Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1519670 (tumor angiogenesis)
 6,052 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously showed that carboxymethyl benzylamide dextran (CMDB7) prevents tumor growth and tumor angiogenesis by binding to angiogenic growth factors, thereby preventing them from reaching their receptors on tumor or stromal cells (Bagheri-Yarmand et al. Br. J. Cancer, 78: 111-118, 1998; Bagheri-Yarmand et al. Cell Growth Differ., 9: 497-504, 1998). In this study, CMDB7 inhibited neovessel formation within the fibroblast growth factor 2-enriched matrigel in mice, and its anticancer effect was then tested in a metastatic breast cancer model. Human MDA-MB435 cells were injected into the mammary fat pad of nude mice, and breast tumors developed within 1 week; all of the mice had lung metastases at 12 weeks. CMDB7 treatment (50, 150, or 300 s.c. or 300 i.v. mg/kg/week for 10 weeks) reduced the incidence of lung metastases to 12%. Histological analysis showed markedly less tumor neovascularization in the CMDB7-treated mice. Pulmonary metastasis incidence was strongly dependent on the intratumoral neoangiogenesis in primary tumors.
 ...
PMID:Carboxymethyl benzylamide dextran blocks angiogenesis of MDA-MB435 breast carcinoma xenografted in fat pad and its lung metastases in nude mice. 997 89

Angiogenesis is essential for tumor growth and metastasis. There are conflicting reports as to whether microvessel density (IMD) in breast cancers is associated with prognosis. This could be due to the use of different antibodies to endothelial cell markers, variation in tissue pretreatment protocols, and nonstandardized counting methods. We have assessed the IMD in 106 breast carcinomas using a pan-endothelial marker, CD34, and a recently described mAb to CD105, which preferentially reacts with endothelial cell in angiogenic tissues. IMD values (separated as above or below median) for CD105 expression showed a statistically significant correlation with overall (P = 0.0029) and disease-free survival (P = 0.0362). In contrast, blood vessel counts using a panendothelial marker CD34 did not correlate with overall or disease-free survival (P = 0.2912 and P = 03153, respectively). When IMD values were subdivided into quartiles and assessed for their prognostic values, there was a statistically significant difference in the overall survival across CD105, but not CD34, values (P = 0.0017 and P = 0.7997, respectively) and also disease-free survival (P = 0.0431 and P = 0.5066, respectively). Further analysis of IMD values demonstrated that there were no deaths in the lowest quartile for CD105 and it differed from the other three quartiles. However, examination of clinical details of patients in the lowest quartile failed to reveal clustering of patients known to be associated with low-risk factors. Multivariate analysis confirmed that IMD values using CD105 were an independent prognostic factor. These results suggest that the ability to quantitatively distinguish between tumor neovascularization and preexisting vessels may be important in the assessment of tumor angiogenesis, but requires confirmation in a greater number of patients with a longer follow-up.
 ...
PMID:Breast carcinoma: vascular density determined using CD105 antibody correlates with tumor prognosis. 1002 75

Experimental evidence has directly implicated matrix metalloproteinases (MMPs) in the remodeling of the stromal tissue surrounding tumors. Thus, MMP inhibitors could limit the expansion of both neoplastic cell compartment and endothelial cell compartment of a tumor. Much of the work on the role of MMP inhibitors has concentrated on their inhibitory effects on tumor cell invasion. We have examined the effects of a new MMP inhibitor, KB-R7785 (acting on MMP-1, MMP-3, and MMP-9), on tumor angiogenesis and metastasis of murine colon adenocarcinoma (C-26) in two tumor models in BALB/c mice (transparent chamber model and lung colonization model). KB-R7785 has not shown inhibitory effects on in vitro growth of either C-26 or KOP2.16 murine endothelial cells. In vivo, KB-R7785 administrated twice daily for 15 days (100 mg/kg, i.p.), starting the day of tumor inoculation (5 x 10(5) C26 cells) in transparent chamber, has resulted in 88.2% suppression of tumor growth, compared with that in vehicle-administered mice (controls). Tumors grown in controls have doubled their area in 3.3 days, whereas those treated by KB-R7785 progressed almost four times slower (tumor area doubling time, 12 days). KB-R7785 rendered centrally avascular tumors with only a rim of peripheral neovasculature, which had significant lower functional vascular density and vascular area than the corresponding parameters in control tumors 10 days after inoculation [79.9+/-6.7 cm/cm2 versus 164.1+/-10.1 cm/cm2 (P < 0.01) and 19.8+/-1.5% versus 42.6+/-2.7% (P < 0.01), respectively]. In the lung colonization model (tail vein inoculation of 5 x 10(5) C-26 cells), administration of KB-R7785 (100 mg/kg, i.p.) twice daily for 20 days has reduced the number of surface metastasis by 85.8% and abolished the tumor burden, as compared with controls. The few metastatic colonies found in the lungs of KB-R7785 treated mice appeared to be dormant (i.e., staining with von Willebrand factor antibody revealed few, if any, positive cells within the metastatic foci from MMP inhibitor-treated lungs, whereas terminal deoxynucleotidyl transferase-mediated nick end labeling showed a 4-fold increase in the rate of tumor cell apoptosis compared with controls. The fact that KB-R7785 interferes with early steps of angiogenesis and cancer spread suggests that MMP inhibitors may control both primary and secondary tumor growths by limiting the expansion of endothelial cells, as well as cancer cells, composing the tumors.
 ...
PMID:Controlling tumor angiogenesis and metastasis of C26 murine colon adenocarcinoma by a new matrix metalloproteinase inhibitor, KB-R7785, in two tumor models. 1009 56

A semi-synthetic analogue of fumagillin, TNP-470, has been shown to be a potent angiogenesis inhibitor. In this study, we evaluated the anti-tumor efficacy of TNP-470 on rabbits bearing VX2 carcinoma of the tongue, by comparison of topical, intra-tumor (i.t.) injection with systemic, intra-venous (i.v.) administration. The i.t. injection of the angiogenesis inhibitor produced much stronger anti-tumor effects, and almost complete tumor regression was achieved at doses of 10 mg/kg or 20 mg/kg. TNP-470 injected intra-tumorally significantly reduced expression of proliferating cell nuclear antigen (PCNA) and microvessel density in the VX2 carcinoma of the tongue. TNP-470 also halted the tumor-associated neovascularization in the rabbit cornea assay. These data suggest that i.t. injection of TNP-470 effectively inhibits tumor angiogenesis and disrupts microvasculature development, which may suppress tumor growth. In conclusion, the i.t. injection of TNP-470 provided remarkable anti-tumor effects on the VX2 carcinoma of the tongue and is expected to have promising therapeutic uses for oral cancer.
 ...
PMID:Intra-tumor injection of an angiogenesis inhibitor, TNP-470, in rabbits bearing VX2 carcinoma of the tongue. 1010 93

There is considerable controversy concerning the importance of tumor-derived angiogenic factors to the neovascularization of solid tumors. Tumor, endothelial, and stromal expression of vascular endothelial growth factor (VEGF) have been hypothesized to be critical for tumor angiogenesis. To determine the relative contribution of tumor versus nontransformed tissue expression of VEGF to tumor growth, we used gene targeting and cre-loxP recombination to generate embryonic stem cell lines in which VEGF can be conditionally deleted. These lines were used to derive mouse embryonic fibroblast lines with null mutations in both alleles of VEGF. Upon immortalization and H-ras transformation, we used these VEGF null fibroblasts to make fibrosarcomas in immunocompromised mice. We report that tumorigenic VEGF expression is critical for ras-mediated tumorigenesis, and the loss of tumorigenic expression causes dramatic decreases in vascular density and vascular permeability and increases in tumor cell apoptosis.
 ...
PMID:Tumor-derived expression of vascular endothelial growth factor is a critical factor in tumor expansion and vascular function. 1019 34

A number of transgenic animal model systems have addressed the mechanistic role of p53 loss in tumor progression. However, many of these tumor models have analyzed p53 function in the context of other transgenes expressing activated oncogenes or defective tumor suppressor genes generated by gene targeting. To examine the role of p53 loss independent of other exogenous oncogenic influences, we analyzed some of the biological aspects of tumor formation and progression in p53-knockout mice containing a null germline p53 allele. We analyzed tumors from p53-/-, p53+/-, and p53+/+ littermates. Some of the p53+/- tumors had lost the remaining p53 allele (p53+/- loss of heterozygosity), whereas others retained the allele (p53+/-). In this report, we show that loss or absence of p53 conferred a tumor growth advantage by increasing the rate of cellular proliferation in a p53 dosage-dependent manner. The apoptotic levels in tumor tissue were found to be modest and not significantly dependent on p53 status. These results contrast with those from some other p53-deficient tumor models, in which p53 loss was associated with more rapid tumor progression through abrogated apoptosis. Finally, as p53 has been shown to regulate certain angiogenic factors, we examined the levels of angiogenesis in p53-containing and p53-deficient tumors. We found no p53-dependent differences in the levels of tumor angiogenesis measured by intratumoral microvessel density.
 ...
PMID:Increased tumor cell proliferation in murine tumors with decreasing dosage of wild-type p53. 1020 4

Malignant gliomas are a prominent target for cancer gene therapy approaches because of their poor prognosis despite all currently available therapies. Gene therapy strategies developed to interfere with the normal function of vascular endothelial growth factor receptors have been successfully used in different experimental models to block tumor angiogenesis and to inhibit tumor growth. In this study we examined whether retroviruses encoding a mutant VEGF receptor 2 (VEGFR-2) could suppress tumor angiogenesis and thereby prolong the survival of rats bearing syngeneic intracerebral glioma tumors. Survival time of rats with intracerebral tumors was significantly prolonged in a dose-dependent manner when retroviruses carrying a VEGFR-2 mutant were cotransplanted with tumor cells. No effect on survival was observed in rats that received virus-producing cells or virus supernatant intracerebrally after 5 days of tumor injection. In established subcutaneous tumors treatment with multiple injections of virus-producing cells also inhibited tumor growth in a dose-dependent manner. After implantation of tumor cells stably transfected with a truncated form of VEGFR-2, rats exhibited a rate of survival similar to that of animals treated with high numbers of virus-producing cells encoding the truncated form of VEGFR-2. Morphologically, tumors showed signs of impaired angiogenesis, such as extensive necrosis and reduced tumor vascular density. These results suggest a dual mode of function of truncated VEGFR-2, namely dominant-negative inhibition of VEGFR-2 function and VEGF depletion by receptor binding. We further explored the safety of retrovirus-mediated gene transfer. Although virus sequences were found in different tissues after intracerebral injection of virus-producing cells, no morphological changes were observed in any tissue after a follow-up time of 6 months. Our results indicate that VEGFR-2 inhibition is useful for the treatment of malignant gliomas.
 ...
PMID:Antiangiogenic gene therapy in a rat glioma model using a dominant-negative vascular endothelial growth factor receptor 2. 1034 May 44

In current scientific discussion, increasing importance is being given to the clinical significance of the new formation of vessels (angiogenesis) in the course of physiological, inflammatory and neoplastic processes. Angiogenesis is best studied in the growth of malignant tumors, since cancer may be regarded as the most important angiogenesis-dependent disease in terms of social and economic aspects. The significance of angiogenesis in gynecological oncology is as follows: 1) Intratumoral vessel density is an indicator for the emergence and growth of malignant tumours and their precursor lesions, 2) intratumoral vessel density is an independent prognostic factor for solid malignancies and 3) the inhibition of tumor angiogenesis by means of anti-angiogenetic substances causes tumor growth to be suppressed. Angiogenesis also plays an important role in the regulation of the female menstrual cycle. Proliferation of the endometrium and the formation of the corpus luteum in the second half of the menstrual cycle are examples of angiogenesis in the physiological field. The function of angiogenetic factors in the emergence of endometriosis and in female and male infertility are currently under study. In obstetrics, the new formation of blood vessels is significant for the implantation of impregnated blastocysts and for the development and growth of the placenta. Preeclempsia (gestational toxicosis), for instance, is a typical pregnancy-related disease whose pathophysiological mechanism is attributed to a disturbed development and function of small placental vessels. The present paper is an overview of current knowledge and current approaches of research concerning angiogenesis in the field of gynecology and obstetrics. The paper is focused on the clinical significance of angiogenesis.
 ...
PMID:[Angiogenesis in gynecology and obstetrics]. 1035 37

The kinase insert domain-containing receptor (KDR) is the human vascular endothelial growth factor (VEGF) receptor responsible for the mitogenic and angiogenic effects of VEGF. There is much experimental evidence to suggest that the VEGF/KDR pathway plays an important role in tumor angiogenesis, a process essential for tumor growth and metastasis. Here we produced a chimeric anti-KDR antibody (IgG1), c-p1C11, from a single chain (scFv) antibody isolated from a phage display library. C-p1C11 binds specifically to the extracellular domain of soluble as well as cell-surface expressed KDR. It effectively blocks VEGF-KDR interaction and inhibits VEGF-stimulated activation of KDR and MAP kinases p44/p42 of human endothelial cells. Furthermore, c-p1C11 efficiently neutralizes VEGF-induced mitogenesis of human endothelial cells. Our results suggest that antibodies against KDR have potential clinical applications in the treatment of cancer and other diseases where pathological angiogenesis is involved.
 ...
PMID:Inhibition of vascular endothelial growth factor induced mitogenesis of human endothelial cells by a chimeric anti-kinase insert domain-containing receptor antibody. 1035 50

In many cases, solid tumors exhibit numerous and highly permeable blood vessels. For a long time, this observation drew little attention. In the early 70's, however, Folkman proposed for the first time the potential relevance of tumor angiogenesis (formation of new vessels) for tumor growth and metastasis (6). He realized that tumors up to a diameter of 1-2 mm could be nurtured with oxygen and energy simply by diffusion (prevascular phase). Further growth, however, would require newly formed blood vessels. He hypothesized that (assuming the formation of new vessels was essential for tumor growth) pharmacological inhibition of angiogenesis could be developed as a new, more specific form of tumor treatment. In recent years, several groups have investigated the pathophysiology of tumor angiogenesis. Folkman's hypothesis that tumor growth is dependent on the formation of new vessels was supported by several experiments: Implants of different tumors into an avascular cornea initially have a slow growth rate that increases exponentially after infiltration of new vessels into the tumors (9). Inversely, the growth rate of solid tumors decreases with increasing distance to the supplying capillaries (27). The onset of neovascularization at the bases of human melanomas is directly associated with tumor growth and metastasis (25). Experiments with transgenic mice have demonstrated that the transition from hyperplastic to malignant cell growth occurs parallel to the onset of angiogenesis (7). Tumor vessel density has been shown to be associated with tumor progression and the clinical course in many human tumors (e.g. of the breast, lung, colon, cervix, prostate and bladder). Aside from the basic research on the formation of new (tumor) vessels, it is the therapeutic potential of various inhibitors of angiogenesis, some of which are currently tested in clinical (phase I/II) studies, that deserves special scientific attention. This review gives an overview of the relevance of angiogenesis for tumor growth, especially for renal cancers. It also discusses the potential advantages and disadvantages of different anti-angiogenic therapeutic approaches.
 ...
PMID:Pathophysiology of tumor angiogenesis and its relevance in renal cell cancer. 1036 45


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>