Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin (IL) 1 alpha induced the up-regulation of cell-surfac-expressed epidermal growth factor (EGF) receptor on both MDA-MB-468 and BT-20 breast cancer cell lines. IL-1 beta and tumor necrosis factor alpha (TNF-alpha) increased the EGF receptor surface expression only on BT-20 breast carcinoma cells. 12-O-tetradecanoylphorbol 13-acetate (TPA) induced up-regulation of EGF receptor on MDA-MB-468 cells, and a marginal but significant increase was determined in BT-20 cells and in interferon gamma (IFN-gamma)-treated MDA-MB-468 cells. CD15 (Lewisx) antigen was down-regulated on MDA-MB-468 cells by TNF-alpha, TPA, IL-1 alpha, as well as by IFN-gamma and all-trans-retinoic acid. 1,25(OH)2-vitamin D3 up-regulated the CD15 antigen surface expression on MDA-MB-468 cells.
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PMID:Modulation of EGF receptor and CD15 (Lewisx) antigen on the cell surface of breast carcinoma cell lines induced by cytokines, retinoic acid, 12-O-tetradecanoylphorbol 13-acetate and 1,25(OH)2-vitamin D3. 790 17

The c-erbB-2 (HER-2/neu) protooncogene encodes an M(r) 185,000 transmembrane glycoprotein with intrinsic tyrosine kinase activity. Agonistic antibodies against p185c-erbB-2 enhance the cytotoxic effect of the DNA alkylator, cisplatin, against c-erbB-2-overexpressing human carcinoma cells (Hancock et al., Cancer Res., 51:4575-4580, 1991). We have studied the possible association between receptor signal transduction and cisplatin-mediated cytotoxicity utilizing the SKBR-3 human breast cancer cell line and the anti-p185 TAb 250 IgG1. TAb 250 induced tyrosine phosphorylation of p185 and the receptor substrate phospholipase C-gamma 1, as well as rapid association of these molecules in vivo. Simultaneously with phosphorylation, phospholipase C-gamma 1 catalytic activity measured in a [3H]phosphatidylinositol-4,5-bisphosphate hydrolysis assay was increased 61 +/- 12% above control. Preincubation of SKBR-3 cells with the tyrosine kinase inhibitor tyrphostin 50864-2 abrogated the enhancement of drug-mediated cell kill induced by TAb 250. The supraadditive drug/antibody effect was not seen in SKBR-3 cells with TAb 263, an anti-p185 IgG1 that does not induce receptor signaling or with TAb 250 in MDA-468 breast cancer cells which do not overexpress c-erbB-2. In addition, transforming growth factor-alpha increased cisplatin-induced cytotoxicity against NIH 3T3 cells overexpressing an epidermal growth factor receptor/c-erbB-2 chimera. Cellular uptake or efflux of [195mPt]cisplatin by SKBR-3 cells was not altered by TAb 250. Finally, simultaneous treatment of SKBR-3 cells with TAb 250 and cisplatin increased cisplatin/DNA intrastrand adduct formation and delayed the rate of adduct decay. Taken together these data support a direct association between p185c-erbB-2 signal transduction and inhibition of cisplatin-induced DNA repair.
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PMID:p185c-erbB-2 signal enhances cisplatin-induced cytotoxicity in human breast carcinoma cells: association between an oncogenic receptor tyrosine kinase and drug-induced DNA repair. 791 7

Promoter elements accounting for HER2 (c-erbB-2/neu) overexpression were searched for in several human breast cancer cell lines (MDA-453, BT-474, ZR-75-1, MCF-7) known to express constitutively a 30-fold range in HER2 transcripts per gene copy. HER2 overexpressing cells showed a single prominent DNase I hypersensitive site near a conserved and hitherto unrecognized ets response element (GAGGAA), located 38 bases down-stream from the CAAT box and directly 5' of the TATA box in the human HER2 promoter. Transient transfection of HER2 promoter constructs (0.125, 0.5, and 2.0 kilobase pairs (kb)) demonstrated that the most proximal promoter region (0.125 kb) was capable of conferring up to 30-fold enhanced activity in HER2-overexpressing cell lines relative to low HER2-expressing control lines. Site-directed mutagenesis of the ets response element (GAGGAA-->GAGAGA) caused a > or = 60% reduction in promoter activity affecting at least 0.5 kb of upstream HER2 regulatory sequence. Gel-shift assays with nuclear extracts and oligonucleotide sequences spanning the 0.125-kb promoter region detected an ETS-immunoreactive complex, present most abundantly in cells overexpressing HER2, whose high-affinity binding depended on the GAGGAA response element. Methylation interference confirmed the ETS-specific pattern of protein binding by this complex to guanine bases in the ets response element. UV cross-linking and immunoprecipitation implicate a approximately 60-kDa ETS protein, and candidate ETS genes expressed in these breast cancer cells include GABP alpha, elk-1, elf-1, and PEA3.
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PMID:Binding of an ETS-related protein within the DNase I hypersensitive site of the HER2/neu promoter in human breast cancer cells. 791 92

MDA-MB-231 is a breast epithelial cell line which possesses large amounts of epidermal growth factor (EGF) receptor on its cell surface but does not respond to EGF under standard culture conditions. 8-bromo-cyclic AMP (8Br-cAMP) and cholera-toxin treatments inhibit its growth by increasing its intracellular cAMP level. However, when inhibited in this way, MDA-MB-231 remains unresponsive to EGF. Similar effects--cAMP accumulation and inhibition of cell growth--are produced by forskolin. In addition, this substance specifically blocks MDA-MB-231 cells in G1 phase of the cell cycle. EGF is able to reverse the effect of forskolin on cell proliferation and prevents accumulation of cells in G1 phase without any change of cAMP level. Thus, only when inhibiting cell growth with forskolin does a mitogenic effect of EGF become evident. As cAMP is increased to a similar degree by all three compounds, yet only the effect of forskolin is antagonised by EGF, we suggest that a non-cAMP-mediated effect of forskolin must be considered to explain this effect. In contrast, the mitogenic effect of EGF on the NPM14T4/9 breast epithelial cell line does not change in the presence of forskolin.
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PMID:Evidence for a growth effect of epidermal growth factor on MDA-MB-231 breast cancer cells. 799 25

Using the breast carcinoma cell line MDA-MB 468 as immunogen, we have produced six new rat monoclonal antibodies (mAbs) against the human EGF receptor (EGFR) and are investigating their use for diagnostic and therapeutic applications in cancer patients whose tumours overexpress these receptors. The mAbs (three IgG2b and one each of IgG2a, IgG1 and IgA) were selected on the basis that they bound to the extracellular domain of the EGFR and blocked growth factor-receptor interaction. Competitive assays showed that, with the exception of antibody ICR65, the mAbs bound to one of two distinct epitopes on the external domain of the EGFR. ICR65, however, cross-reacted with mAbs binding to both epitopes. All of the mAbs immunoprecipitated the 170 kDa glycoprotein from cells expressing the EGFR but not the 185 kDa product of the related c-erbB-2 proto-oncogene. Unlike EGF and TGF alpha none of the mAbs stimulated the growth of quiescent human foreskin fibroblasts but they inhibited the EGF and TGF alpha induced growth stimulation of these cells in vitro. When tested for their effect on tumour cells the mAbs were found to inhibit the growth in vitro of a number of human tumours that overexpressed the EGFR (e.g. HN5, HN6, HN15, A431, MDA-MB 468) but they were without effect on tumour cell lines expressing low or undetectable amounts of the receptor. Our initial results indicate that this new generation of antibodies which bind with high affinity to the EGFR, block growth factor-receptor interaction and inhibit the growth of human squamous carcinoma cell lines overexpressing the receptor have potential for clinical application.
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PMID:The human EGF receptor as a target for cancer therapy: six new rat mAbs against the receptor on the breast carcinoma MDA-MB 468. 809 90

Heregulins (HRGs) induce tyrosine phosphorylation of several members of the erb-B family of receptors. Although originally isolated as the ligands for p185c-erb-2, recent evidence suggests that other receptors of the erbB family, including p180erbB-3 and p180erbB-4, are their true cognate receptors. Stimulation of MDA MB-453 cells with HRG beta 2 resulted in the tyrosine phosphorylation of p185c-erbB-2 and p180erbB-4 in a time- and dose-dependent fashion. This event was accompanied by the formation of multimeric complexes between the activated receptors and SH2-containing proteins. Ligand caused p120-rasGTPase activating protein (GAP), SHC and the p85 subunit of phosphatidylinositol-3'-kinase (PI3K) to be associated with both p185c-erbB-2 and p180erbB-4. In addition, tyrosine phosphorylation of p85-PI3K and SHC, but not of GAP or of its associated p62 and p190 proteins, was also detected. HRG also induced the association of GRB2 with tyrosine phosphorylated p185c-erbB-2, p180erbB-4 and SHC. Activation of mitogen-activated protein kinase (MAPK) ( > 30-fold over untreated controls) was observed upon receptor(s) activation, as it was the induction of the immediate early gene c-fos ( > 200-fold). These observations suggest that p21ras activation plays a role in the HRG pathway. Furthermore, comparative analysis of the binding of p85-PI3K to 185c-erbB-2 and p180erbB-4, revealed a preferential association with activated p180erbB-4. These findings might suggest a model of HRG action in which the relative expression of the various erb-B family members and the partitioning of signal transduction molecules between each type of receptor might determine the nature of the signal elicited by the ligand and the biological response attained.
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PMID:Signal transduction pathways induced by heregulin in MDA-MB-453 breast cancer cells. 862 88

It has been reported that breast tumors that overexpress c-erbB-2/neu are less responsive to certain adjuvant chemotherapy regimens than those that express a normal amount of the gene product. To investigate whether overexpression of the c-erbB-2/neu-encoded p185 can indeed lead to increased chemoresistance in breast cancers, we introduced the human c-erbB-2/neu gene into the very low p185-expressing MDA-MB435 human breast cancer cells and examined Taxol sensitivities among the parental MDA-MB-435 cells and stable transfectants which express increased levels of p185. The p185-overexpressing MDA-MB-435 transfectants were more resistant to Taxol than the parental cells. The increased Taxol resistance was not accompanied by changes in doubling time and S-phase fraction. The increased Taxol resistance was independent from oncogenic transformation since it was observed only in c-erbB-2/neu-transformed cells and not ras-transformed cells when oncogene-transformed NIH3T3 cells were examined. To study whether p185 induced Taxol resistance through the mdr-1 pathway, we examined the mdr-l-encoded p170 levels in these transfectants. The MDA-MB-435 cells expressed very low levels of p170 and there was no increase of p170 expression in the p185-overexpressing MDA-MB-435 transfectants. Furthermore, these transfectants were not sensitized to Taxol treatment by mdr-1 blocker thioradazine. These data demonstrated that overexpression of c-erbB-2/neu can lead to intrinsic Taxol resistance independent from mdr-1 mechanisms.
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PMID:Overexpression of c-erbB-2/neu in breast cancer cells confers increased resistance to Taxol via mdr-1-independent mechanisms. 880 11

Adriamycin (ADM) was chemically conjugated to a murine monoclonal antibody, A0011, which recognizes the c-erbB-2 product, via a disulfide bond using N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP) and 2-iminothiolane (2-IT). The molar ratio of ADM to the monoclonal antibody ranged from 15:1 to 25:1 and enzyme-linked immunosorbent assay (ELISA) showed that the binding activity of the conjugate was almost retained. We compared the efficacy of A0011 alone, ADM alone, the A0011-ADM conjugate, against the human breast cancer cell lines SK-BR-3, MDA-MB-361, MCF-7, and BT-20. The A0011-ADM conjugate was observed to be ten times more cytotoxic to the cell lines overexpressing the c-erbB-2 product, namely, SK-BR-3 and MDA-MB-361, than free ADM, but it showed weak cytotoxicity against the cell lines with a low level of c-erbB-2 product expression, namely, MCF-7 and BT-20. However, free A0011 and nonspecific murine IgM-ADM conjugate showed no cytotoxicity toward any of the four cell lines, while the addition of a tenfold molar excess of A0011 inhibited conjugate cytotoxicity. These data suggest that conjugate cytotoxicity is antibody-mediated. Moreover, conjugate cytotoxicity at 10(-6)M was correlated with antigen volume, and the data were fitted to the regression equation y = -11.63logX + 116.38 where the correlation coefficient = 0.950. Our results indicate that targeting therapy aiming at the c-erbB-2 product may be useful in the treatment of breast cancers overexpressing the c-erbB-2 product.
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PMID:Effectiveness of an adriamycin immunoconjugate that recognizes the C-erbB-2 product on breast cancer cell lines. 884 Apr 31

The breast cancer susceptibility gene BRCA1 encodes an 1863-amino acid protein that acts as a tumor suppressor. The biochemical function of BRCA1 is unknown, and there are conflicting results describing its subcellular location. We have identified a 220-kDa protein, which is reactive with three antibodies raised against the amino- and carboxyl-terminal regions of BRCA1. Immunoflourescence staining with an antibody to the carboxyl terminus of BRCA1 localized the protein to the nucleus of breast, ovarian, and cervical carcinoma-derived cell lines. A similar result was observed by biochemical subcellular fractionation that indicated that the 220-kDa protein was localized primarily to the nucleus of cell lines established from breast carcinomas. In addition to the 220-kDa protein, one antibody, C-20, also recognized a 180-kDa protein in MDA-MB-468 total cell lysates that was not detected by the other two antibodies. Several observations suggest the 180-kDa protein is the epidermal growth factor (EGF) receptor: (i) C-20 reacted avidly with a 180-kDa protein immunoprecipitated by an antibody to the EGF receptor; (ii) an EGF receptor antibody detected a 180-kDa protein immunoprecipitated by C-20; (iii) the affinity purified EGF receptor was both immunoprecipitated and detected on immunoblots by the C-20 antibody but not another BRCA1 antibody; (iv) similar phosphopeptide maps were generated from the EGF receptor and the 180-kDa protein immunoprecipitated by C-20, and this peptide map was distinct from the 220-kDa phosphoprotein; and (v) the C-20 immunizing peptide bears sequence identity to the EGF receptor. These results indicate that BRCA1 is a 220-kDa nuclear protein and that the 180-kDa protein reported previously may be unrelated to BRCA1.
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PMID:Subcellular localization and analysis of apparent 180-kDa and 220-kDa proteins of the breast cancer susceptibility gene, BRCA1. 891 Apr 95

The PEA3 group of transcription factors belongs to the ets family and is composed of 3 known members, PEA3, ERM and ER81, which are more than 95% identical within the DNA-binding ETS domain and exhibit 50% aa identity overall. Recently, transgenic mice bearing the c-erbB-2/neu oncogene have been shown to over-express PEA3 mRNA in mammary adenocarcinomas, suggesting a role for this gene family in mammary tumorigenesis. In the present work we characterized the mRNA expression levels of PEA3-group genes in a series of human epithelial breast cell lines. Each of the 3 genes was highly expressed in normal human HMEC 1001-7 and HMEC 219-4 cells. In breast-cancer cell lines, the 3 genes were highly expressed in the ER- MDA-MB-436, MDA-MB-330, MDA-MB-231 and BT-20 cell lines, but not in the ER+ MDA-MB-134-VI and ZR-75-1 cells. In an attempt to characterize the PEA3-group proteins in breast-cancer cells, we first produced and characterized specific antibodies against each of these 3 proteins. The anti-ERM and anti-ER81 antibodies recognized specific strong bands at approximately 72 kDa and 62 kDa, corresponding to ERM and ER81, respectively, in MDA-MB-231 and Hs-578T cells expressing significant levels of the 3 mRNAs. No protein was detected in MCF-7 cells expressing low levels of mRNA for PEA3-group-family genes, or in ZR-75-1 cells, where mRNA was undetectable by Northern blot. Although in vitro-translated PEA3 is specifically immunoprecipitated by anti-PEA3 anti-serum, we were unable to immunoprecipitate PEA3 protein from MDA-MB-231 and Hs-578T cells. In order to study the transcription factor activity of ERM, PEA3 and ER81 proteins in mammary-cancer cells, we tested their ability to transactivate a reporter plasmid containing 3 Ets-binding sites, and were able to show that, in all the breast-cancer cells tested, transfected ERM, PEA3 and ER81 are able to transactivate. Although the target genes of the PEA3 group of transcription factors in breast-cancer cells have yet to be determined, these genes have a potential role in the regulation of growth and the progression of human breast cancer.
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PMID:Expression of the PEA3 group of ETS-related transcription factors in human breast-cancer cells. 905 61


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