Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1140680 (ovarian cancer)
 28,141 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The protooncogene c-kit encodes a transmembrane receptor-type tyrosine kinase which belongs to the beta-PDGER/CSF-1 receptor tyrosine kinase family. The interaction between c-kit receptor and its corresponding ligand, stem cell factor (SCF), has been suggested to be involved in embryogenesis as well as carcinogenesis via the autocrine/paracrine system. In the present study, cancer cell lines and normal/benign/malignant tissues of the human female genital tract were examined for the expression of both c-kit and SCF by Northern blot and immunohistochemical analyses. Two of 16 cell lines showed mRNA expression of both c-kit and SCF, while 2 and 12 cell lines expressed c-kit and SCF, respectively. In tissues, several cases of malignant tumors, including three cervical cancers, one ovarian cancer, and one ovarian immature teratoma, expressed mRNA of both c-kit and SCF. In normal tissues, squamous epithelium expressed SCF immunohistochemically, while c-kit protein was detected only in melanocytes. Some tissues of malignant tumors, one squamous cell carcinoma of the cervix, two small cell carcinomas of the cervix, two serous adenocarcinomas of the ovary, and two immature teratomas of the ovary, expressed both c-kit and SCF proteins immunohistochemically. It is also notable that c-kit protein was expressed only in malignant germ cells of dysgerminomas, while SCF was expressed in the connective tissues surrounding germ cells. The present study suggests that the c-kit/SCF system may play an important role in the carcinogenesis of the female genital tract.
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PMID:Coexpression of the c-kit receptor and the stem cell factor in gynecological tumors. 751 96

Retroviral gene transfer into human myeloid precursor cells allows introduction of marker genes as well as genes conferring resistance to chemotherapeutic drugs. We transduced a human mutant dihydrofolate reductase (DHFR) cDNA into CD34 antigen-positive peripheral blood cells from patients with breast or ovarian cancer obtained after treatment with chemotherapy and granulocyte colony-stimulating factor (G-CSF). This mutant DHFR has been shown to confer resistance to methotrexate (MTX) in murine bone marrow. We established a transduction protocol that permitted ex vivo expansion and selection of transduced early progenitor cells. The number of progenitor cells from transduced CD34-positive cells increased 50-fold after cytokine prestimulation with interleukin-1 (IL-1), c-kit ligand (KL; stem cell factor), and IL-3 and 2 weeks in liquid culture. Transduced colony-forming unit-granulocyte-macrophage (CFU-GM), assayed directly after the transduction procedure, were protected completely against 2 x 10(-8) mol/L MTX, a concentration that significantly reduced the CFU-GM detected in the control population. Gene transfer of the mutant DHFR led to a twofold selective advantage for a pre-CFU population after exposure to MTX in liquid culture (P < .001). Polybrene, in contrast with protamine, significantly inhibited the expansion of progenitors. The presence of proviral DNA was monitored by polymerase chain reaction (PCR) and was detected in greater than 80% of CFU-GM and ex vivo expanded pre-CFU. We have demonstrated that human hematopoietic precursor cells can be expanded extensively after retroviral gene transfer. The same population of early progenitors can be selected ex vivo with low-dose MTX. As long-term expression of transduced genes in human hematopoietic cells remains a problem in vivo, these results may have implications for future clinical trials, especially for the introduction of nonselectable genes.
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PMID:Ex vivo expansion and selection of human CD34+ peripheral blood progenitor cells after introduction of a mutated dihydrofolate reductase cDNA via retroviral gene transfer. 752 65

Greater than 95% of ovarian cancers originate from the epithelial cells on the surface of the ovary termed ovarian surface epithelium (OSE). A normal aspect of OSE function is repeated proliferation after ovulation, and this is postulated to be involved in part in the onset of ovarian cancer. The hypothesis tested is that locally produced growth factors have an important role in controlling OSE proliferation. The current study investigates the potential role of the growth factor kit ligand (KL)/stem cell growth factor and its receptor c-kit in normal OSE biology and ovarian cancer. Human tumors from borderline, stage I, and stage III cases of ovarian cancer were found to express KL and c-kit protein in the epithelial cell component by ICC analysis. The stromal cell component of human ovarian tumors contained little immunostaining. Bovine ovarian physiology and endocrinology are similar to the human such that cow ovaries were used as a model system to investigate normal OSE functions. KL and c-kit proteins were detected in the OSE from both normal human and bovine ovaries. Adjacent ovarian stromal tissue contained less intense but positive KL and c-kit immunostaining. To extend the ICC results, RNA was collected from normal bovine OSE and ovarian stromal cells to examine KL gene expression. KL transcripts were detected in cultured OSE and stromal cells by Northern blot analysis. KL gene expression was found to be high in freshly isolated OSE but low in freshly isolated stroma using a quantitative polymerase chain reaction procedure. Levels of KL gene expression in cultured OSE and stroma increased to high levels. Observations indicate that normal OSE expresses high levels of KL in vivo and in vitro. The actions of KL on the growth of both normal OSE cells and ovarian cancer cells was investigated. KL was found to stimulate the growth of normal OSE cells in a similar manner to epidermal growth factor. Observations demonstrate the production and action of KL by normal OSE cells and ovarian cancer cells. Coexpression of KL and c-kit by normal OSE suggests that KL can act as an autocrine factor for OSE. The local production and action of KL on OSE provides insight into normal OSE biology, and a factor that may be involved in the onset and progression of ovarian cancer.
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PMID:Expression and action of kit ligand/stem cell factor in normal human and bovine ovarian surface epithelium and ovarian cancer. 1081 61

The regulation of biological functions including cell growth, viability, migration, and adhesion of small cell lung cancer (SCLC) cells depends largely on the autocrine or paracrine stimulation of growth factor receptors and chemokine receptors. Stem cell factor (SCF) and its receptor c-Kit have been identified as important regulators of SCLC viability and are coexpressed in approximately 40-70% of SCLC specimens. In vitro, the inhibition of c-Kit tyrosine kinase activity by the small molecule tyrosine kinase inhibitor STI571 (Gleevec) abrogates cell growth. We have investigated the role of c-Kit and chemokine receptors in the regulation of cell migration and adhesion of SCLC cells. CXCR4, the chemokine receptor for stromal cell-derived factor-1alpha (SDF-1alpha), was found to be the major chemokine receptor commonly expressed in all of the 10 SCLC cell lines tested. SCF and SDF-1alpha increased cellular proliferation over a course of 72 h in both the c-Kit- and the CXCR4-positive NCI-H69 SCLC cell line. Recently, SDF-1alpha and CXCR4 have been shown to be important regulators of migration and metastasis in breast and ovarian cancer. We found that SDF-1alpha dramatically increased cell motility and adhesion in CXCR4-expressing NCI-H446 SCLC cells. In addition, SDF-1alpha altered cell morphology with increased formation of filopodia and neurite-like projections. In NCI-H69 SCLC cells, SCF and SDF-1alpha cooperatively induced morphological changes and activated downstream signaling pathways. Treatment of NCI-H69 cells with STI571 specifically inhibited the c-Kit signaling events of Akt and p70 S6 kinase, whereas SDF-1alpha-mediated activation of Akt or p70 S6 kinase was normal. In contrast, the phosphatidylinositol 3-kinase inhibitor, LY294002, prevented these cells from adhering and completely blocked SCF- and/or SDF-1alpha-induced Akt or p70 S6 kinase phosphorylation. These results demonstrate that the CXCR4 receptor is functionally expressed in SCLC cells and may, therefore, be involved in the pathogenesis of SCLC in vivo. Inhibition of both the CXCR4 and the c-Kit downstream events could be a promising therapeutic approach in SCLC.
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PMID:Regulation of cellular proliferation, cytoskeletal function, and signal transduction through CXCR4 and c-Kit in small cell lung cancer cells. 1241 61

KIT ligand (KL) and its receptor, c-kit, are coexpressed in many types of cancer cells and have been implicated in tumor growth and angiogenesis. While Sertoli cell-specific regulation of the KL promoter has been well characterized, regulation in cancer cells remains to be elucidated. We recently reported microarray results demonstrating that increased high-mobility group (HMG) A1a protein expression correlates with increased KL transcription in MCF-7 human breast cancer cells. Sequence analysis indicates a potential for multiple HMGA1 binding sites within the human KL promoter. In order to better define the underlying molecular mechanisms that HMGA1 uses to facilitate malignant transformation of cancer cells, we have used a variety of methods to determine whether HMGA1a directly regulates the human KL promoter in breast and ovarian cancer cells. Our results indicate that: (i) KL promoter activity is significantly higher in MCF-7 cells overexpressing HMGA1a; (ii) HMGA1a protein binds to AT-rich regions of the KL promoter DNA both in vitro and in vivo; (iii) mutation of the AT-rich regions inhibits HMGA1a binding in vitro; and (iv) HMGA1a-specific inhibition significantly decreases transcription of KL in OCC1 human ovarian cancer cells. In addition, MCF-7 cells with transgenic HMGA1 overexpression stained positive for the KL protein by immunocytochemistry and immunohistochemistry, and were growth-inhibited by KL neutralization. The cumulative evidence indicates that HMGA1 positively regulates the human KL promoter in breast and ovarian cancer cells and implicates serum KL as a diagnostic marker for HMGA1-positive carcinomas.
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PMID:Human KIT ligand promoter is positively regulated by HMGA1 in breast and ovarian cancer cells. 1537 28

Most women with epithelial ovarian cancer are diagnosed with advanced disease. Despite surgery and initial tumor reduction by standard chemotherapy, the tumors frequently recur and the patients eventually die of their disease. New drugs that inhibit tyrosine kinase receptors (TKRs) are being investigated for treatment and this study was undertaken to determine the expression and mutational state for 3 TKRs (c-kit, platelet-derived growth factor receptor [PDGFR] alpha, and PDGFR beta) in ovarian cancer. Tissue arrays containing 84 epithelial ovarian tumors were studied by immunohistochemistry with antibodies specific for c-kit, PDGFR alpha, and PDGFR beta. Immunoreactivity was detected in 78% of the tumor to at least one TKR. PDGFR alpha was expressed in the largest percentage of ovarian tumors (58%) whereas 29% expressed PDGFR beta. Two commercial antibodies against c-kit were studied and 33% of the tumors stained with one but only 6% were interpreted as positive with the second antibody. Activation of TKRs may occur through mutations but, by sequence analysis, no mutations were detected in 6 ovarian tumors with elevated immunoreactivity for each of the TKRs (c-kit, PDGFR alpha, and PDGFR beta). Tyrosine kinase receptors could also be activated through autocrine or paracrine stimulation of receptor by its ligand. Of 43 (35%) tumors tested for both c-kit receptor and its ligand (stem cell factor), 15 expressed both proteins indicating the possibility that this autocrine stimulation feedback loop is a factor in the growth of some ovarian cancers. This study demonstrates that PDGFR alpha, PDGFR beta, and c-kit are expressed in a high percentage of epithelial ovarian cancers suggesting that tyrosine kinase inhibitors may be useful in the treatment of these tumors.
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PMID:Expression and mutational analysis of tyrosine kinase receptors c-kit, PDGFRalpha, and PDGFRbeta in ovarian cancers. 1579 68

Imatinib is a selective protein tyrosine kinase inhibitor currently used in the treatment of chronic myeloid leukaemia (CML). It specifically suppresses the growth of bcr-abl expressing CML progenitor cells by blocking the ATP-binding site of the kinase domain of bcr-abl. Imatinib also inhibits the c-abl, platelet derived growth factor receptor (PDGFR), abl-related gene and stem cell factor receptor, c-kit, protein tyrosine kinases. It is through inhibition of c-kit that imatinib is also used clinically in the treatment of gastrointestinal stromal tumours. We have recently demonstrated that imatinib also specifically targets the macrophage colony stimulating factor receptor, c-fms, at therapeutic concentrations. Although this finding has important implications with regard to potential side effects in patients currently receiving imatinib therapy, these results suggest that imatinib may also be useful in the treatment of diseases where c-fms is implicated. This includes breast and ovarian cancer and inflammatory conditions such as rheumatoid arthritis. We also speculate that imatinib may be used in diseases where bone destruction occurs due to excessive osteoclast activity, such as in the haematologic malignancy, multiple myeloma.
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PMID:Inhibition of c-fms by imatinib: expanding the spectrum of treatment. 1591 50

Platinum-resistant ovarian cancer continues to be a difficult therapeutic problem. Clearly, molecularly targeted agents should be evaluated in this patient population. Patients were eligible for this phase II study with stage III or IV ovarian cancer, whose tumor expressed Kit (CD117) or platelet-derived growth factor receptor (PDGFR) and with relapse of measurable disease within 6 months of completing frontline, platinum- and taxane-based chemotherapy. Patients were treated daily with 400 mg of imatinib mesylate orally. It was assumed that the agent would be of no further interest if the population response rate was less than 10%. A two-stage design was used for patient accrual. A total of 34 patients were registered to the study. Of these, 15 were found to be ineligible or not evaluable (8 because their tumor samples were negative for both DC117 and PDGFR). Of 19 evaluable patients, 2 (11%) tested positively for c-Kit and 17 (89%) tested positively for PDGFR. There were no objective responders. Thirteen patients (68%) had increasing disease or symptomatic deterioration, and six (32%) went off protocol during the first month due to adverse events. Median progression-free survival was 2 months (95% CI 1-3 months) and median overall survival was 10 months (95% CI 6-18 months). Eleven percent of patients experienced grade 4 hematologic/metabolic toxicity and 37% experienced grade 3 nonhematologic toxicity. We conclude that imatinib mesylate as a single agent does not appear to have useful clinical activity in c-Kit and/or PDGFR positive, recurrent ovarian cancer in heavily pretreated patients with ovarian cancer.
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PMID:Phase II trial of imatinib mesylate in recurrent, biomarker positive, ovarian cancer (Southwest Oncology Group Protocol S0211). 1734 7

The objective of this study was to identify and characterize a self-renewing subpopulation of human ovarian tumor cells (ovarian cancer-initiating cells, OCICs) fully capable of serial propagation of their original tumor phenotype in animals. Ovarian serous adenocarcinomas were disaggregated and subjected to growth conditions selective for self-renewing, nonadherent spheroids previously shown to derive from tissue stem cells. To affirm the existence of OCICs, xenoengraftment of as few as 100 dissociated spheroid cells allowed full recapitulation of the original tumor (grade 2/grade 3 serous adenocarcinoma), whereas >10(5) unselected cells remained nontumorigenic. Stemness properties of OCICs (under stem cell-selective conditions) were further established by cell proliferation assays and reverse transcription-PCR, demonstrating enhanced chemoresistance to the ovarian cancer chemotherapeutics cisplatin or paclitaxel and up-regulation of stem cell markers (Bmi-1, stem cell factor, Notch-1, Nanog, nestin, ABCG2, and Oct-4) compared with parental tumor cells or OCICs under differentiating conditions. To identify an OCIC cell surface phenotype, spheroid immunostaining showed significant up-regulation of the hyaluronate receptor CD44 and stem cell factor receptor CD117 (c-kit), a tyrosine kinase oncoprotein. Similar to sphere-forming OCICs, injection of only 100 CD44(+)CD117(+) cells could also serially propagate their original tumors, whereas 10(5) CD44(-)CD117(-) cells remained nontumorigenic. Based on these findings, we assert that epithelial ovarian cancers derive from a subpopulation of CD44(+)CD117(+) cells, thus representing a possible therapeutic target for this devastating disease.
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PMID:Identification and characterization of ovarian cancer-initiating cells from primary human tumors. 1851 91

One emerging model for the development of drug-resistant tumors utilizes a pool of self-renewing malignant progenitors known as cancer stem cells (CSCs) or cancer-initiating cells (CICs). The purpose of this study was to propagate such CICs from the ovarian cancer cell line SKOV3. The SKOV3 sphere cells were selected using 40.0 micromol/l cisplatin and 10.0 micromol/l paclitaxel in serum-free culture system supplemented with epidermal growth factor, basic fibroblast growth factor, leukemia inhibitory factor, and insulin or standard serum-containing system. These cells formed non-adherent spheres under drug selection (cisplatin and paclitaxel) and serum-free culture system. The selected sphere cells are more resistant to cisplatin, paclitaxel, adriamycin, and methotrexate. Importantly, the sphere cells have the properties of self-renewal, with high expression of the stem cell genes Nanog, Oct4, sox2, nestin, ABCG2, CD133, and the stem cell factor receptor CD117 (c-kit). Consistently, flow cytometric analysis revealed that the sphere cells have a much higher percentage of CD133(+)/CD117(+)-positive cells (71%) than differentiated cells (33%). Moreover, the SKOV3 sphere cells are more tumorigenic. Furthermore, cDNA microarray and subsequent ontological analyses revealed that a large proportion of the classified genes were related to angiogenesis, extracellular matrix, integrin-mediated signaling pathway, cell adhesion, and cell proliferation. The subpopulation isolation from the SKOV3 cell line under this culture system offers a suitable in vitro model for studying ovarian CSCs in terms of their survival, self-renewal, and chemoresistance, and for developing therapeutic drugs that specifically interfere with ovarian CSCs.
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PMID:Cancer stem-like cells can be isolated with drug selection in human ovarian cancer cell line SKOV3. 2070 81


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