Search Results - (Author, Cooperation:C. K. Osborne)

2011-12-14

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; Breast Neoplasms/*genetics/metabolism/mortality/pathology ; Cell Cycle ; Cell Line, Tumor ; *Cell Transformation, Neoplastic ; Female ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; *Genes, myc ; Humans ; Mammary Neoplasms, Experimental/genetics/metabolism/mortality/pathology ; Mice ; Mice, Nude ; Mitosis ; Neoplasm Transplantation ; Proto-Oncogene Proteins c-myc/*metabolism ; RNA Interference ; RNA, Small Interfering ; Spindle Apparatus/physiology ; Sumoylation ; *Transcription, Genetic ; Transplantation, Heterologous ; Ubiquitin-Activating Enzymes/antagonists & inhibitors/*genetics/metabolism

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1432-0843

Springer Online Journal Archives 1860-2000

Medicine

Summary Hormone manipulation has been standard therapy for metastatic adenocarcinoma of the prostate for many years. Recently cytotoxic drugs have been studied, but their effectiveness has been limited, indicating the need for new therapeutic approaches. Based upon the hypothesis that cytotoxic drugs are most effective agaist actively proliferating cells, we have designed a clinical pilot study employing cyclical androgen priming to transiently stimulate tumor cells followed by cytotoxic chemotherapy with cyclophosphamide and methotrexate. There were nine responders (43%) out of 21 patients entered in the study, with a median duration of response that has not been reached at 9+ months. Survival was significantly better in responders than in non-responding patients. These results are similar to those of other studies in which chemotherapy was used alone. Chemotherapy toxicity with this schedule was mild. However, the androgen priming frequently resulted in increased bone pain, and there was one episode of spinal cord compression, suggesting that tumor stimulation was achieved. These results demonstrate the need for additional basic studies of the effects of testosterone on tumor cell kinetics before further clinical trials of this approach are initiated.

Electronic Resource

1573-7217

breast cancer ; epidermal growth factor receptor ; immunotoxins ; ligand fusion toxins ; targeted therapy

Springer Online Journal Archives 1860-2000

Medicine

Summary Immunotoxins are a relatively new class of cytotoxic agents consisting of a catalytic toxin linked to an appropriate targeting ligand. The ligand directs the toxin to the surface of a tumor cell, whereupon the toxin enters the cell and catalytically inactivates the ribosome, thus disrupting protein synthesis and effecting cell death. Monoclonal antibodies (or their fragments) have been most commonly used to carry chemically conjugated toxins to proteins or antigens overexposed on the tumor cell surface, but specific ligands for tumor cell surface receptors could also provide effective targeting. The receptor for epidermal growth factor (EGFR) is overexpressed primarily in poor prognosis breast cancers that do not respond well to traditional therapies. Because EGFR is frequently overexpressed in breast cancer tissue and is associated with a poor prognosis, it is an attractive target for antitumor therapy. DAB 389 EGF is an EGFR specific fusion toxin produced with recombinant DNA techniques consisting of sequences for the enzymatically active and membrane translocation domains of diphtheria toxin plus sequences for human epidermal growth factor. DAB 389 EGF is a potent, EGFR specific, cytotoxic agent which rapidly inhibits protein synthesis by a mechanism of action similar to that of diphtheria itself. Preclinical studies in the laboratory and in animals now suggest the feasibility of investigating such an agent in the targeted therapy of patients with human breast cancer.

Electronic Resource

1573-7217

breast cancer ; ELISA ; invasion ; plasminogen activator ; urokinase receptor

Springer Online Journal Archives 1860-2000

Medicine

Summary Urokinase plasminogen activator (uPA) is a proteolytic enzyme involved in degradation of the extracellular matrix during cancer invasion. The levels of uPA and its inhibitor PAI-1 in tumor extracts have previously been demonstrated to be of prognostic value in breast cancer as well as other types of cancer. We have previously characterized a specific cell surface receptor for uPA (uPAR) which strongly enhances the catalytic activity of uPA and is expressed during mammary cancer invasion. In order to quantitate uPAR in breast cancer tissue, we have now developed a sensitive enzyme-linked immunosorbent assay (ELISA), with polyclonal catching antibodies and three monoclonal detecting antibodies. The detection limit of the assay is approximately 0.16 fmol of uPAR in a volume of 100 µl (1.6 pM). There is a linear relationship between signal and uPAR concentration up to at least 6.6 fmol per 100 µl (66 pM). Both free uPAR and uPAR in complex with uPA is detected. The recovery of an internal uPAR standard in breast cancer tissue extracts is above 87%. The intra-assay and inter-assay variation coefficients are 7% and 13%. In order to find a suitable buffer for extraction of various components of the uPA-system from breast cancer tissue, we tested buffers which previously have been used for optimal extraction of estrogen receptor (A), uPA (B), and uPAR (C). Buffer A and B extracted approximately 30% and 50%, respectively, of the amount of uPAR extracted with buffer C. Extracts of samples of breast cancer tissue from 94 patients all contained uPAR in amounts above the detection limit of the present assay, which appears suitable for studies of the potential prognostic value of uPAR in this disease. Significant correlations were found between uPAR, uPA and PAI-1 tumor levels.

Electronic Resource