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)

Phosphorylation of tyrosine residues on the epidermal growth factor (EGF) receptor (EGFr) is an important early event in signal transduction, leading to cell replication for major human carcinomas. CP-358,774 is a potent and selective inhibitor of the EGFr tyrosine kinase and produces selective inhibition of EGF-mediated tumor cell mitogenesis. To assess the pharmacodynamic aspects of EGFr inhibition, we devised an ex vivo enzyme-linked immunosorbent assay for quantification of EGFr-specific tyrosine phosphorylation in human tumor tissue specimens obtained from xenografts growing s.c. in athymic mice. When coupled with pharmacokinetic analyses, this measurement can be used to describe the extent and duration of kinase inhibition in vivo. CP-358,774 is an effective, orally active inhibitor of EGFr-specific tyrosine phosphorylation (ED(50) = 10 mg/kg, single dose). It has a significant duration of action, producing, on average, a 70% reduction in EGFr-associated phosphotyrosine over a 24-h period after a single 100 mg/kg dose. Inhibition of EGFr phosphotyrosine in an ex vivo assay format effectively estimates the potency and degree of inhibition of EGFr-dependent human LICR-LON-HN5 head and neck carcinoma tumor growth. Substantial growth inhibition of human tumor xenografts was achieved with p.o. doses of the compound (ED(50) = 10 mg/kg q.d. for 20 days). Combination chemotherapy with cisplatin produced a significant response above that of cisplatin alone with no detectable effects on body weight or lethal toxicity. Taken together, these observations suggest that CP-358,774 may be useful for the treatment of EGFr-driven human carcinomas.
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PMID:Inhibition of epidermal growth factor receptor-associated tyrosine phosphorylation in human carcinomas with CP-358,774: dynamics of receptor inhibition in situ and antitumor effects in athymic mice. 1052 95

We present an approach for evaluating the efficacy of combination antitumor agent schedules that accounts for order and timing of drug administration. Our model-based approach compares in vivo tumor volume data over a time course and offers a quantitative definition for additivity of drug effects, relative to which synergism and antagonism are interpreted. We begin by fitting data from individual mice receiving at most one drug to a differential equation tumor growth/drug effect model and combine individual parameter estimates to obtain population statistics. Using two null hypotheses: (i) combination therapy is consistent with additivity or (ii) combination therapy is equivalent to treating with the more effective single agent alone, we compute predicted tumor growth trajectories and their distribution for combination treated animals. We illustrate this approach by comparing entire observed and expected tumor volume trajectories for a data set in which HER-2/neu-overexpressing MCF-7 human breast cancer xenografts are treated with a humanized, anti-HER-2 monoclonal antibody (rhuMAb HER-2), doxorubicin, or one of five proposed combination therapy schedules.
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PMID:A model-based approach for assessing in vivo combination therapy interactions. 1055 66

HER-2/neu is overexpressed in 25-30% of human breast cancers. We prepared an anti-HER-2/neu hammerhead ribozyme expressed by a recombinant adenovirus (rAdHER-Rz). Human breast cancer cell lines were transduced with high efficiency, resulting in decreased HER-2/neu expression. In vivo injections of rAdHER-Rz into BT-474 tumors established in nude mice inhibited tumor growth to 20% of mock-treated controls. Similar in vivo effects were shown in MCF-7 cells, which do not overexpress HER-2/neu. The growth inhibitory effects of rAdHER-Rz were greater than those of an antisense-expressing vector. These results suggest the utility of anti-HER-2/neu ribozymes as a rational strategy for gene therapy of breast cancer. Gene Therapy (2000) 7, 241-248.
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PMID:Adenovirus-mediated ribozyme targeting of HER-2/neu inhibits in vivo growth of breast cancer cells. 1069 1

The interaction between the erbB tyrosine kinase receptors and their ligands plays an important role in tumor growth via the regulation of autocrine and paracrine loops. We report the effect of heregulin beta1, the ligand for erbB-3 and erbB-4 receptors, on the regulation of vascular endothelial growth factor (VEGF) expression, using a panel of breast and lung cancer cell lines with constitutive erbB-2 overexpression or engineered to stably overexpress the erbB-2 receptor. We demonstrate that heregulin beta1 induces VEGF secretion in most cancer cell lines, while no significant effect was observed in normal human mammary and bronchial primary cells. Overexpression of erbB-2 receptor results in induction of the basal level of VEGF and exposure to heregulin further enhances VEGF secretion. This is associated with increased VEGF mRNA expression. In contrast, VEGF induction is significantly decreased in a T47D cell line where erbB-2 is functionally inactivated. Conditioned media from heregulin-treated cancer cells, but not from normal cells, stimulates endothelial cell proliferation; this paracrine stimulation is inhibited by co-exposure to a specific VEGF neutralizing antibody. Furthermore, heregulin-mediated angiogenesis is observed in the in vivo CAM assay. This study reports the first evidence of VEGF regulation by heregulin in cancer cells. Oncogene (2000) 19, 3460 - 3469
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PMID:Heregulin selectively upregulates vascular endothelial growth factor secretion in cancer cells and stimulates angiogenesis. 1091 4

Young age does not seem to be directly related to the aggressiveness of the disease among patients with breast cancer. Identification and analysis of the alterations in a susceptibility gene expression in breast cancer occurring in young women may allow identification of those patients in whom tumors will show an aggressive clinical course. The purpose of the present study was to evaluate the association of BRCA1, H-ras, and c-erbB-2 gene expression with clinicopathologic parameters of prognosis in breast cancer. Formalin-fixed, paraffin-embedded tissue from 35 patients with breast cancer younger than 35 years were immunohistochemically stained for BRCA1, H-ras, and c-erbB-2 expression with monoclonal antibodies. For each antibody, immunoreactivity was assessed by a semiquantitative scoring system. Each case was also graded according to the modified Bloom-Richardson criteria and evaluated for Ki-67 labeling index, hormonal status, tumor size, distant metastasis, and axillary lymph node involvement. Strong expression of c-erbB-2 and H-ras were observed in 9 cases (25.7%) and 13 cases (37.2%), respectively. Loss of BRCA1 expression was found in five cases (14.3%). Statistical analysis showed that loss of BRCA1 expression was significantly associated with higher Ki-67 labeling index and greater tumor size. In addition, stronger H-ras expression was significantly associated with lymph node involvement and distant metastasis. However, c-erbB-2 immunoreactivity did not show statistical significance with any prognostic parameters. We conclude that, although care must be taken not to overstate the importance of our results in view of the lack of information on clinical outcome, alterations in BRCA1 and H-ras gene expression might be of prognostic importance because of the role of H-ras protein on metastatic behavior and the role of BRCA1 protein on tumor growth. However, c-erbB-2 expression seems to be of no importance in the prognosis of breast cancer occurring in young women.
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PMID:BRCA1, C-erbB-2, and H-ras gene expressions in young women with breast cancer. An immunohistochemical study. 1093 43

Recent emphasis has focused on the development of an immunotherapeutic approach toward the treatment of breast cancer. In particular, evaluation of antibodies and vaccines are active areas of research. The monoclonal antibody trastuzumab (H), directed against the HER-2/neu protein, has resulted in inhibition of tumor growth in both preclinical and clinical studies. This effect can be increased when used in combination with several chemotherapeutic agents. A randomized trial of chemotherapy alone versus chemotherapy plus H in untreated metastatic breast cancer patients found prolonged survival in the combination therapy arm. Cardiac toxicity was increased with doxorubicin and cyclophosphamide plus H but not for paclitaxel (T) plus H. Several trials of dose-dense weekly T have found minimal toxicity and significant clinical benefit. These findings prompted the initiation of a trial to evaluate weekly 1-h T plus weekly H. Preliminary data from this ongoing study demonstrate few side effects and a response rate of 64% (95%CI 42-76%). The optimal role of H in the treatment of breast cancer has not yet been defined. Additional evaluation in the metastatic and adjuvant settings is planned.
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PMID:An immunotherapeutic approach to treatment of breast cancer: focus on trastuzumab plus paclitaxel. Breast Cancer Medicine Service. 1095 Jan 43

The previous pessimistic view of monoclonal antibodies as cancer therapeutics was largely influenced by the negative results of multiple clinical trials initiated shortly after the introduction of hybridoma technology. Although murine antibodies are of value in cancer therapy, their effectiveness is limited because murine monoclonal antibodies have a short survival time in humans and induce an immune response that neutralizes their therapeutic effect. Furthermore, the responses induced by murine antibodies are limited because they only weakly recruit human effector elements. To circumvent these problems, genetically engineered antibodies were produced which were mouse-human chimeric monoclonal antibodies and humanized antibodies. These antibodies combine the murine variable or hypervariable regions with the human constant or constant and variable framework regions. Numerous published studies demonstrate that erbB-2 oncogene product overexpression is a frequent cause of breast, ovarian, lung, and gastric cancers. Recently, an anti-erbB-2 humanized monoclonal antibody has been generated and used in clinical trials with high clinical response rates. We generated the anti-erbB-2 mouse-human chimeric monoclonal antibody CH401, which was able to kill cancer cells. An analysis of the mechanism of its tumor growth inhibition revealed that the cytotoxicity was induced by apoptosis. This cytotoxic mechanism is not the same a that of other anti-erbB-2 antibodies previously reported.
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PMID:[Antibody treatment for cancer]. 1102 75

The aim of this study was to investigate therapeutic efficacy of adenovirus-mediated E1a gene therapy for ovarian cancer in vitro and in vivo. Recombinant replication-deficient adenoviral vectors were prepared by superinfection of 293 cells, and then purified. The efficacy of the adenovirus vector system to infect ovarian cells was tested using different multiplicity of infection (MOI) and different times (1-4) of Ad.RSVlacZ. SKOV-3 cells (10(3) per well) were infected once with 2 x 10(4) adenovirus. The cells were harvested and counted on different days for 7 days to generate the in vitro growth curve. Tumor-bearing mice were injected intraperitoneally with ovarian cancer cells and treated by intraperitoneal injection of 100 microl (2.5 x 10(8) PFU) viral solution containing either replication-deficient Ad.E1a(+); control virus Ad.E1a(-) which is the same adenovirus as Ad.E1a(+) except for E1a deletion, or just phosphate buffered solution. The transduction efficacy increased with higher MOI and reached a plateau at the 20:1 ratio. When Ad.E1a(+) was used to transduce the HER-2/neu overexpressing human ovarian cancer cell line SKOV-3, tumor cell growth in vitro was greatly inhibited by E1a transduction. Also, Ad.E1a+ greatly inhibited tumor growth of SKOV-3-bearing mice. Immunohistochemistry analysis indicated that Ad.E1a protein was expressed in tumor tissue and expression of HER-2/neu p185 protein was suppressed. Very strong beta-gal staining was detected in tumors, and beta-gal activity in small intestine, lung, heart, stomach, liver, and kidney was detected. No beta-gal activity was detected in the tumor and other organs in control mice injected with Ad.E1a(-) or PBS. Adenovirus-type 5 E1a gene can efficaciously inhibit HER-2/neu-overexpressing ovarian cancer, and this promising procedure could greatly benefit ovarian cancer patients with high expression of HER-2/neu.
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PMID:Adenovirus 5 E1a-mediated gene therapy for human ovarian cancer cells in vitro and in vivo. 1128 29

Tumor-specific immune tolerance limits the effectiveness of cancer vaccines. In addition, tumor vaccines alone have a limited potential for the treatment of measurable tumor burdens. This highlights the importance of identifying more potent cancer vaccine strategies for clinical testing. We tested immune-modulating doses of chemotherapy in combination with a granulocyte/macrophage-colony stimulating factor (GM-CSF)-secreting, HER-2/neu (neu)-expressing whole-cell vaccine as a means to treat existing mammary tumors in antigen-specific tolerized neu transgenic mice. Earlier studies have shown that neu transgenic mice exhibit immune tolerance to the neu-expressing tumors similar to what is observed in patients with cancer. We found that cyclophosphamide, paclitaxel, and doxorubicin, when given in a defined sequence with a GM-CSF-secreting, neu-expressing whole-cell vaccine, enhanced the vaccine's potential to delay tumor growth in neu transgenic mice. In addition, we showed that these drugs mediate their effects by enhancing the efficacy of the vaccine rather than via a direct cytolytic effect on cancer cells. Furthermore, paclitaxel and cyclophosphamide appear to amplify the T helper 1 neu-specific T-cell response. These findings suggest that the combined treatment with immune-modulating doses of chemotherapy and the GM-CSF-secreting neu vaccine can overcome immune tolerance and induce an antigen-specific antitumor immune response. These data provide the immunological rationale for testing immune-modulating doses of chemotherapy in combination with tumor vaccines in patients with cancer.
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PMID:Cyclophosphamide, doxorubicin, and paclitaxel enhance the antitumor immune response of granulocyte/macrophage-colony stimulating factor-secreting whole-cell vaccines in HER-2/neu tolerized mice. 1132 40

Receptors for luteinizing hormone-releasing hormone (LHRH), expressed by ovarian cancers, can be used for targeting chemotherapeutic compounds more selectively to these tumors. We investigated the effects of cytotoxic LHRH analog AN-152, consisting of doxorubicin (DOX)-14-O-hemiglutarate linked to the epsilon-amino group of [D-Lys6]LHRH, on the growth of LHRH receptor-positive ES-2 human ovarian cancer line xenografted into nude mice. A single injection of AN-152, at a dose of 345 nmol/20 g body weight, caused a 34.5% reduction (P<0.05) in tumor growth after 28 days, while its cytotoxic moiety DOX was inactive at the same dose. Since the overexpression of certain growth factors and/or their receptors, such as vascular endothelial growth factor (VEGF), epidermal growth factor receptor (EGFR) and HER-2/neu, as well as various oncogenes like c-fos and c-jun, is associated with unfavorable prognosis and contributes to progressive growth of ovarian carcinomas, their mRNA levels were analyzed by RT-PCR. Treatment with AN-152 significantly (P<0.05) reduced the expression of EGFR, VEGF, c-fos and c-jun, to 49%, 48%, 55% and 58% respectively, compared to controls. HER-2/neu mRNA expression was also decreased to non-detectable levels. Conversely, DOX decreased non-significantly the expression levels for EGFR by 32%, VEGF 35%, both c-fos and c-jun approximately 20% and HER-2/neu by only 15%. In conclusion, cytotoxic LHRH analog AN-152 could be considered for chemotherapy of ovarian cancers expressing LHRH receptors.
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PMID:Targeting of doxorubicin to ES-2 human ovarian cancers in nude mice by linking to an analog of luteinizing hormone-releasing hormone improves its effectiveness. 1149 38


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