UMLS:C0178874 - FACTA Search

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Query: UMLS:C0178874 (tumor progression)
40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Increased expression and/or activity of c-Met, the receptor protein tyrosine kinase for hepatocyte growth factor/scatter factor, occurs commonly during colon tumor progression. To examine potential roles for c-Met in promoting metastasis, we compared the colon tumor cell line KM12C with low metastatic potential to the isogenic variants KM,12L4 and KM12SM with high metastatic potential. KM12C cells express c-Met with low levels of tyrosine phosphorylation in the absence of HGF. The high metastatic cells express a c-Met that is constitutively tyrosine phosphorylated, they have increased colony formation, and are minimally responsive to HGF relative to the parental cells. Tyrosine-phosphorylated beta-catenin was constitutively associated with c-Met in the more metastatic cells, but was inducible only after HGF addition in the less metastatic cells. Functions mediated by beta-catenin, including cell-cell adhesion and migration, and activation of the tcf (T-cell factor) family of transcription factors, were also elevated in the more metastatic KM12SM and L4 cells. Furthermore, analysis of the known tcf transcriptional target genes, cyclin D1, c-Myc, and uPAR, demonstrated increased expression in the high metastatic cells, correlating with the levels of tcf activity. Collectively, these results suggest that endogenous activation of c-Met in highly metastatic KM12SM CRC cells results in increased survival and growth under anchorage independent conditions, increased in vitro migration, and elevated levels of tcf target genes. Thus, beta-catenin association with activated c-Met may contribute to a more aggressive liver metastatic phenotype of these cells.
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PMID:Activation of c-Met in colorectal carcinoma cells leads to constitutive association of tyrosine-phosphorylated beta-catenin. 1285 16

Studies on signal transduction pathways have generated various promising molecular targets for therapeutic inhibition in cancer therapy. Receptor tyrosine kinases represent an important class of such therapeutic targets. c-Met is a receptor tyrosine kinase that has been shown to be overexpressed and/or mutated in a variety of malignancies. A number of c-Met activating mutations, many of which are located in the tyrosine kinase domain, have been detected in various solid tumors and have been implicated in invasion and metastasis of tumor cells. It is known that stimulation of c-Met via its natural ligand, hepatocyte growth factor (also known as scatter factor, HGF/SF) results in a plethora of biological and biochemical effects in the cell. Activation of c-Met signaling can lead to scattering, angiogenesis, proliferation, enhanced cell motility, invasion, and eventual metastasis. In this review, the role of c-Met dysregulation in tumor progression and metastasis is discussed in detail with particular emphasis on c-Met mutations. Moreover, we summarize current knowledge on various pathways of c-Met signal transduction, highlighting the central role in the cytoskeletal functions. In this summary is included recent data in our laboratory indicating that phosphorylation of focal adhesion proteins, such as paxillin, p125FAK, and PYK2, occurs in response to c-Met stimulation in lung cancer cells. Most importantly, current data on c-Met suggest that when mutated or overexpressed in malignant cells, c-Met would serve as an important therapeutic target.
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PMID:c-Met: structure, functions and potential for therapeutic inhibition. 1288 8

Although relatively little is known about the molecular mechanisms underlying tumor progression, recently CD44 glycoproteins and the c-Met receptor tyrosine kinase have been identified as potentially important components of the metastatic cascade. CD44 is a family of transmembrane receptors generated from a single gene by alternative splicing and differential glycosylation. Important biological processes involving CD44 glycoproteins include cell adhesion, lymphocyte homing, hematopoiesis, tumor progression and metastasis. The precise mechanism via which CD44 promotes tumorigenesis have not yet been elucidated. We evaluated the expression of adhesion molecule CD44 variant 6 in pulmonary metastases from colorectal carcinomas and its correlation with clinicopathological parameters. Twenty patients were randomly selected from the patients who had undergone a resection of pulmonary metastasis from colorectal cancer. Formalin-fixed, paraffin-embedded archival specimens of tumor tissues and adjacent normal mucosa from these patients were the subjects of the present study. Immunoreactivity for CD44 was quantified. Specimens were considered positive if almost 25% of the neoplastic cells were stained. CD44 v6 expression was related to the interval between colon resection and metastases diagnosis, the number of pulmonary metastases, and the survival after lung resection. No statistical correlation was found between CD44 v6 positivity and disease-free interval after colon resection, number of metastases or 2-year survival after lung resection. Probably CD44 v6 is necessary and sufficient to confer metastatic potential to carcinoma cells increasing the migration capacity and participating in invasion via changes in adhesion to the extracellular ligands, but is not necessary to modify the clinical history of the metastases. Therefore the evaluation of CD44 v6 expression in lung metastases does not influence the therapeutic scheme.
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PMID:Evaluation of CD44 variant 6 expression and clinicopathological factors in pulmonary metastases from colon carcinoma. 1453 11

Matrix metalloproteinases (MMPs) have been implicated in progression of hepatocellular carcinoma (HCC), as have hepatocyte growth factor (HGF) and its c-Met receptor. We investigated regulation of MMP gene expression by HGF in human HCC. Expression of mRNAs encoding MMPs, HGF and c-Met receptor was examined by quantitative reverse transcription-polymerase chain reaction (RT-PCR) in human HCC and in five human HCC cell lines. HCC cells were treated with HGF, and mRNA expression for MMPs and Ets-1 which activates transcription of MMPs was investigated. Ets binding activity was determined by gel mobility shift assay. MMP promoter activities were evaluated by reporter gene assay. Effects of Ets-1 antisense oligonucleotides were also examined. At the mRNA level, MMP-1, -3, -7 as well as c-Met were overexpressed in HCC compared with corresponding nonneoplastic liver tissues, although MMP-2, -9 or HGF were not. HGF dose-dependently induced Ets-1 together with an increased Ets binding activity, followed by transcription of MMP-1, -3, and -7. HGF increased MMP promoter activity, as did cotransfection with Ets-1. Ets-1 antisense oligonucleotide transfection down-regulated the MMP expression, and abolished induction by HGF. In conclusion, certain MMPs and c-Met, overexpressed in HCC cells, are induced by HGF via Ets-1. This pathway may contribute to tumor progression.
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PMID:Induction of multiple matrix metalloproteinase genes in human hepatocellular carcinoma by hepatocyte growth factor via a transcription factor Ets-1. 1466 17

Radiotherapy represents a major treatment option for patients with pancreatic cancer, but recent evidence suggests that radiation can promote invasion and metastasis of cancer cells. Interactions between cancer cells and surrounding stromal cells may play an important role in aggressive tumor progression. In the present study, we investigated the invasive phenotype of pancreatic cancer cells in response to coculture with irradiated fibroblasts. Using in vitro invasion assay, we demonstrated that coculture with nonirradiated fibroblasts significantly increased the invasive ability of pancreatic cancer cells and, surprisingly, the increased invasiveness was further accelerated when they were cocultured with irradiated fibroblasts. The hepatocyte growth factor (HGF) secretion from fibroblasts remained unchanged after irradiation, whereas exposure of pancreatic cancer cells to supernatant from irradiated fibroblasts resulted in increased phosphorylation of c-Met (HGF receptor) and mitogen-activated protein kinase activity, possibly or partially via increased expression of c-Met. We also demonstrated that scattering of pancreatic cancer cells was accelerated by the supernatant from irradiated fibroblasts. The enhanced invasiveness of pancreatic cancer cells induced by coculture with irradiated fibroblasts was completely blocked by NK4, a specific antagonist of HGF. These data suggest that invasive potential of certain pancreatic cancer cells is enhanced by soluble mediator(s) released from irradiated fibroblasts possibly through up-regulation of c-Met expression/phosphorylation and mitogen-activated protein kinase activity in pancreatic cancer cells. Our present findings further support the potential use of NK4 during radiotherapy for patients with pancreatic cancer.
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PMID:Radiation to stromal fibroblasts increases invasiveness of pancreatic cancer cells through tumor-stromal interactions. 1512 62

We used an experimental in vitro model of human ovarian surface epithelium (OSE), the tissue of origin of >90% of ovarian cancers, to more precisely define the contribution of hepatocyte growth factor (HGF) to various OSE phenotypes at different stages of neoplastic progression. Neoplastic transformation of OSE in cultures was achieved by multiple genetic manipulations, resulting in the nontumorigenic line IOSE-29, the tumorigenic IOSE-Ov29, and the tumor-derived, more highly malignant IOSE-Ov29/T4. We demonstrate here that, compared to IOSE-29, IOSE-Ov29 and IOSE-Ov29/T4 exhibited higher levels of the HGF receptor Met and an increasing duration of ERK1/2 activation with malignant progression, in conjunction with other neoplastic properties. HGF activated Met signaling in all lines but elicited different responses: HGF induced cell dispersion (scattering) and collagen gel invasion in IOSE-Ov29 and IOSE-Ov29/T4 but did not alter the growth pattern of IOSE-29. Inhibition with PD98059 and LY294002 independently prevented HGF-induced invasive growth. Furthermore, our results show that HGF-induced invasion can be mediated through a rapamycin-sensitive p70 S6K cascade, which demonstrates that p70S6K can regulate cell motility in addition to its well-established role in protein synthesis. Taken together, our data correlate specific responses to HGF-mediated signaling with specific signaling pathways and with progressive neoplastic changes.
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PMID:Progressive changes in Met-dependent signaling in a human ovarian surface epithelial model of malignant transformation. 1530 91

Neuroblastoma is the most frequent solid childhood malignancy. Despite aggressive therapy, mortality is high due to rapid tumor progression to advanced stages. The molecules and mechanisms underlying poor prognosis are not well understood. Here, we report that cultured human neuroblastoma cells express the hepatocyte growth factor (HGF) and its receptor c-Met. Binding of HGF to c-Met triggers receptor autophosphorylation, indicating functional relevance of this interaction. HGF activates several downstream effectors of c-Met such as the mitogen-activated protein kinases extracellular signal-regulated kinase 1/extracellular signal-regulated kinase 2 and phospholipase C-gamma, whereas signal transducer and activator of transcription 3 is constitutively activated in neuroblastoma cells expressing c-Met. In addition, HGF is able to stimulate expression and proteolytic activity of matrix metalloproteinase-2 and tissue-type plasminogen activator in neuroblastoma cells, thereby promoting degradation of extracellular matrix components. We show that HGF stimulates invasion of neuroblastoma cells in vitro and in vivo, and it promotes the formation of angiogenic neuroblastomas in vivo. These processes can be blocked by specific inhibitors of the mitogen-activated protein kinase cascade, by inhibitors of phospholipase C-gamma, and also by the expression of a dominant negative signal transducer and activator of transcription 3 mutant. Our data provide the first evidence that the HGF/c-Met pathway is essential for invasiveness and malignant progression of human neuroblastomas. They further suggest that specific inhibitors of this pathway may be suitable as therapeutic agents to improve clinical outcome of neuroblastomas.
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PMID:Hepatocyte growth factor/c-Met signaling promotes the progression of experimental human neuroblastomas. 1534 94

Hepatocyte growth factor (HGF), the ligand for the c-met proto-oncogene product, is a multifunctional protein that enhances tumor cell motility, extracellular matrix invasion, and mitogenic or morphogenic activities of various cell types. In this study we examined the expression of the c-Met receptor in human oral squamous cell carcinoma (SCC) in vivo and in vitro to explore its relationship to tumor progression and invasiveness. Biopsy specimens of human oral SCC were immunohistochemically stained for c-Met. Nearly all primary oral SCC lesions and lymph node metastases consistently showed intense staining for c-Met, whereas normal oral mucosa showed faint to negative staining only on basal cells. In a panel of human oral SCC cell lines, we found a strong correlation between the levels of c-Met expression and the cells' response to HGF in motility and invasion assays. Sensitivity to HGF also correlated with the expression of the c-Met 9-kb mRNA. When the non-invasive HOC-605 cell line, which expresses a low level of c-Met receptor, was transfected with an expression plasmid containing human c-met cDNA, the transfectant cells showed motile and invasive responses to HGF. Immunostaining and immunoprecipitation studies demonstrated that E-cadherin and c-Met were physically associated at SCC cell-cell junctions, suggesting a direct role for c-Met in induction of junctional integrity. Importantly, HGF caused a rapid elevation of unbound beta-catenin, suggesting its availability for nuclear signal transduction and triggering of cell motility and invasiveness. Thus, overexpression of c-Met may facilitate disruption of E-cadherin junctions. Collectively, these results suggest that HGF/c-Met signaling is a common event in oral SCC that may trigger phenotype modulation and enhanced invasion and metastasis.
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PMID:Overexpression of c-met in oral SCC promotes hepatocyte growth factor-induced disruption of cadherin junctions and invasion. 1537 30

Tumor cell invasion and metastasis are the hallmark of malignant neoplasm. Despite advances in the management of thyroid carcinoma and other solid tumors, metastasis continues to be the most significant cause in cancer mortality. To gain new insights into this complex process in thyroid carcinoma, we established a thyroid carcinoma cell line (ARO-met2) with high metastatic capacity to the lung by sequential passage of a human anaplastic thyroid cancer cell line (ARO) through the lung of a nude mouse. Global patterns of gene expression were analyzed in cells of the parental ARO and the ARO-met2, using Atlas human cancer 1.2 array with 1176 cancer-related genes. In total, 184 genes were differentially expressed more than 1.5 times, and 64 genes were differentially expressed over two times. Among those 64 genes, 43 were overexpressed, and 21 genes were underexpressed. Many genes whose increased expression was thought to be related to tumor progression were identified, such as c-Met, ezrin, integrin, motility-related protein-1, cadherin, and S100A4. The most highly expressed gene is the S100A4 (8-fold higher than control), which is a member of a small calcium binding protein family and is involved in the cell proliferation and cancer progression. The S100A4 overexpression in the ARO-met2 cells was later confirmed by Northern blot and real-time reverse transcriptase-PCR. Analysis of 49 thyroid tumor specimens by real-time reverse transcriptase-PCR (eight benign goiters, 36 papillary, and five anaplastic carcinomas) revealed that S100A4 overexpression was present in most advanced thyroid carcinomas and lymph node metastases, and was associated with poor prognosis. None of the benign goiters was found to have S100A4 overexpression. These data suggest that S100A4 could be used as a prognostic marker for thyroid carcinoma. Given that S100A4 is involved in tumor progression and metastasis, it may be a potential target for therapeutic intervention.
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PMID:Microarray analysis of metastasis-associated gene expression profiling in a murine model of thyroid carcinoma pulmonary metastasis: identification of S100A4 (Mts1) gene overexpression as a poor prognostic marker for thyroid carcinoma. 1557 71

Some cancers frequently affect the skeleton, and the bone microenvironment supports growth of certain cancer cells. After tumors metastasize to bone, they stimulate osteoclastogenesis and expand in the bone tissue. Hepatocyte growth factor (HGF), which was originally identified as a potent mitogen for hepatocytes, promotes tumor growth, invasion and metastasis. HGF is mainly produced by cells of mesenchymal origin, and osteoblasts/osteocytes and bone marrow stromal cells originate from mesenchymal cells. However, it is not clear what effect HGF has on tumor progression in bone metastasis. In the present study, we investigated the roles of HGF in bone metastasis using the mouse mammary cancer cell line BALB/c-MC. Cancer cells injected into hearts of mice metastasized to bone in their hind limbs. HGF immunoreactivity was detected in the stroma surrounding the tumor nests, and blood vessels expressing CD31 (a marker of endothelial cells) were observed in the HGF-positive area. To identify the cells producing HGF, we measured concentration of HGF in culture media. HGF concentration was elevated in osteoblast cultures (3.13+/-0.25 ng/ml), whereas HGF was undetectable (<0.4 ng/ml) in BALB/c-MC and bone marrow cell cultures. HGF concentration in osteoblast cultures increased 2.5-fold in response to 10(-6) M PGE(2). Addition of HGF to BALB/c-MC cultures caused doubling of the cell number. Moreover, Western blot analysis revealed expression of c-Met/HGF receptor by BALB/c-MC. In the Matrigel invasion chamber assay, addition of HGF to the bottom well increased the rate at which BALB/c-MC invaded the bottom well through the membrane. Furthermore, when osteoblasts were cultured in the bottom well, the number of BALB/c-MC cells that invaded the bottom well through the membrane increased 3.7-fold, compared to assays without osteoblasts. Addition of NK4, an inhibitor of HGF, completely abolished the enhancement of the invasive potential of the BALB/c-MC cells in the presence of osteoblasts. These findings suggest that HGF produced by osteoblasts induces migration of cancer cells from sinusoidal capillaries to bone marrow space and stimulates growth of cancer cells in the bone microenvironment. Thus, osteoblasts appear to promote bone metastasis of some cancers via HGF-c-Met signaling.
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PMID:Involvement of hepatocyte growth factor in the development of bone metastasis of a mouse mammary cancer cell line, BALB/c-MC. 1645 53

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