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)

Methods such as immunohistochemistry that have enhanced the detection of carcinoma cells in bone marrow aspirates appear to be useful in identifying patients with aggressive tumours. To detect epithelial cells in bone marrow aspirates from breast carcinoma patients, we used a pool of five different monoclonal antibodies (MAbs), which recognise 100% of breast carcinomas, together with the alkaline phosphatase method on cytospun cells obtained from sternum and iliac crest. Primary tumours were also analysed for the expression of the c-erbB-1 and c-erbB-2 oncogene products, and of two differentiation-related markers and laminin receptors. Immunoreactive cells were detected in the bone marrow of 62 of the 197 patients tested (31%) without any correlation with clinical parameters such as tumour size or lymph node metastasis, whereas a significant (P < 0.01) correlation was found with enhanced monomeric laminin receptor expression in the primary tumour. In fact, this receptor was expressed in respectively 63% and 38% of primary tumours from patients with and without immunoreactive cells in the bone marrow aspirates. Thus, the presence of immunoreactive cells in bone marrow correlates with the expression in the primary tumour of a marker of the metastatic potential of the tumour, the 67 kDa laminin receptor.
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PMID:Immunodetection of bone marrow micrometastases in breast carcinoma patients and its correlation with primary tumour prognostic features. 791 Oct 32

The ligand-stimulated tyrosine kinase activity of the normal human epidermal growth factor (EGF) receptor and a truncated EGF receptor lacking 164 carboxy-terminal (C-terminal) amino acids was examined in intact cells and after Triton X-100 extraction into Triton-soluble and -insoluble (cytoskeletal) preparations. Detergent extraction of the intact and truncated receptors appeared complete using 0.3% Triton as demonstrated by anti-EGF receptor immunoblots, tyrosine kinase assays, and marker enzyme (alkaline phosphatase) solubilization. Higher Triton concentrations yielded no additional EGF receptor extraction and began to inhibit EGF-stimulated kinase activity toward angiotensin II (AII). Furthermore, the tyrosine kinase activity of the truncated EGF receptor exhibited increased sensitivity to Triton extraction, suggesting a lower affinity or a more labile association of this receptor with the cytoskeleton. However, both EGF receptor forms had altered catalytic activity when associated with the cytoskeletal fraction, as evidenced by the increased phosphorylation of the exogenous substrates: AII, src-peptide, and [Val5]AII. Kinetic analyses of both receptor types revealed that the cytoskeletal fractions obtained using 0.3% Triton contain EGF receptor activity that exhibits a Michaelis-Menten constant (Km) for AII that is 2- to 3-fold more favorable than that calculated for the soluble receptor forms. EGF treatment of intact cells containing either the intact or truncated receptor revealed similar phosphorylated proteins in the soluble fraction of both cell types, although there was evidence for the enhanced phosphorylation of certain proteins (e.g. 115 and 50 kilodalton proteins) in cells containing the truncated receptor. There was also a greater number of tyrosine-phosphorylated proteins in the Triton-insoluble fraction of cells containing the truncated receptor, suggesting an altered specificity of this receptor toward selected cytoskeletal proteins. This work indicates that EGF receptor-cytoskeletal interaction may be an important consideration in the control of receptor-kinase activity and has examined the detergent sensitivity of this association. These studies also suggest that the C-terminal domain of the EGF receptor may affect cytoskeletal interaction in addition to influencing the receptor's catalytic capacity.
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PMID:Evidence for the potentiation of epidermal growth factor receptor tyrosine kinase activity by association with the detergent-insoluble cellular cytoskeleton: analysis of intact and carboxy-terminally truncated receptors. 824 11

Most of the data regarding the significance of c-erbB-2 oncogene expression as a prognostic marker in breast cancer have been generated in many large retrospective studies by retrieving the corresponding oncoprotein in archival paraffin embedded sections. Recently, employing fresh breast cancer cells obtained by means of fine-needle aspiration biopsy, we found a rate of c-erbB-2 positive breast tumors (58%) higher than that reported in paraffin-embedded tissue sections by others studies. The present analysis was undertaken to investigate the impact of routine tissue processing on the preservation of the c-erbB-2 immunoreactivity. This issue was addressed by assessing the relative rate of c-erbB-2 oncoprotein immunodetection on FNAB smears and matched surgical specimens of breast cancer. The expression of c-erbB-2 oncoprotein was evaluated using the alkaline phosphate-anti-alkaline phosphatase (APAAP) technique in 54 breast aspirates and corresponding surgical specimens of primary breast cancer. Twenty-six (48%) smears and 23 (43%) matched paraffin sections gave specific signal for c-erbB-2 oncoprotein. The slightly higher incidence of c-erbB-2 expression found on smears seems to be mainly due to the better antigen preservation in the fresh cytological preparations. We conclude that routine histological processing may affect c-erbB-2 immunoreactivity; therefore, in mounting prospective studies, it is advisable to assess c-erbB-2 status in fresh tissue. Moreover, the assessment of c-erbB-2 expression on aspirate samples may yield additional information to the pre-surgical prognostic evaluation of breast cancer diagnosed by FNAB.
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PMID:c-erbB-2 expression in FNAB smears and matched surgical specimens of breast cancer. 896 69

Several growth factors and proto-oncogenes play a leading regulatory role during human carcinogenesis. In this systematic immunocytochemical study we observed the expression (overexpression) of the c-erbB-2 and c-erbB-3 oncoproteins in 30 primary cutaneous malignant melanomas (CMMs), 10 already metastasized malignant melanomas (MMMs) and 15 lymph-node negative breast carcinomas (BCs). Both oncoproteins were expressed as a result of either oncogene amplification or post-translational stabilization c-erbB-2 alone is unable to bind neuregulins, but it is able to act as a pan c-erbB receptor subunit. Heterodimerization between cerbB-2 and c-erbB-3 is required to initiate neuregulin directed signal transduction. We employed an indirect, four step streptavidinbiotin conjugated immunocytochemical technique for antigen detection. The visualization of the primary antigen-antibody reaction was carried out with alkaline phosphatase or immunoperoxidase labeling and the use of the appropriate enzymatic substrates. The presence of c-erbB-2 oncoprotein was detected in 12/30 CMMs, 8/10 MMMs and 6/15 BCs, while c-erbB-3 was identified in 14/30 CMMs, 7/10 MMMs and 6/15 BCs. The intensity of the cell membrane localized immunoreactivity was observed to be greater when the c-erbB-2 oncoprotein was targeted (A, AB and B). The c-erbB-3 oncoprotein was also detected in the cytoplasm with medium intensity (B, BC and C). Unfortunately, little is known concerning the range of oncoprotein overexpression after formalin fixation and paraffin embedding. We demonstrated overexpression localized to several cell clones within the oncoprotein positive population of malignant cells. The immunocytochemically defined extent of expression of both oncoproteins was between 10-40% (+ to +2) of the total cell population in the malignant melanomas and 20-35% (+2) of the total cell population in the BCs. In conclusion a) the results of the present study demonstrate the presence of c-erbB-2 and c-erbB-3 oncoprotein expression (overexpression) in melanoma and breast carcinoma, and b) oncogene receptor directed immunotherapy, as part of a more individualized anti-cancer treatment, represents a potentially valuable targeted treatment for the future.
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PMID:Clinical and prognostic significance of the expression of the c-erbB-2 and c-erbB-3 oncoproteins in primary and metastatic malignant melanomas and breast carcinomas. 913 92

We have synthesized a tris-sulfotyrosyl dodecapeptide (3S-peptide-I) that corresponds to the major autophosphorylation domain within the insulin receptor beta-subunit and showed that it potently inhibited insulin receptor dephosphorylation by protein tyrosine phosphatases (PTPases) in vitro. 3S-peptide-I also inhibited tyrosine dephosphorylation of a synthetic peptide by the recombinant PTPase PTP-1B, indicating that 3S-peptide-I interacts directly with PTPase, causing its inactivation. The peptide had no effect on the activity of serine/threonine phosphatases, PP-1 and PP-2A, or alkaline phosphatase. Furthermore, we found that the introduction of a N-stearyl derivative of 3S-peptide-I in CHO/HIRc cells caused a significant increase in insulin-stimulated phosphorylation of the insulin receptor. In contrast, ligand-stimulated phosphorylation of epidermal growth factor (EGF) receptor in CHO cells overexpressing EGF receptors was not affected by the presence of N-stearyl-3S-peptide-I. These data suggest that by inhibiting dephosphorylation of the insulin receptor in intact cells, 3S-peptide-I may specifically enhance insulin signalling.
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PMID:Specific inhibition of insulin receptor dephosphorylation by a synthetic dodecapeptide containing sulfotyrosyl residues as phosphotyrosyl mimetic. 934 28

Single micrometastatic tumor cells encased in mesenchymal tissues, such as bone marrow (BM), are regarded as suitable targets for adjuvant immunotherapy since they are easily accessible for both immunoglobulins and immune effector cells. However, the antigen profile of such cells, to which antibody therapy might be targeted, cannot be deduced from the antigen pattern of the primary tumor. To evaluate the antigen profile of disseminated cells found in BM aspirates from 20 breast cancer patients, we applied a quantitative immuno-cytochemical double-marker assay and typed for 4 common tumor-associated cell-surface antigens (c-erbB-2, CO17-1A, MUC-1, LewisY). Individual breast cancer cells were identified by F(ab) fragments of the pan-cytokeratin (CK) monoclonal antibody (MAb) A45-B/B3, directly conjugated with alkaline phosphatase, which identified cancer cells as sensitively as the standard APAAP procedure (r = 0.998; p < 0.0001). CK+ cells co-expressed c-erbB-2, CO17-1A, MUC-1 and LewisY in 87%, 78%, 79% and 79% of patients, respectively; however, the frequency of double-positive cells per sample varied considerably. The mean percentage of double-positive cells per total number of CK+ cells was 41% for c-erbB-2 (range 0-92%), 47% for CO17-1A (range 0-75%), 49% for MUC-1 (range 0-67%) and 32% for LewisY (range 0-59%). In 14 of these patients, we used an antibody cocktail to type CK+ cells for the combined expression of all 4 antigens. The antibody cocktail labeled significantly more CK+ cells than each of the single MAbs alone, resulting in a mean of 71% double-positive tumor cells (34-100%). We conclude that expression of tumor-associated cell-surface antigens on micrometastatic cancer cells in BM is heterogeneous, which may limit the efficacy of monovalent immunotherapeutic strategies directed against only one particular antigen. Thus, defining target antigens expressed by the actual target cells emerges as a crucial first step in selecting appropriate therapeutic targets.
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PMID:Tumor-antigen heterogeneity of disseminated breast cancer cells: implications for immunotherapy of minimal residual disease. 998 23

A 64-year postmenopausal woman had noticed a left breast lump 5 months before presentation and was admitted due to increasing tumor size. Physical examination showed a well demarcated, movable mass 5 cm in diameter in the upper outer quadrant of the left breast. The lesion was not painful. She had no past history of malignancy or chest wall irradiation. She had no family history of malignancy. Mammography revealed an irregular tumorous lesion with coarse calcifications in the left breast. Intracystic papillary cancer was suspected by ultrasonography. Aspiration breast cytology yielded insufficient material for diagnosis. Laboratory findings were all within the normal limits including alkaline phosphatase and three tumor markers (CEA, CA 15-3, ST-439). An excisional biopsy of the left breast tumor was performed. Histopathological examination revealed malignant phyllodes tumor with osteosarcomatous features and negative tumor margins. Positive vimentin and negative cytokeratin staining was confirmed by immunohistochemistry, suggesting that the tumor did not originate from epithelial cells of the breast. The estrogen receptor (ER) status of the tumor was negative but progesterone receptor (PgR) was weakly positive. Positive p53 nuclear immunoreaction but negative c-erbB-2 overexpression by immunohistochemical staining was observed in this tumor. There was no evidence of generalized disease. She has been well 6 months after surgery without adjuvant therapy.
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PMID:A case of malignant phyllodes tumor of the breast with osteosarcomatous features. 1118 Jul 71

Concentrations of soluble c-erbB-2 were determined in the sera of 64 patients with distant metastasis from advanced breast cancer receiving second-line hormone or chemotherapy in comparison to 35 breast cancer patients without detectable recurrent disease and 17 healthy blood donors. The sera of non-metastatic breast cancer patients contained s-erbB-2 concentrations similar to those of healthy blood donors. Patients with distant metastasis from advanced breast cancer had significantly higher values of s-erbB-2 in comparison to patients with non-disseminated disease (mean: 59.6 vs. 11.6 U/ml; p = 0.022). A significant correlation was observed between s-erbB-2 serum levels and serum LDH concentrations (p < 0.001), levels of alkaline phosphatase (p < 0.001), and the presence of hepatic metastasis (p = 0.001). Time to tumor progression was significantly shorter in patients with s-erbB-2 levels above 40 U/ml (mean: 23.4 vs. 56.7 months; p = 0.002). Furthermore, breast cancer patients with hepatic metastasis and those with elevated s-erbB-2 serum levels above 40 U/ml had limited response to hormone or chemotherapy. Non-responders had significantly higher s-erbB-2 levels (mean: 270.3, range: 42-500 U/ml;) compared with the responder group (mean: 23.1, range: 0-149 U/ml; p < 0.001). Logistic regression analysis indicated that elevated s-erbB-2 serum levels above 40 U/ml independently predicted an unfavorable response to second-line hormone or chemotherapy in patients with advanced metastatic breast cancer.
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PMID:Clinical relevance of soluble c-erbB-2 for patients with metastatic breast cancer predicting the response to second-line hormone or chemotherapy. 1206 44

Reactive oxygen species (ROS) are implicated in cardiovascular diseases. ROS, such as H2O2, act as second messengers to activate diverse signaling pathways. Although H2O2 activates several tyrosine kinases, including the epidermal growth factor (EGF) receptor, JAK2, and PYK2, in vascular smooth muscle cells (VSMCs), the intracellular mechanism by which ROS activate these tyrosine kinases remains unclear. Here, we identified two distinct signaling pathways required for receptor and nonreceptor tyrosine kinase activation by H2O2 involving a metalloprotease-dependent generation of heparin-binding EGF-like growth factor (HB-EGF) and protein kinase C (PKC)-delta activation, respectively. H2O2-induced EGF receptor tyrosine phosphorylation was inhibited by a metalloprotease inhibitor, whereas the inhibitor had no effect on H2O2-induced JAK2 tyrosine phosphorylation. HB-EGF neutralizing antibody inhibited H2O2-induced EGF receptor phosphorylation. In COS-7 cells expressing an HB-EGF construct tagged with alkaline phosphatase, H2O2 stimulates HB-EGF production through metalloprotease activation. By contrast, dominant negative PKC-delta transfection inhibited H2O2-induced JAK2 phosphorylation but not EGF receptor phosphorylation. Dominant negative PYK2 inhibited H2O2-induced JAK2 activation but not EGF receptor activation, whereas dominant negative PKC-delta inhibited PYK2 activation by H2O2. These data demonstrate the presence of distinct tyrosine kinase activation pathways (PKC-delta/PYK2/JAK2 and metalloprotease/HB-EGF/EGF receptor) utilized by H2O2 in VSMCs, thus providing unique therapeutic targets for cardiovascular diseases.
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PMID:Distinct mechanisms of receptor and nonreceptor tyrosine kinase activation by reactive oxygen species in vascular smooth muscle cells: role of metalloprotease and protein kinase C-delta. 1258 78

Overexpression of the lipogenic enzyme fatty acid synthase (FAS) is a common molecular feature in subsets of sex-steroid-related tumors including endometrium and breast carcinomas that are associated with poor prognosis. Pharmacological inhibition of tumor-associated FAS hyperactivity is under investigation as a chemotherapeutic target. We examined the effects of the mycotoxin cerulenin (a covalent FAS inactivator), and the novel small compound C75 (a slow-binding FAS inhibitor) on estradiol (E2)- and tamoxifen (TAM)-stimulated ER-driven molecular responses in Ishikawa cells, an in vitro model of well-differentiated human endometrial carcinoma. We evaluated the effects of FAS inhibition on E2- and TAM-induced estrogen receptor (ER) transcriptional activity by using transient cotransfection assays with an estrogen-response element reporter construct (ERE-Luciferase). Antiestrogenic effects of cerulenin and C75 were observed by dose-dependent inhibition of E2-stimulated ERE-dependent transcription, whereas FAS inhibitors did not significantly increase the levels of ERE transcriptional activity in the absence of E2. Moreover, pharmacological blockade of FAS activity completely abolished TAM-stimulated ERE activity. To address the reliability of transient transfection assays, the effects of FAS inhibitors on E2-inducible gene products were evaluated. FAS blockade induced a dose-dependent decrease in E2-inducible alkaline phosphatase activity. E2-stimulated accumulation of progesterone receptor (PR) and HER-2/neu oncogene was abolished in the presence of FAS blockers. FAS inhibition also resulted in a marked downregulation of E2-stimulated ERalpha expression, and noticeably impaired E2-induced ERalpha nuclear accumulation. A dose-dependent decrease in cell proliferation and cell viability was observed after FAS blockade. A Cell Death ELISA, detecting DNA fragmentation, demonstrated that FAS inhibitors stimulated apoptosis of Ishikawa cells. The analysis of critical E2- and TAM-related cell cycle proteins revealed an increase of both the expression and the nuclear accumulation of cyclin-dependent kinase inhibitors p21WAF1/CIP1 and p27Kip1 following FAS inhibition. To rule out non-FAS cerulenin- and C75-related effects, we finally monitored ER signaling after silencing of FAS gene expression using the highly sequence-specific mechanism of RNA interference (RNAi). The concentrations of E2 and TAM inducing half-maximal ERE activity (EC50) dramatically increased (>100 times) in FAS RNAi-transfected Ishikawa cells. Moreover, depletion of FAS by RNAi also caused loss of ERalpha expression, downregulation of PR, and accumulation of p21WAF1/CIP1 and p27Kip1 in E2-stimulated Ishikawa cells. If chemically stable FAS inhibitors or cell-selective vector systems able to deliver RNAi targeting FAS gene demonstrate systemic anticancer effects in vivo, our results render FAS as a novel target for the prevention and treatment of endometrial carcinoma.
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PMID:Inhibition of tumor-associated fatty acid synthase activity antagonizes estradiol- and tamoxifen-induced agonist transactivation of estrogen receptor (ER) in human endometrial adenocarcinoma cells. 1509 77


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