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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of acetaldehyde administration for 4 weeks on antioxidant protection systems was investigated in liver of rats. Liver SOD activity was decreased from control value 542.4 U/g of tissue to 411.2 U/g of tissue in experimental group (24% decrease). GSH-Px activity was practically unchanged and liver CAT activity was significantly decreased (35%). Sulfhydryl compounds in liver non-proteins following ACH treatment were decreased from 4.22 mumol/g of tissue in control group to 2.86 mumol/g of tissue (23%). Furthermore acetaldehyde treatment caused significant increase in MDA level in liver (78% increase).
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PMID:The diminution of liver glutathione content and changes in activities of antioxidant enzymes in long-term acetaldehyde poisoning. 128 37

The expression of basic fibroblast growth factor (bFGF) and two of its receptors, FGFR1 and FGFR2, was detected using the polymerase chain reaction, and quantified by comparison to the relative amount of product obtained following co-amplification of the ubiquitous glyceraldehyde phosphate dehydrogenase transcript. Varying levels were found in the vast majority of both cancer and non-malignant breast biopsies as well as in samples of several other normal human tissues. Significantly less bFGF was present in cancers (P less than 0.0001). Similarly, FGFR2 product was also much less in cancer tissues (P = 0.0078), as was FGFR1 (P = 0.002). FGFR1 levels in cancers tended to be higher in those which were oestrogen receptor positive (P less than 0.06). Amplification of different coding regions showed evidence of variant forms of FGFR1 RNA. Cancers appeared to have a significantly greater proportion of PCR product corresponding to the region between the third immunoglobulin like domain and the tyrosine kinase domain (P = 0.046). Differential expression was observed in breast cell lines, with bFGF in the normal derived HBL100, HBR SV1.6.1 and 184A1 but little or none in ZR-75-1, MCF-7, T47D and MDA-MB-231. FGFR1 was present in most of these but FGFR2 was absent from T47D, MDA-MB-231 and HBL100. ZR-75-1 cells had a marked preponderance of FGFR1 variants lacking part of the coding sequence. Aberrant receptor processing may provide clues concerning the role of FGF's and their potential involvement in malignancy.
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PMID:Expression of basic fibroblast growth factor, FGFR1 and FGFR2 in normal and malignant human breast, and comparison with other normal tissues. 138 Feb 81

The FLG/FGFRI gene, encoding a receptor for members of the FGF family, is located at 8p11.2-p12. It is amplified, overexpressed, and not grossly rearranged in the MDA-MB-134 breast carcinoma cell line, whereas other genes from the pericentromeric 8p region are not amplified. The FGF4/HSTFI gene, located at 11q13, is also amplified with a substantial portion of the 11q13 region, but is not overexpressed in MDA-MB-134 cells. In this cell line, amplified sequences constitute a large homogeneously staining region (HSR) which is part of a marker chromosome containing chromosome 8 and chromosome 11 sequences. Using probes for the FGF4/HSTFI and the FLG/FGFRI genes in fluorescence chromosomal in situ hybridization, we show that the HSR contains de novo fused and amplified 11q13 and 8p11-p12 sequences associated in a complex structure containing approximately the same number of FGF4 and FGFRI genes. The significance of this genetic abnormality for MDA-MB-134 cells, and for breast carcinogenesis in general, is unknown, but may underlie a particular type of oncogene activation.
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PMID:Fusion and amplification of two originally non-syntenic chromosomal regions in a mammary carcinoma cell line. 138 61

Monoclonal antibody (MAb) 4D5 was used to analyze the phosphorylation of p185HER2, the gene product of c-erbB-2/HER2, in SK-BR-3 cells. Culture in the continuous presence of 4D5 reduced the in vivo steady-state levels of p185HER2 phosphorylation by 80% in a dose-dependent manner, suggesting that MAb 4D5 may have interfered with the activation of phosphorylation of p185HER2. The observed MAb-mediated reduction of p185HER2 phosphorylation could not be completely accounted for by down-regulation. When cultures were grown under serum-free conditions, the steady-state levels of p185HER2 phosphorylation were reduced by 56%, and addition of 4D5 further inhibited phosphorylation to 20% of steady-state levels. With continuous exposure to increasing concentrations of newborn calf serum in these cultures, there was a linear increase in tyrosine-specific phosphorylation of p185HER2, reaching a 5.4-fold increase with 10% newborn calf serum. Phosphorylation of p185HER2 in the presence of newborn calf serum was not attributable to stimulation of the epidermal growth factor receptor by epidermal growth factor or by transforming growth factor-alpha. Extension of these observations to two other mammary carcinoma cell lines. MDA-MB-453 and BT-474, also demonstrated a significant capacity of serum to induce p185HER2 phosphorylation. The demonstration of antibody-mediated partial inhibition of phosphorylation under serum-free conditions suggests that mammary carcinoma cells may also produce and secrete a factor or factors which may activate p185HER2. Our observation that growth-inhibitory MAb 4D5 is able to reduce the phosphorylation of p185HER2 by newborn calf serum and by a cellular-derived factor(s) suggests the existence of a growth factor(s) which uses phosphorylation of p185HER2 as a signal transduction pathway to regulate cell proliferation.
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PMID:Regulation of phosphorylation of the c-erbB-2/HER2 gene product by a monoclonal antibody and serum growth factor(s) in human mammary carcinoma cells. 167 Dec 97

The insulin-like growth factor binding proteins (IGF-BPs) are structurally and immunologically distinct from the IGF type 1 or type 2 receptors and are characterized by two major forms: a large, GH-dependent BP found in human plasma (Mr = 150 k) and a small GH-independent BP (Mr = 28-42 k) present in human plasma, amniotic fluid, and HEP G2 cells. Using affinity cross-linking techniques, we have identified several binding proteins secreted by human breast cancer cell lines (Hs578T, MDA-231, T-47D, and MCF-7). Under nonreducing conditions these proteins migrated at an apparent Mr = 35, 28, 27, and 24 k, while reducing conditions revealed bands of apparent Mr = 35, 32, 27, and 24 k. Competitive binding studies in T-47D-conditioned media demonstrated that these BPs bound more IGF-II than IGF-I, and that IGF-II potently inhibited binding of either IGF-I or -II. Immunological studies using a polyclonal antibody against the HEP G2 small BP revealed no immunoreactive BP in conditioned media from MCF-7 and T-47D and only slight immunoreactivity in conditioned media from Hs578T and MDA 231. Analysis by Northern blot, using a probe from the cDNA sequence of the HEP G2 BP, demonstrated that Hs578T and MDA-231 cell lines contained small amounts of the 1.65 kilobase mRNA characteristic of the HEP G2 BP, while MCF-7 and T-47D tested negative.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization of insulin-like growth factor binding proteins from human breast cancer cells. 247 92

Athymic (nu/nu) mice are T cell deficient and can accept xenografts of human tumor material. Hormone-dependent tumor growth can be demonstrated in ovariectomized athymic mice by estrogen administration. Estrogen receptor (ER) positive MCF-7 breast cancer cells implanted into the axillary mammary fat do not grow into palpable tumors unless sustained release preparations of estrogen are administered. The non-steroidal antiestrogen tamoxifen, though it exhibits estrogenic properties in the mouse, does not facilitate MCF-7 tumor growth (during short term, i.e. 8 weeks of therapy) and can prevent estradiol-stimulated growth. In contrast, ER negative MDA-MB-231 cells grow with or without estrogen administration and tamoxifen does not control tumor growth. These statements reflect current dogma concerning the value of athymic mice to confirm the hormone dependent growth of cancer cells in vivo. Our aim has been to define the limits of this dogma and to investigate the growth relationship of hormone-dependent and independent cells with their host environment. The potential endocrine or paracine effect of ER negative tumors on the growth of ER positive tumors was evaluated by transplantation on opposite sides of athymic mice or by the inoculation of different ratios of ER positive/negative cells (MCF-7:MDA-MB-231 9:1, 99:1, 999:1). MCF-7 cells could not be encouraged to grow by a rapidly growing MDA-MB-231 tumor on the opposite side of the animal. Similarly ER negative tumors grew out of the mixed tumor inoculates suggesting that ER positive tumors could not be encouraged to grow preferentially by the paracrine influences of ER negative cells. However, estrogen facilitates the growth of an ER positive tumor following inoculation of mixed cell populations. Antiestrogen treatment can blunt estrogen-stimulated growth but cannot control the growth of ER positive/negative containing tumors. ER positive endometrial tumors grow in response to estrogen treatment and some (EnCa101) have been shown to grow in response to tamoxifen or a combination of tamoxifen and estrogen. More unusual though is our recent observation that an ER negative primary endometrial tumor (BR) and its metastasis (BR-MET) grow more rapidly in estrogen-treated athymic mice. This finding seems to have far-ranging consequences for our view of hormone-dependent growth. Either our view of estrogen-stimulated growth needs to be modified or the host is specifically altered during estrogen treatment. We have taken the position that since natural killer cells (present in athymic mice) can be lowered by estrogen this may result in an increased tumor cell survival in the heterotransplant model.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Immune-deficient animals to study "hormone-dependent" breast and endometrial cancer. 262 14

The mouse monoclonal antibody (mAb) 225 IgG1 against the epidermal growth factor (EGF) receptor has been investigated for its capacity to localize in human tumor xenografts. The EGF receptor is the product of the c-erb-B proto-oncogene (also known as EGFR). Elevated expression of EGF receptors has been demonstrated in many human tumors and tumor cell lines. We studied A431 human vulvar squamous cell carcinoma cells, with 2 X 10(6) receptors per cell; MDA-MB-468 (MDA 468) human breast adenocarcinoma cells, with 3 X 10(5) receptors per cell; and MCF-7 human breast adenocarcinoma cells, with 5 X 10(3) receptors per cell. The 111In-labeled pentetic acid (DTPA), derivative of mAb 225 (111In-DTPA-225) was injected intraperitoneally into nude mice bearing subcutaneous tumor xenografts. We measured uptake by quantifying radioactivity in tumor and normal tissues and by obtaining gamma camera images. Uptake in A431 xenografts was 28% +/- 2.4% of the injected dose per gram of tumor on day 3 and 12.4% +/- 3.0% on day 7. Distribution ratios comparing uptake in the tumor with that in normal tissues were consistently greater than 4. In contrast, there was far less uptake of the control mAb KS1/4S-1 labeled with 111In. This conjugate, 111In-DTPA-KS1/4S-1, has an IgG1 isotype but does not bind to human or murine cells. Imaging of the tumor with mAb 225 was excellent, especially on days 3-7. MDA 468 xenografts exhibited reduced localization of mAb 225 in the tumor. For MCF-7 xenografts, the tumor uptake of mAb 225 after 7 days was only 0.70% +/- 0.10% of the injected dose per gram of tumor, which was comparable to the uptake of the KS1/4S-1 control mAb. The ratio of the concentration of radioactivity in the tumor to that in normal tissue (distribution ratio) showed poor selectivity of uptake, and imaging was not obtained. These observations suggest that labeled mAb can target the product of a proto-oncogene, the EGF receptor, when it is expressed at high levels in human tumor xenografts.
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PMID:Imaging of human tumor xenografts with an indium-111-labeled anti-epidermal growth factor receptor monoclonal antibody. 279 90

Three passive samplers are now commercially available for NO2. This field validation, conducted in an underground mine, attempted to address both the precision and accuracy of the three now commercially available. The probable sources of NO2 were identified as diesel engines and blasting operations. Comparative sampling was conducted with the passive samplers versus the standard "baseline" impingement method. The three NO2 samplers were as follows: 1) PRO-TEK (DuPont); 2) Palmes (MDA); 3) VaporGard (MSA). Three sets of data consisting of impingers and passive sampler results were taken on top of a moving diesel vehicle over a three-day period. An expanded metal screen was welded in a "free standing" plane above the vehicle to serve as a sampling platform. The evaluation of concentration data suggested that correlations of accuracy and precision versus the impinger method were best for the Palmes and VaporGard samplers. The PRO-TEK sampler does not seem to produce accurate data, but it is somewhat precise. Factors of sensitivity, accuracy, precision, cost, ease of analysis, and stability must be weighed.
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PMID:Field validation study of NO2 personal passive samplers in a "diesel" haulage underground mine. 665 Apr 1

HER2, the erbB-2/neu proto-oncogene product, is a 185-kDa transmembrane glycoprotein related to the epidermal growth factor receptor. Overexpression of HER2 was reported in several human adenocarcinomas, including mammary and ovarian carcinomas. A family of glycoproteins, the heregulin/neu differentiation factors, was characterized and implicated as the ligands for HER2. Recently, it has been shown that HER2 alone is not sufficient to reconstitute high affinity heregulin receptors and that HER3 or HER4 may be the required components of the heregulin receptors on mammary carcinoma cells (Sliwkowski, M.X., Schaefer, G., Akita, R.W., Lofgren, J.A., Fitzpatrick, V.D., Nuijens, A., Fendly, B.M., Cerione, R.A., Vandlen, R.L., and Carraway, K.L., III (1994) J. Biol. Chem. 269, 14661-14665; Plowman, G.D., Green, J.M., Culouscou, J.-M., Carlton, G.W., Rothwell, V.M., and Buckley, W. (1993) Nature 366, 473-475). Using the Cytosensor to measure the extracellular acidification rate, we have examined the effects of recombinant human heregulin-alpha on three mammary carcinoma cell lines expressing HER2 (MDA-MB-453, SK-BR-3, and MCF-7), an ovarian carcinoma cell line expressing HER2 (SK-OV-3), and CHO-K1 and 293-EBNA cells stably transfected with HER2. By reverse transcription polymerase chain reaction and Western blotting, we found that the breast cells also express HER3 and that the ovarian line co-expresses the HER4 message. A dramatic increase in the acidification rate was observed for the mammary carcinoma cells co-expressing high levels of HER2 and HER3. In contrast, the ovarian cells expressing high levels of HER2 and low levels of HER4 or CHO-K1 and 293-EBNA cells expressing HER2 alone were not responsive to heregulin. When these same transfected cells were exposed to monoclonal anti-HER2 antibody followed by anti-IgG to cause aggregation of the HER2 molecules, an increase in the acidification rate was observed, indicating coupling of transfected HER2 to the signal transduction pathway. Transfection of HER2 into MCF-7 cells, on the other hand, gave 4-fold enhanced acidification responses. These data, together with the previously reported high affinity heregulin binding and activation of tyrosine phosphorylation in HER2 and HER3 co-transfected cells support the role of HER2 and HER3 as components of the heregulin receptor in breast cells.
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PMID:Heregulin activation of extracellular acidification in mammary carcinoma cells is associated with expression of HER2 and HER3. 767 53

Athymic mice bearing xenografts of human tumours that overexpress the receptor (EGFR) for EGF and TGF alpha have been used to evaluate the therapeutic potential of three new rat monoclonal antibodies (mAbs) directed against two distinct epitopes on the extracellular domain of the human EGFR. The antibodies, ICR16 (IgG2a), ICR62 (IgG2b) and ICR64 (IgG1), have been shown (Modjtahedi et al., 1993) to be potent inhibitors of the growth in vitro of a number of human squamous cell carcinomas because they block receptor-ligand interaction. When given i.p. at 200 micrograms dose, the three antibodies were found to induce complete regression of xenografts of the HN5 tumour if treatment with antibody commenced at the time of tumour implantation (total doses: ICR16, 3.0 mg; ICR62, 1.2 mg; ICR64, 2.2 mg). More importantly when treatment was delayed until the tumours were established (mean diam. 0.5 cm) both ICR16 and ICR62 induced complete or almost complete regression of the tumours. Furthermore, treatment with a total dose of only 0.44 mg of ICR62 was found to induce complete remission of xenografts of the breast carcinoma MDA-MB 468, but ICR16 was less effective at this dose of antibody and only 4/8 tumours regressed completely. ICR16 and ICR62 were poor inhibitors of the growth in vitro of the vulval carcinoma A431, but both induced a substantial delay in the growth of xenografts of this tumour and 4/8 tumours regressed completely in the mice treated with ICR62 (total dose 2.2 mg). Although ICR16 and ICR64 were more effective than ICR62 as growth inhibitors in vitro, ICR62 was found to be substantially better at inducing regression of the tumour xenografts due perhaps to additional activation of host immune effector functions by the IgG2b antibody. We conclude that these antibodies may be useful therapeutic agents that can be used alone without conjugation to other cytotoxic moieties.
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PMID:Immunotherapy of human tumour xenografts overexpressing the EGF receptor with rat antibodies that block growth factor-receptor interaction. 767 81


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