth in PB mononuclear cells isolated from patients with MPDs seems to be a frequent phenomenon in contrast to the healthy controls and may present a marker of malignancy.
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PMID:Spontaneous granulocyte-macrophage colony growth by peripheral blood mononuclear cells in myeloproliferative disorders. 862 19

The immunohistochemical expression of c-kit proto-oncogene product in 57 breast cancer tissues was studied using anti-c-kit proto-oncogene product antibody in comparison with 20 normal breast tissues and 58 benign breast tumours. In normal breast tissues, the c-kit proto-oncogene product was strongly expressed on cell membrane and/or cytoplasm of alveolar and ductal cells. The immunoreactive score (IRS) of c-kit proto-oncogene product in normal mammary epithelia was 6.22 +/- 2.11 (mean +/- s.d.). In benign breast diseases, the c-kit proto-oncogene product was detected heterogeneously with a reduced IRS (3.33 +/- 2.44). In breast cancer tissues, the expression of the immunoreactive c-kit proto-oncogene product was often deleted and the average IRS was significantly reduced compared to those of normal breast tissues or benign breast diseases tissues. Among benign diseases, the average IRS of intraductal papilloma was significantly reduced (1.34 +/- 1.70) and the staining intensity and pattern were found to be similar to those seen in breast cancer. The results in this study suggested that the c-kit proto-oncogene product is correlated with the growth control or the differentiation of normal breast epithelium. Also, the loss of the expression of this protein may indicate the change of the signal transduction in relation to malignant transformation in human mammary epithelium.
Br J Cancer 1996 May
PMID:Immunohistochemical expression of the c-kit proto-oncogene product in human malignant and non-malignant breast tissues. 863 Feb 84

Antisense methods to control aberrant gene expression have been investigated as therapeutic strategies. A proto-oncogene c-kit, which encodes a transmembrane tyrosine kinase, is overexpressed in some malignancies, including small-cell lung cancer (SCLC), and is thought to be involved in their pathogenesis. To test the feasibility of using adenovirus vectors for antisense strategies and to target c-kit in SCLC therapy, we constructed replication-deficient recombinant adenovirus vectors which express fragments of c-kit transcripts in antisense (Ad.kitAS) or sense orientation (Ad.kitS: control). In vitro infection of SBC-1 cells, which are c-Kit protein-producing SCLC cells, by these vectors resulted in the expression of artificial c-kit transcripts. The Ad.kitAS-infected SBC-1 cells showed reductions in the amount of c-Kit protein. As expected, at 10 days after infection (1 multiplicity of infection), Ad.kitAS-infected SBC-1 cells showed approximately 40% growth inhibition compared to uninfected or Ad.kitS-infected cells in vitro. Such a significant growth inhibition by Ad.kitAS was not induced in SBC-5 cells, which are SCLC cells producing no c-Kit protein. These results demonstrate the usefulness of adenovirus vectors in antisense strategies, and the feasibility of targeting c-kit in the therapy of c-Kit-producing SCLC.
Jpn J Cancer Res 1996 May
PMID:Specific growth inhibition of small-cell lung cancer cells by adenovirus vector expressing antisense c-kit transcripts. 864 92

The biological effects of c-kit ligand (stem-cell factor: SCF) on an immortalized human megakaryocytic cell line (CMK) was evaluated using methods including the 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, surface marker analysis, DNA cell-cycle analysis and immunoblotting. SCF stimulated the growth of CMK cells. Incubation with SCF resulted in increased expression of IIb/IIIa platelet-related glycoprotein (gpIIb, IIIa), indicating enhanced differentiation of CMK cells. Treatment of CMK cells with SCF resulted in a decrease in the subpopulation in the G1 phase, with a reciprocal increase in those in the S phase and the G2 + M phase. Moreover, SCF significantly increased cellular expression of cyclin A, a regulatory subunit of cyclin-dependent protein kinase (CDK), and the ratio of phosphorylated/dephosphorylated retinoblastoma gene product (RB protein). These results suggest that SCF stimulates the growth and differentiation of megakaryocytic cells possibly through mechanisms related to the activation of cell-cycle-dependent serine/threonine kinase and inactivation of the nuclear tumor-suppressor gene product.
J Cancer Res Clin Oncol 1996
PMID:Stem-cell factor regulates the expression of cyclin A and retinoblastoma gene product in the growth and differentiation pathway of human megakaryocytic cells. 869 43

The lymphohematopoietic progenitors represent < 0.01% of nucleated marrow cells. We have shown that murine lymphohematopoietic progenitors can be immortalized by a recombinant retroviral vector harboring a dominant-negative retinoic acid (RA) receptor. The immortalized progenitors proliferate as a stem-cell factor-dependent clonal line designated EML C1. The EML C1 cell line spontaneously generates prepro-B-lymphocytes and erythroid and myeloid progenitors. Upon stimulation with interleukin 7 and marrow stromal cells, the prepro-B-lymphocytes express recombination-activating gene 1 (RAG-1) and undergo D-J rearrangements of the immunoglobulin heavy-chain genes. With erythropoietin, the erythroid progenitors proliferate and differentiate into red cells. Generation of the common progenitors for neutrophils and macrophages [colony-forming units-granulocyte-macrophage (CFU-GM)] is suppressed in EML C1 cells but is inducible by high concentrations of RA. An additional block in neutrophil differentiation occurs at the promyelocyte stage, but this can also be overcome by high concentrations of RA. Although c-fms is homologous to c-kit, which encodes the receptor for stem-cell factor (SCF), EML C1 cells neither express c-fms nor respond to macrophage colony-stimulating factor (M-CSF), the ligand for c-fms. Transduction and expression of c-fms cDNA in EML C1 cells confers responsiveness to M-CSF. This finding indicates that c-kit and c-fms share substantially overlapping signal-transduction pathways. However, c-fms-transduced EML C1 cells (EML C1/c-fms cells) exhibit different development patterns when stimulated by SCF alone or by M-CSF alone. When stimulated by SCF alone, EML C1/c-fms cells show mostly erythroid and B-lymphoid development. When stimulated by M-CSF alone, development switches to mostly myeloid (neutrophil and macrophage) development. This observation suggests that c-kit and c-fms must have unique signal-transduction pathways in addition to the common ones.
Cancer Chemother Pharmacol 1996
PMID:Differential effects of c-fms and c-kit ligands on the lineage development of the lymphohematopoietic cell line EML C1. 876 19

Glycoprotein (gp) 130, a receptor component for interleukin 6 (IL-6), can associate with a soluble IL-6 receptor (sIL-6R)-IL-6 complex. To examine the role of gp130 signaling in human hematopoietic progenitor-cell proliferation and differentiation, we studied the effects of the sIL-6R-IL-6 complex in combination with other cytokines on human CD34+ cells in clonal and suspension cultures. The sIL-6R-IL-6 complex, but not sIL-6R or IL-6 alone, in the presence of stem-cell factor (SCF) produced dramatic increases in the populations of various cell lineages, including erythroid cells and various hematopoietic progenitors, in suspension culture. Significant numbers of colonies of (particularly) multilineage and blast cells were generated in methylcellulose culture supplemented with a combination of sIL-6R-IL-6 complex and SCF. Addition of anti-gp130 monoclonal antibodies (MAbs) and anti-IL-6R MAbs to the above-mentioned cultures dose-dependently inhibited the generation of cells of various lineages and of progenitor cells in suspension culture and completely blocked multilineage colony production in methylcellulose culture; an anti-erythropoietin antibody did not cause inhibition. These findings demonstrate that both proliferation and differentiation of hematopoietic progenitor cells can be induced through gp130 and c-Kit signaling, indicating that progenitor cells are responsive to the sIL-6R-IL-6 complex, even though they do not express IL-6R. Together with previous studies showing that detectable levels of sIL-6R, IL-6, and SCF are present in human serum, these results suggest that gp130 signaling may play an important role in human hematopoiesis in vivo.
Cancer Chemother Pharmacol 1996
PMID:Role of glycoprotein 130 and c-Kit signaling in proliferation and differentiation of human hematopoietic progenitor cells. 876 20

Interleukin 11 (IL-11) is a newly identified hematopoietic growth factor that exerts its primary effect on megakaryocyte maturation and platelet production. It has a unique receptor, signaling by which is mediated by the glycoprotein (GP) 130 pathway. IL-11 is synergistic with stem-cell factor (c-kit ligand) in vitro, enhancing proliferation of primitive hematopoietic stem cells, and has been shown to be critical to the process of polyploidization and maturation. In preclinical models, IL-11 was shown to enhance platelet recovery following intensive chemotherapy, and in murine bone-marrow transplant models it accelerates the recovery of all hematopoietic lineages. Nonhuman primate studies have demonstrated a dose-related thrombopoietic effect; however, no myeloid effect has been observed. In clinical phase I trials, subcutaneous IL-11 was well tolerated and induced a dose-related thrombopoietic effect in women with breast cancer. IL-11 at doses of > 25 micrograms/kg per day appeared to reduce the severity of chemotherapy-induced thrombocytopenia. In a randomized phase II trial, IL-11 at 50 micrograms/kg reduced the requirement for platelet transfusions as compared with that in placebotreated controls. IL-11 is an interesting factor; however, further studies are needed to confirm its activity and are in progress.
Cancer Chemother Pharmacol 1996
PMID:Thrombopoietic activity of recombinant human interleukin 11 in cancer patients receiving chemotherapy. 876 26

The growth and survival of many types of cancer cells are known to be supported by specific growth factor/cytokine systems. Among these, the activation of c-kit receptor and its ligand steel factor participates in several types of human carcinogenesis. W mutations of laboratory mouse strains are loss of functional mutations of the c-kit receptor. To examine the validity of these mutants in investigating c-kit-mediated carcinogenesis and in the treatment of c-kit-dependent tumors, we introduced various W mutations (W, Wv, and W42) into a transgenic mouse strain carrying human papillomavirus oncogenes, in which c-kit/Steel-mediated tumorigenesis occurs with a very high incidence. In all transgenic strains carrying a W mutation, the c-kit deficiency affected the tumorgenic process to various degrees. Tumor development was markedly suppressed in transgenic strains carrying kinase defective mutations (Wv and W42) in a heterozygous condition. In null-type (W) heterozygous transgenic mice, tumorigenesis was suppressed at a lower level. Moreover, minimal focal legions or, in some cases, no focal legions were found in the testes of W/Wv heterozygous transgenic mice, showing a close relationship between tumor cell growth and the degree of c-kit inactivation. These results indicated that c-kit activity is a pivotal determinant of testicular tumor development and that the kinase defective mutants of c-kit are valuable for treating c-kit-dependent cancer, as well as for clarifying the c-kit-mediated carcinogenesis.
Cancer Res 1996 Oct 01
PMID:Abrogation of c-kit/Steel factor-dependent tumorigenesis by kinase defective mutants of the c-kit receptor: c-kit kinase defective mutants as candidate tools for cancer gene therapy. 881 20

Molecular investigations into the neoplastic transformation of a normal spermatogenic precursor cell into a germ-cell malignancy have implicated a wide array of DNA and RNA alterations. Previous epidemiologic and familial patterns of cancer presentation had suggested that testicular cancer developed from one or more genetic alterations. In particular, mutations in cellular oncogenes such as c-kit and tumor-suppressor genes such as the retinoblastoma gene product have been identified as putative etiologic agents in the development and progression of testicular germ-cell tumors. Additionally, alterations in the transcription of RNA that are regulated through a process of genomic imprinting have been identified in human testis cancers. This report provides a framework for integrating this growing literature on the molecular biology of testicular germ-cell tumors into a potential etiologic hypothesis.
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PMID:Molecular mechanisms of testicular carcinogenesis. 891 75

Morphologic, immunologic, cytogenetic, and clinical features were studied in 9 cases of acute undifferentiated leukemia (AUL). These patients were unclassifiable by FAB criteria, they were CD34+ and did not express myeloid- or lymphoid-associated antigens (CD13, CD33, CD14, CD15, CD61, CD19, CD10, CD22, CD7, CD2, CD5, CD3). Clonal abnormalities were seen in 8 of 9 cases. Del(5q) as the sole anomaly was observed in 3 cases; +13 was the primary change in 3 cases, and isolated trisomy 12 was found in 1 patient. A complex karyotype with trisomy 12q, in association with del 17p and trisomy 21q was detected in 1 case. One patient with 5q- relapsed with refractory anemia with excess of blasts; the presence of dysgranulopoiesis and a few blasts with possible monocytoid morphology in the remaining 2 patients point to a "myeloid nature" of these leukemias. Analysis of cytologic features in our 3 patients with +13, in combination with previously reported cases, suggests the occurrence of immature stem cell involvement with limited differentiation potential, possibly more along the myeloid than the lymphoid lineage. The significance of trisomy 12q in this subset of leukemia remains elusive; some clues of minimal differentiation towards the myeloid lineage in our cases are provided by positivity for the CD117 (c-kit) antigen and by relapse with acute myeloid leukemia without maturation (M1) in one patient. We conclude that, with presently available diagnostic techniques, AUL is a rare subset of leukemia, in which cytogenetic changes are confined to a few chromosomes, with prevalent involvement of 5q and of chromosomes 13 and 12. Chromosome findings may be of value in clinical practice, especially in those cases with "myeloid-oriented" karyotype.
Cancer Genet Cytogenet 1996 Nov
PMID:Cytogenetic and clinicobiological features of acute leukemia with stem cell phenotype: study of nine cases. 895 68


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