Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1658953 (tumor vasculature)
 2,390 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunization against angiogenic-associated antigens selectively expressed on tumor vasculature provides for a novel strategy to block tumor growth. The feasibility of this approach has recently been borne out in several reports demonstrating that the protein or DNA of angiogenic molecules, such as VEGF-R2, can be used as vaccines to generate an effective cytotoxic T cell and antibody response against tumor vessels, thereby blocking tumor growth and metastasis.
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PMID:Vaccination against tumor neovascularization: Promise and reality. 1249 9

Angiogenesis is required for invasive tumor growth and metastasis and constitutes an important point in the control of cancer progression. Its inhibition may be a valuable new approach to cancer therapy. Avascular tumors are severely restricted in their growth potential because of the lack of a blood supply. For tumors to develop in size and metastatic potential they must make an "angiogenic switch" through perturbing the local balance of proangiogenic and antiangiogenic factors. Frequently, tumors overexpress proangiogenic factors, such as vascular endothelial growth factor, allowing them to make this angiogenic switch. Two strategies used in the development of antiangiogenic agents involve the inhibition of proangiogenic factors (eg, anti-vascular endothelial growth factor monoclonal antibodies) as well as therapy with endogenous inhibitors of angiogenesis, such as endostatin and angiostatin. Therapy with endogenous angiogenic inhibitors such as endostatin and angiostatin may reverse the angiogenic switch preventing growth of tumor vasculature. Preclinical studies have shown that endostatin effectively inhibits tumor growth and shrinks existing tumor blood vessels. Phase 1 clinical trials of endostatin and angiostatin are ongoing, and preliminary results show minimal toxicities.
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PMID:Role of angiogenesis in tumor growth and metastasis. 1251 34

Angiogenic activity and formation of a vascular network facilitate tumor perfusion and play a critical role in tumor growth and metastasis. Tumor vasculature may be visualized by means of parametric imaging of specific morphological and physiological characteristics that collectively describe its properties. In this review, we describe advanced magnetic resonance imaging (MRI) techniques that have been developed in order to image and quantify the distribution of tumor vasculature throughout the tumor and characterize its function. These techniques have been used to monitor changes in the magnetic resonance signal intensity of tissue water hydrogens generated by intrinsic effects, as well as by exogenous contrast agents administered into the blood circulation. We further describe specific applications of magnetic resonance imaging using a contrast agent, gadolinium diethylene triamine penta-acetic acid (GdDTPA), which has long been approved for clinical use. Examples include studies of the vascular properties of breast cancer tumors and metastases in animal models, as well as of breast cancer vasculature in patients. We also discuss the use of MRI to improve breast cancer diagnosis in humans by quantifying the permeability of the tumor vasculature. By maximizing the spatial resolution of the images in both animal and human studies, the capacity of magnetic resonance imaging to enhance our understanding of the processes regulating tumor angiogenesis, and improve the diagnosis of cancer, could be clearly demonstrated.
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PMID:Magnetic resonance imaging of tumor vasculature. 1254 Sep 50

Vascular endothelial growth factor (VEGF) is a primary stimulant of tumor angiogenesis. We previously raised a neutralizing anti-VEGF monoclonal antibody 2C3 that blocks the interaction of VEGF with VEGFR2 (KDR/Flk-1) but not with VEGFRI (FLT-1/flt-1). Here, we describe the therapeutic effects of 2C3 on tumor growth in an orthotopic model of MDA-MB-231 human breast carcinoma implanted in the mammary fat pads (MFP) of nude mice. Administration of 2C3 to mice with 100-150 mm3 tumors inhibited tumor growth by 75%, as compared to recipients of the isotype-matched irrelevant control IgG, C44. Treatment with 2C3 also inhibited the establishment of tumor colonies and reduced tumor burden in the lungs of mice injected intravenously with MDA-MB-231 cells. No toxicity was observed in these studies. The mean microvascular density (MVD) of tumors in 2C3-treated mice was 55 +/- 5 per mm2, as compared to 188 +/- 5 per mm2 in the C44-treated control group. The decrease in MVD closely correlated with the degree of inhibition of tumor growth. Treated tumors mostly contained mid-size and large vessels. Microvessels were mainly confined to the peripheral layer of tumor that bordered on the normal MFP epithelium. Tumor vessels had decreased expression of VEGFR2, indicating that neutralization of tumor-derived VEGF by 2C3 down-regulates the expression of VEGFR2 on tumor vasculature. This, in turn, may limit reinitiation of angiogenesis by either tumor-derived or stromal VEGF. These findings suggest that 2C3 is a candidate for treating primary cancer and for preventing the outgrowth of tumor metastases in cancer patients.
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PMID:A monoclonal antibody that blocks VEGF binding to VEGFR2 (KDR/Flk-1) inhibits vascular expression of Flk-1 and tumor growth in an orthotopic human breast cancer model. 1254 58

Anaplastic thyroid carcinoma (ATC) is a fatal malignancy the clinical outcome of which is unaltered by current therapeutic modalities. A recent phase 1 clinical trial of combretastatin A4 phosphate (CA4P) produced a long-lasting total remission in a patient with ATC. CA4P is a tubulin-binding agent derived from the African bush willow, Combretum caffrum, which possesses tumor vascular-targeting activity. In order to discriminate primary antineoplastic effects from tumor antivascular activity, we evaluated CA4P cytotoxicity in eight human ATC cell lines and compared it to paclitaxel, another tubulin-binding agent with significant clinical activity. CA4P displayed significant cytotoxicity against the ATC cell lines, comparable to that of paclitaxel, and these effects were longer lasting in two cell lines compared to the duration of paclitaxel. We further investigated the effects of CA4P on xenograft tumors from four ATC cell lines injected in athymic nude mice. Significantly lower tumor weights were observed in animals treated with CA4P compared to those treated with vehicle alone. Continuous monitoring of xenograft tumor volumes from one of the ATC cell lines also revealed a significantly lower rate of tumor growth in the CA4P-treated mice compared to those receiving vehicle alone. These results suggest that antitumoral effects of CA4P can be consequent to a combination of primary antineoplastic effects as well as the potential destruction of tumor vasculature.
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PMID:Combretastatin A4 phosphate has primary antineoplastic activity against human anaplastic thyroid carcinoma cell lines and xenograft tumors. 1259 19

The goal of our study was to raise monoclonal antibodies (mAbs) against endothelial cell-surface proteins specific for tumor vasculature. Here, we describe the generation and intensive characterization of mAb AA98, including its functional properties and its antigen identification. In our study, an enhanced mAb AA98 immunoreactivity was observed on stimulated human umbilical vein endothelial cells (HUVECs). In addition, mAb AA98 showed remarkably restricted immunoreactivity against intratumoral neovasculature compared with blood vessels of normal tissues. We identified the AA98 antigen as human CD146, an adhesion molecule belonging to the immunoglobulin superfamily. Data from in vitro experiments imply structural and signaling functions for endothelial CD146; however, the role of CD146 in vivo is largely unknown. Here, we show that mAb AA98 displays antiangiogenic properties in vitro and in vivo. Proliferation and migration of HUVECs were inhibited by mAb AA98 as was angiogenesis in chicken chorioallantoic membrane (CAM) assays and tumor growth in 3 xenografted human tumor models in mice. Our data provide new insights into the function of CD146 on endothelial cells, validate CD146 as a novel target for antiangiogenic agents, and demonstrate that mAb AA98 has potential as a diagnostic and therapeutic agent in vascular and cancer biology.
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PMID:A novel anti-CD146 monoclonal antibody, AA98, inhibits angiogenesis and tumor growth. 1260 48

Hyperthermia (HT) associated with radiotherapy or chemotherapy is a promising method for cancer treatment, although the molecular mechanisms of this process are not well understood. HT exhibits various antitumor effects, including damage of tumor vasculature. Here, we investigate the effect of HT on in vitro and in vivo angiogenesis. We show that heat treatment of endothelial cells (ECs) affect their differentiation into capillary-like structures in two models of in vitro angiogenesis. Furthermore, the formation of new vessels promoted by angiogenic inducers in the chick embryo chorioallantoic membrane assay is impaired after heat treatment. These effects cannot be explained by direct cytotoxicity but are dependent on modulation of angiogenesis-involved genes. Gene expression profile of ECs subjected to heat shock demonstrates that plasminogen activator inhibitor 1 (PAI-1), a protein involved in the control of extracellular matrix degradation, is specifically up-regulated. The use of anti-PAI-1-neutralizing antibodies reverts the effect of HT on the in vitro EC morphogenesis and in vivo vessel formation. Moreover, microvessel outgrowth from PAI-1(-/-) aortic rings was not affected by HT compared with aortic rings from PAI-1(+/+) mice. Heat treatment of murine mammary adenocarcinomas results in inhibition of tumor growth, associated with a reduction of microvessel number and an increase of PAI-1 expression. These results indicate that heat-mediated PAI-1 induction is an important pathway by which HT exerts its antitumor activity and may represent a rationale for a combined cancer therapy based on HT associated with antiangiogenic molecules.
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PMID:Hyperthermia inhibits angiogenesis by a plasminogen activator inhibitor 1-dependent mechanism. 1267 Aug 96

Both enhanced vascular permeability and angiogenesis of tumor sustain rapid growth of tumor involving many vascular mediators and high vascular density. On the contrary, however, they can be utilized for macromolecular drug delivery to tumor. Impaired reticuloendothelial/lymphatic clearance of macromolecules from the tumor, or lack of such clearance, is another unique characteristic of tumor tissue, which results intratumor retention of macromolecular drugs thus delivered (Figure 1). Consequently, enhanced permeability and retention (EPR) effect is the basis for the selective targeting of macromolecular drugs to tumor, and the EPR concept is now utilized for selective delivery of many macromolecular anticancer agents in aqueous formation for i.v. or i.a. as well as oily formation for i.a. dosing, which is not possible for low-molecular-weight drugs because of rapid washout by capillary vascular blood flow. This EPR concept has been validated in clinical settings with hepatoma and other solid tumors. In our laboratories, several promising macromolecular anticancer drugs after SMANCS, such as PEG-XO, PEG-DAO, PEG-ZnPP, were developed, warranting further investigation for clinical application. More efficient drug delivery to tumor, especially of macromolecular drugs, may be possible by enhancing the EPR effect with the use of various vascular permeability mediators or potentiators. Suppression of the EPR effect by the use of appropriate inhibitors or antidotes, such as the bradykinin antagonist HOE 140 and protease inhibitors or NOS inhibitors, may also be possible. Thus, one may be able to suppress or retard tumor growth and tumor metastasis. Also, by suppressing vascular permeability with antidotes such as the bradykinin antagonist HOE 140, pleural fluid in lung cancer and ascitic fluid in abdominal carcinomatosis may be controlled and the clinical course of cancer patients may be improved. In summary, tumor vasculature can be an excellent target for delivery of macromolecular anticancer drugs; the most beneficial class of drugs in view of tumor-selective targeting based on the EPR effect in solid tumor as well as compliance of patients and ultimate therapeutic efficacy.
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PMID:Factors and mechanism of "EPR" effect and the enhanced antitumor effects of macromolecular drugs including SMANCS. 1267 6

Targeting of tumor vasculature is a promising strategy for cancer treatment. Among endothelial cell markers, Endoglin, a cell membrane glycoprotein, is emerging as an attractive therapeutic target on angiogenetic blood vessels, and it currently represents a powerful marker to quantify tumor angiogenesis. In normal human tissues, Endoglin is weakly expressed on erytroid precursors, stromal cells and activated monocytes, whereas it is strongly expressed on proliferating endothelial cells. In human neoplasias of different histotype, Endoglin is mainly present on endothelial cells of both peri- and intra-tumoral blood vessels, while it is weakly expressed or absent on neoplastic cells. Endoglin is an accessory component of the receptor complex of Transforming Growth Factor (TGF)-beta, a pleiotropic cytokine that modulates angiogenesis by the regulation of different cellular functions including proliferation, differentiation and migration. Interestingly, the over-expression of Endoglin antagonizes several cellular responses to TGF-beta1, while its down-regulation potentiates cellular responses to TGF-beta1. In animal models, administration of radiolabeled anti-Endoglin monoclonal antibodies (mAb) efficiently images primary tumors, and naked or conjugated anti-Endoglin mAb suppress angiogenesis and tumor growth. In this review we will summarize the complex of experimental evidences pointing to Endoglin as a vascular target to design innovative bioimmunotherapeutic strategies in human neoplasias.
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PMID:Endoglin (CD105): a target for anti-angiogenetic cancer therapy. 1269 49

The systemic administration of endogenous inhibitors significantly reduced the growth of human glioma in vivo, but required the production of a large amount of biologically active protein. In this study we reduced the amount of protein needed and optimized the therapeutical response by delivering the endogenous inhibitors locally into the brain by osmotic minipumps. Human hemopexin fragment of MMP-2 or COOH-terminal fragment of platelet factor-4 were delivered locally and continuously into the brain of mice implanted intracranially with glioma cells, by osmotic minipumps connected to an intracranial catheter. Local delivery of human hemopexin fragment of MMP-2 and COOH-terminal fragment of platelet factor-4 significantly inhibited the growth of well-established malignant glioma in nude and BALB/C mice. When the inhibitors were given at the same concentration, the efficacy of the local delivery was much higher than that reached with the systemic administration, both when the inhibitor was administered daily or continuously by s.c. minipumps. Moreover, the local delivery reduced the amount of protein needed to reach a significant therapeutic response. Intracerebral delivery maintained a long-term control of glioma growth and inhibited glioma recurrence in a surgical resection model. Treatment showed no side effects. Histochemical analysis of tumors showed that the tumor growth inhibition was the result of a decrease in tumor vasculature and a change in tumor vessel morphology. Our data demonstrate that local intracerebral delivery of endogenous inhibitors effectively inhibits malignant glioma growth and reduces the amount of protein needed to reach a therapeutical response.
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PMID:Local intracerebral delivery of endogenous inhibitors by osmotic minipumps effectively suppresses glioma growth in vivo. 1275 Feb 72


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