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)

NO (nitric oxide) biology has provided the impetus for the development of anticancer agents based on their ability to release NO. NO-NSAIDs (NO-donating non-steroidal anti-inflammatory drugs), consisting of a conventional NSAID to which an NO-releasing moiety is covalently attached, are promising chemopreventive agents against cancer. Compared with their parent compounds, NO-NSAIDs are up to several hundred times more potent in inhibiting the growth of cancer cell lines and prevent colon and pancreatic cancer in animal models. Their chemopreventive effect is due to inhibition of proliferation, induction of cell death and inhibition of cell-cycle-phase transitions. NO-ASA (NO-aspirin), the best-studied NO-NSAID, induces oxidative stress in target cells. Major downstream signalling effects involve the Wnt, NOS2 (nitric oxide synthase 2), MAPK (mitogen-activated protein kinase), NF-kappaB (nuclear factor kappaB) and Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2) pathways. NO-NSAIDs, particularly NO-ASA, appear to be safe compounds, as suggested by many animal and early human studies. An ongoing clinical trial is designed to determine whether NO-ASA can inhibit early stages of colon carcinogenesis in subjects at risk for colon cancer. It is clinical trials that will ultimately determine the role of NO-NSAIDs in cancer prevention and perhaps treatment.
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PMID:Novel agents for cancer prevention based on nitric oxide. 1795 52

The inhibitory effect of NO-donating aspirin (NO-ASA) on colon cancer has been demonstrated in vivo and in vitro but its mechanism is still obscure. We investigated the effect of NO-ASA on angiogenesis. Four groups of athymic mice (N = 12) bearing subcutaneous xenotransplants of HT-29 human colon cancer cells were injected intratumorally twice a week for 3 weeks with vehicle or m-NO-ASA or p-NO-ASA; the fourth group received no injections. The necrotic area of tumors, expressed as percentage of total area, was similar in the non-injected and vehicle-injected groups (51.8 +/- 2.8 versus 52.2 +/- 4.1, P > 0.05; mean +/- SEM for these and subsequent values). Compared with the vehicle group, the necrotic area of tumors was higher in the m-NO-ASA-treated (61.0 +/- 2.7, P < 0.02) and p-NO-ASA (65.8 +/- 2.4, P < 0.001)-treated groups. NO-ASA decreased microvessel density: vehicle = 11.7 +/- 0.8; m-NO-ASA = 7.8 +/- 0.6 (P = 0.0003 versus vehicle) and p-NO-ASA 6.2 +/- 0.7 (P = 0.0001 versus vehicle). The expression of vascular endothelial growth factor (VEGF) was significantly reduced in response to NO-ASA, with the p- isomer being more potent than the m-. NO-ASA altered the spatial distribution of VGEF expression, with 16.7% of the vehicle-treated xenografts displaying diminished VEGF in the inner region of the area between necrosis and the outer perimeter of the tumor, compared with those treated with m- (58.3%) or p-NO-ASA (75%, P < 0.01 for both versus control). Our findings indicate that NO-ASA suppresses the expression of VEGF, which leads to suppressed angiogenesis. The antiangiogenic activity of NO-ASA may be part of its antineoplastic effect.
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PMID:NO-donating aspirin inhibits angiogenesis by suppressing VEGF expression in HT-29 human colon cancer mouse xenografts. 1854 66

Angiogenesis is crucial for the progression of colorectal carcinomas in which the bioavailability of Vascular Endothelial Growth Factor (VEGF) plays a major role. VEGF bioavailability is regulated by proteolytic release or cleavage. In colorectal cancer patients, we observed a significant correlation between circulating VEGF and tumour tissue Matrix Metalloproteinase-9 (MMP-9) levels but not with MMP-2. Therefore, we evaluated the role of MMP-9 in regulating VEGF bioavailability and subsequent angiogenesis in 3-dimensional human cell culture models. MMP-9 treatment released VEGF dose-dependently from HT29 colon carcinoma spheroids, comparable to heparitinase, a known mediator of VEGF release. Conditioned medium from human neutrophils, containing high amounts of active MMP-9, released VEGF comparable to recombinant MMP-9, in contrast to myofibroblast medium. MMP-9 treated spheroids showed decreased extracellular levels of heparan sulphates, required for VEGF binding to the matrix, whereas the levels in the medium were increased. Western blot analysis revealed that VEGF(165) is the major isoform released by MMP-9 treatment. In vitro experiments indicated that MMP-9 is not capable to cleave VEGF(165) into smaller isoforms, like plasmin does. These data suggested that MMP-9 mediates release rather than the cleavage of larger VEGF isoforms. Medium from MMP-9 treated HT29 spheroids induced endothelial cell sprouting in an angiogenesis assay, comparable to the effect of recombinant VEGF(165). Anti-VEGF antibody treatment resulted in a strongly reduced number of sprouts. In conclusion, we have shown that neutrophil-derived MMP-9 is able to release biologically active VEGF(165) from the ECM of colon cancer cells by the cleavage of heparan sulphates.
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PMID:VEGF release by MMP-9 mediated heparan sulphate cleavage induces colorectal cancer angiogenesis. 1869 82

Anticancer agents act, at least in part, by inducing reactive oxygen and nitrogen species (RONS). We examined the redox effect on SW480 and HT-29 colon cancer cells of four anticancer compounds, arsenic trioxide, phosphoaspirin, phosphosulindac, and nitric oxide-donating aspirin (NO-ASA). All compounds inhibited the growth of both cell lines (IC(50), 10-90 micromol/L) and induced RONS detected by a general RONS molecular probe. NO-ASA, which induced at least four individual RONS (NO, H(2)O(2), superoxide anion, and peroxynitirte), induced apoptotic and necrotic cell death that was RONS-mediated (cell death paralleled RONS levels and was abrogated by N-acetyl cysteine but not by diphenylene iodonium, which displayed prooxidant activity and enhanced cell death). Nuclear factor-kappaB and mitogen-activated protein kinases were modulated by RONS. Thioredoxin-1 (Trx-1), an oxidoreductase involved in redox regulation, was heavily oxidized in response to RONS and mediated the growth inhibitory effect of the anticancer agents; knocking-down trx-1 expression by small interfering RNA abrogated cell death induced by them. These compounds also inhibited the activity of Trx reductase that reduces oxidized Trx-1, whereas the Trx reductase inhibitor aurothiomalate synergized with NO-ASA in the induction of cell death. Our findings indicate that the Trx system mediates to a large extent redox-induced cell death in response to anticancer agents. This mechanism of action may be shared by more anticancer agents and deserves further assessment as a candidate mechanism for the pharmacologic control of cancer.
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PMID:The thioredoxin system mediates redox-induced cell death in human colon cancer cells: implications for the mechanism of action of anticancer agents. 1892 98

Spontaneously mutated multiple oncogenes and/or tumor suppressor genes in colon epithelial cell and its progeny, may cause proliferation out of control and create benign colon neoplasm (colon polyp). If additional mutations involve genes responsible for cell adhesion and movement, aberrant epithelial cells may become malignant (colon cancer) and invade surrounding and remote tissues, creating secondary tumors called metastases. Incidence of colorectal cancer dramatically increases at 50-65 year of age. In Europe in 2006 colorectal cancer consisted 12.9% of all cancers and caused 207,400 deaths. To laboratory detection and monitoring of colon cancer are used tumor markers. Tumor markers are substances produced by the body in response to cancer, or by cancer tissue itself. Glycoconjugate markers for colon cancer include aberrant: mucins covering the surface of the colon epithelial cells, cadherins, selectins and Ig-like adhesion molecules mediating cell-cell adhesion, integrins and integral membrane proteoglycans responsible for adhesion of colon epithelial cells to extracellular matrix, glycoconjugate components of ECM, as well as lysosomal membrane glycoproteins and exoglycosidases. Detection of colon cancer at early non malignant stage is crucial in its prevention and eradication. As colon cancer is the effect of accumulation many somatic mutations in oncogens, supressors, mismatch repair genes and many genes responsible for posttranslational modifications of proteins, multidirectional approach should be applied for its detection. A glycobiological approach to diagnosis and treatment of colorectal cancer should be directed to detection changes in glycosylation accompanying every step of colon cancer progression, and correlation between changes in glycosylation and tumor progression.
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PMID:Carbohydrate markers in colon carcinoma. 1912 67

Studies indicate that peroxisome proliferator-activated receptor-beta/delta (PPAR beta/delta) can either attenuate or potentiate colon cancer. One hypothesis suggests that PPAR beta/delta is upregulated by the adenomatous polyposis coli (APC)/beta-CATENIN pathway and a related hypothesis suggests that PPAR beta/delta is downregulated by nonsteroidal antiinflammatory drugs (NSAIDs). The present study examined these possibilities using in vivo and in vitro models. While APC/beta-CATENIN-dependent expression of CYCLIN D1 was observed in vivo and in vitro, expression of PPAR beta/delta was not different in colon or intestinal polyps from wild-type or Apc(min) heterozygous mice or in human colon cancer cell lines with mutations in APC and/or beta-CATENIN. No difference in the level of PPAR beta/delta was found in colon from wild-type or Apc(min) heterozygous mice following treatment with NO-donating aspirin (NO-ASA). NSAIDs inhibited cell growth in RKO (wild-type APC) and DLD1 (mutant APC) human colon cancer cell lines but expression of PPAR beta/delta was not downregulated in these cell lines in response to a broad concentration range of celecoxib, indomethacin, NS-398, or nimesulide. However, indomethacin caused an increase in PPAR beta/delta mRNA and protein that was accompanied with increased expression of a known PPAR beta/delta target gene. Interestingly, expression of PPAR alpha was also increased in the human colon cancer cell lines by several NSAIDs at the highest concentration examined. Results from these studies provide additional evidence indicating that PPAR beta/delta is not upregulated by the APC/beta-CATENIN pathway. Further, these studies suggest that increased PPAR beta/delta and/or PPAR alpha by NSAIDs in human colon cancer cell lines could contribute to the mechanisms underlying the chemopreventive effects of NSAIDs.
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PMID:Regulation of peroxisome proliferator-activated receptor-beta/delta by the APC/beta-CATENIN pathway and nonsteroidal antiinflammatory drugs. 1941 98

In many epidemiologic studies, investigators have reported an inverse relation between nonsteroidal antiinflammatory drugs (NSAIDs) and colon cancer, but fewer researchers have examined the relation with gastric cancer. Cases for this study consisted of incident gastric adenocarcinomas (n = 643) identified between 1993 and 2004 among members of the Multiethnic Cohort (Hawaii and Los Angeles, California). Aspirin and nonaspirin NSAID use was assessed on the basis of a self-administered questionnaire. Multivariate-adjusted hazards ratios and 95% confidence intervals were calculated using Cox proportional hazards regression. Compared with no regular use, regular use of aspirin was associated with a decreased risk of distal gastric cancer (hazard ratio (HR) = 0.73, 95% confidence interval (CI): 0.61, 0.89; P(trend) = 0.009), but use of nonaspirin NSAIDs was not (HR = 1.00, 95% CI: 0.81, 1.24; P(trend) = 0.99). The inverse association with regular aspirin use was observed only for intestinal-type distal gastric adenocarcinoma (HR = 0.66, 95% CI: 0.47, 0.95; P(trend) = 0.01), as opposed to diffuse-type distal gastric adenocarcinoma (HR = 0.92, 95% CI: 0.53, 1.60; P(trend) = 0.45). In this study, the authors found aspirin use to be inversely associated with distal gastric adenocarcinoma, particularly of the intestinal type.
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PMID:Nonsteroidal antiinflammatory drugs and risk of gastric adenocarcinoma: the multiethnic cohort study. 1958 32

Aspirin was commercialized more than a 100 years ago. Today, this compound is still widely prescribed, and new mechanisms of action and indications are being tested. Inhibition of cyclooxygenase (COX)-1 and COX-2 by aspirin or its related compounds, nonsteroidal antiinflammatory drugs (NSAIDs), has been associated with both adverse and beneficial effects in the gastrointestinal (GI) tract. Inhibition of COX-1 has been linked to GI adverse effects. Adverse effects of NSAIDs and aspirin in the upper GI tract include esophagitis, peptic ulcer, peptic ulcer complications, and death. Effective preventive therapies are available that have been associated with a progressive decline in the rate of hospitalization due to upper GI complications. NSAIDs and aspirin can also damage the small bowel and the colon. NSAID enteropathy is frequent and in most cases subclinical (increased mucosal permeability, inflammation, erosion, ulcer). However, more serious clinical outcomes such as anemia, bleeding, perforation, obstruction, diverticulitis, and deaths have also been described. Prevention therapy of NSAID damage to the lower GI tract is not well defined. Inhibition of COX-2 by NSAIDs, coxibs, or aspirin seems to provide beneficial effects to the GI tract. Observational studies show that these compounds reduce the risk of both upper and lower GI cancers. Randomized controlled trials have shown that aspirin and coxibs reduce the recurrence rate of colonic polyps, and long-term cohort studies have shown that aspirin reduces the risk of colon cancer time and dose dependently. New studies will have to define the appropriate population that may benefit with these therapies.
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PMID:Nonsteroidal antiinflammatory drugs and cyclooxygenase inhibition in the gastrointestinal tract: a trip from peptic ulcer to colon cancer. 1968 14

We studied the mechanism by which the para and meta positional isomers of nitric oxide-donating aspirin (NO-ASA) inhibit human colon cancer cell growth. These compounds are promising chemopreventive agents and represent a broader class of novel drugs. The two isomers differ drastically in their 24-h IC50s for cell growth, which are 12 microM for p-NO-ASA and 230 microM for m-NO-ASA. We examined their effects on cell signaling cascades, including predominantly the mitogen activated protein kinases (MAPKs). The principal differences between the two isomers were: a) p-NO-ASA exerts its effect earlier than m-NO-ASA; b) the predominant effect of m-NO-ASA is on ERK1/2 and Akt; whereas that of p-NO-ASA is on JNK1/2, while both activate p38, with p-NO-ASA showing a stronger and earlier effect; c) ATF-2 is more responsive to m-NO-ASA and c-Jun to p-NO-ASA; d) both isomers seem to have similar effects on AP-1 binding, the main difference between them being the timing of the effect; p-NO-ASA's effect is early and m-NO-ASA's is late; e) p-NO-ASA has an earlier and stronger effect on p21, while m-NO-ASA's effect occurs later and is weaker; and f) cell cycle changes follow the effect on p21 expression. Our findings underscore the role of positional isomerism in modulating the pharmacological effects of drugs and have potentially important implications for the further development of these chemoprevention agents.
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PMID:The differential cell signaling effects of two positional isomers of the anticancer NO-donating aspirin. 1972 20

Cyclooxygenase-2 (COX-2) catalyzes the rate-limiting step in the production of prostaglandins, potent mediators of inflammation. Chronic inflammation plays an important role in the development and progression of colorectal cancer. Aspirin inhibits COX-2 activity and lowers the risk for colorectal adenomas and cancer. We investigated whether common genetic variation in COX-2 influenced risk for colorectal adenoma recurrence among 979 participants in the Aspirin/Folate Polyp Prevention Study who were randomly assigned to placebo or aspirin and followed for 3 years for the occurrence of new adenomas. Of these participants, 44.2% developed at least one new adenoma during follow-up. Adjusted relative risks and 95% confidence intervals (95% CI) were calculated to test the association between genetic variation at six COX-2 single-nucleotide polymorphisms and adenoma occurrence and interaction with aspirin treatment. Two single-nucleotide polymorphisms were significantly associated with increased adenoma recurrence: for rs5277, homozygous carriers of the minor C allele had a 51% increased risk compared with GG homozygotes (relative risk, 1.51; 95% CI, 1.01-2.25), and for rs4648310, heterozygous carriers of the minor G allele had a 37% increased risk compared with AA homozygotes (relative risk, 1.37; 95% CI, 1.05-1.79). (There were no minor allele homozygotes.) In stratified analyses, there was suggestive evidence that rs4648319 modified the effect of aspirin. These results support the hypothesis that COX-2 plays a role in the etiology of colon cancer and may be a target for aspirin chemoprevention and warrant further investigation in other colorectal adenoma and cancer populations.
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PMID:Cyclooxygenase-2 polymorphisms, aspirin treatment, and risk for colorectal adenoma recurrence--data from a randomized clinical trial. 1975 47


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