pepstatin and Ovarian-Neoplasms

Topics: alpha 1-Antitrypsin; Animals; Aprotinin; Breast Neoplasms; Cathepsin B; Cathepsins; Cell Transformation, Neoplastic; Female; Humans; Laryngeal Neoplasms; Lung Neoplasms; Mice; Neoplasms; Ovarian Neoplasms; Pancreatic Neoplasms; Pepstatins; Peptide Hydrolases; Protease Inhibitors; Rats; Stomach Neoplasms

Chemotherapy resistance is one of the major factors contributing to mortality from human epithelial ovarian cancer (EOC). Identifying drugs that can effectively kill chemotherapy-resistant EOC cells would be a major advance in reducing mortality. Glycosylated antitumour ether lipids (GAELs) are synthetic glycolipids that are cytotoxic to a wide range of cancer cells. They appear to induce cancer cell death in an apoptosis-independent manner.. Herein, the effectiveness of two GAELs, GLN and MO-101, in killing chemotherapy-sensitive and -resistant EOC cells lines and primary cell samples was tested using monolayer, non-adherent aggregate, and non-adherent spheroid cultures.. Our results show that EOC cells exhibit a differential sensitivity to the GAELs. Strikingly, both GAELs are capable of inducing EOC cell death in chemotherapy-sensitive and -resistant cells grown as monolayer or non-adherent cultures. Mechanistic studies provide evidence that apoptotic-cell death (caspase activation) contributes to, but is not completely responsible for, GAEL-induced cell killing in the A2780-cp EOC cell line, but not primary EOC cell samples.. Studies using primary EOC cell samples supports previously published work showing a GAEL-induced caspase-independent mechanism of death. GAELs hold promise for development as novel compounds to combat EOC mortality due to chemotherapy resistance.

Topics: Antineoplastic Agents; Apoptosis; Carcinoma, Ovarian Epithelial; Cell Death; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cells, Cultured; Cisplatin; Dose-Response Relationship, Drug; Drug Resistance, Neoplasm; Glycolipids; Humans; Neoplasms, Glandular and Epithelial; Ovarian Neoplasms; Pepstatins

Cathepsin D (CD), the major intracellular aspartyl protease, is a mediator of IFN-gamma and TNF-alpha induced apoptosis. Using subtractive hybridization screening we isolated CD as an upregulated transcript in PA1 human ovarian cancer cells undergoing adriamycin-induced apoptosis. CD mRNA levels increased in wild-type p53-expressing PA1, ML1 leukemia and U1752 lung cancer cells but not in mutant p53-expressing cells following adriamycin exposure. Overexpression of CD inhibited growth of colon, liver, and ovarian cancer cells. CD protein expression was increased by exposure of ML1 cells to etoposide, adriamycin or gamma-radiation. Inhibition of CD protease with Pepstatin A suppressed p53-dependent apoptosis in lymphoid cells, suggesting a possible role for CD in p53-dependent cell death. CD-/- fibroblasts were found to be more resistant to killing by adriamycin and etoposide, as compared to CD+/+ cells. Two p53 DNA-binding sites located in the CD-promoter specifically bound to p53 protein in vitro and appeared to mediate transactivation of a CD-promoter luciferase-reporter during p53-dependent apoptosis. These observations link CD protease to p53-dependent tumor suppression and chemosensitivity.

Topics: Animals; Apoptosis; Cathepsin D; Cell Line; Colonic Neoplasms; DNA Damage; Doxorubicin; Drug Resistance, Neoplasm; Etoposide; Female; Fibroblasts; Genes, p53; Humans; Mice; Ovarian Neoplasms; Pepstatins; RNA, Messenger; Transcriptional Activation; Tumor Cells, Cultured; Up-Regulation

High concentration of human calcitonin (hCT) was found in an ovarian carcinoid by radioimmunoassay. The hCT value was not affected by the presence of protease inhibitors. To confirm the presence of hCT in an ovarian carcinoid, hCT was isolated by the Baghdiantz method. The molecular weight of the ovarian hCT was determined using Sephadex G-75 gel filtration. Though the molecular weight of the ovarian hCT was variable, 90% corresponded to that of the authentic hCT. The carcinoid cells were examined by immunoperoxidase techniques. Those composed of strumal and trabecular structure were all argyrophilic, but hCT was only found in strumal structure. Significant concentrations of hCT were also found in ovarian cancers.

Topics: Aprotinin; Benzamidines; Biomarkers, Tumor; Calcitonin; Carcinoid Tumor; Chromatography, Gel; Edetic Acid; Female; Gabexate; Guanidines; Humans; Ovarian Neoplasms; Pepstatins; Prostaglandins E; Radioimmunoassay; Struma Ovarii

We have investigated the adhesive properties and invasiveness of cells of the human ovarian carcinoma line, NIH:OVCAR-3, in vitro. OVCAR-3 cells exhibited a similar rate of adhesion to all substrates tested including laminin, fibronectin, and collagens I and IV. The synthetic peptide YIGSR-NH2, which corresponds to an attachment site in laminin, inhibited the adhesion of the cells to laminin, but not to fibronectin. In contrast, a GRGDS-NH2 peptide blocked adhesion to fibronectin but not to laminin. OVCAR-3 cells invaded and formed branched colonies on Matrigel. Colony formation was retarded by both YIGSR-NH2 and GRGDS-NH2 peptides. Serine protease inhibitors and human recombinant TIMP, the tissue inhibitor of metalloproteases, inhibited ovarian tumor cell invasion while a synthetic collagenase IV inhibitor (SC-44463) had no effect. These studies suggest that metalloproteases other than collagenase IV may be important for the invasive activity of ovarian cancer cells. It is possible that synthetic peptides with antiadhesive cellular activity and certain antiproteases could be used to control the progressive colonization and invasion of peritoneal surfaces by malignant ovarian cancer cells.

Topics: Amides; Amino Acid Sequence; Aminocaproates; Antineoplastic Agents; Benzamidines; Biocompatible Materials; Cell Adhesion; Cell Line; Chemotaxis; Collagen; Dose-Response Relationship, Drug; Drug Combinations; Female; Glycoproteins; Humans; In Vitro Techniques; Laminin; Leupeptins; Metalloendopeptidases; Molecular Sequence Data; Neoplasm Invasiveness; Oligopeptides; Ovarian Neoplasms; Pepstatins; Polyamines; Protease Inhibitors; Proteoglycans; Tissue Inhibitor of Metalloproteinases; Tumor Cells, Cultured; Tyrosine