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)

Numerous studies demonstrate that the chemopreventive effect of non-steroidal anti-inflammatory drugs on colon cancer is mediated through inhibition of cell growth and induction of apoptosis. For these effects non-steroidal anti-inflammatory drugs have been recently employed as sensitising agents in chemotherapy. We have shown previously that treatments with aspirin and NS-398, a cyclo-oxygenase-2 selective inhibitor, affect proliferation, differentiation and apoptosis of the human colon adenocarcinoma Caco-2 cells. In the present study, we have evaluated the effects of aspirin and NS-398 non-steroidal anti-inflammatory drugs on sensitivity of Caco-2 cells to irinotecan (CPT 11) and etoposide (Vp-16) topoisomerase poisons. We find that aspirin co-treatment is able to prevent anticancer drug-induced toxicity, whereas NS-398 co-treatment poorly affects anticancer drug-induced apoptosis. These effects correlate with the different ability of aspirin and NS-398 to interfere with cell cycle during anticancer drug co-treatment. Furthermore, aspirin treatment is associated with an increase in bcl-2 expression, which persists in the presence of the anticancer drugs. Our data indicate that aspirin, but not NS-398, determines a cell cycle arrest associated with death suppression. This provides a plausible mechanism for the inhibition of apoptosis and increase in survival observed in anticancer drug and aspirin co-treatment.
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PMID:Effect of non-steroidal anti-inflammatory drugs on colon carcinoma Caco-2 cell responsiveness to topoisomerase inhibitor drugs. 1198 87

Non-steroidal anti-inflammatory drugs (NSAID) may inhibit colon cancer development through affecting proliferation and apoptosis. However, their use in cancer chemoprevention is still limited due to toxicities. There is longstanding clinical experience with the aminosalicylate mesalazine in the treatment of patients with inflammatory bowel disease with very few side effects. So far, most studies on the cellular effects of mesalazine were focused on its anti-inflammatory properties. Recent data, however, indicate that mesalazine may also reduce cell growth in vivo. We therefore investigated the growth inhibitory effect of mesalazine on human colon cancer cells in vitro compared with established chemopreventive agents. We also wished to determine the underlying cellular mechanisms of the effect. Here we show that mesalazine dose- and time-dependently inhibited the proliferation of colon cancer cells. Mesalazine was less potent in reducing cell growth than sulindac sulfide or indomethacin but growth effective mesalazine concentrations were comparable with concentrations achievable in vivo under standard mesalazine treatment. While other NSAID induced a robust G(1) arrest, mesalazine specifically blocked cells in mitosis although microtubule polymerization or spindle orientation was not affected. In addition, mesalazine induced apoptosis in colon cancer cells possibly through activation of caspase-3 whereas the levels of bcl-2 family proteins were not altered. We conclude that mesalazine inhibits growth of colon cancer cells largely through a mitotic arrest, which has not been reported for NSAID so far. Mesalazine also induces apoptosis through partial activation of caspases similar to, although weaker than, established chemopreventive agents. These findings may suggest a potential of mesalazine as a chemopreventive agent for colorectal cancer.
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PMID:Mesalazine causes a mitotic arrest and induces caspase-dependent apoptosis in colon carcinoma cells. 1266 3

We have shown that fish oil is protective against colon tumorigenesis, primarily by upregulating apoptosis. Production of prostaglandin E2 (PGE2) in colon cancer cells by cyclooxygenase (COX)-I and -II is known to inhibit apoptosis by induction of bcl-2. Because we have shown that fish oil downregulates PGE2 and COX-II, we hypothesized that this upregulation of apoptosis would be coincident with a downregulation of bcl-2. Bcl-2 was localized within the colonic crypt by quantitative immunohistochemistry (IHC), and scraped colonic mucosa was used for immunoblot analysis of bcl-2. The tissue used for bcl-2 analysis was from the rats used to determine apoptosis. Briefly, tissues were collected from rats consuming diets containing either corn oil or fish oil at 3, 6, 9, and 12 h after carcinogen injection. The correlation between bcl-2 and apoptosis was also determined. Bcl-2 expression decreased until 9 h (P < 0.05), whereas apoptosis increased until 9 h (P < 0.01). Bcl-2 expression and apoptosis were negatively correlated in both the proximal (P < 0.05) and distal colon (P < 0.005). Fish oil decreased bcl-2 expression (P < 0.05) and increased apoptosis (P < 0.05) in the top third of the crypt in the distal colon. In conclusion, one pathway by which fish oil may mediate apoptosis and thus protect against colon tumorigenesis is by downregulation of anti-apoptotic bcl-2.
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PMID:Fish oil enhances targeted apoptosis during colon tumor initiation in part by downregulating Bcl-2. 1292 3

Chemotherapy of advanced stages of colorectal carcinoma is unsatisfactory. Retinoids inhibit cell growth and induce apoptosis in a variety of human malignancies. We compared the effect of the synthetic retinoid adapalene (ADA) and 9-cis-retinoic acid (CRA) on carcinoma cell lines in vitro. Colon carcinoma cell lines CC-531, HT-29 and LOVO as well as human foreskin fibroblasts were exposed to different concentrations of ADA and CRA for 3-72 hr. Proliferation was assessed by BrdU incorporation and apoptosis by FACS analysis. Breakdown of DeltaPsi(m) was determined by JC-1 staining and activity of caspases 3 and 8, by a colorimetric assay. Quantitative Western blots were performed to detect changes in bax, bcl-2 and caspase-3. Both retinoic derivatives suppressed DNA synthesis and induced apoptosis in all tested cell lines time- and dose-dependently. While the natural retinoid CRA showed moderate antiproliferative and proapoptotic effects only at the highest concentration (10(-4) M), the synthetic retinoic ADA was significantly more effective, showing remarkable effects even at 10(-5) M. ADA and CRA disrupt DeltaPsi(m) and induce caspase-3 activity in responsive tumor cells. Quantitative Western blots showed a shift of the bax:bcl-2 ratio toward proapoptotic bax in ADA-treated cells. Our results clearly indicate the superiority of ADA compared to CRA. Therefore, we suggest that ADA may be far more suitable as an adjunctive therapeutic agent for treatment of colon cancer in vivo.
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PMID:The synthetic retinoid adapalene inhibits proliferation and induces apoptosis in colorectal cancer cells in vitro. 1450 47

Bcl-2 and TGF-beta receptors type II (RII) in colon carcinomas were studied in a series of 113 patients, to determine their prognostic significance and to correlate their expression with other prognostic indicators. Bcl-2 expression in the tumor cells showed a reverse relation with tumor size (P = 0.018), histological grade (P = 0.04), and stage (P = 0.013). Univariate survival analysis using the log rank test showed that the survival of patients with bcl-2-positive tumors was significantly better than the survival of patients with bcl-2-negative tumors (P = 0.02). However, when entered into a multivariate analysis model, it was not found to be of independent prognostic significance. TGF-beta RII expression was correlated with stage (P = 0.03), while no statistically significant correlation was found between TGF-beta RII expression and histological grade or survival. In conclusion, these results provide additional evidence for the role of bcl-2 and TGF-beta RII in carcinogenesis of the colon, while they do not support the use of these factors as prognostic markers in patients with colon cancer.
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PMID:Prognostic significance and correlation with survival of bcl-2 and TGF-beta RII in colon cancer. 1471 14

This study was designed to elucidate the possible relationship between tumour related genes and angiogenesis in colon cancer. The protein expression of p53, bcl-2, Von Willebrand factor and vascular endothelial growth factor (VEGF) were analysed by immunohistochemistry in 57 paraffin-embedded colon cancer. The results showed that microvessel density (MVD) was lower in VEGF negative tumours than in VEGF positive ones (P<0.0001). MVD and VEGF in p53 negative tumours were significantly lower than in p53 positive tumours (respectively, P=0.003 and P<0.0001). Moreover, positive correlations were recorded between VEGF expression and MVD, and bcl-2 expression (respectively, P<0.0001 and P=0.009). Our data confirm the central role of VEGF in angiogenesis and suggest direct correlations among p53, bcl-2 and VEGF expression in colon cancer.
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PMID:Correlation of p53 and bcl-2 expression with vascular endothelial growth factor (VEGF), microvessel density (MVD) and clinico-pathological features in colon cancer. 1514 82

The combination of 5-fluorouracil (5-FU) plus Cisplatin (CDDP) (FP treatment) possesses synergistic cytotoxicity against colon cancer. The molecular mechanisms by which chemotherapeutic agents induce apoptosis have been clarified by identifying apoptosis-related genes such p53 and bcl-2. We previously established a new experimental technique in which cancer cells are distributed in thin collagen gel as 1 or 2 cell layers. additionally, we evaluated the efficacy and toxicity of FP treatment in the gastric and colon cancer cell lines, and examined the relationship between the response to FP treatment and apoptosis. In these results we reported transfection of normal p53 gene into p53 mutant and analyzed the impact of the p53 gene in a sensitivity test. In this study, we examined induced apoptosis in colon cancer cell lines and the status of p53 expression in response to treatment of HCT116, COLO320, SW480 and DLD1 with 5-FU alone, CDDP alone and FP treatment under flow cytometric analysis. Transfection of SW480 and DLD1 cells was performed to compare the chemosensitivity of naturally occurring mutant-type p53 SW480 and DLD1 cells with neo-transfected SW480 and DLD1 cells and transfected SW480 and DLD1 cells. Appreciable apoptosis was induced in HCT116 and COLO320 (p53 wild-type) but not in SW480 and DLD1 cells (p53 mutant-type). Transfected SW480 and DLD1 cells underwent significantly more apoptosis (p<lt;0.001) than naturally occurring mutant-type p53 SW480 and DLD1 cells. p53 expression may further induce apoptosis in FP treatment. Patients with p53 wild-type may be better candidates for FP therapy than patients with p53 mutant-type in colon cancer. Therefore, we think that p53 may be also effective against colon cancer in FP therapy.
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PMID:p53 dependence and apoptosis in response to FP treatment with p53-transfected colon cancer cell lines by use of thin layer collagen gel. 1525 2

Trigonella foenum graecum (fenugreek) is traditionally used to treat disorders such as diabetes, high cholesterol, wounds, inflammation, and gastrointestinal ailments. Recent studies suggest that fenugreek and its active constituents may possess anticarcinogenic potential. We evaluated the preventive efficacy of dietary fenugreek seed and its major steroidal saponin constituent, diosgenin, on azoxymethane-induced rat colon carcinogenesis during initiation and promotion stages. Preneoplastic colonic lesions or aberrant crypt foci (ACF) were chosen as end points. In addition, we assessed the mechanism of tumor growth inhibition of diosgenin in HT-29 human colon cancer cells. To evaluate the effect of the test agent during the initiation and postinitiation stages, 7-week-old male F344 rats were fed experimental diets containing 0% or 1% fenugreek seed powder (FSP) or 0.05% or 0.1% diosgenin for 1 week and were injected with azoxymethane (15 mg/kg body weight). Effects during the promotional stage were studied by feeding 1% FSP or 0.1% diosgenin 4 weeks after the azoxymethane injections. Rats were sacrificed 8 weeks after azoxymethane injection, and their colons were evaluated for ACF. We found that, by comparison with control, continuous feeding of 1% FSP and 0.05% and 0.1% diosgenin suppressed total colonic ACF up to 32%, 24%, and 42%, respectively (P < or = 0.001 to 0.0001). Dietary FSP at 1% and diosgenin at 0.1% fed only during the promotional stage also inhibited total ACF up to 33% (P < or = 0.001) and 39% (P < or = 0.0001), respectively. Importantly, continuous feeding of 1% FSP or 0.05% or 0.1% diosgenin reduced the number of multicrypt foci by 38%, 20%, and 36% by comparison with the control assay (P < or = 0.001). In addition, 1% FSP or 0.1% diosgenin fed during the promotional stage caused a significant reduction (P < or = 0.001) of multicrypt foci compared with control. Dietary diosgenin at 0.1% and 0.05% inhibited total colonic ACF and multicrypt foci formation in a dose-dependent manner. Results from the in vitro experiments indicated that diosgenin inhibits cell growth and induces apoptosis in the HT-29 human colon cancer cell line in a dose-dependent manner. Furthermore, diosgenin induced apoptosis in HT-29 cells at least in part by inhibition of bcl-2 and by induction of caspase-3 protein expression. On the basis of these findings, the fenugreek constituent diosgenin seems to have potential as a novel colon cancer preventive agent.
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PMID:Diosgenin, a steroid saponin of Trigonella foenum graecum (Fenugreek), inhibits azoxymethane-induced aberrant crypt foci formation in F344 rats and induces apoptosis in HT-29 human colon cancer cells. 1529 63

Puerarin was isolated from Pueraria radix and has beneficial effects on cardiovascular, neurological, and hyperglycemic disorders. The current study showed that puerarin also possessed anti-cancer properties. Methyl thiazolyl tetrazolium assay (MTT) assay revealed a dose-dependent reduction of HT-29 cellular growth in response to puerarin treatment. Apoptosis was observed following treatments ;with >or=25 microM puerarin, as reflected by the appearance of the subdiploid fraction and NDA fragmentations. We then investigated effects of puerarin on expression of apoptosis-associated genes and the results revealed an increase of bax and decreases of c-myc and bcl-2. Finally, puerarin treatment significantly increased the activation of caspase-3, a key executioner of apoptosis. These findings indicate that puerarin may act as a chemopreventive and/or chemotherapeutic agent in colon cancer cells by reducing cell viability and inducing apoptosis.
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PMID:Induction of apoptosis by puerarin in colon cancer HT-29 cells. 1605 62

Conjugated linolenic acids (CLN) are geometric and positional isomers of linolenic acid. Growth inhibition and apoptosis induction by alpha-eleostearic acid (c9,t11,t13-CLN), beta-eleostearic acid (t9,t11,t13-CLN), alpha-calendic acid (t8,t10,c12-CLN) and beta-calendic acid (t8,t10,t12-CLN) were compared. beta-Eleostearic acid and beta-calendic acid, which have all-trans-conjugated double bonds, exerted stronger growth inhibition and more DNA fragmentation, an indicator of apoptosis induction, in the human colon cancer cells Caco-2 than alpha-eleostearic acid and alpha-calendic acid with the cis configuration. Down-regulation of bcl-2 and up-regulation of bax mRNA by beta-eleostearic acid were also greater than by alpha-eleostearic acid. Interestingly, the cytotoxic effects of beta-eleostearic acid and beta-calendic acid were not counteracted completely by alpha-tocopherol, whereas the cytotoxic effects of alpha-eleostearic and alpha-calendic acids were lost in the presence of alpha-tocopherol. These results suggest that beta-eleostearic and beta-calendic acids have signaling pathways different from those of alpha-eleostearic and alpha-calendic acids and exhibit high potency for reducing the cell viability of Caco-2.
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PMID:Growth inhibition and apoptosis induction by all-trans-conjugated linolenic acids on human colon cancer cells. 1682 17


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