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

Non-steroidal anti-inflammatory drugs (NSAIDs) and specific inhibitors of cyclooxygenase (COX)-2, are therapeutic groups widely used for the treatment of pain, inflammation and fever. There is growing experimental and clinical evidence indicating NSAIDs and COX-2 inhibitors also have anti-cancer activity. Epidemiological studies have shown that regular use of Aspirin and other NSAIDs reduces the risk of developing cancer, in particular of the colon. Molecular pathology studies have revealed that COX-2 is expressed by cancer cells and cells of the tumor stroma during tumor progression and in response to chemotherapy or radiotherapy. Experimental studies have demonstrated that COX-2 over expression promotes tumorigenesis, and that NSAIDs and COX-2 inhibitors suppress tumorigenesis and tumor progression. Clinical trials have shown that NSAIDs and COX-2 inhibitors suppress colon polyp formation and malignant progression in patients with familial adenomatous polyposis (FAP) syndrome. Recent advances in the understanding of the cellular and molecular mechanisms of the anti-cancer effects of NSAIDs and COX-2 inhibitors have demonstrated that these drugs target both tumor cells and the tumor vasculature. The therapeutic benefits of COX-2 inhibitors in the treatment of human cancer in combination with chemotherapy or radiotherapy are currently being tested in clinical trials. In this article we will review recent advances in the understanding of the anti-tumor mechanisms of these drugs and discuss their potential application in clinical oncology.
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PMID:Non steroidal anti-inflammatory drugs and COX-2 inhibitors as anti-cancer therapeutics: hypes, hopes and reality. 1464 30

Advanced stages of neuroblastoma show increased expression of matrix metalloproteinases MMP-2 and MMP-9, that have been implicated in many steps of tumor progression, suggesting that they play a contributory role. Using pharmacological and genetic approaches, we have examined the role of these MMPs in progression of SK-N-BE (2).10 human neuroblastoma tumors orthotopically xenotransplanted into immunodeficient mice. Mice treated with Prinomastat, a synthetic inhibitor of MMPs, showed an inhibition of tumor cell proliferation in implanted tumors and a prolonged survival (50 versus 39 days in control group, P < 0.035). Treatment with Prinomastat did not affect formation of liver metastases (P = 0.52) but inhibited intravascular colonization by the tumor cells in the lung by 73.8% (P = 0.03) and angiogenesis in both primary tumors and experimental liver metastases. The primary tumors from Prinomastat-treated mice showed a 39.3% reduction in endothelial area detected by PECAM/CD31 staining in tumor sections (P < 0.001), primarily due to the presence of smaller vessels (P = 0.004). MMP-2 is expressed by neuroblastoma tumor cells and stromal cells, whereas MMP-9 is exclusively expressed by stromal cells, particularly vascular cells. To examine the contribution of MMP-9 to tumor angiogenesis, we generated RAG1/MMP-9 double-deficient mice. We observed a significant inhibition of angiogenesis in the immunodeficient RAG1/MMP-9 double-deficient mice orthotopically implanted with tumor cells (P = 0.043) or implanted s.c. with a mixture of tumor cells and Matrigel (P < 0.001). Using an FITC-labeled lectin, we demonstrated an inhibition in the architecture of the tumor vasculature in MMP-9-deficient mice, resulting in fewer and smaller blood vessels. These changes were associated with a 48% decrease in pericytes present along microvessels. Taken together, the data demonstrate that in neuroblastoma, stromally derived MMP-9 contributes to angiogenesis by promoting blood vessel morphogenesis and pericyte recruitment.
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PMID:Stromal matrix metalloproteinase-9 regulates the vascular architecture in neuroblastoma by promoting pericyte recruitment. 1499 27

The microenvironmental physiology of tumors is uniquely different from that of normal tissues. It is characterized, inter alia, by O(2) depletion (hypoxia, anoxia), glucose and energy deprivation, high lactate levels, and extracellular acidosis, parameters that are anisotropically distributed within the tumor mass. This hostile microenvironment is largely dictated by the abnormal tumor vasculature and heterogeneous microcirculation. Hypoxia and other hostile microenvironmental parameters are known to directly or indirectly confer resistance to irradiation leading to treatment failure. Hypoxia directly leads to a reduced "fixation" of radiation-induced DNA damage. Indirect mechanisms include a restrained proliferation, changes in gene expression and alterations of the proteome (eg, elevated activity of DNA-repair enzymes and resistance-related proteins, increased transcription of growth factors), and genomic changes (genomic instability leading to clonal heterogeneity and selection of resistant clonal variants). These changes, caused by the hostile microenvironment, can favor tumor progression and acquired treatment resistance, both resulting in poor clinical outcome and prognosis. Pretreatment assessment of critical microenvironmental parameters is therefore needed to allow the selection of patients who could benefit from special treatment approaches (eg, hypoxia-targeting therapy). Because of a relatively high risk of local relapse or distant metastasis, patients with hypoxic and/or "high-lactate" tumors should undergo close surveillance.
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PMID:Tumor microenvironmental physiology and its implications for radiation oncology. 1525 62

Two of the most promising new targets in the treatment of colorectal cancer are the epithelial growth factor receptor (EGFR) and the vascular endothelial growth factor (VEGF). Agents that inhibit the EGFR or bind to VEGF have demonstrated clinical activity as single agents and in combination with chemotherapy in phase II and phase III clinical trials. The most promising of these agents are cetuximab, which blocks the binding of EGF and transforming growth factor alpha (TGF-alpha) to EGFR, and bevacizumab, which binds free VEGF. Cetuximab and irinotecan have been evaluated in two clinical studies in the USA (IMCL CP02-0141 and IMCL CP02-9923). Study IMCL CP02-0141 evaluated the antitumor activity of single-agent cetuximab in patients with irinotecan-refractory, EGFR-positive metastatic colorectal carcinoma. There were 6 partial responses in 57 treated patients, for a response rate of 10.5%. Study IMCL CP02-9923 evaluated the combination of cetuximab and irinotecan in a total of 139 patients enrolled at 27 study sites. In this trial 22.5% of patients with progressive disease on irinotecan achieved an objective response (19% by investigator assessment) showing that the combination of cetuximab and irinotecan has antitumor activity in this population. A large randomized phase II trial evaluating similar study populations in Europe confirmed these findings, demonstrating response rates for cetuximab/irinotecan and cetuximab alone of 22.9% and 10.8%, respectively. The other promising agent bevacizumab is a humanized variant of the anti-VEGF monoclonal antibody. VEGF is produced by healthy and neoplastic cells. Its activities are mediated by two receptor tyrosine kinases. VEGF signaling is often a rate-limiting step in physiologic and pathologic angiogenesis. Bevacizumab has been studied as an antiangiogenic cancer therapeutic as a single agent and in combination with chemotherapy in patients with stage III and IV colon cancer. In addition to its direct antiangiogenic effects, bevacizumab may allow more efficient delivery of chemotherapy by altering tumor vasculature and decreasing the elevated interstitial pressure common in tumors. In this regard, some of the most robust phase II data using bevacizumab are from a randomized study of chemotherapy [fluorouracil (5-FU) and leucovorin (LV)] with or without bevacizumab in metastatic colorectal cancer. In this study, treatment with bevacizumab plus 5-FU/LV resulted in higher response rates, longer median time to disease progression, and longer median survival. Recently, a phase III, multicenter, double-blind, randomized, placebo-controlled trial was designed to investigate the addition of bevacizumab to first-line irinotecan, 5-FU, and LV chemotherapy (IFL). The trial showed a higher response rate, longer time to tumor progression, and prolonged overall survival in patients with metastatic colorectal cancer. It was the first large, randomized, phase III survival trial to assess the importance of targeting VEGF and tumor angiogenesis for the treatment of human cancer. Integration of novel agents targeting VEGF and EGFR with irinotecan-based chemotherapy has shown clinical activity in patients with metastatic colorectal cancer. The goal in the future will be to predict which specific chemotherapy and targeted agent combination will most likely benefit individual patients.
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PMID:Integration of novel agents in the treatment of colorectal cancer. 1530 12

Eph receptors are a unique family of receptor tyrosine kinases (RTK) that play critical roles in embryonic patterning, neuronal targeting, and vascular development during embryogenesis. In adults, Eph RTKs and their ligands, the ephrins, are frequently overexpressed in a variety of cancers and tumor cell lines, including breast, prostate, non-small cell lung and colon cancers, melanomas, and neuroblastomas. Unlike traditional oncogenes that often function only in tumor cells, recent data show that Eph receptors mediate cell-cell interaction both in tumor cells and in tumor microenvironment, namely the tumor stroma and tumor vasculature. As such, Eph RTKs represent attractive potential targets for drug design, as targeting these molecules could attack several aspects of tumor progression simultaneously. This review will focus on recent advances in dissecting the role of Eph RTKs in tumor cells, tumor angiogenesis, and possible contribution to trafficking of inflammatory cells in cancer.
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PMID:Eph receptor tyrosine kinases in tumor and tumor microenvironment. 1554 26

Particularly interesting new cysteine-histidine-rich protein (PINCH), a LIM domain adapter protein that functions in the integrin and growth factor signal transduction pathway, is upregulated in stroma associated with many common cancers. The finding suggested that PINCH may be involved in promoting tumor-stromal interactions that support tumor progression, and, if so, tumors with abundant PINCH stromal staining may have a worse prognosis. To test this hypothesis, 174 primary colorectal adenocarcinomas with 39 distant normal mucosa samples and 26 metastases in the lymph nodes were studied by immunohistochemistry, and 7 additional colon tumors were studied by Western blot analysis and immunofluorescence. The abundance of PINCH protein in stroma increased from normal mucosa to primary tumor to metastasis (P <.05), and was more intense at the invasive margin than it was in the intratumoral stroma. Strong stromal immunostaining for PINCH was shown to predict a worse outcome (rate ratio 2.1, 95% CI 1.16-3.37, P=.01), independent of Dukes stage, growth pattern, and tumor differentiation. PINCH was detected in fibroblasts, myofibroblasts, and a proportion of endothelial cells of the tumor vasculature, supporting the involvement of PINCH in promoting tumor-stromal interactions that support tumor progression. Interestingly, stromal staining for PINCH was an independent prognostic indicator in colorectal cancer.
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PMID:Stromal staining for PINCH is an independent prognostic indicator in colorectal cancer. 1572 Aug 6

The contribution of the tumor stroma to cancer progression has been increasingly recognized. We had previously shown that in human neuroblastoma tumors orthotopically implanted in immunodeficient mice, stromal-derived matrix metalloproteinase-9 (MMP-9) contributes to the formation of a mature vasculature by promoting pericyte recruitment along endothelial cells. Here we show that MMP-9 is predominantly expressed by bone marrow-derived CD45-positive leukocytes. Using a series of bone marrow transplantation experiments in MMP-9(+/+) and MMP-9(-/-) mice xenotransplanted with human neuroblastoma tumors, we show that bone marrow-derived MMP-9 is critical for the recruitment of leukocytes from bone marrow into the tumor stroma and for the integration of bone marrow-derived endothelial cells into the tumor vasculature. Expression of MMP-9 by bone marrow-derived cells in the tumor stroma is also critical for the formation of a mature vasculature and coverage of endothelial cells with pericytes. Furthermore, in primary human neuroblastoma tumor specimens of unfavorable histology, we observed a higher level of tumor infiltration with MMP-9 expressing phagocytic cells and a higher degree of coverage of endothelial cells by pericytes when compared with tumor specimens with a favorable histology. Taken together, the data show that in neuroblastoma, MMP-9 plays a critical role in the recruitment of bone marrow-derived cells to the tumor microenvironment where they positively contribute to angiogenesis and tumor progression.
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PMID:The contribution of bone marrow-derived cells to the tumor vasculature in neuroblastoma is matrix metalloproteinase-9 dependent. 1583 51

Eph receptors are a unique family of receptor tyrosine kinases (RTK) that play critical roles in embryonic patterning, neuronal targeting, and vascular development during normal embryogenesis. Eph RTKs and their ligands, the ephrins, are also frequently overexpressed in a variety of cancers and tumor cell lines. In particular, one family member, EphA2, is overexpressed in breast, prostate, lung, and colon cancers. Unlike traditional oncogenes that often function only in tumor cells, recent data show that Eph receptors mediate cell-cell interactions both in tumor cells and in the tumor microenvironment, namely the tumor stroma and tumor vasculature. Thus, EphA2 receptors are attractive targets for drug design, as targeting these molecules could simultaneously inhibit several aspects of tumor progression. This review focuses on the multiple roles of EphA2 in cancer progression, the mechanisms by which EphA2 inhibition may halt this progression, and the pre-clinical results of EphA2 inhibition in various cancer model systems.
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PMID:EphA2 receptor tyrosine kinase as a promising target for cancer therapeutics. 1589 16

Therapeutic targeting of the tumor vasculature that destroys preexisting blood vessels of the tumor and antiangiogenesis therapy capitalize on the requirement of tumor cells on an intact vascular supply for oxygen and nutrients for growth, expansion and metastasis to the distal organs. Whereas these classes of agents show promise in delaying tumor progression, they also create glucose and oxygen deprivation conditions within the tumor that could trigger unintended prosurvival responses. The glucose-regulated protein GRP78, a major endoplasmic reticulum chaperone, is inducible by severe glucose depletion, anoxia, and acidosis. Here we report that in a xenograft model of human breast cancer, treatment with the vascular targeting agent, combretastatin A4P, or the antiangiogenic agent, contortrostatin, promotes transcriptional activation of the Grp78 promoter and elevation of GRP78 protein in surviving tumor cells. We further show that GRP78 is overexpressed in a panel of human breast cancer cells that has developed resistance to a variety of drug treatment regimens. Suppression of GRP78 through the use of lentiviral vector expressing small interfering RNA sensitizes human breast cancer cells to etoposide-mediated cell death. Our studies imply that antivascular and antiangiogenesis therapy that results in severe glucose and oxygen deprivation will induce GRP78 expression that could lead to drug resistance.
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PMID:Vascular targeting and antiangiogenesis agents induce drug resistance effector GRP78 within the tumor microenvironment. 1599 54

Neovascularization is an early and critical step in tumor development and progression. Tumor vessels are distinct from their normal counterparts morphologically as well as at a molecular level. Recent studies on factors involved in tumor vascular development have identified new therapeutic targets for inhibiting tumor neovascularization and thus tumor progression. However, the process of tumor blood vessel formation is complex, and each tumor exhibits unique features in its vasculature. An understanding of the relative contribution of various pathways in the development of tumor vasculature is critical for developing effective and selective therapeutic approaches. Several such agents are currently in clinical trials, and many others are under development. In this review, the mechanisms and factors involved in tumor blood vessel formation are discussed. In addition, selected novel classes of antivascular therapies, including those targeting tumor endothelial cells and other components of the tumor vasculature, are summarized.
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PMID:The merits of vascular targeting for gynecologic malignancies. 1622 81


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