8-bromocyclic-gmp and Adenocarcinoma

Topics: Adenocarcinoma; Animals; Antineoplastic Agents; Apoptosis; Caspase 3; Cell Line, Tumor; Colonic Neoplasms; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Drug Resistance, Neoplasm; Drug Synergism; Drugs, Chinese Herbal; Humans; Hypoxia; Male; Mice, Inbred BALB C; Nitroso Compounds; Oxadiazoles; Oxazines; Phosphodiesterase 5 Inhibitors; Plant Extracts; Reactive Oxygen Species; Serum Albumin, Human; Soluble Guanylyl Cyclase; Vardenafil Dihydrochloride

The natural hormone uroguanylin regulates intestinal fluid homeostasis and bowel function through activation of guanylate cyclase-C (GC-C), resulting in increased intracellular cyclic guanosine-3',5'-monophosphate (cGMP). We report the effects of uroguanylin-mediated activation of the GC-C/cGMP pathway in vitro on extracellular cGMP transport and in vivo in rat models of inflammation- and stress-induced visceral hypersensitivity. In vitro exposure of intestinal Caco-2 cells to uroguanylin stimulated bidirectional, active extracellular transport of cGMP into luminal and basolateral spaces. cGMP transport was significantly and concentration dependently decreased by probenecid, an inhibitor of cGMP efflux pumps. In ex vivo Ussing chamber assays, uroguanylin stimulated cGMP secretion from the basolateral side of rat colonic epithelium into the submucosal space. In a rat model of trinitrobenzene sulfonic acid (TNBS)-induced visceral hypersensitivity, orally administered uroguanylin increased colonic thresholds required to elicit abdominal contractions in response to colorectal distension (CRD). Oral administration of cGMP mimicked the antihyperalgesic effects of uroguanylin, significantly decreasing TNBS- and restraint stress-induced visceromotor response to graded CRD in rats. The antihyperalgesic effects of cGMP were not associated with increased colonic spasmolytic activity, but were linked to significantly decreased firing rates of TNBS-sensitized colonic afferents in rats in response to mechanical stimuli. In conclusion, these data suggest that the continuous activation of the GC-C/cGMP pathway along the intestinal tract by the endogenous hormones guanylin and uroguanylin results in significant reduction of gastrointestinal pain. Extracellular cGMP produced on activation of GC-C is the primary mediator in this process via modulation of sensory afferent activity.

Topics: Acetylcholine; Acetylglucosamine; Adenocarcinoma; Animals; Cell Differentiation; Cell Line, Tumor; Colitis; Colon; Colorectal Neoplasms; Cyclic GMP; Disease Models, Animal; Dose-Response Relationship, Drug; Drug Interactions; Electric Stimulation; Female; Gastrointestinal Diseases; Gene Expression Regulation, Neoplastic; Guanylate Cyclase; Humans; Hyperalgesia; Intestinal Mucosa; Male; Mast Cells; Morphine; Multidrug Resistance-Associated Proteins; Natriuretic Peptides; Organic Anion Transporters, Sodium-Independent; Peroxidase; Rats; Rats, Sprague-Dawley; Rats, Wistar; Restraint, Physical; RNA, Messenger; Signal Transduction; Trinitrobenzenesulfonic Acid; Visceral Pain

Tumor cell migration is considered as a major event in the metastatic cascade. Here we examined the effect of grape seed proanthocyanidins (GSPs) on migration capacity and signaling mechanisms using nonsmall cell human lung cancer cells. Using in vitro migration assay, we found that treatment of A549 and H1299 cells with GSPs resulted in concentration-dependent inhibition of migration of these cells. The migration capacity of cells was reduced in presence of N(G)-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthase. GSPs suppressed the elevated levels of endogenous NO/NOS in A549 and H1299 cells and blocked the migration promoting capacity of L-arginine. Treatment with guanylate cyclase (GC) inhibitor 1-H-[1,2,4]oxadiaxolo[4,3-a]quinolalin-1-one (ODQ) reduced the migration of A549 cells whereas additional presence of 8-bromoguanosine 3'5'-cyclic monophosphate (8-Br-cGMP, cGMP analogue) restored the migration of these cells, suggesting a role for GC in migration of A549 cells. GSPs reduced the elevated levels of cGMP in cancer cells and also blocked the migration restoring activity of 8-Br-cGMP. The mitogen-activated protein kinase kinase (MAPKK) inhibitor, UO126, inhibited the migration of A549 cells, indicating a role for MAPKK in the migration. Additionally, UO126 and ODQ inhibited the migration restoring effects of L-arginine in L-NAME-treated cells, suggesting the involvement of cGMP and MAPK pathways in NO-mediated migration. GSPs inhibited L-arginine and 8-Br-cGMP-induced activation of ERK1/2 in A549 cells. Together, these results indicate sequential inhibition of NO/NOS, GC, and MAPK pathways by GSPs in mediating the inhibitory signals for cell migration, an essential step in invasion and metastasis.

Topics: Adenocarcinoma; Blotting, Western; Carcinoma, Large Cell; Carcinoma, Non-Small-Cell Lung; Cell Movement; Cell Proliferation; Cell Survival; Cyclic GMP; Enzyme Inhibitors; Fluorescent Antibody Technique; Grape Seed Extract; Guanylate Cyclase; Humans; Lung Neoplasms; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Oxadiazoles; Plant Extracts; Proanthocyanidins; Quinoxalines; Receptors, Cell Surface; Signal Transduction; Tumor Cells, Cultured; Vitis