Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.1.3.1 (alkaline phosphatase)
47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

There has been considerable variability in the reported results of immunohistochemical staining for some diagnostically relevant antigens. Our objectives in this study were to (1) use a multitumor tissue microarray with tissue from 351 cases received in our department, representing 16 normal tissues and 47 different tumor types, to compare immunohistochemical staining results in our laboratory with published data, using a panel of 22 antibodies; (2) assess interlaboratory variability of immunohistochemical staining for S-100 using this microarray; and (3) test the ability of hierarchical clustering analysis to group tumors by primary site, based on their immunostaining profile. Tissue microarrays consisting of duplicate 0.6-mm cores from blocks identified in the hospital archives were constructed and stained according to our usual protocols. Antibodies directed against the following antigens were used: B72.3, bcl-2, carcinoembryonic antigen, c-kit, pankeratin, CD 68, CD 99, CK 5/6, CK 7, CK 8/18, CK19, CK 20, CK 22, epithelial membrane antigen, estrogen receptor, melan-A, p53, placental alkaline phosphatase, S-100, synaptophysin, thyroid transcription factor-1, and vimentin. Staining results on the array cases were compared with published results, and hierarchical clustering analysis was performed based on the immunohistochemical staining results. Unstained slides of the multitumor tissue microarray were sent to five other diagnostic immunohistochemistry laboratories and stained for S-100 protein. The staining results from the different laboratories were compared. Staining results using our current methods and samples from our laboratory were compatible with those described in the literature for most antigens. Placental alkaline phosphatase staining was not specific with our protocol, showing staining of a broad spectrum of different tumors; this finding initiated a review of our recent requests for placental alkaline phosphatase immunostaining and revealed two instances in which placental alkaline phosphatase positivity was incorrectly interpreted as evidence of a germ cell tumor. S-100 staining was less sensitive but more specific for the diagnosis of melanoma or neural tumor in our laboratory, compared to some published reports. Assessment of interlaboratory variability of S-100 immunostaining showed that there was more frequent staining of carcinomas in some laboratories, resulting in decreased specificity of S-100 staining in distinguishing melanoma from carcinoma. Hierarchical clustering analysis showed a strong trend for tumors to cluster by tissue of origin, but there were significant exceptions. We conclude that multiple-tumor microarrays are an efficient method for assessing the sensitivity and specificity of staining with any antibody used diagnostically. As a tool for quality assurance, they offer the advantage of taking into account local differences in tissue fixation, processing, and staining. They also allow cost-effective assessment of interlaboratory variability in immunohistochemical staining. Results of hierarchical clustering analysis show the potential for panels of immunohistochemical stains to identify the primary site of metastatic carcinomas but also confirm the limitations of currently available antibodies in giving unequivocal tissue-specific staining patterns.
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PMID:Tissue microarrays are an effective quality assurance tool for diagnostic immunohistochemistry. 1248 Oct 20

Xenoestrogens, phytoestrogens and synthetic estrogens, are able to bind to estrogen receptors, and to mimic estrogenic activities in a cell and tissue specific manner. For the characterization of environmental estrogens mainly mammary derived and yeast based models have been used. The aim of this study was therefore to assess selected natural and synthetic compounds in an endometrial derived model. We measured the relative estrogenic potency of phytoestrogens (genistein, daidzein, coumestrol, some naringenins), synthetic estrogens (bisphenol A, octylphenol, nonylphenol, o,p'-DDT), mycoestrogen (zearalanone) as well as extracts of Cimicifuga racemosa on alkaline phosphatase (AlkP) activity in the endometrial derived adenocarcinoma cell line Ishikawa. We used a modified multiwell plate in vitro bioassay based on the estrogen-specific and dose-dependent enhancement of AlkP activity in this cell line. Estradiol, which induced AlkP at levels as low as 10(-8)M, was used as positive control. Most of the compounds studied showed a clear dose-dependent estrogenic effect. Compared to the vehicle control (ethanol) all phyto- and mycoestrogens, stimulated the AlkP activity 2-4-fold at a concentration of 10(-6)M. The synthetic chemicals bisphenol A and nonylphenol showed an effect at 10(-6)M, octylphenol at 10(-5)M. Effects of o,p'-DTT could not be measured. ICI 182,780, a pure estrogen receptor antagonist, significantly inhibited these effects. The latter result demonstrated the estrogen receptor dependency of this process. In summary, most of the phytoestrogens and industrial chemicals tested, behaved as estrogen receptor agonists in terms of the stimulation of AlkP activity.
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PMID:Stimulation of alkaline phosphatase activity in Ishikawa cells induced by various phytoestrogens and synthetic estrogens. 1265 Jul 20

Analysis of cellular morphology is the most general approach to neuronal classification. With the increased use of genetically engineered mice, there is a growing need for methods that can selectively visualize the morphologies of specified subsets of neurons. This capability is needed both to define cell morphologic phenotypes and to mark cells in a noninvasive manner for lineage studies. To this end, we describe a bipartite genetic system based on a Cre-estrogen receptor (ER) fusion protein that irreversibly activates a plasma membrane-bound alkaline phosphatase reporter gene by site-specific recombination. Because the efficiency and timing of gene rearrangement is controlled pharmacologically, a sparse subset of labeled cells can be generated from the set of CreER-expressing cells at any time during development. Histochemical visualization of alkaline phosphatase activity reveals neuronal morphology with strong and uniform labeling of all processes.
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PMID:A noninvasive genetic/pharmacologic strategy for visualizing cell morphology and clonal relationships in the mouse. 1265 90

Genistein, a soybean isoflavone, has estrogen-like activity in mammals, including the prevention of bone loss. However, whether its mechanism of action on bone turnover is distinct from that of estrogen or raloxifene is unknown. Although genistein has been reported to bind both estrogen receptor (ER) isoforms (alpha and beta), little is known concerning differential activation of gene expression via these ER isoforms. To examine this question, comparison of the responses of normal fetal osteoblast (hFOB) cells stably expressing either ERalpha (hFOB/ERalpha9) or ERbeta (hFOB/ERbeta6), to treatment with genistein, 17beta-estradiol (E(2)) or raloxifene were conducted. In hFOB/ERalpha9 cells, both genistein and E(2) increased the endogenous gene expression of the progesterone receptor (PR), the proteoglycan versican, and alkaline phosphatase (AP), but inhibited osteopontin (OP) gene expression and interleukin-6 (IL-6) protein levels. Raloxifene had no effect on these bone markers. Genistein, but not raloxifene, also mimicked E(2) action in the hFOB/ERbeta6 cells increasing PR gene expression and inhibiting IL-6 production. To determine whether the gene regulatory actions of genistein in human osteoblast cells occur at the level of transcription, its action on the transcriptional activity of a PR-A promoter-reporter construct was assessed. Both genistein and E(2) were found to stimulate the PR promoter in the hFOB cell line when transiently co-transfected with either ERalpha or ERbeta. Whereas hFOB cell proliferation was unaffected by E(2), raloxifene or genistein at low concentrations, higher concentrations of genistein, displayed significant inhibition. Together, these findings demonstrate that genistein behaves as a weak E(2) agonist in osteoblasts and can utilize both ERalpha and ERbeta.
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PMID:Phytoestrogen genistein acts as an estrogen agonist on human osteoblastic cells through estrogen receptors alpha and beta. 1276 96

4-Methylbenzylidene-camphor (4-MBC) is an organic sunscreen that protects against UV radiation and may therefore help in the prevention of skin cancer. Recent results on the estrogenicity of 4-MBC have raised concerns about a potential of 4-MBC to act as an endocrine disruptor. Here, we investigated the direct interaction of 4-MBC with estrogen receptor (ER) alpha and ERbeta in a series of studies including receptor binding, ER transactivation and functional tests in human and rat cells. 4-MBC induced alkaline phosphatase activity, a surrogate marker for estrogenic activity, in human endometrial Ishikawa cells. Interestingly, 4-MBC induced weakly ERalpha and with a higher potency ERbeta mediated transactivation in Ishikawa cells at doses more than 1 microM, but showed no distinct binding affinity to ERalpha or ERbeta. In addition, 4-MBC was an effective antagonist for ERalpha and ERbeta. In an attempt to put 4-MBC's estrogenic activity into perspective we compared binding affinity and potency to activate ER with phyto- and xenoestrogens. 4-MBC showed lower estrogenic potency than genistein, coumestrol, resveratrol, bisphenol A and also camphor. Analysis of a potential metabolic activation of 4-MBC that could account for 4-MBC's more distinct estrogenic effects observed in vivo revealed that no estrogenic metabolites of 4-MBC are formed in primary rat or human hepatocytes. In conclusion, we were able to show that 4-MBC is able to induce ERalpha and ERbeta activity. However, for a hazard assessment of 4-MBC's estrogenic effects, the very high doses of 4-MBC required to elicit the reported effects, its anti-estrogenic properties as well as its low estrogenic potency compared to phytoestrogens and camphor has to be taken into account.
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PMID:Activation of estrogen receptor alpha and ERbeta by 4-methylbenzylidene-camphor in human and rat cells: comparison with phyto- and xenoestrogens. 1276 43

The estrogen receptor (ER) status in primary breast cancer represents an important prognostic factor and has a profound impact on therapeutic decisions. However, ER expression profile on disseminated breast cancer cells is largely unknown, although these cells are one of the main target structures in adjuvant therapy after local curative resection (R0) achieved in most breast cancer patients. Thus, the present pilot study was designed to evaluate the ER expression profile on disseminated epithelial cells in bone marrow, one of the preferential organs for manifestation of distant metastases in breast cancer. Using the alkaline phosphatase anti-alkaline phosphatase-immunogold double staining procedure, in a panel of 17 breast cancer patients, epithelial cells (mab CK2) detected in bone marrow were analyzed for ER expression (mab 1D5) and compared with ER expression in the corresponding primary tumors. Whereas eleven of the 17 patients (64.7%) were ER-positive in primary carcinomas, only two patients (11.8%) revealed ER-positive epithelial cells in bone marrow. In addition, one of these two patients demonstrated a heterogeneous ER expression pattern, with both ER-positive and ER-negative epithelial cells in bone marrow. Although in both of these cases the ER-positive epithelial cells in bone marrow derived from ER-positive primary tumors, in this small patient cohort none of the prognostic relevant clinical and pathological factors tested, i.e., TNM-classification, grading, and ER status in primary breast cancer, correlated with the ER status in bone marrow. The striking discrepancy between ER expression in primary breast cancers and the corresponding disseminated epithelial cells in bone marrow suggests either the selective dissemination of ER-negative tumor cells into the bone marrow or a negative impact of the bone marrow microenvironment on epithelial ER expression. This phenomenon might influence therapeutic effects of antihormonal treatment.
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PMID:Estrogen receptor expression profile of disseminated epithelial tumor cells in bone marrow of breast cancer patients. 1279 Mar 28

Estrogen replacement therapy has been correlated with an increased risk for developing breast and endometrial cancers. One potential mechanism of estrogen carcinogenesis involves metabolism of estrogens to 2- and 4-hydroxylated catechols, which are further oxidized to electrophilic/redox active o-quinones that have the potential to both initiate and promote the carcinogenic process. Previously, we showed that the equine estrogens, equilin and equilenin, which are major components of the estrogen replacement formulation Premarin (Wyeth-Ayerst), are primarily metabolized to the catechol, 4-hydroxyequilenin. This catechol was found to autoxidize to an o-quinone causing oxidation and alkylation of DNA in vitro and in vivo. To block catechol formation from equilenin, 4-halogenated equilenin derivatives were synthesized. These derivatives were tested for their ability to bind to the estrogen receptor, induce estrogen sensitive genes, and their potential to form catechol metabolites. We found that the 4-fluoro derivatives were more estrogenic than the 4-chloro and 4-bromo derivatives as demonstrated by a higher binding affinity for estrogen receptors alpha and beta, an enhanced induction of alkaline phosphatase activity in Ishikawa cells, pS2 expression in S30 cells, and PR expression in Ishikawa cells. Incubation of these compounds with tyrosinase in the presence of GSH showed that the halogenated equilenin compounds formed less catechol GSH conjugates than the parent compounds, equilenin and 17beta-hydroxyequilenin. In addition, these halogenated compounds showed less cytotoxicity in the presence of tyrosinase than the parent compounds in S30 cells. Also, as stated above, the 4-fluoro derivatives showed similar estrogenic effects as compared with parent compounds; however, they were less toxic in S30 cells as compared to equilenin and 17beta-equilenin. Because 17beta-hydroxy-4-halogenated equilenin derivatives showed higher estrogenic effects than the halogenated equilenin derivatives in vitro, we studied the relative ability of the 17beta-hydroxy-4-halogenated equilenin derivatives to induce estrogenic effects in the ovariectomized rat model. The 4-fluoro derivative showed higher activity than 4-chloro and 4-bromo derivatives as demonstrated by inducing higher vaginal cellular differentiation, uterine growth, and mammary gland branching. However, 17beta-hydroxy-4-fluoroequilenin showed a lower estrogenic activity than 17beta-hydroxyequilenin and estradiol, which could be due to alternative pharmacokinetic properties for these compounds. These data suggest that the 4-fluoroequilenin derivatives have promise as alternatives to traditional estrogen replacement therapy due to their similar estrogenic properties with less overall toxicity.
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PMID:Effect of halogenated substituents on the metabolism and estrogenic effects of the equine estrogen, equilenin. 1280 57

Selective estrogen receptor modulators (SERMs) are estrogen receptor (ER) ligands that function as antagonists in some tissues, but have either partial or full agonist activity in others. SERMs often display variable partial agonist activity in uterine tissues and this activity can be displayed in uterine cell lines such as the human Ishikawa endometrial adenocarcinoma cell line. In this study, we compared the effects of several ER ligands including some SERMs on alkaline phosphatase (AP) activity and the expression of an ER target gene, the progesterone receptor (PR), in Ishikawa cells. As expected, estradiol (E2) was a potent and efficacious activator of both AP activity and PR mRNA expression. 4-Hydroxytamoxifen (4OHT) stimulated AP activity to a level 47% of that of E2 (100nM), while CP 336156 (lasofoxifene) increased AP activity 18%. A benzothiophene, such as LY 117018, a raloxifene analog, stimulated AP even less with values approximately 11% of E2-stimulated levels. A pure antiestrogen, ICI 182,780 did not stimulate AP activity. Interestingly, when we examined the ability of these compounds to increase the expression of the ER target gene, PR, a different rank order of efficacy was detected. After E2, CP 336156 was the most efficacious in increasing PR mRNA with a maximal stimulation of 20% of E2 levels, while 4OHT stimulated only 17%. LY 117018 increased PR mRNA expression 8% while ICI 182,780 did not increase PR mRNA expression at all. These data illustrate the target specificity that a SERM is able to display within a single cell type independent of "tissue specificity" and differential levels of expression of various cofactors. While 4OHT is 160% more active than CP 336156 in terms of inducing AP activity in the Ishikawa cells, CP 336156 has equivalent activity as 4OHT when one examines the ability of these SERMs to induce PR mRNA expression. Since the stimulation of Ishikawa cells by ER ligands is often used to assess the potential in vivo uterotrophic activity, these data indicate that examination of several endpoints in these cells may be necessary in order to fully characterize the activity of SERMs.
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PMID:Target specificity of selective estrogen receptor modulators within human endometrial cancer cells. 1294 42

Postmenopausal osteoporosis is preventable. An increasing number of antiresorptive therapies including estrogen, selective estrogen receptor modulators (the so-called designer estrogens), bisphosphonates and calcitonins are now available as treatment options for osteoporosis. These agents reduce the level of bone turnover and consequently slow or arrest bone loss and decrease the risk of fracture. However, these therapies are only effective if they are taken as prescribed. Unfortunately, most women who initiate antiresorptive therapy are unwilling or unable to make a long-term commitment to maintain such therapy. The test for biochemical markers of bone turnover can be used to confirm a biochemical response of bone within 3-6 months of initiating therapy, far sooner than the 2 years required for bone density testing. Such information incorporates a timely assessment of the woman's physiologic response with therapeutic compliance. A test result indicating the expected response to treatment may motivate some patients to remain compliant and maintain the therapy for an extended period of time. Bone turnover markers with demonstrated efficacy in monitoring the reduction of bone turnover induced by antiresorptive therapies include bone-specific alkaline phosphatase and osteocalcin (bone formation markers), and free deoxypyridinoline, N-telopeptide and C-telopeptide (bone resorption markers).
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PMID:Monitoring antiosteoporotic treatment of postmenopausal women using biochemical markers of bone turnover. 1297 83

Raloxifene, a nonsteroidal selective estrogen receptor modulator (SERM), increases bone mineral density (BMD), decreases biochemical markers of bone turnover, and prevents incident vertebral fractures in postmenopausal women, while sparing the breast and endometrium from the undesirable stimulation caused by estrogen. How the long-term beneficial effects of raloxifene on bone turnover, as assessed by bone histomorphometry, compare with hormone replacement therapy (HRT) and placebo are not known. We studied 66 healthy postmenopausal women (age 55 to 75 years, mean 63 years) who were randomized to either raloxifene 150 mg/day, HRT (Premarin 0.625 mg/day, and Provera 2.5 mg/day), or placebo for 1 year. All women received 1-1.5 g of calcium/day. Following double tetracycline labeling, transiliac bone biopsies were obtained at baseline and 1 year and analyzed for changes in histologic indexes of bone remodeling on the cancellous surface as well as at the endocortical subdivision of the endosteal envelope, the location of the greatest fraction of postmenopausal bone loss. BMD and biochemical markers of bone turnover were also determined at baseline and 1 year. Four paired biopsies were obtained in the HRT group, six in the raloxifene group, and five in the placebo group. The frequency of remodeling events on cancellous bone and rate of bone formation in both cancellous and endocortical bone increased in the placebo group, while these measurements decreased in both drug treatment groups. Using analysis of mean percentage changes, when compared with the placebo group, these changes were significantly different for both raloxifene and HRT treatment groups (p<0.02). In all subjects, the bone was lamellar with discrete tetracycline labels and there was no evidence of marrow fibrosis or abnormal bone cells. BMD increased from baseline at the lumbar spine (p<0.05 in the HRT group) and in the total body (p<0.05 for both raloxifene and HRT). Compared with that of the raloxifene group, the increase in BMD was greater in the HRT group at the lumbar spine but not in the total body. Serum bone alkaline phosphatase, serum osteocalcin, and urine C-terminal cross-linking telopeptide of type I collagen significantly decreased (p<0.05) in both active treatment groups, changes significantly different from those seen with placebo. Overall, these results support the hypothesis that raloxifene preserves bone mass by reducing the elevated bone turnover found in postmenopausal women receiving placebo, by mechanisms similar to those operative in postmenopausal women receiving HRT.
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PMID:Effects of raloxifene, hormone replacement therapy, and placebo on bone turnover in postmenopausal women. 1461 Jun 42


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