cyclic-gmp and Urinary-Bladder-Neoplasms

Delivery systems are a powerful technology for enhancing the effect of cancer immunotherapy. We have been in the process of developing lipid-based delivery systems for controlling the physical properties and dynamics of immunofunctional molecules such as antigens and adjuvants. The lipid nanoparticulation of these molecules improves their physical properties, resulting in a good water dispensability, greater stability, and small size. The cell wall skeleton of bacille Calmette-Guerin (BCG-CWS) could be used to replace live BCG as a drug for treating bladder cancer, but problems associated with the physical properties of BCG-CWS have prevented its use. To overcome such problems, we developed a novel packaging method that permits BCG-CWS to be encapsulated into lipid nanoparticles, which induce antitumor responses against bladder cancer. Lipid nanoparticulation also improves the intracellular trafficking and biodistribution of immunofunctional molecules. Cyclic di-GMP (c-di-GMP) is an adjuvant that is recognized by the cytosolic sensor. However, c-di-GMP cannot pass through the cell membrane. We encapsulated c-di-GMP into lipid nanoparticles containing a pH-responsive lipid that was developed in our laboratory and achieved efficient cytosolic delivery and the induction of antitumor immunity. Furthermore, we are attempting to control the functions of immune cells by RNA interference. We have recently succeeded in the efficient delivery of small interfering RNA into mouse dendritic cells (DCs), which led to the enhancement of antitumor activity of DCs. In this review, our recent efforts regarding cancer immunotherapy using lipid-based nanoparticles are reviewed.

Topics: Adjuvants, Immunologic; Animals; Cell Wall Skeleton; Cyclic GMP; Dendritic Cells; Drug Delivery Systems; Drug Design; Humans; Immunotherapy; Lipids; Mice; Mycobacterium bovis; Nanoparticles; Neoplasms; RNA Interference; Urinary Bladder Neoplasms

Nitric oxide (NO) is produced by a group of synthase enzymes (NOS). By means of different pathways, NO exerts several functions in benign and malignant human bladder tissues. The current paper describes the NO/guanylate cyclase (sGC)/cyclic guanosine monophosphate (cGMP) and the NO/oxidative pathways in human bladder tissues.. Bladder carcinoma tissues were collected from 18 patients by transurethral resection procedures. Normal benign vesical tissue specimens from a further eight patients with benign diseases served as controls. Immunohistochemistry was conducted for localization of sGC, cGMP, and nitrotyrosine in benign and malignant vesical tissues, evaluating two-three tissue sections per patient.. Positive immunolabeling for sGC and cGMP was detected in vascular endothelial cells of normal and malignant vesical tissues. Those signals were most intense in bladder carcinoma tissues. Immunolabeling for sGC and cGMP was also detected in normal urothelial cells. In bladder carcinoma cells, a heterogeneous immunolabeling for sGC and cGMP was seen, with a wide spectrum of signal intensity. Positive immunostaining for sGC and cGMP was also observed in stromal round cells in benign and malignant bladder tissues. Immunolabeling for nitrotyrosine was mainly observed in endothelial cells, with a much stronger immunolabeling in bladder carcinoma tissues compared to normal benign controls. A weak immunolabeling for nitrotyrosine was also observed in bladder carcinoma cells. Normal urothelial cells did not show such nitrotyrosine expression.. The current report provides evidences that NO play several roles through different pathways in benign and malignant vesical tissues. The influences generated by NO molecules can be divided into cGMP-mediated effects (those resulting from the NO/sGC/cGMP pathway) and non-cGMP-mediated effects (those resulting from the NO/oxidative pathway). Increased angiogenesis is a cGMP-mediated effect, while nitrotyrosine production is a non cGMP-mediated oxidative effect. Such an NO/oxidative pathway is observed more often in bladder carcinoma.

Topics: Aged; Blotting, Western; Carcinoma; Cell Transformation, Neoplastic; Cyclic GMP; Free Radical Scavengers; Guanylate Cyclase; Humans; Immunohistochemistry; Neovascularization, Pathologic; Nitric Oxide; Nitric Oxide Synthase; Oxidation-Reduction; Tyrosine; Urinary Bladder Neoplasms

Exisulind (Aptosyn) is a novel antineoplastic drug being developed for the prevention and treatment of precancerous and malignant diseases. In colon tumor cells, the drug induces apoptosis by a mechanism involving cyclic GMP (cGMP) phosphodiesterase inhibition, sustained elevation of cGMP, and protein kinase G activation. We studied the effect of exisulind on bladder tumorigenesis induced in rats by the carcinogen, N-butyl-N-(4-hydroxybutyl) nitrosamine. Exisulind at doses of 800, 1000, and 1200 mg/kg (diet) inhibited tumor multiplicity by 36, 47, and 64% and tumor incidence by 31, 38, and 61%, respectively. Experiments on the human bladder tumor cell line, HT1376, showed that exisulind inhibited growth with a GI(50) of 118 microM, suggesting that the antineoplastic activity of the drug in vivo involved a direct effect on neoplastic urothelium. Exisulind also induced apoptosis as determined by DNA fragmentation, caspase activation, and morphology. Analysis of phosphodiesterase (PDE) isozymes in HT1376 cells showed PDE5 and PDE4 isozymes that were inhibited by exisulind with IC(50)s of 112 and 116 microM, respectively. Inhibition of PDE5 appears to be pharmacologically relevant, because treatment of HT1376 cells increased cGMP and activated protein kinase G at doses that induce apoptosis, whereas cyclic AMP levels were not changed. Immunocytochemistry showed that PDE5 was localized in discrete perinuclear foci in HT1376 cells. Immunohistochemistry showed that PDE5 was overexpressed in human squamous and transitional cell carcinomas compared with normal urothelium. The data lead us to conclude that future clinical trials of exisulind for human bladder cancer treatment and/or prevention should be considered and suggest a mechanism of action involving cGMP-mediated apoptosis induction.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; 3',5'-Cyclic-GMP Phosphodiesterases; Animals; Anticarcinogenic Agents; Apoptosis; Cell Division; Cyclic AMP; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cyclic Nucleotide Phosphodiesterases, Type 4; Cyclic Nucleotide Phosphodiesterases, Type 5; Dose-Response Relationship, Drug; Enzyme Activation; Female; Humans; Inhibitory Concentration 50; Microscopy, Fluorescence; Rats; Rats, Inbred F344; Sulindac; Tumor Cells, Cultured; Urinary Bladder Neoplasms

Topics: Aged; Cyclic AMP; Cyclic GMP; Female; Humans; Male; Middle Aged; Urinary Bladder Neoplasms; Urogenital Neoplasms