cyclic-gmp and Carcinoma

PDE5 is a key enzyme involved in the regulation of cGMP-specific signaling pathways in normal physiological processes such as smooth muscle contraction and relaxation. For this reason, inhibition of the enzyme can alter those pathophysiological conditions associated with a lowering cGMP level in tissues. For example, selective PDE5 inhibitors, such as sildenafil (Viagra, Pfizer), tadalafil (Cialis, Lilly-ICOS), and vardenafil (Levitra, Bayer), have been successfully used to treat the condition of human erectile dysfunction. More recently, the involvement of this enzyme has been proposed to influence antiproliferation and proapoptotic mechanism in multiple carcinomas. The data supporting this idea is based on increases in PDE5 activities in many carcinomas and the ability of PDE5 inhibitors such as exisulind and its analogs related to anticancer activities. Inhibition of PDE5 that results in sustained increases in [cGMP](i) are required to modify the process of apoptosis and mitotic arrest in those carcinoma cells with enhanced PDE5 expressions. Increases in PDE5 are also involved in contributing to the pathological changes in the pulmonary system resulting in hyper-proliferative remodeling of both smooth muscle and endothelium in models of pulmonary hypertension. For this reason, the use of PDE5 inhibitors in the treatment of human pulmonary hypertension has met with some success. The differences that we have previously noted in PDE isoenzymes in pulmonary arterial and microvascular endothelial cells may provide a more selective cellular strategy for use of such inhibitor. Additional studies on structure biology of these enzymes should lead to the development of agents with better cellular specificity than currently available drugs. Considering the enormous progress that has been made in the last few years, the future looks promising for agents affecting this enzyme and related systems.

Topics: 3',5'-Cyclic-GMP Phosphodiesterases; Amino Acid Sequence; Animals; Base Sequence; Carcinoma; Coronary Vessels; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; DNA; Humans; Lung; Molecular Sequence Data; Phosphodiesterase Inhibitors; Structure-Activity Relationship

Previously, we showed that basal activity of nitric oxide (NO)/cyclic GMP (cGMP)/protein kinase G (PKG) signaling pathway protects against spontaneous apoptosis and confers resistance to cisplatin-induced apoptosis in human ovarian cancer cells. The present study determines whether basal PKG kinase activity regulates Src family kinase (SFK) activity and proliferation in these cells. PKG-Ialpha was identified as predominant isoform in both OV2008 (cisplatin-sensitive, wild-type p53) and A2780cp (cisplatin-resistant, mutated p53) ovarian cancer cells. In both cell lines, ODQ (inhibitor of endogenous NO-induced cGMP biosynthesis), DT-2 (highly specific inhibitor of PKG-Ialpha kinase activity), and PKG-Ialpha knockdown (using small interfering RNA) caused concentration-dependent inhibition of DNA synthesis (assessed by bromodeoxyuridine incorporation), indicating an important role of basal cGMP/PKG-Ialpha kinase activity in promoting cell proliferation. DNA synthesis in OV2008 cells was dependent on SFK activity, determined using highly selective SFK inhibitor, 4-(4'-phenoxyanilino)-6,7-dimethoxyquinazoline (SKI-1). Studies using DT-2 and PKG-Ialpha small interfering RNA revealed that SFK activity was dependent on PKG-Ialpha kinase activity. Furthermore, SFK activity contributed to endogenous tyrosine phosphorylation of PKG-Ialpha in OV2008 and A2780cp cells. In vitro coincubation of recombinant human c-Src and PKG-Ialpha resulted in c-Src-mediated tyrosine phosphorylation of PKG-Ialpha and enhanced c-Src autophosphorylation/activation, suggesting that human c-Src directly tyrosine phosphorylates PKG-Ialpha and the c-Src/PKG-Ialpha interaction enhances Src kinase activity. Epidermal growth factor-induced stimulation of SFK activity in OV2008 cells increased PKG-Ialpha kinase activity (indicated by Ser(239) phosphorylation of the PKG substrate vasodilator-stimulated phosphoprotein), which was blocked by both SKI-1 and SU6656. The data suggest an important role of Src/PKG-Ialpha interaction in promoting DNA synthesis/cell proliferation in human ovarian cancer cells. The NO/cGMP/PKG-Ialpha signaling pathway may provide a novel therapeutic target for disrupting ovarian cancer cell proliferation.

Topics: Carcinoma; Cell Line, Tumor; Cell Proliferation; CSK Tyrosine-Protein Kinase; Cyclic GMP; Cyclic GMP-Dependent Protein Kinase Type I; Cyclic GMP-Dependent Protein Kinases; DNA Replication; Dose-Response Relationship, Drug; Enzyme Activation; Enzyme Inhibitors; Epidermal Growth Factor; Female; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Nitric Oxide; Ovarian Neoplasms; Phosphorylation; Protein-Tyrosine Kinases; RNA Interference; src-Family Kinases

Tumor cell migration is considered as a major event in the metastatic cascade. Here we examined the effect of (-)-epigallocatechin-3-gallate (EGCG) on migration capacity and molecular mechanism using 4T1 murine mammary cancer cells as a model. Using an in vitro migration assay, we found that treatment of 4T1 cells with EGCG 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. EGCG suppressed the elevated levels of endogenous NO/NOS in 4T1 cells and blocked the migration promoting capacity of l-arginine. Treatment with guanylate cyclase inhibitor 1-H-[1,2,4]oxadiaxolo[4,3-a]quinolalin-1-one (ODQ) reduced the migration of 4T1 cells. EGCG reduced the elevated levels of cGMP in cancer cells and blocked the migration restoring activity of 8-Br cGMP (cGMP analogue). These results indicate for the first time that EGCG inhibits mammary cancer cell migration through the inhibition of NO/NOS and guanylate cyclase.

Topics: Animals; Anticarcinogenic Agents; Carcinoma; Catechin; Cell Line, Tumor; Cell Movement; Cyclic GMP; Enzyme Inhibitors; Guanylate Cyclase; Mammary Neoplasms, Animal; Mice; NG-Nitroarginine Methyl Ester; Nitric Oxide Synthase; Nitrogen Oxides; Oxadiazoles; Quinoxalines

In order to examine the cyclic nucleotides (cGMP) role in carcinoma growth and invasivity. We analyzed two cell lines, LSHT29 and 17GT, and tissues in patients with carcinoma and malignant tissues with (N+) and without (N-) lymph node metastases. Higher cGMP levels in pathological samples suggest a strong correlation between intracellular cGMP concentration and carcinoma progression.

Topics: Carcinoma; Carcinoma, Squamous Cell; Cell Line, Tumor; Chromatography, High Pressure Liquid; Cyclic GMP; Disease Progression; Gingival Neoplasms; Guanosine Monophosphate; Humans; Indicators and Reagents; Lymphatic Metastasis; Mouth Neoplasms; Quinolines

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

Certain pathogenic bacteria produce a family of heat stable enterotoxins (STa) which activate intestinal guanylyl cyclases, increase cGMP, and elicit life-threatening secretory diarrhea. The intracellular effector of cGMP actions has not been clarified. Recently we cloned the cDNA for a rat intestinal type II cGMP dependent protein kinase (cGK II) which is highly enriched in intestinal mucosa. Here we show that cGK II mRNA and protein are restricted to the intestinal segments from the duodenum to the proximal colon, with the highest amounts of cGK II protein in duodenum and jejunum. cGK II mRNA and protein decreased along the villus to crypt axis in the small intestine, whereas substantial amounts of both were found in the crypts of cecum. In intestinal epithelia, cGK II was specifically localized in the apical membrane, a major site of ion transport regulation. In contrast to cGK II, cGK I was localized in smooth muscle cells of the villus lamina propria. Short circuit current (ISC), a measure of Cl- secretion, was increased to a similar extent by STa and by 8-Br-cGMP, a selective activator of cGK, except in distal colon and in monolayers of T84 human colon carcinoma cells in which cGK II was not detected. In human and mouse intestine, the cyclic nucleotide-regulated Cl- conductance can be exclusively accounted for by the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel. Viewed collectively, the data suggest that cGK II is the mediator of STa and cGMP effects on Cl- transport in intestinal-epithelia.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Animals; Biological Transport; Carcinoma; Cecum; Chlorides; Colon; Colonic Neoplasms; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cystic Fibrosis Transmembrane Conductance Regulator; Enterotoxins; Enzyme Induction; Esophagus; Humans; In Situ Hybridization; Intestinal Mucosa; Intestine, Small; Isoenzymes; Male; Membrane Proteins; Microvilli; Muscle, Smooth; Organ Specificity; Rats; Rats, Sprague-Dawley; RNA, Messenger; Stomach; Tumor Cells, Cultured

In in vitro studies, SR 48692, a nonpeptide neurotensin receptor antagonist, inhibited the binding of [3H] or [125I]neurotensin to membrane preparations from 10-day-old mouse brains and from HT-29 cells with Ki values of 3.9 and 8.6 nM, respectively. SR 48692 also antagonized the neurotensin-induced mobilization of intracellular calcium in HT-29 cells, in agreement with previous findings. In rat cerebellar slices SR 48692 blocked the increase in cyclic GMP levels evoked by neurotensin in a dose-dependent manner. In vivo, SR 48692 antagonized the increase in rat brain mesolimbic dopamine turnover induced by the systemically active neurotensin peptide, EI [(N-Me)Arg-Lys-Pro-Trp-tert-Leu-Leu]. No effects on dopamine turnover of either EI or SR 48692 were observed in the striatum. SR 48692 did not antagonize the EI-induced decreases in mouse body temperature and spontaneous locomotor activity (LMA) or the decreases in LMA induced by ICV-administered neurotensin. Although other explanations are possible, these findings support the hypothesis that a subtype of the NT receptor may mediate the locomotor and hypothermic actions of this peptide and that it is different from the NT receptor that is involved in dopamine turnover.

Topics: Animals; Brain Chemistry; Calcium; Carcinoma; Cells, Cultured; Colonic Neoplasms; Cyclic GMP; Dopamine; Humans; Hypothermia; Locomotion; Male; Membranes; Mice; Neurotensin; Oligopeptides; Psychotropic Drugs; Pyrazoles; Quinolines; Radioligand Assay; Rats

1. Neurotensin stimulated inositol monophosphate (IP1) formation in both human colonic carcinoma HT29 cells and in mouse neuroblastoma N1E115 cells with EC50 values of 3.5 +/- 0.5 nM (n = 4) and 0.46 +/- 0.02 nM (n = 3), respectively. Neurotensin also stimulated cyclic GMP production with an EC50 of 0.47 +/- 1.2 nM and inhibited cyclic AMP accumulation induced by forskolin (0.5 microM) with an IC50 of 1.33 +/- 1.5 nM (n = 3) on the N1E115 cell line. 2. The competitive antagonism by the non-peptide neurotensin receptor antagonist, SR48692 of neurotensin-induced IP1 formation revealed pA2 values of 8.7 +/- 0.2 (n = 3) for HT29 and 10.1 +/- 0.2 (n = 3) for N1E115 cells. SR48692 also antagonized the cyclic GMP and cyclic AMP responses induced by neurotensin in the N1E115 cell line with pA2 values of 10.7 +/- 0.7 (n = 3) and 9.8 +/- 0.3 (n = 3), respectively. 3. In CHO cells transfected with the rat neurotensin receptor, neurotensin stimulated IP1 and cyclic AMP formation with EC50 values of 3.0 +/- 0.5 nM (n = 3) and 72.2 +/- 20.7 nM (n = 3), respectively. Both effects were antagonized by SR48692, giving pA2 values of 8.4 +/- 0.1 (n = 3) for IP1 and 7.2 +/- 0.4 (n = 3) for cyclic AMP responses. 4. Radioligand binding experiments, performed with [125I]-neurotensin (0.2 nM), yielded IC50 values of 15.3 nM (n = 2) and 20.4 nM (n = 2) for SR48692 versus neurotensin receptor binding sites labelled in HT29 and N1E115 cells, respectively. 5 In conclusion, SR48692 appears to be a potent, species-independent antagonist of the signal transduction events triggered by neurotensin receptor activation in both neuronal and non-neuronal cell systems.

Topics: Animals; Carcinoma; Cell Line; Colon; Cyclic AMP; Cyclic GMP; Dose-Response Relationship, Drug; Humans; Inositol Phosphates; Mice; Neuroblastoma; Neurotensin; Pyrazoles; Quinolines; Receptors, Neurotensin

Chloride channels at the apical membrane of intestinal epithelial cells are involved in the excessive fluid secretion in diarrhea and diminished secretion in cystic fibrosis (CF). Diarrhea induced by heat-stable toxin from Escherichia coli is associated with elevated guanosine 3',5'-cyclic monophosphate (cGMP) in intestinal epithelial cells, but it is unknown whether chloride secretion is regulated by cGMP directly or via cGMP-dependent protein kinase (PKG). Single-channel recordings (inside-out excised patches) from the apical membrane of T84 cells reveal a 10-pS chloride channel with a linear current-voltage relationship, which is opened when an endogenous membrane-bound PKG is activated with ATP (1 mM) and cGMP (100 microM). Soluble PKG (200 nM) isolated from bovine lung, added to the intracellular face of patches, also opens this channel. No activation occurs with Ringer solution alone or only ATP or cGMP. Addition of nonhydrolyzable forms of ATP (AMP-PNP, 1 mM) or a combination of ATP, cGMP, plus H-8 (5 microM), an inhibitor of PKG, also does not stimulate the channel. The catalytic subunit of adenosine 3',5'-cyclic mono-phosphate-dependent protein kinase (PKA, 200 nM, with 1 mM ATP) activates a channel with similar characteristics. The 10 pS channel has a PNa/PCl ratio of 0.06, an anion selectivity of Br- (1.2) greater than Cl- (1.0) greater than I- (0.8) greater than F- (0.4), and a low affinity for the chloride channel blockers, 4,4-dinitrostilbene-2,2-disulfonic acid and 5-nitro-2-(3-phenylpropylamino)benzoic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenosine Triphosphate; Carcinoma; Chloride Channels; Chlorides; Colonic Neoplasms; Cyclic GMP; Electric Conductivity; Humans; Ion Channel Gating; Membrane Proteins; Nitrobenzoates; Protein Kinases; Stilbenes; Tumor Cells, Cultured

The present study demonstrates the activation of Cl- channels in HT29 cells by agonist (ATP, neurotensin, carbachol) increasing cytosolic Ca2+, by hypotonic cell swelling and by cGMP. Cell-attached nystatin patch-clamp (CAN) as well as slow and fast whole-cell recordings were used. The cell membrane potential was depolarized in a dose-dependent manner with half-maximal effects at 0.4 mumol/l for ATP, 60 pmol/l for neurotensin and 0.8 mumol/l for carbachol. The depolarization, which was caused by Cl- conductances increases, occurred within 1 s and was accompanied by a simultaneous and reversible increase of the input conductance of the cell-attached membrane from 295 +/- 32 pS to 1180 +/- 271 pS (ATP; 10 mumol/l, n = 21) and 192 +/- 37 pS to 443 +/- 128 pS (neurotensin; 1 nmol/l, n = 8). The effects of the agonists could be mimicked by ionomycin (0.2 mumol/l), suggesting that an increase in intracellular Ca2+ was responsible for the activation of Cl- channels. The depolarization was followed by a secondary hyperpolarization. Hypotonic cell swelling also depolarized the cells and induced an increase in the membrane conductance. With 120 mmol/l NaCl the depolarization was 10 +/- 0.8 mV and the cell-attached conductance increased from 228 +/- 29 pS to 410 +/- 65 (n = 26) pS. NaCl at 90 mmol/l and 72.5 mmol/l had even stronger effects. Comparable conductance increases were also obtained when the different agonists or hypotonic cell swelling were examined in whole cell experiments. 5-Nitro-2-(3-phenylpropylamino)-benzoate (1 mumol/l) did not prevent the effects of Ca(2+)-increasing hormones and of hypotonic solutions.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adenosine Triphosphate; Calcium; Carbachol; Carcinoma; Chlorides; Colonic Neoplasms; Culture Media; Cyclic GMP; Cytosol; Hypotonic Solutions; Ion Channels; Ionomycin; Membrane Potentials; Neurotensin; Nitrobenzoates; Osmolar Concentration; Tumor Cells, Cultured

STa, the heat-stable enterotoxin of Escherichia coli, is a specific activator of membrane-bound guanylyl cyclase and stimulates secretion of Cl- in a human colonic carcinoma cell line (T84). We investigated the effect of the cholinergic agent carbachol on the secretory response to STa. T84 cell monolayers were studied under voltage-clamped conditions in modified Ussing chambers. Simultaneous addition of STa and carbachol resulted in a biphasic synergistic response characterized by a brief peak in short-circuit current (Isc) followed by a prolonged plateau phase lasting up to 90 min. A synergistic response was also seen with sequential addition of the agonists, and was altered by the order and timing of agonist addition. Pretreatment with STa enhanced the synergistic response to carbachol, while the reverse order of additions produced synergy only when STa was added during or immediately after the Isc response to carbachol. Synergy occurred only with a concentration of STa sufficient to produce an Isc response alone. However, a concentration of carbachol that caused neither an increase in Isc nor intracellular Ca2+ mobilization was sufficient to evoke a synergistic response. Addition of 8-bromoguanosine 3',5'-cyclic monophosphate also produced a synergistic Isc response with carbachol, although maximal synergism was seen with simultaneous addition. Augmentation of the intracellular Ca2+ response to carbachol by STa is not the mechanism of synergy. Although the mechanism of synergy is not understood, these studies suggest that STa-induced cGMP interacts with other second messengers to produce the synergistic response, and that multiple intracellular mediators may influence the ability of STa to cause disease.

Topics: 8-Bromo Cyclic Adenosine Monophosphate; Bacterial Toxins; Calcium; Carbachol; Carcinoma; Chlorides; Colonic Neoplasms; Cyclic GMP; Drug Stability; Drug Synergism; Escherichia coli; Histamine; Hot Temperature; Humans; Intracellular Membranes; Tumor Cells, Cultured

Flow cytometry has enabled the objective assessment of cellular morphology and activity, which can also be biochemically evaluated by measuring products of cellular metabolism, such as cyclic 3'5' guanosine monophosphate (cGMP). Using paraffin-embedded formalin-fixed material obtained from the primary operation, an analysis of the correlation between nuclear ploidy and the proliferative index (PI) as quantified by flow cytometry with pre-treatment urinary cGMP was performed in 40 epithelial ovarian cancer (EOC) patients. The majority of the study group had advanced disease (28 FIGO III/IV) and residual disease (31). All but three (stage I) patients received single agent high dose cisplatinum as first-line therapy (100 mg m-2 x 5); in patients with evaluable disease there was a response rate of 64%. Thirty-one patients have died; the median survival of the study population being 27 months. There was a significant association between cGMP and PI. Significantly more aneuploid tumours had elevated PI values (P = 0.02). No variable predicted response. An initial univariate log rank analysis identified stage, the amount of residual disease, cGMP and PI as prognostic factors. Because of the interrelation between these and other factors and because PI did not conform to the proportional hazards model, a multivariate stepwise discriminant analysis was performed using survival at 36 months (the minimum follow-up for surviving patients) as the end-point. On the basis of this analysis, stage and residual disease were the most important prognostic factors, but cyclic GMP continued to have prognostic value even when these other factors were entered into the predictive model. However, the additional information gained has little clinical relevance.

Topics: Biomarkers, Tumor; Carcinoma; Cell Division; Cyclic GMP; Female; Flow Cytometry; Humans; Ovarian Neoplasms; Ploidies; Prognosis

alpha 2-adrenergic receptor-mediated signal transduction in rat adrenocortical carcinoma cells occurs through the opposing regulation of two second messengers, cyclic GMP and cyclic AMP, in which guanylate cyclase is coupled positively and adenylate cyclase negatively to the receptor signal. We now show that in these cells phorbol 12-myristate 13-acetate (PMA), a known activator of protein kinase C, inhibits the alpha 2-agonist (p-aminoclodine)-dependent production of cyclic GMP in a dose-dependent and time-dependent fashion. The half-maximal inhibitory concentration of PMA was 10(-10) M. A protein kinase C inhibitor, 1-(5-isoquinolinyl-sulfonyl)-2-methyl piperazine (H-7), caused the release of the PMA-dependent attenuation of p-aminoclodine-stimulated cyclic GMP formation. These results suggest that protein kinase C negatively regulates the alpha 2-receptor coupled cyclic GMP system in these cells, a feature apparently shared with the other cyclic GMP-coupled receptors such as those of muscarine, histamine, and atrial natriuretic factor.

Topics: 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; Adrenal Cortex Neoplasms; Animals; Carcinoma; Clonidine; Cyclic GMP; Dose-Response Relationship, Drug; Enzyme Activation; Guanylate Cyclase; Isoquinolines; Kinetics; Piperazines; Protein Kinase C; Rats; Receptors, Adrenergic, alpha; Tetradecanoylphorbol Acetate; Tumor Cells, Cultured

Isolated fasciculata cells of rat adrenal cortex, when incubated with atrial natriuretic factor (ANF), stimulated the levels of cyclic GMP and corticosterone production in a concentration-dependent manner without a rise in the levels of cyclic AMP. The ANF-dependent elevation of cyclic GMP was rapid, with a detectable increment in 30 s. ANF also stimulated the particulate guanylate cyclase. These results not only indicate the coupling of cyclic GMP and corticosterone production with ANF signal, but also demonstrate that, like the ACTH signal, cyclic AMP is not the mediator of ANF-induced adrenocortical steroidogenesis.

Topics: Adrenal Cortex; Adrenal Cortex Neoplasms; Animals; Atrial Natriuretic Factor; Carcinoma; Corticosterone; Cyclic AMP; Cyclic GMP; Rats; Stimulation, Chemical

Topics: Animals; Carcinoma; Cyclic AMP; Cyclic GMP; Fish Diseases; Fishes; Neoplasms, Experimental

Cyclic nucleotide phosphodiesterase activity has been measured in muscle biopsies taken from healthy controls and from cancer patients. In both groups the muscles were clinically and morphologically normal. The phosphodiesterase activity was significantly increased in muscles from cancer patients using both cyclic AMP and cyclic GMP as substrate. These findings are in line with previous reports indicating that malignancy may interfere with metabolism of the host muscular tissues, and suggest the possibility that the observed biochemical changes might be an aspect of an early muscle neurogenic involvement.

Topics: 2',3'-Cyclic-Nucleotide Phosphodiesterases; Carcinoma; Cyclic AMP; Cyclic GMP; Humans; Liver Neoplasms; Lung Neoplasms; Muscles; Phosphoric Diester Hydrolases; Rectal Neoplasms; Stomach Neoplasms

Topics: Adenylyl Cyclases; Adrenal Cortex Neoplasms; Adrenal Gland Neoplasms; Adrenocorticotropic Hormone; Carcinoma; Cell Line; Corticosterone; Cyclic AMP; Cyclic GMP; Cycloheximide; Dactinomycin; Guanylate Cyclase; Protein Kinases

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Adenofibroma; Adenylyl Cyclases; Breast; Breast Neoplasms; Carcinoma; Cyclic AMP; Cyclic GMP; Cytosol; Female; Humans; Hyperplasia

Cyclic AMP and cyclic GMP phosphodiesterase activities (3',5'-cyclic AMP 5'-nucleotidohydrolase, EC 3.1.4.17) were investigated in the human thyroid gland from patients with hyperthyroidism. Low substrate concentration (0.4 muM) was used. About 60% of the cyclic-AMP and 80% of the cyclic-GMP hydrolytic activities in the homogenate were obtained in the soluble fraction (105 000 X g supernatant). The thyroid gland contains two forms of cyclic-AMP phosphodiesterase, one with a Km of 1.3-10(-5) M and the second with a Km of 2-10(-6) M. Cyclic-AMP and cyclic-GMP phosphodiesterase were purified by gel filtration on a Sepharose-6B column. Cyclic-AMP phosphodiesterase activities were found in a broad area corresponding to molecular weights ranging from approx. 200 000 to 250 000 and cyclic-GMP phosphodiesterase activity was found in a single area corresponding to a molecular weight of 260 000. Cyclis-AMP phosphodiesterase activities were stimulated by the protein activator which was found in human thyroid and this stimulation was dependent on Ca2+. Stimulation of cyclic-AMP phosphodiesterase by the activator was not significant even in the presence of enough Ca2+. The effect of D,L-triiodothyronine, D,L-thyroxine, L-diiodotyrosine, L-monoiodotyrosine, L-thyronine, L-diiodothyronine, thyrotropin, hydrocortisone, adrenocorticotropin, cyclic-AMP and cyclic-GMP on the phosphodiesterase activities was studied. Cyclic-AMP, cyclic-GMP, D,L-triiosothyronine, D,L-thyroxine, adrenocorticotropin and hydrocortisone where found to inhibit the phophodiesterase. Triiodothyronine and thyroxine inhibited cyclic-AMP phosphodiesterase more effectively than cyclic-GMP phosphodiesterase. Thyroxine was a more potent inhibitor than triiodothyronine. The concentration of cyclic AMP producing a 50% inhibition of cyclic-GMP phosphodiesterase activity was 5-10(-5) M, while the concentration of cyclic GMP producing a 50% inhibition of cyclic-AMP phosphodiesterase was 3-10(-3) M. Both cyclic-AMP and cyclic-GMP phosphodiesterase activities in the homogenate of hyperthyroidism, thyroid carcinoma and adenoma were higher than in normal thyroid tissue, when assayed with a low concentration of the substrate (0.4 muM). When a higher concentration (1 mM) of cyclic nucleotides was used as the substrate, cyclic-AMP hydrolytic activity in adenoma tissue was similar to that of normal tissue, while the other activities were higher than normal.

Topics: 3',5'-Cyclic-AMP Phosphodiesterases; Adenoma; Calcium; Carcinoma; Cyclic AMP; Cyclic GMP; Enzyme Activation; Hormones; Humans; Hyperthyroidism; Kinetics; Phosphoric Diester Hydrolases; Subcellular Fractions; Thyroid Gland; Thyroid Neoplasms; Thyroxine; Triiodothyronine

Topics: Animals; Antineoplastic Agents; Antiviral Agents; Arabinonucleotides; Arabinose; Carcinoma; Cell Line; Culture Techniques; Cyclic AMP; Cyclic GMP; HeLa Cells; Herpesviridae; Humans; Laryngeal Neoplasms; Mouth Neoplasms; Phosphoric Diester Hydrolases; Protein Kinases; Sarcoma 180

Topics: Adrenal Gland Neoplasms; Adrenocorticotropic Hormone; Animals; Carcinoma; Chromatography, Thin Layer; Corticosterone; Cortisone; Cyclic AMP; Cyclic GMP; Depression, Chemical; In Vitro Techniques; Microscopy, Electron; Neoplasms, Experimental; Pregnenolone; Progesterone; Rats; Tritium

Topics: Adrenal Gland Neoplasms; Adrenal Glands; Animals; Carcinoma; Cell Fractionation; Cell Line; Cell-Free System; Cyclic AMP; Cyclic GMP; Cytosine Nucleotides; Hydrolysis; Inosine Nucleotides; Kinetics; Nucleotides; Phosphoric Diester Hydrolases; Phosphoric Monoester Hydrolases; Rats; Rats, Inbred Strains; Thymidine; Tritium; Uridine