Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.1.17 (ornithine decarboxylase)
 6,351 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We assessed the anti-mutagenic and anti-promotion properties of two flavones, apigenin and robinetin, and of indole-3-carbinol, because these compounds have been reported in vegetables, the consumption of which has been associated with reduced rates of cancer. However, the active components of these foods and their effects on carcinogenesis have not been established. Anti-mutagenicity was determined in the Salmonella typhimurium assay by measuring the effects of the test compounds on bacterial mutagenesis induced by methyl-nitrosourea (MNU), methyl-n-nitro-N-nitrosoguanidine (MNNG), benzo[a]pyrene (BaP) or 2-aminoanthracene (2-AA). Inclusion of apigenin resulted in a 62% and a 43% inhibition of mutagenicity with 13 nmol of 2-AA and 30 nmol BaP respectively. Robinetin caused an 87% inhibition of mutagenicity by 2-AA, but indole-3-carbinol had little or no effect on the mutagenicity of any of the compounds. None of the three compounds inhibited mutagenesis by MNU or MNNG and none were mutagenic or toxic when tested in the absence of mutagenic compounds at doses up to 20 micrograms/plate. Anti-promotion properties were assessed by measuring the effects of apigenin, robinetin and indole-3-carbinol on induction of ornithine decarboxylase activity (ODC) in mouse epidermis by 17 nmol 12-O-tetradecanoyl phorbol-13-acetate (TPA). Pretreatment of the skin half an hour before TPA with apigenin, robinetin, butylated hydroxyanisole, 13-cis-retinoic acid (all at 50 mumol) or di-fluoromethylornithine (1.6 mumol) inhibited ODC induction at 6 h after TPA by 67-80%. Pretreatment with 50 mumol indole-3-carbinol caused a 78% elevation in the TPA induction at this time. Dose response measurements were conducted with apigenin, indole-3-carbinol and robinetin. Inhibition by 30-90% of TPA-induced ODC was observed at 6 h after TPA in mice pretreated with 12.5-100 mumol apigenin. Pretreatment with 37.5 or 50 mumol indole-3-carbinol or 0.5, 12.5 or 25 mumol robinetin resulted in elevated induction of epidermal ODC by TPA at 6 h after TPA. However, treatment with 50 or 100 mumol robinetin diminished ODC induction at 6 h after TPA. Treatment with 100 mumol apigenin or 50 or 100 mumol indole-3-carbinol in non-TPA-treated mouse skin caused elevations in epidermal ODC. In comparing the time course of ODC induction, indole-3-carbinol (50 mumol) pretreatment shifted the induction of epidermal ODC to earlier times, in addition to elevating ODC induction by TPA.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Anti-mutagenesis and anti-promotion by apigenin, robinetin and indole-3-carbinol. 370 57

Anti-estrogenic effects of yuehchukene were observed in rat uterotrophic, mice vaginal smear and MCF-7 cell growth assays. Whereas yuehchukene per se was estrogenic in these bioassay models, the co-administration of yuehchukene and an optimal dose of 3,17 beta-estradiol (estradiol) could attenuate the maximum estrogenic response due to estradiol alone. The anti-estrogenic effect of yuehchukene in rat uterine hypertrophy was corroborated by a parallel attenuation of ornithine decarboxylase activity in these tissues. Yuehchukene binds to rat, mice and MCF-7 cell estrogen receptors with a relative binding affinity of 1/150 to 1/300. This binding affinity was positively related to estrogenicity as determined by uterotrophic assay and MCF-7 cell growth. However, this estrogenic effect did not correlate with the degree of competitive receptor binding by a weaker agonist. Indole-3-carbinol and methylbutadienylindole could induce ethoxyresorufin O-deethylase and estradiol-2-hydroxylase in rat liver and MCF-7 cells. It is postulated that the 'free' indole moiety of yuehchukene could possess similar induction activity. Thus yuehchukene may have a dual pharmacological function. While the intact molecule is a weak estrogen, the 'free' indole moiety in yuehchukene may induce an enhancement of estradiol-2-hydroxylase, thus terminating the biological activity of the endogenous estrogen pool. There is obvious benefit in attenuating the estrogen level in post-menopausal breast cancer patients without going directly to the use of tamoxifen or aromatase inhibitor. Yuehchukene may serve this purpose. In this context, the pharmacological evaluation of a hydroxylated yuehchukene analogue and the anti-estrogenic effect of methylbutadienylindole acid-condensation products are now being studied in earnest.
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PMID:Mixed estrogenic and anti-estrogenic activities of yuehchukene--a bis-indole alkaloid. 782 37

Ninety potential chemopreventive agents were screened using 6 chemoprevention-associated biochemical end points. These compounds were tested using rodent (tracheal epithelial or liver) cells and human cells [neonatal foreskin fibroblasts, bronchial epithelial cells, or human leukemic cells (HL-60)]. The effects measured were: (a) inhibition of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced tyrosine kinase activity in HL-60 cells; (b) inhibition of TPA-induced ornithine decarboxylase (ODC) activity in rat tracheal epithelial cells; (c) inhibition of poly(ADP-ribose)polymerase in propane sultone-treated primary human fibroblasts; (d) inhibition of benzo[a]pyrene(B[a]P)-DNA binding in human bronchial epithelial cells; (e) induction of reduced glutathione in Buffalo rat liver cells; and (f) inhibition of TPA-induced free radical formation in primary human fibroblasts or HL-60 cells. Fifty compounds were highly effective in inhibiting TPA-induced tyrosine kinase activity. This assay identified compounds from a wide variety of chemical classes as effective inhibitors, including all the vitamins, retinoic acid analogues, protein kinase C inhibitors, and chemicals belonging to the amino acid category. Fifty-two chemicals were classified as highly positive compounds when examined for their ability to inhibit TPA-induced ODC activity. These agents showed a dose-dependent inhibition or inhibition at all doses. Retinoids, in general, exhibited strong inhibition of ODC activity. A category of compounds showing dose-dependent inhibition were the sulfur compounds, especially the thiols and thiones. Among the natural products, terpenes were strong inhibitors of ODC. Forty-seven compounds were classified as strong inhibitors of poly(ADP-ribose)polymerase. In the carcinogen-DNA binding inhibition assay, 21 compounds were identified as strong inhibitors, which include phenolic compounds as well as sulfur compounds. Vitamins and their analogues were also good inhibitors. Testing for induced glutathione yielded 19 compounds that were good inducers. Sulfur-containing compounds and most of the phenolic compounds were also inducers of glutathione. Twenty compounds were highly positive for inhibition of TPA-induced free radical formation. A significant number of phenolic and sulfur compounds were again strong oxygen radical scavengers. Some antiinflammatory agents were also identified as free radical inhibitors. In general, retinoids were quite active in all the assays. Eight compounds were positive in all of the six assays; these were vitamin C (ascorbic acid), bismuththiol, esculetin, etoperidone, folic acid, hydrocortisone, indole-3-carbinol, and tocopherol succinate. Agents that were positive in these assays may inhibit the carcinogenesis process by similar mechanisms in humans and are identified as candidates for development as chemopreventive agents.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Screening of potential chemopreventive agents using biochemical markers of carcinogenesis. 795 13

Indole-3-carbinol (I3C) was examined for its ability to inhibit aflatoxin B1 (AFB1)-induced hepatocarcinogenesis in male Fischer rats when administered either before or after the carcinogen. After 13 weeks, animals pretreated with I3C (0.5% in the diet) for 2 weeks prior to administration of AFB1 and with continuing treatment during exposure to the carcinogen were protected from development of preneoplastic lesions, as determined by the classical markers gamma-glutamyltranspeptidase (GGT) and glutathione S-transferase (GST) P. In animals receiving AFB1 for 6 weeks before treatment with I3C, there was no obvious protective effect at 13 weeks compared with animals receiving only AFB1. Using cytokeratin 18 expression as a marker, animals fed AFB1 alone had a small number of positive foci at 13 weeks. However, no cytokeratin-positive foci were visible in the majority of livers from either group receiving I3C in combination with AFB1 and after 43 weeks all animals in these groups were protected from liver tumour formation. These results suggest that expression of cytokeratin 18, a later phenotypic change in foci than induction of GST-P and GGT, correlates more closely with tumour outcome in this model. I3C appeared to retard progression of AFB1-induced carcinogenesis at both the initiation and promotion stages. Continuous treatment with I3C for 13 weeks caused significant induction of CYP1A1, 1A2, 3A and 2B1/2, GST Yc2, aflatoxin B1 aldehyde reductase and quinone reductase. Such alteration of the drug metabolizing capacity of the liver by I3C contributes to blocking of initiation, while the observed inhibition of ornithine decarboxylase, a rate limiting enzyme in polyamine biosynthesis, and of tyrosine kinase activity may contribute to the suppressive effect of I3C.
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PMID:Chemoprevention of aflatoxin B1-induced carcinogenesis by indole-3-carbinol in rat liver--predicting the outcome using early biomarkers. 980 66

Identification and use of effective cancer chemopreventive agents have become an important issue in public health-related research. For identification of potential cancer chemopreventive constituents we have set up a battery of cell- and enzyme-based in vitro marker systems relevant for prevention of carcinogenesis in vivo. These systems include modulation of drug metabolism (inhibition of Cyp1A activity, induction of NAD(P)H:quinone reductase (QR) activity in Hepa1c1c7 murine hepatoma cell culture), determination of radical scavenging (DPPH scavenging) and antioxidant effects (scavenging of superoxide anion-, hydroxyl- and peroxyl-radicals), anti-inflammatory mechanisms (inhibition of lipopolysaccharide (LPS)-mediated nitric oxide (NO) generation by inducible NO synthase (iNOS) in Raw 264.7 murine macrophages, cyclooxygenase-1 (Cox-1) inhibition), and anti-tumor promoting activities (inhibition of phorbol ester-induced ornithine decarboxylase (ODC) activity in 308 murine keratinocytes). We have tested a series of known chemopreventive substances belonging to several structural classes as reference compounds for the identification of novel chemopreventive agents or mechanisms. These include organosulfur compounds (phenethylisothiocyanate (PEITC), diallylsulfide, diallyldisulfide), terpenes (limonene, perillyl alcohol, oleanolic acid, 18-beta-glycyrrhetinic acid), short-chain fatty acids (sodium butyrate), indoles (indole-3-carbinol), isoflavonoids (quercetin, silymarin, genistein), catechins ((-)-epigallocatechin gallate (EGCG)), simple phenols (ellagic acid, resveratrol, piceatannol, curcumin), pharmaceutical agents (piroxicam, acetylsalicylic acid, tamoxifen), and vitamins/derivatives (ascorbic acid, Trolox). We confirmed known chemopreventive mechanisms of these compounds. Additionally, we could demonstrate the usefulness of our approach by identification of hitherto unknown mechanisms of selected agents. As an example, we detected anti-inflammatory properties of PEITC, based on NF-kappaB-mediated inhibition of NO production. Further, PEITC inhibited phorbol ester-induced superoxide anion radical production in granulocytes, and ODC induction in the 308 cell line. These mechanisms might contribute to the chemopreventive potential of PEITC.
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PMID:Mechanism-based in vitro screening of potential cancer chemopreventive agents. 1262 14