Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0596263 (carcinogenesis)
 64,820 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Both 2,3,5-trimethyl-6-(12-hydroxy-5,10-dodecadiynyl)-1,4-benzoquinone (AA861) and 3,4,2',4'-tetrahydroxychalcone inhibited 12-lipoxygenase of mouse epidermis. The IC50 of AA861 and 3,4,2',4'-tetrahydroxychalcone for epidermal 12-lipoxygenase were 1.9 and 0.2 microM, respectively. These agents showed very weak inhibitory actions on epidermal cyclooxygenase, with the potency of inhibition for cyclooxygenase less than 1/50 of that for lipoxygenase. Induction of epidermal ornithine decarboxylase by 12-O-tetradecanoylphorbol-13-acetate (TPA; 10 nmol/mouse) was potently inhibited by these agents in a dose-dependent manner (1-30 mumol/mouse). TPA (5 nmol/mouse)-induced skin tumor formation was also strongly suppressed by these agents (15 mumol/mouse). Both AA861 and 3,4,2',4'-tetrahydroxychalcone failed to inhibit partially purified epidermal protein kinase C activity. These results support the proposed involvement of lipoxygenase product(s) of arachidonic acid in TPA-induced skin tumor promotion.
Carcinogenesis 1986 Nov
PMID:Inhibition of 12-O-tetradecanoylphorbol-13-acetate-mediated epidermal ornithine decarboxylase induction and skin tumor promotion by new lipoxygenase inhibitors lacking protein kinase C inhibitory effects. 309 75

The role of glucuronidation and sulfation in the control of proximal and ultimate carcinogens is briefly reviewed. In accordance with the adopted practice of tumor risk assessment, data from two rodent species (rat, mouse) and man have been compared. Sulfate esters have been established as ultimate carcinogens in 2-acetylaminofluorene, safrole and estragole induced hepatocarcinogenesis. In interspecies comparisons the tumor incidence paralleled sulfotransferase activity (Miller and Miller 1981). Glucuronides are often stable transport forms of carcinogens and in this way determine their organ specificity, for example in 2-naphthylamine-induced bladder carcinogenesis and in colon carcinogenesis produced by 2',3-dimethyl-4-aminobiphenyl. In contrast to sulfotransferase activity certain UDP-glucuronyltransferase activities are differentially inducible by xenobiotics. A 3-methylcholanthrene-inducible phenol-glucuronyltransferase (GT1), present in rat, mouse and man, appears to be part of an adaptive program to detoxify aromatic hydrocarbons. After initiation of hepatocarcinogenesis permanent alterations of these enzymes occur; GT1 is markedly increased whereas sulfotransferase is decreased. Together with changes of other drug metabolizing enzymes these alterations often lead to toxin-resistance of initiated hepatocytes. This phenomenon may facilitate selective growth of initiated hepatocytes and may enhance the probability of multiple hits in their genome.
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PMID:Species differences of glucuronidation and sulfation in relation to hepatocarcinogenesis. 310 20

The effects of promoter treatments prior to initiation on subsequent promotion by mezerein were examined in SENCAR mice. Groups of mice received two applications of various complete as well as first and second stage promoters given at various time intervals prior to initiation ranging from 3 days to 10 weeks. The mice were then initiated with 2 micrograms of 7,12-dimethylbenz[a]anthracene (DMBA) followed 2 weeks later by twice-weekly treatments with 2 micrograms of mezerein. The papilloma response in mice, receiving pretreatments with 2 micrograms of 12-O-tetradecanoylphorbol-13-acetate (TPA) either 3 days, 1, 2, 3 or 5 weeks before initiation, was similar to that seen when TPA was given after initiation during stage I of promotion followed by stage II of promotion with mezerein (4-5 papillomas per mouse in all groups). Surprisingly, pretreatment with the stage II promoter, mezerein (2 micrograms), either 2 or 5 weeks prior to initiation, also gave papilloma responses similar to that induced with the standard two-stage promotion protocol (4.7 and 6.4 papillomas per mouse, respectively). The papilloma response was less than that in the standard two-stage promotion protocol when pretreatments with the stage I promoter A23187 (80 micrograms/mouse) were given either 2 or 5 weeks before initiation (2.6 and 2.3 papillomas per mouse, respectively). However, a repeat experiment (currently in progress) with a higher dose of A23187 (160 micrograms/mouse) given 2 weeks prior to initiation indicates that it is more effective than the 80 micrograms dose. When the time interval between pretreatment and initiation was increased to 10 weeks, the papilloma response with TPA and A23187 pretreatment was reduced to below two papillomas per mouse and with mezerein pretreatment to below three papillomas per mouse, indicating the effect was reversible. Histological changes in epidermis of mice which received two applications of these compounds correlated with the tumor response. In this regard, treatment with two applications of TPA and mezerein resulted in an epidermal hyperplasia of similar magnitude (epidermal thickness of 53.5 +/- 1.5 and 50.0 +/- 1.1 microns, respectively). The hyperplasia produced by treatment with two applications of 80 micrograms A23187 (39.4 +/- 1.8 microns) was significantly less. The ability of pretreatments with benzoyl peroxide (20 mg) and chrysarobin (50 micrograms) to affect the subsequent promoting activity of mezerein was also examined.(ABSTRACT TRUNCATED AT 400 WORDS)
Carcinogenesis 1988 Mar
PMID:Enhancement of mezerein-promoted papilloma formation by treatment with 12-O-tetradecanoylphorbol-13-acetate or mezerein prior to initiation. 312 93

The present study examined the effect of several prototypic inhibitors of phorbol ester skin tumor promotion on skin tumor promotion by chrysarobin, an anthrone tumor promoter. Retinoic acid (RA) inhibited skin tumor promotion by chrysarobin; however, the degree of inhibition was dependent on the treatment protocol. When RA (10 micrograms/mouse) was given 1 h after each twice-weekly application of chrysarobin (220 nmol/mouse), a marked inhibition of papilloma formation was observed (78%). In additional experiments, using a once-weekly application of chrysarobin, RA also inhibited skin tumor promotion but the magnitude of inhibition was less. Interestingly, RA (10 micrograms/mouse), given 1 or 6 h after the promoter, did not inhibit the induction of epidermal ornithine decarboxylase (ODC) activity induced by a single topical application of chrysarobin (220 nmol). Fluocinolone acetonide (1 microgram/mouse), given 5 min before each twice-weekly application of chrysarobin (220 nmol/mouse) effectively inhibited skin tumor promotion (88%). A 0.5 or 0.25% supplement of alpha-difluoromethylornithine (alpha-DFMO) in the drinking water inhibited the induction of epidermal ODC following chrysarobin (220 nmol/mouse) treatment by 85 or 70%, respectively. Supplements of both 0.25 and 0.5% of alpha-DFMO also led to a 50 and 61% inhibition, respectively, in the number of papillomas per mouse after 25 weeks of promotion with chrysarobin. Interestingly, 0.25% alpha-DFMO in the drinking water did not reduce the number of papillomas per mouse after 20 weeks of promotion with 1.7 nmol 12-O-tetradecanoylphorbol-13-acetate (TPA). However, the number of papillomas per mouse that were greater than or equal to 4 mm in diameter was significantly reduced in both chrysarobin- and TPA-treated mice. The data indicate that RA, FA and alpha-DFMO may be general inhibitors of tumor promoter regardless of the chemical class of tumor promoter. The ability of these inhibitors of phorbol ester promotion to inhibit anthrone promotion indicates that some common biochemical pathways may exist for both classes of skin tumor promoters.
Carcinogenesis 1988 Aug
PMID:Modulation of chrysarobin skin tumor promotion. 313 55

The influence of initiator dose and promoter dose, duration, and type on the progression of papillomas to carcinomas was examined in Sencar mice. A good dose-response relationship for promotion of papilloma formation by 12-O-tetradecanoylphorbol-13-acetate (TPA) [following initiation with 6.5 micrograms of 7,12-dimethylbenz(a)anthracene (DMBA)] was observed in the range of 0.125 to 2.0 micrograms/mouse. A maximal papilloma response was induced with 2 micrograms/mouse (24 papillomas/mouse). When adjusted for mortality, the carcinoma incidence after 60 wk of promotion was essentially the same (approximately 80%) for doses above 0.5 micrograms/mouse. In a related experiment, mice were given an initiation dose of either 2 or 20 micrograms of DMBA followed by applications of 2 micrograms of TPA for 3, 5, 7, or 60 wk. Papilloma formation was proportional to length of treatment, with a maximum of 29 papillomas/mouse (20-micrograms initiating dose of DMBA) and 10 papillomas/mouse (2-micrograms initiating dose of DMBA) occurring between 10 and 15 wk of promotion. In this experiment, the carcinoma incidence was clearly proportional to the duration of promoter treatment at the low initiation dose of DMBA. The carcinoma incidence, on the other hand, was similar (approximately 70%) in groups of mice given an initiation dose of 20 micrograms of DMBA and promotion treatment for greater than or equal to 5 wk. Thus, the initiator dose had a dramatic effect on the outcome of these experiments. Additional experiments were performed to compare tumor progression with the anthrone promoter, chrysarobin. At optimal promoting doses, chrysarobin treatment produced a maximum number of papillomas that was approximately 1/3 that produced by TPA (6.4 versus 17.0 papillomas per mouse, respectively). However, the carcinoma response was very similar in these two treatment groups, confirming previous work from this laboratory. In addition, chrysarobin treatment following 10 wk of TPA promotion did not enhance the progression of preexisting papillomas to carcinomas. The data presented in this paper are consistent with a model in which several types or stages of papillomas are initially produced during two-stage carcinogenesis in mouse skin with different probabilities of progressing to carcinomas. However, the data indicate that optimal doses of promoter and initiator exist and can influence interpretation of tumor progression studies in mouse skin.
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PMID:Tumor progression in Sencar mouse skin as a function of initiator dose and promoter dose, duration, and type. 314 81

SENCAR mice have been selectively bred for hypersusceptibility to 2-stage chemical skin carcinogenesis. In this study the relative susceptibilities of SENCAR, BALB/c and CD-1 mice to systemic carcinogenesis by N-nitrosohexamethyleneimine (NHEX) were examined. NHEX was administered twice weekly (1 mg/mouse) in corn oil by gavage for 30 weeks. NHEX caused primarily liver and lung tumors in all 3 strains of mice. Hemangiosarcomas (but not other liver tumors) were more common in CD-1 mice than BALB/c or SENCAR mice. Lung tumors (adenomas and adenocarcinomas) and forestomach tumors (squamous carcinomas) were more common in SENCAR mice than BALB/c or CD-1 mice. Survival was better in SENCAR mice dosed with NHEX than in the other 2 strains. These results indicate that SENCAR mice are not unusually sensitive to liver carcinogenesis by NHEX, but are relatively sensitive to tumorigenesis in 2 epithelial tissues, lung and forestomach.
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PMID:Strain comparison of systemic N-nitrosohexamethyleneimine carcinogenesis in BALB/c, SENCAR and CD-1 mice. 340 40

The present study was designed to compare the skin tumor promoting and epidermal ornithine decarboxylase (ODC) inducing activities of various structural analogs of anthralin (1,8-dihydroxy-9-anthrone) and chrysarobin (1,8-dihydroxy-3-methyl-9-anthrone). Groups of 30 SENCAR mice each were initiated with 7,12-dimethylbenz[a]anthracene and 2 weeks later promoted with once- or twice-weekly applications of various doses of these anthrone derivatives. Carbon-10 (C10)-acyl derivatives of anthralin were active skin tumor promoters in the range of 25-440 nmol per mouse. 10-Acetylanthralin was significantly more active than 10-myristoyl-anthralin at low doses (e.g. 25 and 50 nmol per mouse) and nearly as potent as the unsubstituted compound. Higher doses (greater than or equal to 100 nmol per mouse) of this derivative were toxic, hence, reducing the final papilloma response. On a relative activity scale where anthralin is 1.0, these derivatives had activities that were approximately 0.7 and 0.2, respectively. 10,10-Dipropylanthralin was totally inactive at the doses tested. C6-Substituted derivatives of chrysarobin demonstrated diverse tumor promoting activities when tested in the range of 25-440 nmol per mouse. On a relative activity scale where chrysarobin is 1.0, 6-methoxychrysarobin (physcion anthrone) was approximately 0.9, whereas 6-hydroxychrysarobin (emodin anthrone) had no activity. Chrysophanic acid (1,8-dihydroxy-3-methyl-9,10-anthraquinone) was also inactive as a tumor promoter at the doses tested. In general, the tumor promoting activities of these anthrone derivatives correlated very well with their ability to induce epidermal ODC after a single topical application indicating an important role for this enzyme in skin tumor promotion by anthones. The ability of C10-substituted derivatives of anthralin to undergo base catalyzed oxidation in vitro correlated with both ODC inducing and tumor promoting activities. In addition, copper(II)bis(diisopropylsalicylate) was found to inhibit both ODC induction and skin tumor promotion by chrysarobin. These latter data, when taken together, suggest a role for oxidation at C10 in skin tumor promotion by anthrone derivatives.
Carcinogenesis 1988 Aug
PMID:Structure-activity relationships for epidermal ornithine decarboxylase induction and skin tumor promotion by anthrones. 340 40

The effect of dietary beta-carotene on colon carcinogenesis induced by 1,2-dimethylhydrazine [(DMH) CAS: 540-73-8] was studied in female inbred Swiss Webster (ICR) mice. At age 10 weeks and continuing throughout the experiment, mice received diets consisting mainly of natural foods (laboratory chow) and containing 2 or 22 mg beta-carotene/kg. At age 15 weeks they received 7 weekly sc injections of DMH (total dose: 196 mg DMH X diHCI/kg body wt). When autopsied 31 weeks after the first DMH injection, the incidence (percent of mice with tumors) and multiplicity (number of tumors/tumor-bearing mouse) of colon tumors were reduced by half in the mice supplemented with beta-carotene. There was a much greater decrease in adenocarcinomas than in adenomas. Mice observed for 13 additional weeks revealed that the mortality rate, due largely or wholly to colon cancer, was only about half in supplemented mice. Mice sacrificed 12 weeks after the first dose of DMH (i.e., well before tumors appeared) showed mild colon mucosal hyperplasia. beta-Carotene supplementation, however, did not alter this, indicating that the protective effect against colon cancer may have occurred at a late stage of carcinogenesis.
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PMID:Protective effect of beta-carotene against colon tumors in mice. 347 57

We have studied the effects of the co-carcinogen catechol (1,2-dihydroxybenzene) on the metabolic activation of [3H] benzo[a]pyrene (BaP) in mouse skin, in vivo and on the binding of BaP metabolites to DNA and protein at intervals from 0.5-24 h. Upon topical application of 0.015 mg [3H]BaP and 0.25 or 0.5 mg catechol per mouse, catechol had little effect on the total amount of [3H]BaP metabolized in mouse skin, but it affected the relative proportions of [3H]BaP metabolites. Catechol (0.5 mg/mouse) decreased the proportion of water-soluble [3H]BaP metabolites, ethyl acetate-soluble polar metabolites and quinones, but doubled the levels of unconjugated 3-hydroxy-BaP at all measured intervals after treatment. Catechol also caused a small increase in the levels of trans-7,8-dihydroxy-7,8-dihydroBaP and trans-9,10-dihydroxy-9,10-dihydroBaP 0.5 h after treatment. Two hours after treatment, the levels of these metabolites subsided to those of the controls. Catechol did not affect the levels of glutathione conjugates of BaP. However, it caused a decrease in glucuronide and sulphate conjugate formation from BaP. Catechol caused an approximately 2-fold increase in the formation of anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydroBaP (BPDE) DNA adducts and elevated the ratio of anti-syn-BPDE-DNA adducts 1.6 to 2.9-fold. Catechol treatment increased the radioactivity associated with epidermal proteins after [3H]BaP application. Because catechol increased levels of 3-hydroxyBaP, we considered the possibility that 3-hydroxyBaP might enhance the tumor initiating activities of BaP or BPDE in mouse skin; a bioassay demonstrated that this was not the case. The results of this study indicate that one important effect of catechol related to its co-carcinogenicity is its ability to enhance formation of anti-BPDE-DNA adducts in mouse skin.
Carcinogenesis 1986 Jan
PMID:Effects of the co-carcinogen catechol on benzo[a]pyrene metabolism and DNA adduct formation in mouse skin. 351 Jul 52

The effects of cabbage and vitamin E on colon carcinogenesis were investigated in Swiss mice treated with 1,2-dimethylhydrazine. Throughout the experiment the mice were fed a laboratory chow diet (46 mg vitamin E per kg) or chow containing 13 g cabbage per 100 g or 180 mg vitamin E per kg. Starting after 31 days of diet treatment the mice received 7 weekly s.c. injections of DMH. They were sacrificed 17 weeks after the first dose of DMH. While diet did not significantly alter colon tumor response, some trends were observed. Female mice given cabbage had a higher incidence (percent of mice with a tumor) and multiplicity (tumors per tumor bearing mouse) of colon tumors. Males were little affected by cabbage apart from a lower incidence of adenocarcinomas. Compared with mice fed the control diet those given vitamin E had a higher colon tumor incidence. This effect, which was stronger in females, was due to an increased incidence of adenomas. Vitamin E had little apparent affect on tumor multiplicity apart from a reduction in adenocarcinomas in females and adenomas in males. The data do not support the view that cabbage and vitamin E are protective against colon cancer.
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PMID:Cabbage and vitamin E: their effect on colon tumor formation in mice. 356 89


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