Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0178874 (tumor progression)
 40,807 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

TMF/ARA160 is a Golgi resident protein whose cellular functions have not been conclusively revealed. Herein we show that TMF/ARA160 can direct the proteasomal degradation of the key cell growth regulator - Stat3. TMF/ARA160 was dispersed in the cytoplasm of myogenic C2C12 cells that were grown under low-serum conditions. The cytoplasmic distribution of TMF/ARA160 was accompanied by its transient association with the tyrosine kinase Fer and with Stat3, which underwent proteasomal degradation under those conditions. Moreover, serum deprivation induced the association of ubiquitinated proteins, with the TMF/ARA160 complex. However, TMF/ARA160 did not bind Stat1, whose cellular levels were increased in serum-starved C2C12 cells. Amino-acid sequence analysis identified a BC-box element in TMF/ARA160 that mediated the binding of this protein to elongin C. Ectopic expression of TMF/ARA160 in serum-starved C2C12 cells drove the ubiquitination and proteasomal degradation of Stat3, an effect that was not caused by TMF/ARA160 devoid of the BC-box motif. Thus, the Golgi apparatus harbors a novel BC-box-containing protein that can direct Stat3 to proteasomal degradation. Interestingly, the level of TMF/ARA160 was significantly decreased in malignant brain tumors, implying a suppressive role of that protein in tumor progression.
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PMID:TMF/ARA160 is a BC-box-containing protein that mediates the degradation of Stat3. 1546 33

We identify a novel alternative TrkA splice variant, TrkAIII, with deletion of exons 6, 7, and 9 and functional extracellular IG-C1 and N-glycosylation domains, that exhibits expression restricted to undifferentiated early neural progenitors, human neuroblastomas (NBs), and a subset of other neural crest-derived tumors. This NGF-unresponsive isoform is oncogenic in NIH3T3 cells and promotes tumorigenic NB cell behavior in vitro and in vivo (cell survival, xenograft growth, angiogenesis) resulting from spontaneous tyrosine kinase activity and IP3K/Akt/NF-kappaB but not Ras/MAPK signaling. TrkAIII antagonizes NGF/TrkAI signaling, which is responsible for NB growth arrest and differentiation through Ras/MAPK, and its expression is promoted by hypoxia at the expense of NGF-responsive receptors, providing a mechanism for converting NGF/TrkA/Ras/MAPK antioncogenic signals to TrkAIII/IP3K/Akt/NF-kappaB tumor-promoting signals during tumor progression.
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PMID:TrkA alternative splicing: a regulated tumor-promoting switch in human neuroblastoma. 1548 58

Normal and metastatic cells continuously exchange information with the surrounding tissue environment, and this communication governs many aspects of cell behavior. In particular, the physical placement or adhesions of cells within their environment are increasingly understood to facilitate this communication. Classically, cell-cell and cell-extracellular matrix adhesions have been viewed as separable events that are independently controlled. This simple view is changing, as evidence emerges of coordinated regulation of cellular adhesions. Here, we show that the EphA2 tyrosine kinase, which is overexpressed in many aggressive cancers, regulates a fine balance of cell-cell and cell-extracellular matrix adhesions in epithelial cells. EphA2 selectively inhibits cell-cell adhesions by increasing cell attachment and up-regulating the extracellular matrix protein fibronectin. We also show that fibronectin can contribute to important aspects of malignant character. Antibody-based targeting of EphA2 inhibits malignant cell growth by decreasing fibronectin and thereby inducing apoptotic death. Our findings strengthen a concept that cancer progression is regulated by a bidirectional communication between tumor cells and their surrounding microenvironment.
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PMID:EphA2 induction of fibronectin creates a permissive microenvironment for malignant cells. 1549 27

Hepatocellular carcinoma is the fifth leading cause of cancer worldwide and its incidence is increasing. Surveillance programs allow doctors to identify patients at early stages of the disease, when the tumor may be curable by radical treatments such as resection, liver transplantation, or local ablation. In the West, these treatments can be applied to 30% to 40% of patients. Resection yields favorable results in patients with single tumors and a well-preserved liver function (5-year survival rate is 60%). Recurrence complicates two thirds of the cases, and there is no effective adjuvant treatment. Liver transplantation is the best treatment for patients with single tumors that are less than 5 cm in diameter and liver failure, or in those presenting with three nodules less than 3 cm, but organ shortage greatly limits its applicability. Long-term survival is expected to be around 50% to 70% at 5 years depending upon the drop-out rate of patients on the waiting list. Chemoembolization and local ablation are the neo-adjuvant treatments applied to patients on the waiting list to prevent tumor progression; no controlled study proving their efficacy has yet been published. In nonsurgical candidates, percutaneous treatments (ethanol injection or radiofrequency ablation) are the best therapeutic approach and improve survival in Child-Pugh A class patients with small tumors that achieve initial complete response (5-year survival rate is 40% to 50%). At more advanced stages, chemoembolization, a technique combining intra-arterial chemotherapy and selected ischemia, has shown to slightly improve survival in a meta-analysis of randomized trials. No survival advantages have been demonstrated with intra-arterial or systemic chemotherapy, hormonal compounds, or radiation. New agents, such as inhibitors of the tyrosine kinase receptors of growth factors and antiangiogenic agents, are currently being tested in phase II/III trials.
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PMID:Treatment of Hepatocellular Carcinoma. 1552 9

Scatter factor (SF), also known as hepatocyte growth factor, is ubiquitously present in the extracellular matrix of tissues in the form of an inactive precursor (pro-SF). In order to acquire biological activity, pro-SF must be cleaved by specific proteases present on the cell surface. The mature form of SF controls invasive cues in both physiological and pathological processes through activation of its receptor, the Met tyrosine kinase. By substituting a single amino acid in the proteolytic site, we engineered an unprocessable form of pro-SF (uncleavable SF). Using lentivirus vector technology, we achieved local or systemic delivery of uncleavable SF in mice. We provide evidence that (a) uncleavable SF inhibits both protease-mediated pro-SF conversion and active SF-induced Met activation; (b) local expression of uncleavable SF in tumors suppresses tumor growth, impairs tumor angiogenesis, and prevents metastatic dissemination; and (c) systemic expression of uncleavable SF dramatically inhibits the growth of transplanted tumors and abolishes the formation of spontaneous metastases without perturbing vital physiological functions. These data show that proteolytic activation of pro-SF is a limiting step in tumor progression, thus suggesting a new strategy for the treatment or prevention of the malignant conversion of neoplastic lesions.
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PMID:An uncleavable form of pro-scatter factor suppresses tumor growth and dissemination in mice. 1554 93

It is well established that growth factors and their receptors are overexpressed in brain tumors and play a key role in tumor cell proliferation. Glycoconjugate molecules expressed at the plasma membrane of mammalian cells have been also reported to be associated with tumor progression. Growth factor receptors and glycoconjugate molecules are able to interact with each other and this interaction usually results in modulation of growth factor receptor mediated signaling and the biological function of the cell. This review addresses the expression of both growth factor receptors and glycoconjugates molecules in the brain and brain tumors. The mechanism by which these two entities interact with each other and the consequences of their interaction on the biological function of tumor cell are also discussed. Glycoconjugate molecules seems to act more specifically on growth factor receptor signaling pathways than most of tyrosine kinase inhibitors. The use of glycoconjugates or their derivatives may represent a new approach to modulate the proliferative behavior of tumors that overexpress growth factor receptors such as brain tumors.
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PMID:Modulation of Growth Factor response in brain tumors by complex carbohydrates. 1556 57

Cancer growth and progression is often critically influenced by the production of vascular endothelial growth factor (VEGF), a key mediator of angiogenesis. VEGF produced by tumor cells stimulates endothelial cell growth through the binding and activation of the KDR/Flk-1 receptor (VEGFR-2) on endothelial cells. Recently, some human breast cancer epithelial cells have been shown to express VEGF receptors, suggesting a potential autocrine-mediated growth stimulation of a subset of cancers by VEGF. We demonstrate that mammary tumors in the C3(1)/Tag transgenic model express VEGF and VEGF receptors and tumor growth is stimulated by this autocrine mechanism. GW654652, an indazolylpyrimidine, is a VEGFRs tyrosine kinase inhibitor that dramatically reduces both angiogenesis and tumor cell growth in this model, as demonstrated using both in vitro and in vivo assays. GW654652 significantly decreased cell proliferation and induced apoptosis in human umbilical vein endothelial cells and M6 mammary tumor cells derived from C3(1)/Tag (Tag: simian virus 40 T-antigen) transgenic mice. A 75% reduction in VEGF-induced angiogenesis was observed with GW654652 using the chick chorioallantoic membrane assay, whereas GW654652 produced an approximately 85% reduction in angiogenesis as assessed by the Matrigel plug assay. A profound inhibitory effect on tumor growth in the C3(1)/Tag transgenic model of human breast cancer was observed with oral administration of GW654652 as measured by delayed tumor onset, decreased multiplicity, reduced tumor volume, and extended animal survival. The antitumor effects of GW654652 were associated with reduced tumor vascularization and no apparent toxicity. Tumor growth, however, rapidly advanced following cessation of treatment. This is the first demonstration that a VEGF receptor inhibitor, GW654652, has a strong inhibitory effect on angiogenesis and tumor progression in a transgenic model of mammary cancer, suggesting that this is a useful approach for preclinical testing of such agents.
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PMID:Inhibition of VEGF receptors significantly impairs mammary cancer growth in C3(1)/Tag transgenic mice through antiangiogenic and non-antiangiogenic mechanisms. 1559 23

Merkel cell carcinoma (MCC) is an aggressive neuroendocrine tumor of the skin that is associated with a high incidence of recurrence and metastasis. The therapeutic arsenal for this malignancy is limited and once it spreads, there is no effective treatment. c-kit expression has been demonstrated previously in primary MCCs thus raising the possibility of treating MCCs with imatinib mesylate, the tyrosine kinase inhibitor that has shown promise in the management of c-kit expressing tumors. In this study we examine 25 additional primary MCCs and also 6 of their lymph node metastases. Formalin-fixed, paraffin-embedded tissues were stained immunohistochemically with an antibody directed against the KIT receptor. Percentage and intensity of staining were analyzed semiquantitatively using a three-tiered system. Twenty-one of the 25 (84%) primary tumors stained positively for KIT, of which 14 (67%) showed widespread positivity. Five of the 6 lymph nodes (83%) were similarly positive. High mitotic rate and vascular invasion in the primary tumors tended to be associated with prominent staining in the lymph node metastases. No association was found between c-kit expression and outcome. We confirm that the majority of primary MCCs express c-kit and further find that metastases are positive for the KIT receptor as well. Thus, c-kit expression may be an early event in the transformation of MCC, but not a marker for tumor progression.
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PMID:c-kit expression in primary and metastatic merkel cell carcinoma. 1561 26

Malignant gliomas are highly lethal tumors that display striking genetic heterogeneity. Novel therapies that inhibit a single molecular target may slow tumor progression, but tumors are likely not dependent on a signal transduction pathway. Rather, malignant gliomas exhibit sustained mitogenesis and cell growth mediated in part through the effects of receptor tyrosine kinases and the mammalian target of rapamycin (mTOR). AEE788 is a novel orally active tyrosine kinase inhibitor that decreases the kinase activity associated with the epidermal growth factor receptor and, at higher concentrations, the vascular endothelial growth factor receptor 2 (kinase domain region). RAD001 (everolimus) is an orally available mTOR inhibitor structurally related to rapamycin. We hypothesized that combined inhibition of upstream epidermal growth factor receptor and kinase domain region receptors with AEE788 and inhibition of the downstream mTOR pathway with RAD001 would result in increased efficacy against gliomas compared with single-agent therapy. In vitro experiments showed that the combination of AEE788 and RAD001 resulted in increased rates of cell cycle arrest and apoptosis and reduced proliferation more than either agent alone. Combined AEE788 and RAD001 given orally to athymic mice bearing established human malignant glioma tumor xenografts resulted in greater tumor growth inhibition and greater increases in median survival than monotherapy. These studies suggest that simultaneous inhibition of growth factor receptor and mTOR pathways offer increased benefit in glioma therapy.
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PMID:Combination therapy of inhibitors of epidermal growth factor receptor/vascular endothelial growth factor receptor 2 (AEE788) and the mammalian target of rapamycin (RAD001) offers improved glioblastoma tumor growth inhibition. 1565 58

The epidermal growth factor receptor (EGFR) is the prototypical member of the erbB receptor family. The EGFR axis is activated by a variety of ligands that are crucial in the formation and propagation of many tumors, including colorectal cancer, through their effects on cell signaling pathways, cellular proliferation, control of apoptosis, and angiogenesis. The importance of the EGFR axis in tumorigenesis and tumor progression makes it an attractive target for the development of anticancer therapies. A variety of targeting strategies to exploit the role of EGFR in tumors have been employed. The most highly developed of these anti-EGFR approaches are the monoclonal antibodies and the tyrosine kinase inhibitors (TKIs). Clinical evaluations of these compounds have yielded some promising results. The role of the EGFR axis in colorectal cancer formation and progression is reviewed and the clinical development of these anticancer EGFR-targeted drugs is reviewed and updated.
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PMID:The epidermal growth factor receptor as a target for colorectal cancer therapy. 1572 6


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