Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The inhibitory effects of N-(4-hydroxyphenyl)retinamide (HPR) and its glucuronide derivative on the growth of MCF-7 human breast cancer cells in vitro were compared. The results indicate that the glucuronide had slightly greater potency and much less cytotoxicity than the free retinoid. At a concentration of 10(-6) M, HPR inhibited MCF-7 cell growth by approximately 25%, whereas an equimolar concentration of the glucuronide caused a 40% growth inhibition. Higher concentrations of HPR were highly cytotoxic. At a 10(-5) M concentration of the glucuronide, cell viability was 77%, and 65% of the cells were able to resume growth. On the other hand, at 10(-5) M HPR, cell viability dropped to 49%, and only 15% of the cells were capable of resuming growth. The lower cytotoxicity and higher potency of the retinoid glucuronide compared to the parent retinamide suggest that the conjugate may have a chemotherapeutic advantage over the parent compound. The apparent higher efficacy of HPR in combination with glucarate (GT) compared to the single agents could be due to increased net formation of HPR glucuronide conjugate following conversion of GT to the beta-glucuronidase inhibitor, D-glucaro-1,4-lactone. However, HPLC analysis of the cell metabolites did not show any detectable levels of the retinoid glucuronide upon treatment of MCF-7 cells with HPR and GT.
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PMID:Growth suppression of human breast carcinoma cells in culture by N-(4-hydroxyphenyl)retinamide and its glucuronide and through synergism with glucarate. 182 40

We briefly review some biochemical aspects of benign breast disease (BBD), mainly focusing on free and conjugate estrogen content of breast cyst fluid (BCF), also in relation to cyst type. Evidence is reported that high K(+)-type I-cysts clearly associate with low Cl- levels and accumulate significantly higher quantities of dehydroepiandrosterone sulfate (DHAS) and estrone-3-sulfate (E1S). In spite of the limited number of cases, both increasing DHAS and E1S levels correlate with the increment of K+ to Na+ ratio. A positive correlation was also found between DHAS and E1S. Using electrochemical detection (ECD) on-line to high performance liquid chromatography (HPLC) in the reverse phase mode, we also studied the free estrogen profile. We observed that in type I BCF there are significantly increased amounts of free estrone (E1). The E1S to E1 ratio was significantly different in the two cyst subpopulations; again, a positive correlation was found between free and sulfated E1 (r = 0.820, p less than 10(-6). This last, together with other experimental observations, allows us to hypothesize that in BCF a main pathway of steroids should be E1S----E1. Besides, high specific activity of sulfatase, as well as beta-glucuronidase enzymes, has been demonstrated for BBD. Preliminary information is also reported concerning the BCF pattern of free estrogens, including the highly polar ones, i.e., catecholestrogens (CCE) and the parent methoxy (MeO) conjugates, which represent, in BCF, a predominant portion of all free estrogens. Both CCE levels and ratios appear unevenly distributed in the two different cyst types. In addition, some BCFs show very high concentrations of 16 alpha-OH-E1. Further studies are needed to answer the main question: whether estrogen patterns could represent additive parameters to further categorize breast cystic disease (BCD) or whether they are of minor interest to determine patients' risk of developing breast cancer.
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PMID:Steroid patterns of benign breast disease. 214 55

Platelets contain mitogenic activities for MCF-7 human breast cancer cells when assayed under serum-free chemically defined conditions. Purification from outdated human platelets identified insulinlike growth factor I (IGF-I) as the most potent breast cancer cell mitogen in lysates (Karey KP, Sirbasku DA: see accompanying article, this issue). In this study the release and subcellular localization of IGF-I was investigated. Degranulation of platelets by thrombin treatment caused release of lysosomal enzymes (beta-glucuronidase and N-acetyl-D-glucosaminidase), alpha-granule proteins (beta-thromboglobulin and fibrinogen) as well as mitogenic activity for MCF-7 cells and IGF-I as measured by radioimmunoassay (RIA) and radioreceptor assay. Release of mitogenic activity and immunologically identified IGF-I was induced tenfold over controls by thrombin and was nearly complete as compared to platelets disrupted by repeated freezing and thawing. Disruption of platelets by nitrogen cavitation followed by separation of the organelles by sucrose density gradient sedimentation showed that IGF-I and mitogenic activity localized predominantly to fractions containing alpha-granules rather than soluble cellular components, lysosomes, or dense granules. The morphology of MCF-7 cells in serum-free medium supplemented with supernatants from thrombin-treated platelets also indicated the release of important cell-adhesion factors for human breast cancer cells.
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PMID:Human platelet-derived mitogens. II. Subcellular localization of insulinlike growth factor I to the alpha-granule and release in response to thrombin. 275 54

The enzyme activity of cancerous tissue and the adjacent normal epithelium of 40 patients with breast cancer was determined. This enzymatic activity was correlated with the responsiveness of those tumors to the chemotherapy. It was found that the presence of cytochrome oxidase and alkaline phosphatase and the absence of leucine aminopeptidase, beta-glucuronidase and dehydrogenases in cancerous tissues was related to good response. On the contrary, the absence of alkaline phosphatase and cytochrome oxidase and the presence of leucine aminopeptidase, beta-glucuronidase and dehydrogenases in the cancerous tissues was related to poor response and therefore to poor survival.
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PMID:Correlation of histoenzymological studies with the response to chemotherapy and survival in breast cancer patients. 284 63

The clinical efficacy of four laboratory tests in detecting leptomeningeal metastases in 57 patients with breast carcinoma was assessed. The sensitivity and specificity of beta-glucuronidase, beta 2-microglobulin, carcinoembryonic antigen and lactate dehydrogenase in cerebrospinal fluid were determined. As a single test beta-glucuronidase was the most sensitive (93%) and specific (93%) for discriminating between leptomeningeal metastases and other CNS metastases from breast cancer. Lactate dehydrogenase was the next most useful marker. Both beta 2-microglobulin and carcinoembryonic antigen had a sensitivity of 60%. More specific results were achieved by combining beta-glucuronidase and lactate dehydrogenase. CSF beta-glucuronidase may be useful by itself and in combination with lactate dehydrogenase in the detection of leptomeningeal metastases from breast carcinoma.
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PMID:Sensitivity and specificity of single and combined tumour markers in the diagnosis of leptomeningeal metastasis from breast cancer. 972 63

Metabolism of tamoxifen by rat hepatocytes and hydrolysis of the resulting polar metabolites corresponding to conjugates with beta-glucuronidase gave a major component which was identified as 1-[4-(2-hydroxyethoxy)phenyl]-1-(4-hydroxyphenyl)-2-phenyl-1-butene by comparison of mass spectral properties with those of synthetic material. This compound, which was not observed as a phase I metabolite, is believed to have been found previously in rat bile and in human faeces (metabolite F) but its structure had been incorrectly assigned. Its binding affinity for the estrogen receptor was greater than that of tamoxifen but less than that of 4-hydroxytamoxifen, and it possessed a corresponding degree of antitumour activity against the MCF-7 breast cancer cell line. By carrying out the hepatocyte incubation separately under oxygen and air, it has been shown that the N-oxidation of tamoxifen is favoured by a high concentration of oxygen during in vitro metabolism but that the rate of 4-hydroxylation is not dependent on oxygen availability.
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PMID:Metabolism of tamoxifen by isolated rat hepatocytes. Identification of 1-[4-(2-hydroxyethoxy)phenyl]-1-(4-hydroxyphenyl)-2-phenyl-1-butene and the dependence of N-oxidation on oxygen availability. 357 87

Certain enzymes in tissues and body fluids may, through reversal of the detoxification process, influence the composition and availability of steroid hormones, toxins, and carcinogens. The ubiquitous enzyme beta-glucuronidase, which hydrolyzes glucuronide conjugates, thereby reversing one of the main detoxification and excretion pathways, was found to vary in concentration in different cysts over a 300-fold range. The distribution was a continuum, devoid of discrete sub-populations. Evidence obtained on selected cyst fluids of high and low beta-glucuronidase activities indicated that the level of the enzyme significantly influenced the ratio of unconjugated: glucuronidated estradiol. The patients with fibrocystic breast disease fell into 2 distinct subpopulations on the basis of their serum beta-glucuronidase activity. In one group the activity was near normal, while in the second group the average serum beta-glucuronidase activity was 3-fold higher than in the women who did not have benign breast disease.
Breast Cancer Res Treat 1986
PMID:beta-Glucuronidase levels in patients with fibrocystic breast disease. 359 87

Activity of acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase in peripheral blood neutrophils of 30 women with breast cancer has been studied by means of semiquantitative cytochemical methods. In comparison to 20 healthy women the patients showed an increased activity of acid phosphatase and beta-glucuronidase whereas that of N-acetyl-beta-D-glucosaminidase was significantly lowered. It has been suggested that observed intracellular enzymatic deficiency is of importance with regard to lowered antitumor activity of neutrophils. Analogous deficiency of N-acetyl-beta-D-glucosaminidase within the neutrophils has previously been observed by the authors in women with malignant tumors of reproductive organs.
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PMID:Lysosomal enzymes of neutrophils in women with breast cancer. 666 9

Sprague-Dawley rats bearing 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors were treated with either of two aromatic alkylating agents, aniline mustard or melphalan, alone or combined with ovariectomy. Both drugs were applied once a week for 8 weeks. Eight-four percent of the tumors responded to ovariectomy, 38% regressing completely and 46% regressing partially. Aniline mustard, though virtually ineffective as a single agent, appeared synergistic with ovariectomy: a 100% regression rate (72% complete, 28% partial) was observed for this combination. Treatment with melphalan was as effective as ovariectomy, but the combination of melphalan with ovariectomy was no more effective than either treatment alone. The end product of aniline mustard metabolism, p-hydroxyaniline mustard O-glucuronide, may be more extensively activated by beta-glucuronidase in hormonally regressing than in growing or stationary tumors. Intratumoral levels of beta-glucoronidase occurring in DMBA-induced tumors 4 days after ovariectomy were found to be similar to those in the aniline mustard-sensitive mouse plasma cell tumor ADJ/PC6. It remains to be more extensively studied whether an effect of endocrine treatment on tumor beta-glucuronidase levels, and possibly on intracellular distribution of enzyme, could be used therapeutically. An effectively scheduled cytostatic treatment (with a drug conjugate such as that formed metabolically from aniline mustard) in conjunction with ovariectomy might be effective in the treatment of hormone-responsive breast cancer.
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PMID:Enhanced cytostatic effectiveness of aniline mustard against 7,12-dimethylbenz[a]anthracene-induced rat mammary tumors during regression in response to ovariectomy. 678 69

N-Acetyl-beta-glucosaminidase (NAG) and beta-glucuronidase were measured in the serum of 70 patients with breast and digestive-tract neoplasms and in 70 healthy subjects. The mean value of the NAG activity was significantly (P < 0.001) elevated in patients with gastric, liver and pancreas cancer as compared with the reference population. In patients with liver and pancreas cancer the very high sensitivity contrasted with a low specificity. NAG elevations above normal were observed in 14 (78%) patients with breast cancer, in 11 (100%) with gastric cancer, in 17 (70%) with colorectal cancer, in 8 (100%) with liver cancer and in 9 (100%) with pancreas cancer. In patients with breast and gastric cancer the enzyme shows a good specificity and sufficient sensitivity as a tumor marker. beta-Glucuronidase appeared less sensitive and was significantly elevated (100%) only in patients with pancreas cancer.
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PMID:A study of serum glycosidases in cancer. 786 Jun 21


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