Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1140680 (ovarian cancer)
 28,141 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The neu/cerb-B2 gene is frequently amplified and/or overexpressed in human epithelial ovarian cancers. We have established an inbred animal model for ovarian cancer that mimics aspects of human ovarian cancer by transducing a spontaneously immortalized rat ovarian surface epithelial cell line in culture with ecotropic retroviruses expressing a mutated rat neu/c-erb-B2 oncogene. Transfectants expressing neu at a high level exhibited altered morphology and behavior in two-dimensional and three-dimensional culture in Matrigel, could be cloned in soft agar, and were more invasive through a Matrigel membrane than control transfectants transduced with a similar retrovirus expressing the beta-galactosidase gene. When injected intraperitoneally, neu-expressing transfectants produced highly invasive, rapidly growing tumors that coated the peritoneal cavity and induced ascites formation. Furthermore, neu transfectants could be grown as solid tumors when injected subepithelially into the ovary. The neu-transfected cells also formed tumors when injected subcutaneously into the mammary fat pad, although they grew relatively poorly and often regressed. Transfectants expressing beta-galactosidase failed to produce tumors at any of the sites injected. A second rat ovarian surface epithelial cell line was similarly transduced with the neu/c-erb-B2-expressing retrovirus. However, transformed phenotypes and tumorigenicity were not induced in this cell line. These experiments show directly that overexpression of neu in an established line of rat ovarian epithelium is extremely oncogenic. This animal model system may prove useful for the study of ovarian cancer biology in immunocompetent animals.
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PMID:Transfection of rat ovarian surface epithelium with erb-B2/neu induces transformed phenotypes in vitro and the tumorigenic phenotype in vivo. 942 47

In different types of human cancer there is an overexpression of the c-erbB-2 (HER2/neu) oncogene, which is thought to be involved in tumor progression. Therefore the c-erbB-2 oncogene is an attractive target for tumor-specific gene therapy. In this report we have characterized a hammerhead ribozyme against the c-erbB-2 mRNA with high cleavage activity. To select the optimum sequence, the activity of five hammerhead ribozymes was tested in a cell-free assay. The hammerhead ribozyme recognizing the GUC sequence at position +631 to +633 of the c-erbB-2 mRNA (RZ631) efficiently cleaves in vitro transcribed fragments of the c-erbB-2 mRNA [169 to 1450 nucleotides (nt)] under multiple-turnover conditions. The ribozyme coding sequence was subsequently cloned between the A and the B box promoter sequences of the fowl adenovirus type 1 virus-associated RNA (CELO VA) gene. The in vitro activity of RZ631 was shown to be unaffected by the polymerase III promoter flanking sequences. The ability of RZ631 to inhibit the synthesis of the c-erbB-2 gene product in tumor cells was assayed by cotransfection of the ribozyme with a fusion gene of c-erbB-2 and the gene for the enhanced green fluorescent protein as a reporter. The synthesis of the fluorescent fusion protein in NIH:OVCAR-3 ovarian cancer cells was potently inhibited by RZ631, as assayed by flow cytometry. An antisense control vector, where the catalytic core was replaced by a single base, showed a weaker inhibition of expression of the c-erbB-2 derivative. The results suggest that the inhibitory effect of this c-erbB-2 ribozyme is caused by an antisense effect as well as by an additional ribozyme-mediated increase in inhibition. We conclude that this c-erbB-2 ribozyme in conjunction with a polymerase III-based expression system should be useful for the efficient downregulation of the c-erbB-2 oncogene in ovarian cancer cells.
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PMID:Selection of a high activity c-erbB-2 ribozyme using a fusion gene of c-erbB-2 and the enhanced green fluorescent protein. 947 66

Despite recent advances in the chemotherapy of ovarian cancer, the development of alternative therapies that retain activity against drug-resistant tumors remains a high priority. Our knowledge regarding growth factors, cytokines, and the immune response continues to expand, and molecular biology has provided an increased diversity of reagents for clinical evaluation. This review focuses on regulatory targets in ovarian cancer, including Her2/neu (c-erbB2) and other growth factor receptors; interferons, interleukins, and other immunoregulatory cytokines; cellular adhesion molecules; antigen-specific T lymphocytes and adoptive immunotherapy; choice of monoclonal antibody reagents and advances in antibody engineering, including recombinant single-chain binding sites, chimeric proteins, radioconjugates, cytotoxic drug conjugates, immunotoxins, and bispecific antibodies. Although specific roles for biologic therapy in the management of ovarian cancer have yet to be defined, current priorities for clinical research are reviewed.
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PMID:Biological therapy of ovarian cancer: current directions. 963 51

The introduction of adenovirus 5 E1A into the SKOV3ip1 ovarian cancer cell line was shown previously to suppress HER2/neu expression and reduce the malignant potential of these cells (Yu et al., Cancer Res., 53: 891-898, 1993). In this report, we show that reduction of p185 in cells stably expressing E1A protein was coincident with increased sensitivity to cytotoxic agents. The LD50 of cisplatin was reduced 6-fold, and the LD50 of paclitaxel and doxorubicin was reduced 10-fold in E1A-expressing cells compared with control cells. The growth of SKOV3ip1 and control cells was unchanged in the presence of 150 ng/ml of tumor necrosis factor-alpha, whereas the growth of E1A-expressing cells was reduced by 30 to 40%. When we used a physiologically obtainable concentration of paclitaxel (0.5 microM), DNA laddering consistent with apoptotic cell death was seen after a 24-h exposure in the E1A-expressing cells, whereas laddering and DNA fragmentation were only detected in DNA from control cells after longer exposure (48 h) at a 20-fold higher concentration of paclitaxel. The SKOV3ip1 cells do not express p53 protein; hence, the induction of apoptosis by paclitaxel is through a p53-independent pathway. Despite their diverse mechanisms of action, the cytotoxic effects of cisplatin, doxorubicin, paclitaxel, and tumor necrosis factor-alpha were enhanced by the expression of E1A proteins in the SKOV3ip1 ovarian cancer cells. This suggests that these agents share a common final pathway of cell killing, which may represent a potential therapeutic target in resistant ovarian cancers.
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PMID:Adenovirus E1A expression enhances the sensitivity of an ovarian cancer cell line to multiple cytotoxic agents through an apoptotic mechanism. 981 92

We identified an NH2-terminally truncated HER-2/neu product of M(r) 95,000 with in vitro kinase activity by Western blotting and immunoprecipitations using domain-specific antibodies. p95 levels correlated with the extracellular domain (ECD) shed from different cells under varied conditions. Both ECD and p95 were at approximately 20-fold lower levels in SKOV3 ovarian carcinoma cells, as compared to BT474 breast carcinoma cells. Both were stimulated by treatment of cells with the phorbol ester tumor promoter phorbol 12-myristate 13-acetate and the lysosomotrophic agent chloroquine. The hydroxamate inhibitor of metalloproteases, TAPI, suppressed both p95 and ECD in a dose-dependent fashion, with maximal inhibition at < or = 10 microM in BT474 cells. Cancer tissues were analyzed by Western blotting and scored for p95HER-2/neu and for p185HER-2/neu expression. Breast and ovarian cancer tissues were both found to express p95HER-2/neu in addition to p185HER-2/neu. Of 161 breast cancer tissues, 22.4% expressed p95, 21.7% overexpressed p185, and 14.3% were p95 positive and overexpressed p185. A higher proportion of node-positive patients (23 of 78) than node-negative patients (9 of 63) expressed p95 in all tumors combined (P = 0.032). In the group that overexpressed p185, those that contained p95 were associated with node-positive patients (15 of 21), whereas those that were p95 negative were associated with node-negative patients (8 of 11; P = 0.017). Neither p95- nor p185-rich patients significantly correlated with tumor size or with hormone receptor status in this study. Our findings show that breast cancers, which express the HER-2/neu oncogene, are heterogeneous with respect to HER-2/neu protein products. p95HER-2/neu appears to distinguish tumors that have metastasized to the lymph nodes from those in node-negative patients.
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PMID:NH2-terminally truncated HER-2/neu protein: relationship with shedding of the extracellular domain and with prognostic factors in breast cancer. 982 22

HER-2/neu is a "self" tumor antigen that is overexpressed in 15-30% of human adenocarcinomas. Vaccine strategies directed against HER-2/neu and other self tumor antigens require development of methods to overcome immune tolerance to self-proteins. In rats, rat neu peptide vaccines have been shown to be an effective way of circumventing tolerance to rat neu protein and generating rat neu-specific immunity. The present report validates that a similar peptide-based vaccine formulation is effective for inducing T-cell immunity to HER-2/neu protein in humans with breast and ovarian cancer. The vaccine formulation included groups of peptides derived from the HER-2/neu extracellular domain (ECD) or intracellular domain (ICD) mixed with granulocyte macrophage colony stimulating factor as an adjuvant. These peptides were 15-18 amino acids in length and designed to elicit a CD4 T helper-specific immune response. Patients underwent intradermal immunization once a month for a total of two to six immunizations. To date, all of the patients immunized with HER-2/neu peptides developed HER-2/neu peptide-specific T-cell responses. The majority of patients (six of eight) also developed HER-2/neu protein-specific responses. Responses to HER-2/neu protein occurred with epitope spreading. Immune T cells elicited by vaccination were shown to migrate outside the peripheral circulation by virtue of generating delayed type hypersensitivity responses distant from the vaccine site, which indicated the potential ability to traffic to the site of tumor. The use of peptide-based vaccines may be a simple, yet effective, vaccine strategy for immunizing humans to oncogenic self-proteins.
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PMID:Generation of immunity to the HER-2/neu oncogenic protein in patients with breast and ovarian cancer using a peptide-based vaccine. 1038 11

Bispecific antibody (bsAb)-based clinical trials of cancer have been conducted primarily using intact murine monoclonal antibody (mAb)-derived molecules. In some of these trials, toxicity resulting from the interactions of antibody Fc domains with cellular Fc receptors has limited the doses of antibody (Ab) that can be employed. Furthermore, human anti-mouse Ab responses prohibit multiple therapy courses. These factors have decreased the efficacy of the bsAb 2B1, which targets the extracellular domains (ECD) of the HER2/neu protooncogene product and the human FcgammaRIII (CD16). To address these obstacles, we have constructed and characterized a fully human gene-fused bsAb from single-chain Fv (scFv) molecules specific for HER2/neu and CD16. The human anti-CD16 scFv component, NM3E2, was isolated from a human scFv phage display library. As binding of NM3E2 to human neutrophil-associated CD16 decreased in the presence of plasma IgG, we have concluded that NM3E2 recognizes an epitope in the vicinity of the Fc binding pocket. Furthermore, the NM3E2 scFv was found by surface plasmon resonance-based epitope mapping to share an overlapping epitope with the Leu-11c mAb. The human anti-HER2/neu scFv component, C6.5, which was previously isolated from a human scFv phage display library, was employed as fusion partner for the creation of a bispecific scFv (bs-scFv). In the presence of the C6.5 x NM3E2 bs-scFv, peripheral blood lymphocytes promoted significant lysis of human SK-OV-3 ovarian cancer cells overexpressing HER2/neu. Biodistribution studies performed in SK-OV-3 tumor-bearing scid mice revealed that 1% ID/g of 125I-labeled C6.5 x NM3E2 bs-scFv was specifically retained in tumor at 23 h following injection. These results indicated that both scFv components of the bs-scFv retained their function in the fusion protein. This bsAb should overcome some of the problems associated with the 2B1 bsAb. C6.5 x NM3E2 bs-scFv offers promise as a platform for multifunctional binding proteins with potential clinical applications as a result of its human origin, lack of an Fc domain, ease of production, high level of in vitro tumor cell cytotoxicity and highly selective tumor targeting.
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PMID:Isolation and characterization of an anti-CD16 single-chain Fv fragment and construction of an anti-HER2/neu/anti-CD16 bispecific scFv that triggers CD16-dependent tumor cytolysis. 1044 96

Amplification and resulting overexpression of the HER-2/ neu proto-oncogene is found in approximately 30% of human breast and 20% of human ovarian cancers. To better understand the molecular events associated with overexpression of this gene in human breast cancer cells, differential hybridization was used to identify genes whose expression levels are altered in cells overexpressing this receptor. Of 16 000 clones screened from an overexpression cell cDNA library, a total of 19 non-redundant clones were isolated including seven whose expression decreases (C clones) and 12 which increase (H clones) in association with HER-2/ neu overexpression. Of these, five C clones and 11 H clones have been confirmed to be differentially expressed by northern blot analysis. This group includes nine genes of known function, three previously sequenced genes of relatively uncharacterized function and four novel genes without a match in GenBank. Examination of the previously characterized genes indicates that they represent sequences known to be frequently associated with the malignant phenotype, suggesting that the subtraction cloning strategy used identified appropriate target genes. In addition, differential expression of 12 of 16 (75%) cDNAs identified in the breast cancer cell lines are also seen in HER-2/ neu -overexpressing ovarian cancer cells, indicating that they represent generic associations with HER-2/ neu overexpression. Finally, up-regulation of two of the identified cDNAs, one novel and one identified but as yet uncharacterized gene, was confirmed in human breast cancer specimens in association with HER-2/ neu overexpression. Further characterization of these genes may yield insight into the fundamental biology and pathogenetic effects of HER-2/ neu overexpression in human breast and ovarian cancer cells.
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PMID:Identification of differentially expressed genes associated with HER-2/neu overexpression in human breast cancer cells. 1049 65

HER-2/neu-overexpressing breast cancer cells are more resistant to the chemotherapeutic agent paclitaxel (Taxol) than low-HER-2/neu-expressing breast cancer cells, and the adenoviral type 5 EIA can down-regulate HER-2/neu overexpression. Therefore, in this study, we asked (a) whether EIA might sensitize response to paclitaxel in human HER-2/neu-overexpressing ovarian cancer cells, and, if so, what is the mechanism responsible; and (b) whether this enhanced chemosensitivity would translate into a therapeutic effect in an ovarian cancer xenograft model. Consequently, we demonstrated that: (a) adenovirus type 5 E1A could enhance the sensitivity of paclitaxel in paclitaxel-resistant HER-2/neu-overexpressing human ovarian cancer cells in vitro by inducing apoptosis, (b) this induction was heavily dependent on activation of the caspase-3 pathway, and (c) nude mice bearing i.p. HER-2/neu-overexpressing human ovarian cancer cells and treated with both paclitaxel and E1A gene therapy survived significantly longer than did mice treated only with paclitaxel or E1A gene therapy. Thus, we concluded that the E1A gene enhanced both the in vitro and in vivo sensitivity of paclitaxel in paclitaxel-resistant HER-2/ neu-overexpressing ovarian cancer SKOV3.ipl cells. Because a Phase I clinical trial using E1A gene targeted to HER-2/neu down-regulation has recently been completed, the current study also provided a scientific basis to further develop a novel therapy that combines paclitaxel and E1A gene therapy and its testing in a Phase II trial.
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PMID:E1A-mediated paclitaxel sensitization in HER-2/neu-overexpressing ovarian cancer SKOV3.ip1 through apoptosis involving the caspase-3 pathway. 1065 56

The proto-oncogene neu (HER2 or c-erbB2) is overexpressed with or without gene amplification in 20-30% of breast cancers. In patients, neu amplification or overexpression in breast and ovarian cancer correlates with poor prognosis and tumor resistance to chemotherapy. neu-induced transformation can be reversed by the suppression of neu gene transcription. To further understand how neu gene transcription is regulated and to identify a possible transcriptional repressor(s) of neu, we identified a negative regulatory element known previously to be located within a 1-kilobase (kb) DNA fragment of an unknown sequence, upstream of the proximal neu gene promoter. One of several DNA fragments subcloned from this region suppressed transcriptional activity of the proximal neu gene promoter. Sequencing of the 1-kb fragment confirmed the location of the repressor element to be between an AluI and a RsaI sites, around 1.4 kb upstream to the translation start site. Various deletions were introduced into the AluI-RsaI fragment and subcloned into both the native neu promoter and a heterologous thymidine kinase promoter. Subsequent transfections and reporter gene assays in cell lines of various tissues of origin confirmed and narrowed the repressor activity to a 120-base pair NlaIV-MslI fragment located between -1385 and -1266. Importantly, specific protein binding activity to this element could be detected with nuclear extracts isolated from these cell lines. In contrast, a 28-base pair MslI-RsaI fragment (-1265 to -1238), located immediately 3' of the putative repressor element, was found to form protein-DNA complexes with only nuclear extracts isolated from a colon carcinoma cell line. This specific protein binding activity correlated with a previously unknown transcriptional stimulatory activity only in this cell line.
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PMID:Characterization of a repressor element and a juxtaposed tissue-restricted activator element located on the distal neu gene promoter. 1069 68


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