Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0598934 (tumor growth)
 58,965 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

RNA interference (RNAi) represents a powerful, naturally occurring biological strategy for inhibition of gene expression. It is mediated through small interfering RNAs (siRNAs), which trigger specific mRNA degradation. In mammalian systems, however, the application of siRNAs is severely limited by the instability and poor delivery of unmodified siRNA molecules into the cells in vivo. In this study, we show that the noncovalent complexation of synthetic siRNAs with low molecular weight polyethylenimine (PEI) efficiently stabilizes siRNAs and delivers siRNAs into cells where they display full bioactivity at completely nontoxic concentrations. More importantly, in a subcutaneous mouse tumor model, the systemic (intraperitoneal, i.p.) administration of complexed, but not of naked siRNAs, leads to the delivery of the intact siRNAs into the tumors. The i.p. injection of PEI-complexed, but not of naked siRNAs targeting the c-erbB2/neu (HER-2) receptor results in a marked reduction of tumor growth through siRNA-mediated HER-2 downregulation. Hence, we establish a novel and simple system for the systemic in vivo application of siRNAs through PEI complexation as a powerful tool for future therapeutic use.
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PMID:RNAi-mediated gene-targeting through systemic application of polyethylenimine (PEI)-complexed siRNA in vivo. 1561 3

Breast and ovarian cancer are two of the leading causes of death for women in the United States. HER2/neu overexpression is an unfavorable prognosis factor associated with low patient survival rate of multiple cancer types including breast and ovarian cancer. Downregulation of the HER2/neu gene expression in cancer cells has been shown to be a useful strategy to significantly reverse the malignant characteristics induced by HER2/neu overexpression. It is possible that HER2/neu overexpression can be repressed through inhibiting the promoter activity of the gene. We have identified a number of potent transcriptional regulators, including the adenovirus type 5 E1A, the SV40 large T antigen, and the ets family member PEA3, and have tested their activity to repress HER2/neu overexpression. Ectopic expression of these transcriptional regulators resulted in downregulation of the HER2/neu promoter activity and reversed the transformed phenotype of the cancer cells in vitro. These observations were followed by a series of studies to investigate whether these HER2/neu repressors could act therapeutically as tumor suppressor genes for cancers overexpressing HER2/neu. The results of these preclinical studies clearly indicated that transcriptional repressors, which downregulate HER2/neu overexpression, can be an effective regimen for cancer treatment in a gene therapy format combined with an appropriate gene delivery system such as the cationic liposome DC-Chol or replication-deficient adenovirus vector. Our results have demonstrated that these delivery systems can effectively transfer the therapeutic genes into the cancer cells in vivo and lead to significant suppressive effects on tumor growth. Furthermore, tumor-free survival rate of treated animals is increased dramatically using nontoxic doses, compared with animals without the treatment. A great body of evidence has revealed the potential of using transcriptional repressors to suppress HER2/neu overexpression and abolish tumor growth. Thus, suppression of oncogenic gene expression using transcription factors can be a novel field for cancer treatment and prevention.
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PMID:Suppressing HER2/neu-mediated cell transformation by transcriptional repressors. 1568 99

The therapeutic efficacy of radioimmunotherapy (RIT) of 188Re-labeled herceptin, which is a humanized anti-p185-HER2/neu monoclonal antibody (mAb), was studied. The nude mice bearing nasopharyngeal carcinoma (NPC) expressing HER2/neu protooncogene were injected with 188Re-herceptin intratumorally and intravenously. The biodistribution was observed on day 2 (n = 3). The tumor growth inhibition rate (IR) was determined by measurement of tumor volume. In the intratumorally treated mice, tumor uptake of 188Re-herceptin was significantly greater than in the intravenously treated mice [11.53% injected dose (ID)/g vs. 2.79% ID/g at 48 h], and lower normal organ uptake was also seen. The intratumoral administration of 188Re-herceptin caused greater inhibition of tumor growth at the fourth week as compared to the intravenous administration. It is concluded that intratumoral administration of 188Re-herceptin makes high level of radioactivity retained in tumor with significantly lower radioactivity retained in normal tissues, and provides a more effective regional therapy for NPC overexpressing HER2/neu.
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PMID:The experimental study on the radioimmunotherapy of the nasopharyngeal carcinoma overexpressing HER2/neu in nude mice model with intratumoral injection of 188Re-herceptin. 1569 62

As seen with the proto-oncogene Her-2/neu, antibodies targeting different parts of a receptor can have opposing effects. Depending on epitope specificity, in this case, tumor growth can be inhibited--but also enhanced. Therefore, the definition of molecular binding sites is of increasing importance in modern medicine. We here introduce a novel approach for binding site localization, utilizing information obtained by the phage display technique. This is a high throughput screening method for identification of peptide mimics, so called mimotopes, of any binding structure of interest. All target molecules whose structure is available in the RCSB Protein Data Bank can be scanned for mimotope matches on their surface. In this study, we present the matching results of five mimotopes defined for the epitope recognized by trastuzumab (Herceptin), a humanized monoclonal antibody inhibiting tumor growth, on Her-2/neu. The localization thus obtained corresponds to the known trastuzumab epitope. We therefore suggest the algorithm as a novel way of binding site definition, circumventing co-crystallization experiments.
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PMID:Matching of trastuzumab (Herceptin) epitope mimics onto the surface of Her-2/neu--a new method of epitope definition. 1582 1

Tumor cells express tumor-associated antigens (TAAs), which can serve as targets for the immune system. However, the majority of TAAs are overexpressed products of normal cellular genes; as such, self-tolerance mechanisms have hindered their use for the induction of effective antitumor responses. One such normal self-protein is the growth factor receptor Her-2/neu, which is overexpressed in 25-35% of all mammary carcinomas in humans. In previous studies, we have demonstrated that Her-2/neu mice are functionally tolerant to neu antigens and contain only a low avidity T-cell repertoire to neu antigens. However, this residual low-avidity T-cell repertoire has antitumor activity. In this study, we compared the immune responses of Her-2/neu mice immunized with dendritic cells (DCs) pulsed with soluble neu protein or with apoptotic tumor cells. Analysis of the antitumor response shows that Her-2/neu mice vaccinated with DCs pulsed with Her-2/neu antigens retard tumor growth; however, vaccination with DCs pulsed with apoptotic tumor cells induces a stronger antitumor effect. Administration of multiple immunizations in combination with the costimulatory agonist anti-OX40 or anti-4-1BB MAb significantly enhanced the immune responses in these mice, resulting in complete tumor rejection if the tumor burden was small and substantial tumor reduction with a larger tumor burden. These results have important implications for the design of tumor vaccination strategies, suggesting that the use of vaccines that stimulate a broad immune response in combination with costimulatory molecules as immunomodulators could significantly improve the antitumor immune response in tolerant hosts.
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PMID:Vaccination with dendritic cells pulsed with apoptotic tumors in combination with anti-OX40 and anti-4-1BB monoclonal antibodies induces T cell-mediated protective immunity in Her-2/neu transgenic mice. 1585 73

In the present study, we demonstrate that a physical association between the extracellular domain of human HER2/neu receptor (ECDHER2) plus anti-HER2/neu IgG3-(IL-2) or anti-HER2/neu IgG3-(GM-CSF) was required to elicit the most effective anti-tumor immune response against a syngeneic tumor expressing rat HER2/neu. Immune effectors including CD4+, CD8+, and NK cells contributed to protection against tumor growth. Vaccinated B-cell deficient mice did not elicit tumor protection, suggesting a critical role for B-cells in a protective immune response. These results provide insights into the mechanisms responsible for the protective tumor immunity elicited when antibody-(IL-2 or GM-CSF) are used as enhancers of vaccines targeting tumor antigens.
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PMID:Insights into the mechanism of anti-tumor immunity in mice vaccinated with the human HER2/neu extracellular domain plus anti-HER2/neu IgG3-(IL-2) or anti-HER2/neu IgG3-(GM-CSF) fusion protein. 1596 44

Tumor metastasis is the major cause of morbidity and mortality in patients with breast cancer. It is critical to identify metastasis enabling genes and understand how they are responsible for inducing specific aspects of the metastatic phenotype to allow for improved clinical detection and management. Protein kinase C epsilon (PKC epsilon), a member of a family of serine/threonine protein kinases, is a transforming oncogene that has been reported to be involved in cell invasion and motility. In this study, we investigated the role of PKC epsilon in breast cancer development and progression. High-density tissue microarray analysis showed that PKC epsilon protein was detected in 73.6% (106 of 144) of primary tumors from invasive ductal breast cancer patients. Increasing PKC epsilon staining intensity was associated with high histologic grade (P = 0.0206), positive Her2/neu receptor status (P = 0.0419), and negative estrogen (P = 0.0026) and progesterone receptor status (P = 0.0008). Kaplan-Meier analyses showed that PKC epsilon was significantly associated with poorer disease-free and overall survival (log-rank, P = 0.0478 and P = 0.0414, respectively). RNA interference of PKC epsilon in MDA-MB231 cells, an aggressive breast cancer cell line with elevated PKC epsilon levels, resulted in a cell phenotype that was significantly less proliferative, invasive, and motile than the parental or the control RNA interference transfectants. Moreover, in vivo tumor growth of small interfering RNA-PKC epsilon MDA-MB231 clones was retarded by a striking 87% (P < 0.05) and incidence of lung metastases was inhibited by 83% (P < 0.02). PKC epsilon-deficient clones were found to have lower RhoC GTPase protein levels and activation. Taken together, these results revealed that PKC epsilon plays a critical and causative role in promoting an aggressive metastatic breast cancer phenotype and as a target for anticancer therapy.
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PMID:Protein kinase C epsilon is a predictive biomarker of aggressive breast cancer and a validated target for RNA interference anticancer therapy. 1616 14

Current therapies used in the treatment of breast cancer are limited by systemic toxicity, rapid drug metabolism and intrinsic and acquired drug resistance. We have previously shown that adenoviral-mediated transfer of the melanoma differentiation-associated gene-7 (mda-7) elicits growth inhibition and apoptosis in various tumor types. Here, we evaluate the effects of Ad-mda7, alone and in combination with other therapies, against a panel of nine breast tumor cell lines and their normal counterparts; we report selective Ad-mda7-mediated p53-independent growth inhibition, G2/M cell cycle arrest, and apoptosis. In vivo, Ad-mda7 induced p53-independent tumor growth inhibition (P<0.004) in multiple xenograft models. We then evaluated the combination of Ad-mda7 with agents commonly used to treat breast cancer: radiotherapy (XRT), Tamoxifen, Taxotere, Adriamycin, and Herceptin. These agents exhibit diverse modes of action, including formation of bulky adducts, inhibition of DNA replication (Adriamycin, XRT), damage to microtubules (Taxotere), nonsteroidal estrogen antagonists (Tamoxifen), or Her2/neu receptor blockade (Herceptin). Treated with conventional anticancer drugs or radiation, MDA-7-expressing cells display additive or synergistic cytotoxicity and apoptosis that correlates with decreased BCL-2 expression and BAX upregulation. In vivo, animals that received Ad-mda7 and XRT underwent significant reduction of tumor growth (P<0.002). This is the first report of the synergistic effects of Ad-mda7 combined with chemotherapy or radiotherapy on human breast carcinoma cells.
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PMID:mda-7 gene transfer sensitizes breast carcinoma cells to chemotherapy, biologic therapies and radiotherapy: correlation with expression of bcl-2 family members. 1628 87

alphavbeta3 or alphavbeta5 integrins are widely expressed on blood and endothelial cells. Inhibition of the functions of these integrins has been reported to suppress neovascularization and tumor growth, suggesting that they may be critical modulators of angiogenesis. However, mice lacking these integrins exhibit extensive angiogenesis. Tumors arising from s.c. injections of tumor cells into mice lacking one or both integrins show enhanced tumor growth compared with growth in control mice due to both increased angiogenesis and to altered innate immune response. Other data suggest additional roles for these integrins, on either platelets or the tumor cells themselves, in enhancing tumor progression and metastasis. Here, we investigate the involvement of beta3 and beta5 integrins in the development and progression of mammary carcinomas. We intercrossed mouse mammary tumor virus (MMTV)-c-neu transgenic mice with beta3 or beta5 or beta3beta5 integrin-deficient mice and observed that multiple, large mammary tumors developed in 100% of mice on all genetic backgrounds. A statistically significant earlier onset of tumor growth was observed in the MMTV-c-neu/beta3beta5 integrin-null females compared with control mice. No major differences were observed in tumor size or number, vessel number or vessel structure and lung metastases were observed with similar frequency and size in all strains. MMTV-c-neu/beta3beta5 integrin-null mice had higher numbers of mammary acini, which may account for the earlier onset of tumors in this strain. These data indicate that alphavbeta3 or alphavbeta5 integrins are not essential for tumor growth and progression, although they might play some role in mammary gland development.
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PMID:A direct test of potential roles for beta3 and beta5 integrins in growth and metastasis of murine mammary carcinomas. 1628 21

Here, the structure, function, biological and pathological significance and clinical utility of the principal biomolecular markers of breast cancer is reviewed. Each marker was scored for clinical utility using a recently developed tumor marker utility grading system (TMUGS). Among the tissue markers, ERs and PRs are important prognostic/predictive factors and the only tissue markers routinely determined. ER cross-talks with other growth factors while co-regulatory factors enhance (co-activators) or decrease (co-repressors) its transcriptional activity. C-erbB-2 and Ki67/MIB-1 select for adjuvant chemotherapy a subgroup of lymph-node negative patients at a high risk of relapse. Monoclonal antibodies (trastuzumab, gefitinib, erlotinib and bevacizumab) targeting tissue markers and involved in tumor growth and metastasization (EGFR, C-erbB-2, VEGF) have been developed; they showed therapeutical single agent activity as well as potent synergy with chemotherapy agents in metastatic cancer. Among circulating markers, some are potentially useful in the early detection and monitoring of metastatic disease; nevertheless, none is routinely recommended. To suspect distant metastases, CEA-TPA-CA15.3 panel attained accuracy of about 90%. ECD HER2-neu, p53 and nucleophosmin antibodies seem suitable candidates for different associations. Preliminary observations suggest that an early detection with tumor markers and successive treatment of relapses significantly prolongs disease-free and overall survival in selected patients. In conclusion, biomolecular markers are improving understanding of biology and management of breast cancer.
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PMID:Biomolecular markers of breast cancer. 1636 59


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