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)

3-Hydroxybenzo[a]pyrene (3-OH-BaP) is oxidized by the horseradish peroxidase/H2O2 system to benzo[a]pyrene-3,6-quinone. In the presence of N-acetylcysteine one other product is also formed. This was identified by its chemical, and u.v., mass and n.m.r. spectral properties as 6-(H-acetyl-cystein-S-yl)-3-hydroxybenzo[a]pyrene (6-NAc-cys-3-OH-BaP). Replacement of the N-acetylcysteine by glutathione leads to the formation of a 3-OH-BaP-glutathione adduct. Enzymic hydrolysis of benzo[a]pyrene-3-glucuronide in the presence of N-acetylcysteine yields, in addition to 3-OH-BaP, a product which co-chromatographs with 6-NAc-cys-3-OH-BaP and has identical chemical and spectral characteristics.
Carcinogenesis 1986 Mar
PMID:Reactive intermediates from 3-hydroxybenzo[a]pyrene and its glucuronide. 394 31

Benzidine is oxidized by the peroxidase/H2O2 system, yielding reactive intermediates. In the presence of thiols, covalent adducts are formed. We used h.p.l.c. to separate the products of the reaction of benzidine with N-acetylcysteine. The major product was identified by n.m.r. spectroscopy (1H-n.m.r.) as 3-(N-acetylcystein-S-yl)-benzidine.
Carcinogenesis 1985 Jan
PMID:Identification of the N-acetylcysteine conjugate of benzidine formed in the peroxidase activation system. 396 36

Twenty eight patients with colonic cancer, who were asymptomatic after intestinal resection and anastomosis, underwent colonoscopy as part of their routine follow up, and biopsies were obtained from the anastomosis and several other sites. Sections were stained by haematoxylin and eosin, several methods for mucin, and by the peroxidase-antiperoxidase method for carcinoembryonic antigen. Non-specific inflammatory changes were seen at the anastomosis in 11 of the 28 cases, apparent in several two years after operation; focal surface ulceration was seen in over half these samples. Neither dysplastic nor adenomatous change was detected, but at seven anastomoses the so called transitional change, which has been regarded as a preneoplastic change, was apparent. There was no consistent alteration in carcinoembryonic antigen reactivity. It is concluded that there is morphological evidence of a continued stimulus to regenerative activity at some anastomoses and that this may represent a promoting factor enhancing further carcinogenesis.
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PMID:Mucosal abnormalities at the anastomosis site in patients who have had intestinal resection for colonic cancer. 398 51

Adriamycin (ADR) failed to inhibit and paradoxically enhanced the biological action of 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse epidermis in vivo and in vitro. In the presence of ADR, the tumor promoter caused a greater sequential rapid increase and prolonged decrease in glutathione (GSH) peroxidase (GSH:H2O2 oxidoreductase, EC 1.11.1.9) activity accompanied by a greater decrease in the ratio of reduced (GSH)/oxidized (GSSG) glutathione in isolated epidermal cells. The ability of ADR to deplete the intracellular level of GSH correlated with its ability to increase basal and TPA-induced ornithine decarboxylase (ODC, L-ornithine carboxylase, EC 4.1.1.17) activities. In vivo, topical ADR treatments also enhanced TPA-induced ODC activity as well as the tumor-promoting ability of TPA in the two-stage system of mouse skin carcinogenesis. Since lipid peroxidation has been associated with ADR toxicity, these data suggest that the enhancement of the tumor-promoting ability of TPA by ADR may be the result of an increased oxidative challenge that overwhelms the GSH-dependent antioxidant protective system of the epidermal cells.
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PMID:Enhancement by adriamycin of the effects of 12-O-tetradecanoylphorbol-13-acetate on mouse epidermal glutathione peroxidase activity, ornithine decarboxylase induction and skin tumor promotion. 407 83

Preneoplastic liver foci were produced in female Wistar rats by the administration of 2-acetylaminofluorene (0.03% w/w) in the diet for 174 days. Increased UDP-glucuronyltransferase (UDP-GT) could be visualized immunohistochemically in the same focal areas which were ATPase-negative and gamma-glutamyltranspeptidase-positive. Immunohistochemical detection was possible using rabbit anti-UDP-GT and peroxidase-labeled swine anti-rabbit immunoglobulins. The results of immunohistochemistry were substantiated by enzyme determination in microdissected material. UDP-GT activity was 5-fold higher in focal areas in comparison with the surrounding liver tissue. Increased UDP-GT activity in conjunction with the altered pattern of other drug-metabolizing enzymes is consistent with increased resistance of preneoplastic cells to the cytotoxicity of carcinogens. Immunohistochemical detection of UDP-GT may provide a new marker for preneoplastic lesions which, in conjunction with other markers, may prove useful in analyzing the various stages of liver carcinogenesis and the remodeling of preneoplastic lesions after cessation of carcinogenic stimuli.
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PMID:Immunohistochemical and biochemical detection of uridine-diphosphate-glucuronyltransferase (UDP-GT) activity in putative preneoplastic liver foci. 613 91

A method is proposed for the simultaneous staining of neutral and acidic, periodate reactive and nonperiodate reactive mucosubstances, glycogen and keratin in paraffin sections. Briefly, sections are stained by the Alcian blue (pH 2.5)-PAS method, followed by a peroxidase-antiperoxidase immunohistochemical stain for keratin. The proposed method modifies an existing method, and expands the range of polysaccharides and mucosubstances which may be demonstrated. The proposed method is easily performed within a single working day and promises to be of value in surgical pathology as well as in studies of bronchial carcinogenesis.
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PMID:An Alcian blue (pH 2.5)-PAS-keratin immunoperoxidase method for the simultaneous demonstration of keratin and neutral and acidic mucosubstances. 619 75

Prostaglandin H synthase (PHS) and horseradish peroxidase catalyze the oxidation of benzidine to the same free radical species. No radical was observed if either benzidine, H2O2 or enzyme was omitted. The similarity of the fine structure of this radical to a computer-simulated model suggests the presence of a free cation radical of benzidine. Neither superoxide nor hydroxyl radicals appear to be involved in the co-oxidation of benzidine or 2-amino-4-(5-nitro-2-furyl)-thiazole (ANFT) by PHS. Production of the benzidine radical by PHS was inhibited by ANFT, acetaminophen, cyanide and ascorbate. ANFT was metabolized by PHS but not by horseradish peroxidase. ANFT had no effect on either radical production or 14C-metabolism of benzidine by horseradish peroxidase. These results indicate that different peroxidases may exhibit specificity with respect to the carcinogens they activate. The free radical cation of benzidine may be the electrophilic intermediate responsible for PHS-catalyzed binding of benzidine to protein and nucleic acids.
Carcinogenesis 1983
PMID:Prostaglandin H synthase metabolism of the urinary bladder carcinogens benzidine and ANFT. 629 1

Variation of the binding Ulex europaeus agglutinin-I (Ulex-I), a lectin specific for blood group H(O) substance, was examined in normal, dysplastic and cancerous esophageal epithelium from 43 instances of carcinoma by means of the lectin- antilectin peroxidase-antiperoxidase method. The normal epithelium showed strong staining at the cell border, although the basal cells were entirely negative. In mild and moderate dysplasia, staining was negative, while in some cases of severe dysplasia positive staining was found in the basal cells. Most of the basal cells in carcinoma in situ revealed granular or diffuse positive staining in the cytoplasm. The results indicate that the loss of blood group H antigen occurs during carcinogenesis of the esophageal mucosa. Thus, Ulex-I may be a useful marker of cytoplasmic differentiation of the esophagus.
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PMID:Blood group H(O) antigen in normal, dysplastic and carcinomatous esophageal epithelium. 637 74

The prostaglandin synthase and horseradish peroxidase catalyzed binding of p-phenetidine to DNA was investigated. The addition of arachidonic acid to an incubation containing ram seminal vesicle microsomes, [14C]p-phenetidine and DNA resulted in a rapid incorporation of radioactivity into DNA. This was inhibited by greater than 75% by indomethacin (0.1 mM) or butylated hydroxyanisole (0.5 mM). Hydrogen peroxide was as efficient as arachidonic acid in mediating the activation of p-phenetidine thus implicating the involvement of the hydroperoxidase activity of prostaglandin synthase in this reaction. Horseradish peroxidase and hydrogen peroxide also catalyzed the activation of p-phenetidine to DNA-binding metabolites. Reduced glutathione (GSH) stimulated the binding of p-phenetidine to DNA by greater than 3-fold in both the prostaglandin synthase and the horseradish peroxidase system, whereas cysteine and N-acetylcysteine reduced the DNA-binding in the prostaglandin synthase system by up to 62% under the conditions used. Furthermore, water-soluble metabolites formed in the presence of GSH also bound to DNA. Seventy-two hour dialysis of DNA samples from incubations with GSH present reduced the amount of bound material by 75%. In contrast, the radioactivity which associated with DNA in the absence of GSH was not decreased by dialysis.
Carcinogenesis 1984 Feb
PMID:Prostaglandin synthase and horseradish peroxidase catalyzed DNA-binding of p-phenetidine. 642 1

Complex carbohydrates in premalignant lesions of mouse submandibular gland tumors were examined by the lectin-peroxidase conjugate method. Peroxidase-conjugated lectins of PNA, RCA-1, DBA, SBA, UEA-1 and WGA were used to detect specific sugar residues of complex carbohydrates in premalignant lesions during experimental carcinogenesis. Marked reduction of PNA and SBA bindings occurred in duct-like structures and cystic lesions which were transformed from granular convoluted tubule cells. Premalignant lesions bound slightly to PNA, RCA-1, DBA, SBA and WGA and manifested increased UEA-1 binding. Squamous metaplastic epithelia of premalignant lesions manifested increased binding to PNA, RCA-1 and SBA as compared to those of duct-like structure and cystic epithelia.
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PMID:Lectin-binding in premalignant lesions during submandibular gland carcinogenesis. 643 17


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