Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0699790 (colon cancer)
 28,837 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Arg-Gly-Asp (RGD)-containing peptide is a ligand for integrin alpha(V)beta3 and acts as an angiogenic inhibitor. A novel cyclic RGD peptide, cyclo(-RGDf==V-) (f==V), was synthesized and its biological activities were characterized and compared with its analogs, cyclo(-RGDfV-) (fV) and cyclo(-RGDf-MeV-) (fMeV). It bound to integrin alpha(V)beta3 with almost the same affinity as the fV and fMeV analogs. All three compounds inhibited the adhesion and growth of HUVEC cells in a dose-dependent manner in vitro. Out of three, fMeV had the strongest effect, f==V was almost as strong as fMeV, and fV had the least effect. However, in vivo, f==V significantly decreased the intratumoral microvessel density (MVD) in the DLD-1 (human colon cancer cell) inoculated mice, while fMeV had little effect. These results suggest the potential usefulness of the cyclo(-RGDf==V-) as an antiangiogenic agent for clinical use in the future.
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PMID:A novel synthetic Arg-Gly-Asp-containing peptide cyclo(-RGDf==V-) is the potent inhibitor of angiogenesis. 1167 1

Angiostatin (AS) is a potent antiangiogenic agent which inhibits tumor growth through specific action on proliferating endothelial cells. Imaging of radiolabeled AS would enhance our knowledge on the pharmacokinetics of AS and might provide useful information relating to tumor neovasculature. We therefore investigated the potential of radiolabeled AS as a novel tumor imaging agent. Human angiostatin was radioiodine labeled using the lactoperoxidase method. Competition binding studies showed a dose-dependent inhibition of (125)I-AS binding to endothelial cells by excess unlabeled AS, and a displacement curve demonstrated that specific binding was dose dependent and saturable, with a K(d) value of 169 n M. Gel analysis showed that (125)I-AS remained stable in serum for up to 24 h without significant degradation. Intravenously injected (125)I-AS in rats was cleared from the blood in an exponential fashion. Biodistribution data from human colon cancer-bearing Balb/C nude mice showed high uptake in the kidneys, stomach, liver, and lungs. Tumor uptake was 3.2+/-0.7, 2.6+/-0.2, and 1.7+/-0.2%ID/g at 2, 4, and 9 h after injection, respectively. Tumor to muscle count ratio increased from 3.1+/-0.5 at 2 h to 4.4+/-0.5 at 9 h. Serial scintigraphy from 1 to 5 h after (123)I-AS injection demonstrated high uptake in the kidneys and bladder, consistent with renal excretion. There was clear demarcation of tumor by 1 h, with gradual increase in contrast over time (4-h tumor to contralateral thigh ratio =4.7+/-1.1). Thus, radioiodine-labeled angiostatin binds specifically to endothelial cells and has potential as a novel tumor imaging agent.
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PMID:Specific endothelial binding and tumor uptake of radiolabeled angiostatin. 1255 52

Endostatin has been considered a highly specific inhibitor of endothelial cell proliferation and/or migration. To explore the use of endostatin in antiangiogenic gene therapy, we generated a recombinant adenovirus, AdEndo, carrying the gene for mouse endostatin. Injection of 10(9) PFU of AdEndo resulted in a low but significant suppression (25%) of preestablished tumor growth in murine models involving murine Lewis lung carcinoma (LLC) and human breast cancer MDA-MB-231 tumors. Greater anticancer activity was observed when the same dose of AdEndo was injected into two other preestablished murine models involving C51 murine colon cancer and HT29 human colon cancer (55 and 47% tumor growth reduction, respectively). In vitro, endostatin derived from AdEndo-infected MRC-5 fibroblasts inhibited the growth of C51 and HT29 cell lines (72 and 61%, respectively). The extent of this inhibition was comparable to that observed in endothelial cells: 75% for microcapillary endothelial cell line HMEC-1, 52% for human dermal microvascular endothelial cells, 46% for human umbilical vein endothelial cells, and 67% for calf pulmonary arterial endothelial cells. Both endothelial and colon cancer cells showed a clear increase in cell apoptosis (4- to 5-fold for endothelial cells and 5- to 10-fold for colon cancer cells) and an accumulation in the G(1) phase of the cell cycle. This antiproliferative activity was not observed in other tumor cell lines: LLC, MDA-MB-231, murine colon adenocarcinoma MC38, human prostate cancer cell line DU145, and human breast cancer cell line CAL51. Taken together, these results provide evidence that, in addition to its antiangiogenic activity, endostatin exerts a direct anticancer action that appears to be restricted to some tumor cell lines. Thus, endostatin could be used in some colon cancer treatments and its clinical efficacy would depend on the response of tumor cells themselves.
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PMID:Endostatin exhibits a direct antitumor effect in addition to its antiangiogenic activity in colon cancer cells. 1286 17

Angiogenesis, the formation of new capillary blood vessels, is a fundamental process essential for reproduction and embryonic development. It is crucial to the healing of tissue injury because it provides essential oxygen and nutrients to the healing site. Angiogenesis is also required for cancer growth and progression since tumor growth requires an increased nutrient and oxygen supply. Nonsteroidal anti-inflammatory drugs (NSAIDs) are the most widely used drugs worldwide for treating pain, arthritis, cardiovascular diseases, and more recently for colon cancer prevention. However, NSAIDs produce gastrointestinal ulcers and delay ulcer healing. Recently NSAIDs have been demonstrated to inhibit angiogenesis, but the underlying mechanisms are only beginning to be elucidated. The inhibition of angiogenesis by NSAIDs is a causal factor in the delay of ulcer healing, and it is becoming clear that this is also likely to be one of the mechanisms by which NSAIDs can reduce or prevent cancer growth. Based on the experimental data and the literature, the mechanisms by which NSAIDs inhibit angiogenesis appear to be multifactorial and likely include local changes in angiogenic growth factor expression, alteration in key regulators and mediators of vascular endothelial growth factor (VEGF), increased endothelial cell apoptosis, inhibition of endothelial cell migration, recruitment of inflammatory cells and platelets, and/or thromboxane A2 mediated effects. Some of these mechanisms include: inhibition of mitogen-activated protein (Erk2) kinase activity; suppression of cell cycle proteins; inhibition of early growth response (Egr-1) gene activation; interference with hypoxia inducible factor 1 and VEGF gene activation; increased production of the angiogenesis inhibitor, endostatin; inhibition of endothelial cell proliferation, migration, and spreading; and induction of endothelial apoptosis.
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PMID:Inhibition of angiogenesis by NSAIDs: molecular mechanisms and clinical implications. 1367 97

Chemotherapy for the treatment of advanced or metastatic colon cancer, utilizing agents such as 5-fluorouracil (5-FU) and irinotecan (CPT-11), produce a 5-year survival of about 10%. Thus, the identification of new, effective, therapeutic regimens to treat this disease remains critically important. To this end, selected antiangiogenic agents, compounds that inhibit neovascularization, have been shown to produce a modest tumor growth-inhibitory effect with little systemic toxicity. Thus these agents are attractive candidates for use with conventional chemotherapeutic agents to treat this disease. To evaluate this approach, experiments were undertaken to assess the cytotoxic and antineoplastic activity of CPT-11 and the antiangiogenic agent thrombospondin-1 (TSP-1) in the HT-29 model of human colon cancer. These agents were chosen since CPT-11 is a camptothecin analogue efficacious in the treatment of colon cancer and TSP-1 is a human glycoprotein that possess antiangiogenic activity. As expected, in vitro studies revealed that a 5-day exposure to TSP-1 at concentrations up to 130 microg/ml was not cytotoxic alone and did not affect the cytotoxicity of CPT-11, or of its active metabolite SN38, in HT-29 cells. Similarly, in human umbilical vein endothelial cells, TSP-1 alone induced only a slight cell growth-inhibitory effect and did not significantly increase the cytotoxicity of either CPT-11 or SN38. The antineoplastic activities of TSP-1 and CPT-11 were assessed in athymic (nude) female mice bearing advanced subcutaneous xenografts of HT-29 cells. Mice received TSP-1 alone (5-40 mg/kg per day) intraperitoneally (i.p.), CPT-11 alone (100-300 mg/kg, i.p.), TSP-1 (10 mg/kg per day) plus CPT-11 (125 mg/kg), or TSP-1 (20 mg/kg per day) plus CPT-11 (150 mg/kg). TSP-1 was injected daily (Monday through Friday) for 4 weeks (20 injections in total) whereas CPT-11 was administered once weekly on days 0, 7, 14 and 21. By day 28, treatment with TSP-1 alone (5, 10 or 20 mg/kg per day) induced a dose-dependent inhibition of xenograft growth. Further, treatment with 10 or 20 mg/kg per day resulted in an average treated tumor size/control tumor size (T/C) on day 28 of 0.68 (range 0.64-0.71) or 0.58 (range 0.54-0.60), respectively. CPT-11 at all doses significantly inhibited tumor growth with an average T/C value of 0.21 (range 0.15-0.27). However, the 250 and 300 mg/kg regimens induced significant toxicity and mortality. When TSP-1 was combined with CPT-11, a significant ( P< or = 0.05) inhibition of tumor growth also was observed (T/C < or = 0.17, range 0.11-0.20). Importantly, this enhanced tumor growth inhibition was obtained without significant toxicity. The therapeutic implications of these findings are discussed.
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PMID:Thrombospondin-1 plus irinotecan: a novel antiangiogenic-chemotherapeutic combination that inhibits the growth of advanced human colon tumor xenografts in mice. 1465 7

Human endostatin has an internal Asn-Gly-Arg (NGR) motif at position 126-128 following a proline at position 125. Asn-Gly-Arg-containing peptides have been shown to target tumour vasculature and inhibit aminopeptidase N activity. We previously compared the in vitro and in vivo biological activities of native endostatin and endostatin with a proline to alanine mutation (P125A-endostatin). P125A-endostatin exhibited greater inhibition of both endothelial cell proliferation and human ovarian cancer growth compared to native endostatin. Here we explore further the effects on biological activity of the P125A mutation, and show that aminopeptidase N is not involved. To determine whether the increased biological activity of the mutant was due to unmasking of downstream NGR-sequence, effect of endostatin on aminopeptidase N activity was investigated. Neither the native nor the P125A-endostatin inhibited aminopeptidase N. However, synthetic peptides consisting of the S118-T131 region of endostatin inhibited aminopeptidase N. These results suggest that the internal NGR site in native or mutant endostatin is not accessible to aminopeptidase N, and that this activity is not involved in the enhanced biological activity of the P125A form. P125A-endostatin bound to endothelial cells more efficiently than native endostatin and exhibited greater inhibition of not only proliferation but also migration of endothelial cells. P125A-endostatin also localised into tumour tissue to a higher degree than the native protein, and displayed greater inhibition of growth of colon cancer in athymic mice. Both proteins inhibited tumour cell-induced angiogenesis effectively. Real-time PCR analysis showed that both native and P125A-endostatin decreased expression of key proangiogenic growth factors. Vascular endothelial growth factor and angiopoietin 1 were downregulated more by the mutant. These studies suggest that the region around P125 can be modified to improve the biological activity of endostatin.
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PMID:Improved biological activity of a mutant endostatin containing a single amino-acid substitution. 1508 96

Tumor vasculatures express high levels of alphaVbeta3/alphaVbeta5 and alpha5beta1 integrins. Consequently, peptides containing the RGD (Arg-Gly-Asp) sequence, which is present in ligands of integrins, is effective in targeting therapeutic reagents to tumor vascular endothelium. In our study, we investigated whether the biologic activity of endostatin can be enhanced by the addition of an integrin targeting sequence. RGD sequence was added to either the amino or carboxyl terminus of endostatin containing a point mutation, P125A-endostatin. Earlier we have shown that the P125A mutation did not affect the biologic activity of endostatin but in fact had better antiangiogenic activity when compared to the native molecule. Further modification of P125A-endostatin with the RGD motif showed specific and increased binding to endothelial cells, and the increased binding coincided with improved antiangiogenic properties. Both amino and carboxyl terminal RGD-modification of P125A-endostatin resulted in greater inhibition of endothelial cell migration and proliferation. RGD modification increased tumor localization without affecting the circulatory half-life of P125A-endostatin, and RGD-modified P125A-endostatin was found to be more effective when compared to the P125A-endostatin in inhibiting ovarian and colon cancer growth in athymic mice. Complete inhibition of ovarian tumor growth was observed when P125A-endostatin-RGD was encapsulated into alginate beads. These studies demonstrate that addition of a vascular targeting sequence can enhance the biologic activity of an antiangiogenic molecule.
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PMID:Addition of integrin binding sequence to a mutant human endostatin improves inhibition of tumor growth. 1530 Jul 95

Endostatin (ED) is a carboxyl-terminal fragment of collagen XVIII with strong antiangiogenic activity. ED has been considered as a highly specific inhibitor of endothelial cell proliferation and migration through interaction with its receptor on the surface of endothelial cells. Recently, direct antitumor effects of ED in colon cancer cells and head and neck squamous cell carcinoma cells has been reported. However, its effect on lung cancer cells has not been clarified. The purpose of the present study was to determine the effect of ED on in vitro lung cancer cell function and to identify its receptor on lung cancer cells. We revealed that alpha5 integrin is capable of being a functional ED receptor among several integrins that are expressed on murine lung cancer (Lewis lung cancer [LLC]) cells. We further demonstrated that the ED-integrin interaction modulates various in vitro biological functions of LLC cells as we revealed that immobilized ED helps in LLC cell adhesion and migration in an integrin-dependent manner. Furthermore, ED inhibited LLC cell proliferation and induced apoptosis. Interestingly, ED did not demonstrate any antiproliferative activity against the other murine lung cancer cell line, KLN205, that lacks alpha5 integrin but binds to immobilized ED through the beta1 integrin. In addition, the binding of ED to alpha5 integrin on LLC cells induced phosphorylation of focal adhesion kinase. Taken together, these results suggest that the interaction between ED and alpha5 integrin may play an important role in lung cancer cell function.
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PMID:Signal transduction mediated by endostatin directly modulates cellular function of lung cancer cells in vitro. 1741 9

Although turmeric (Curcuma longa; an Indian spice) has been described in Ayurveda, as a treatment for inflammatory diseases and is referred by different names in different cultures, the active principle called curcumin or diferuloylmethane, a yellow pigment present in turmeric (curry powder) has been shown to exhibit numerous activities. Extensive research over the last half century has revealed several important functions of curcumin. It binds to a variety of proteins and inhibits the activity of various kinases. By modulating the activation of various transcription factors, curcumin regulates the expression of inflammatory enzymes, cytokines, adhesion molecules, and cell survival proteins. Curcumin also downregulates cyclin D1, cyclin E and MDM2; and upregulates p21, p27, and p53. Various preclinical cell culture and animal studies suggest that curcumin has potential as an antiproliferative, anti-invasive, and antiangiogenic agent; as a mediator of chemoresistance and radioresistance; as a chemopreventive agent; and as a therapeutic agent in wound healing, diabetes, Alzheimer disease, Parkinson disease, cardiovascular disease, pulmonary disease, and arthritis. Pilot phase I clinical trials have shown curcumin to be safe even when consumed at a daily dose of 12g for 3 months. Other clinical trials suggest a potential therapeutic role for curcumin in diseases such as familial adenomatous polyposis, inflammatory bowel disease, ulcerative colitis, colon cancer, pancreatic cancer, hypercholesteremia, atherosclerosis, pancreatitis, psoriasis, chronic anterior uveitis and arthritis. Thus, curcumin, a spice once relegated to the kitchen shelf, has moved into the clinic and may prove to be "Curecumin".
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PMID:Curcumin as "Curecumin": from kitchen to clinic. 1790 May 36

Ki23057 is a new, small synthetic tyrosine kinase inhibitor that blocks autophosphorylation of the VEGF receptor2 (VEGFR2). To determine the effect of Ki23057 as an anti-angiogenic agent, we studied the effect of Ki23057 for colon cancer and vascular endothelial cells in vitro and in vivo. Ki23057 inhibited VEGF-induced proliferation of human umbilical vein endothelial cells (HUVECs), whereas no inhibitory effect of Ki23057 on the proliferation of three colon cancer cells (LM-H3, LoVo and LS174T) was observed by means of the cell count assay. Ki23057 inhibited tube formation of HUVECs. Immunoprecipitation demonstrated that Ki23057 inhibited tyrosine phosphorylation of VEGFR2 in HUVECs. Ki23057 exhibited a significant inhibitory effect on the growth of the xenografted LM-H3 tumours and the spreading of cancer cells to the liver. Anti-CD31 antibody stained significantly fewer microvessels in the xenografted tumours treated with Ki23057 compared with controls. Ki23057 may be a promising new antiangiogenic agent for colon cancer.
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PMID:A novel angiogenesis inhibitor, Ki23057, is useful for preventing the progression of colon cancer and the spreading of cancer cells to the liver. 1794 68


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