cyclic-gmp and Lung-Neoplasms

Since the function of microRNA (miR)-210 in non-small cell lung cancer (NSCLC) remains unclear, we aimed to explore the clinical significance of miR-210 in NSCLC.. NSCLC-related data from 1673 samples on Gene Expression Omnibus and 1090 samples on The Cancer Genome Atlas were obtained and analyzed. The expression level of miR-210 was validated via real-time quantitative PCR analysis with 125 paired clinical samples. A meta-analysis was performed to generate a comprehensive understanding of miR-210 expression and its clinical significance in NSCLC. In addition, bioinformatics analysis was also conducted to reveal the potential underlying mechanism of miR-210 action in NSCLC.. miR-210 expression was consistently elevated in NSCLC solid tissue samples. However, its expression was controversial in easily obtained body fluids (i.e., blood, plasma, and serum). Moreover, an overall pooled meta-analysis implied a comparatively higher level of miR-210 expression in NSCLC cancerous tissue than in normal control tissue (P < 0.001). In addition, a meta-analysis of outcome revealed a significant diagnostic capacity of miR-210 in NSCLC by detecting its expression in serum and sputum (area under the summary receiver operating characteristic curve 0.82 and 0.81, respectively). miR-210 overexpression was associated with poor progression-free survival (PFS) in NSCLC and was negatively related to overall survival and disease-free survival. Bioinformatic gene enrichment and annotation analyses showed that the target genes of miR-210 were greatly enriched in cell adhesion and plasma membrane, and three pathways were considered to be the main functional circuits of miR-210: renin secretion, the cGMP-PKG signaling pathway, and cell adhesion molecules.. In NSCLC, miR-210 expression was elevated and overexpression indicated poor PFS. Expression level of miR-210 in serum and sputum showed significant diagnostic value for NSCLC.

Topics: Area Under Curve; Biomarkers, Tumor; Carcinoma, Non-Small-Cell Lung; Cell Adhesion Molecules; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Databases, Genetic; Disease-Free Survival; Humans; Lung Neoplasms; MicroRNAs; Prognosis; Renin; ROC Curve; Signal Transduction; Sputum; Survival Rate

One-third of patients with lung cancer and hyponatremia have no evidence of ectopic arginine vasopressin (AVP) production and the cause of their hyponatremia is not conclusively established. We sought to distinguish patients with hyponatremia caused by elevated AVP versus those with ectopic atrial natriuretic peptide (ANP) via this detailed metabolic study.. We enrolled 24 patients recently diagnosed with lung cancer in a metabolic study in which patients were placed on sodium and fluid restriction for 4 days. Serum electrolytes, osmolality, urine electrolytes and osmolality, plasma AVP, ANP, aldosterone, urinary cyclic AMP and cyclic guanosine 3',5'-monophosphate were measured daily and tumor tissue was obtained to measure ectopic hormone production. We attempted to characterize the pathophysiology of hyponatremia caused by ectopic ANP production in patients with small cell lung cancer (SCLC) and to determine its effect on the aldosterone axis.. Seven of the nine patients with SCLC presented with hyponatremia and three had elevated ANP levels at presentation without elevation of AVP. All three patients who presented with hyponatremia and elevated ANP showed a decline in serum sodium following fluid restriction, whereas two patients with SCLC and elevated AVP had normalized serum sodium levels. The combination of hyponatremia and elevated ANP was associated with a persistent natriuresis and inappropriately low aldosterone levels despite sodium restriction, suggesting ANP suppression of the aldosterone axis.. Management of patients with hyponatremia and SCLC should be guided by the knowledge that some patients with SCLC have ectopic production of ANP as the cause of their hyponatremia.

Topics: Adult; Aged; Aldosterone; Arginine Vasopressin; Atrial Natriuretic Factor; Carcinoma, Non-Small-Cell Lung; Carcinoma, Small Cell; Cyclic AMP; Cyclic GMP; Female; Humans; Hyponatremia; Lung Neoplasms; Male; Middle Aged

Lung cancer is one of the most frequent types of cancers that lead to death. Sildenafil is a potent inhibitor of phosphodiesterase-5 and showed potential anticancer effects, which has not yet been fully evaluated. Thus, this study aims to investigate the potential anticancer effect of sildenafil in urethane-induced lung cancer in BALB/c mice.. Five-week-old male BALB/c mice were treated with either (i) normal saline only, (ii) sildenafil only 50 mg kg-1/ P.O every other day for the last four successive weeks, (iii) urethane 1.5 gm kg-1 i.p (at day 1 and day 60), (iv) carboplatin after urethane induction, or (v) sildenafil after urethane induction.. It was shown that sildenafil significantly increased the levels of cGMP and Caspase-3 with a reduction of NF-κB, Bcl-2, Cyclin D1, intercellular adhesion molecule 1, matrix metalloproteinase-2 levels and normalisation of Nrf2 along with pronounced improvement in the histological patterns.. These results indicated that sildenafil markedly induces cell cycle arrest, apoptosis and inhibits the metastatic activity through activation of cyclic guanosine monophosphate/protein kinase G pathway and down-regulation of cyclin D1 and nuclear factor kappa light chain enhancer of activated B cells with downstream anti-apoptotic gene Bcl-2, which underscores the critical importance of future using sildenafil in the treatment of lung cancer.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Cycle Checkpoints; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cyclin D1; Drug Repositioning; Lung Neoplasms; Matrix Metalloproteinase 2; Mice; Mice, Inbred BALB C; NF-kappa B p50 Subunit; Phosphodiesterase 5 Inhibitors; Proto-Oncogene Proteins c-bcl-2; Sildenafil Citrate; Treatment Outcome

Arsenite is a well-documented human lung carcinogen but the detailed mechanisms of carcinogenesis remain unclear. In this study, human bronchial epithelial (16-HBE) cells were continuously exposed to 2.5μM arsenite for about 13 weeks to induce the phenotypes of malignant transformation. Our results showed that Nrf2 expression was gradually decreased whereas no significant change was observed on NF-κB activation with increased time of arsenite exposure. To test the roles of Nrf2-meidtaed oxidative damage in the arsenite-induced malignant transformation, we compared the levels of cGMP, PKG and oxidative damage-related indicators between arsenic-transformed cells and control cells. Our data demonstrated there were no significantly differences on the contents of cGMP, PKG, MDA and the production of ROS, but the levels of GSH and NO, the activities of SOD, tNOS and iNOS were significantly enhanced in the arsenic-transformed cells. Importantly, Nrf2 inactivation could be modulated by miR-155, and inhibition of miR-155 remarkably attenuated the malignant phenotypes and promoted apoptotic cell death in the arsenic-transformed cells. Together, our findings provide the novel mechanism that miR-155 may regulate arsenite-induced cell malignant transformation by targeting Nrf2-mediated oxidative damage, indicating that inhibition of miR-155 may be a potential strategy against lung carcinogenesis of arsenite.

Topics: Apoptosis; Arsenites; Bronchi; Carcinogens; Cell Line; Cell Transformation, Neoplastic; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Epithelial Cells; Gene Expression Regulation, Neoplastic; Humans; Lung Neoplasms; MicroRNAs; NF-E2-Related Factor 2; NF-kappa B; Nitric Oxide Synthase Type II; Oxidative Stress; Phenotype; Signal Transduction; Superoxide Dismutase; Time Factors

Phosphodiesterase 5 (PDE5) inhibitors prevent the breakdown of cGMP that results in prolonged protein kinase G activation and the generation of nitric oxide. PDE5 inhibitors enhanced the anti-NSCLC cell effects of the NSCLC therapeutic pemetrexed. [Pemetrexed + sildenafil] activated an eIF2α - ATF4 - CHOP - Beclin1 pathway causing formation of toxic autophagosomes; activated a protective IRE1 - XBP-1 - chaperone induction pathway; and activated a toxic eIF2α - CHOP - DR4 / DR5 / CD95 induction pathway. [Pemetrexed + sildenafil] reduced the expression of c-FLIP-s, MCL-1 and BCL-XL that was blocked in a cell-type -dependent fashion by either over-expression of HSP90 / GRP78 / HSP70 / HSP27 or by blockade of eIF2α-CHOP signaling. Knock down of PKGI/II abolished the ability of sildenafil to enhance pemetrexed toxicity whereas pan-inhibition of NOS using L-NAME or knock down of [iNOS + eNOS] only partially reduced the lethal drug interaction. Pemetrexed reduced the ATPase activities of HSP90 and HSP70 in an ATM-AMPK-dependent fashion that was enhanced by sildenafil signaling via PKGI/II. The drug combination activated an ATM-AMPK-TSC2 pathway that was associated with reduced mTOR S2448 and ULK-1 S757 phosphorylation and increased ULK-1 S317 and ATG13 S318 phosphorylation. These effects were prevented by chaperone over-expression or by expression of an activated form of mTOR that prevented autophagosome formation and reduced cell killing. In two models of NSCLC, sildenafil enhanced the ability of pemetrexed to suppress tumor growth. Collectively we argue that the combination of [pemetrexed + PDE5 inhibitor] should be explored in a new NSCLC phase I trial.

Topics: A549 Cells; Animals; Antineoplastic Combined Chemotherapy Protocols; Cell Line, Tumor; Cyclic GMP; Drug Synergism; Endoplasmic Reticulum Chaperone BiP; Humans; Lung Neoplasms; Male; Mice; Molecular Chaperones; Nitric Oxide; Pemetrexed; Phosphodiesterase 5 Inhibitors; Xenograft Model Antitumor Assays

Previous research has led to the recognition of a cGMP signaling pathway governing drug transport. This study is to investigate whether inhibitors of phosphodiesterase type 5 (PDE5), which increase intracellular cGMP levels, modulate the cytotoxicity and uptake of anti-cancer drugs in cancer cells.. The experiments were conducted with and without PDE5 inhibitors: dipyridamole, vardenafil, and/or sildenafil. The cytotoxicity of doxorubicin, cisplatin and oxaliplatin was determined in multiple cancer cell lines derived from different tissues. The cellular uptake of structurally diverse compounds was further examined in lung cancer cells with and without various endocytotic inhibitors. The tumor accumulation and the anti-tumor effect of trastuzumab were examined in a lung cancer xenograft mouse model.. Dipyridamole could modulate the cytotoxicity of doxorubicin, cisplatin, and oxaliplatin in cancer cells. Particularly, PDE5 inhibitors increased cellular uptake of structurally diverse compounds into lung cancer cells both in vitro and in vivo. The effect of vardenafil on drug uptake could be blocked by endocytotic inhibitors. The growth of lung cancer xenograft in nude mice was significantly suppressed by addition of vardenafil to trastuzumab treatment.. PDE5 inhibitors may increase the efficacy of anti-cancer drugs by increasing endocytosis-mediated cellular drug uptake, and thus serve as adjuvant therapy for certain cancers such as lung cancer.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Endocytosis; HeLa Cells; Hep G2 Cells; Humans; Lung Neoplasms; MCF-7 Cells; Mice; Mice, Nude; Phosphodiesterase 5 Inhibitors

We show that in melanoma cells oncogenic BRAF, acting through MEK and the transcription factor BRN2, downregulates the cGMP-specific phosphodiesterase PDE5A. Although PDE5A downregulation causes a small decrease in proliferation, its major impact is to stimulate a dramatic increase in melanoma cell invasion. This is because PDE5A downregulation leads to an increase in cGMP, which induces an increase in cytosolic Ca(2+), stimulating increased contractility and inducing invasion. PDE5A downregulation also this leads to an increase in short-term and long-term colonization of the lungs by melanoma cells. We do not observe this pathway in NRAS mutant melanoma or BRAF mutant colorectal cells. Thus, we show that in melanoma cells oncogenic BRAF induces invasion through downregulation of PDE5A.

Topics: Animals; Calcimycin; Calcium; Cardiac Myosins; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Down-Regulation; Gene Expression; Gene Expression Regulation, Neoplastic; Heterocyclic Compounds, 4 or More Rings; Homeodomain Proteins; Humans; Lung Neoplasms; Melanoma; Mice; Mice, Nude; Myosin Light Chains; Neoplasm Invasiveness; Phosphodiesterase 5 Inhibitors; Phosphorylation; POU Domain Factors; Promoter Regions, Genetic; Protein Binding; Protein Kinase Inhibitors; Proto-Oncogene Proteins B-raf; RNA, Small Interfering; Transplantation, Heterologous

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

Within 24 h four peptide hormones, i.e. vessel dilator, long acting natriuretic peptide, kaliuretic peptide, and atrial natriuretic peptide and their intracellular mediator cyclic GMP decreased the number of human squamous lung cancer cells 51, 22, 25, 21, and 30%, respectively. There was not any proliferation in the 3 days following this decrease in cell number. Vessel dilator decreased DNA synthesis 85% in the squamous lung cancer cells. Thus, vessel dilator significantly decreased the number of human squamous lung cancer cells and their DNA synthesis, mediated in part by cyclic GMP, more than other peptide hormones.

Topics: Atrial Natriuretic Factor; Carcinoma, Squamous Cell; Cell Proliferation; Cyclic GMP; DNA Replication; DNA, Neoplasm; Humans; Lung Neoplasms; Peptide Fragments; Protein Precursors; Tumor Cells, Cultured

Tumour hypoxia is associated with resistance to therapy and with increased invasion and metastatic potential. Recent studies in our laboratory have shown that the hypoxic up-regulation of tumour cell invasiveness and chemoresistance is in part due to reduced nitric oxide (NO) signaling. Using B16F10 murine melanoma cells, we demonstrate here that the increased metastatic potential associated with exposure to hypoxia is mediated by a reduction in cGMP-dependent NO-signaling. Pre-incubation of B16F10 cells in hypoxia (1% vs. 20% O(2)) for 12 hr increased lung colonization ability by over 4-fold. This effect of hypoxia on metastasis was inhibited by co-incubation with low concentrations of the NO-mimetic drugs glyceryl trinitrate (GTN) and diethylenetriamine NO adduct (DETA/NO). In a manner similar to hypoxia, pharmacological inhibition of NO synthesis resulted in a significant increase in lung nodule formation, an effect that was prevented by co-incubation with GTN. An important NO-signaling pathway involves the activation of soluble guanylyl cyclase and the consequential generation of cGMP. Culture in the presence of a non-hydrolysable cGMP analogue (8-Br-cGMP) abrogated the hypoxia-induced lung nodule formation, suggesting that the effects of NO on metastasis are mediated via a cGMP-dependent pathway. These findings suggest that a novel mechanism whereby hypoxia regulates metastatic potential involves a downstream inhibition of cGMP-dependent NO signaling.

Topics: Animals; Cyclic GMP; Female; Hypoxia; Lung Neoplasms; Melanoma, Experimental; Mice; Neoplasm Metastasis; Neoplasm Transplantation; Nitric Oxide; Signal Transduction; Tumor Cells, Cultured; Tumor Stem Cell Assay

Icariin (ICA) is a kind of new biological respone modifier(BRM) and differentiational agent. In order to further elucidate the reversion of malignant phenotypes of tumor cells and the mechanism of its action, highly metastatic human lung cancer cells(PG) were treated with ICA in vitro. In this study, MTT assay, radioimmune assay, flow cytometry(FCM) and invasion assay were used. The results showed that ICA could influence the distribution of PG cells cycle and reduce S phase. Moreover, ICA increased the level of cAMP in PG cells, reduced the level of cGMP and increased the cAMP/cGMP ratio. On the other hand, ICA decreased PG cells adhesive ratio to laminin substrate and decreased the ability of invasion or migration. These data demonstrate that ICA maybe a kind of effective anticancer drug.

Topics: Animals; Antineoplastic Agents, Phytogenic; Cell Adhesion; Cell Division; Cyclic AMP; Cyclic GMP; Flavonoids; Flow Cytometry; Humans; Lung Neoplasms; Mice; Tumor Cells, Cultured

To test the hypothesis that neural mechanisms evoked by unilateral pulmonary artery occlusion (UPAO) affect the release of atrial natriuretic peptides (ANP) from the heart, hemodynamics and levels of plasma ANP and cyclic guanosine monophosphate (c-GMP) were studied in 11 patients with lung cancer. The UPAO induced a significant rise in heart rate by 5.3 percent, increased mean pulmonary artery pressure by 31 percent without affecting right atrial pressure, and decreased plasma ANP levels in the coronary sinus by 17.4 percent (p < 0.05) from 202.5 +/- 27.1 pg/ml to 167.2 +/- 27.4 pg/ml. Atropine sulfate (0.04 mg/kg) injection increased the heart rate by 38.2 percent (p < 0.01), reduced the stroke volume index by 25.1 percent, decreased coronary sinus ANP levels from 198.5 +/- 16.4 pg/ml to 124.8 +/- 19.6 pg/ml (p < 0.01), and decreased coronary sinus plasma c-GMP levels from 4.6 +/- 0.5 pmol/ml to 3.1 +/- 0.4 pmol/ml (p < 0.05). After atropine pretreatment, UPAO induced a significant (p < 0.05) increase of 34.8 percent in the coronary sinus ANP level. Thus, it is concluded that in UPAO, the secretion of ANP from the heart is modulated partly by the autonomic nervous system.

Topics: Adenocarcinoma; Aged; Atrial Natriuretic Factor; Atropine; Carcinoma, Squamous Cell; Catheterization, Peripheral; Cyclic GMP; Female; Heart; Hemodynamics; Humans; Lung Neoplasms; Male; Middle Aged; Pulmonary Artery; Time Factors

Cytokines are produced by tumor cells in vitro, but evidence for in vivo increased production of cytokines in cancer patients is controversial. Conversely, nitric oxide (NO) is implicated increasingly in the mediation of cytokine effects. Lung cancer patients may show an increased local production of cytokines and NO, and chronic paracrine exposure of epithelial lung cells to these medicators may influence the production of surfactant phosphatidylcholine.. The presence of the cytokine tumor necrosis factor (TNF alpha), interleukin-1 (IL-1), and interleukin-6 (IL-6), as well as NO, cyclic guanosine 3'5' monophosphate (cGMP) and phosphatidylcholine levels in bronchoalveolar lavage fluid (BLF) of lung cancer patients were investigated. Bronchoalveolar lavage fluid was obtained from 30 male smokers: 22 patients with squamous cell lung cancer and 8 subjects without cancer.. When compared with the control subjects, the cancer patients had elevated BLF levels of TNF alpha (1.58 +/- 0.47 vs. 0.04 +/- 0.02 pg/microgram protein, P < 0.001), IL-6 (1.39 +/- 0.29 vs. 0.04 +/- 0.02 pg/microgram protein, P < 0.001), and NO2-/NO3- (23.3 +/- 5.6 vs 1.1 +/- 0.6 nmol/mg protein, P < 0.001). However, phosphatidylcholine levels were lower in those with cancer than in the control subjects (3.0 +/- 1.2 vs. 24.8 +/- 6.4 micrograms protein, P < 0.001).. The results showed in vivo production of inflammatory cytokines in human lung cancer and increased tumor-associated NO production, as suggested by increased levels of nitrite/nitrate in the BLF. A decreased phosphatidylcholine content in the BLF also was found in patients with lung cancer.

Topics: Bronchoalveolar Lavage Fluid; Carcinoma, Bronchogenic; Carcinoma, Squamous Cell; Cyclic GMP; Cytokines; Humans; Interleukin-1; Interleukin-6; Lung Diseases; Lung Neoplasms; Male; Middle Aged; Nitrates; Nitric Oxide; Nitrites; Phosphatidylcholines; Smoking; Tumor Necrosis Factor-alpha

Small cell lung cancer cell (SCLC) lines, NCI-H82, NCI-H660, and NCI-H1284, and HeLa cells were analyzed for the presence of atrial natriuretic peptide (ANP) receptors. In these SCLC cell lines and HeLa cells, ANP A receptor mRNA was identified by Southern blot analyses of polymerase chain reaction products and RNase protection assays using poly(A)(+)-selected RNA. Saturable binding assays revealed that HeLa cells had 2000 to 5000 high affinity atrial natriuretic peptide receptors per cell with a dissociation constant of 140 pM. In the SCLC cell lines, the binding was saturable but too low to accurately estimate the number of binding sites. After addition of human ANP, radioimmunoassays revealed accumulation of cyclic GMP in SCLC cells as well as HeLa cells in a dose-dependent fashion. The half-maximal stimulation concentration of cyclic GMP accumulation in HeLa and these SCLC cell lines was approximately 2 nM. Tetrazolyl blue assays and tritiated thymidine incorporation did not show any remarkable growth inhibition or growth stimulation of SCLC cell lines after addition of human ANP up to 3.3 microM, more than 1000-fold greater than the half-maximal stimulation concentration of cyclic GMP accumulation. Our results indicate that human SCLC cells express functional ANP receptors but ANP addition produced no detectable change in their growth pattern.

Topics: Atrial Natriuretic Factor; Base Sequence; Blotting, Southern; Carcinoma, Small Cell; Cell Division; Cyclic GMP; HeLa Cells; Humans; Iodine Radioisotopes; Lung Neoplasms; Molecular Sequence Data; Polymerase Chain Reaction; Radioimmunoassay; Receptors, Atrial Natriuretic Factor; Ribonucleases; RNA, Messenger; Stimulation, Chemical; Tetrazolium Salts; Thiazoles; Thymidine; Tritium; Tumor Cells, Cultured

The effects of prostaglandin E1(PGE1), prostaglandin synthesis inhibitor and indomethacin (IN) on the growth and metastasis of Lewis lung carcinoma (LLC) were studied and their mechanisms of action were investigated. Seventy-five C57BL mice of both sexes were utilized in the experiment. It was found that both PGE1 and IN could significantly retard the growth of transplanted LLC and reduce the number of pulmonary metastatic foci. PGE1 obviously decreased the acid phosphatase (ACP) activity of LLC cells while IN showed no such effect. Besides, PGE1 could markedly elevate the plasma cAMP level of LLC-bearing mice, but not normal controls. Meanwhile, it could decrease plasma cGMP concentration of both normal and tumor-bearing mice. IN, like PGE1, could increase plasma cAMP and decrease plasma cGMP levels of LLC-bearing animals. TEM observation revealed that tumor cells treated with PGE1 and IN presented a series of degenerative and destructive changes. In addition, PGE1 and IN exhibited a different effect on several cell-mediated immune responses of the tumored hosts, the former inhibitory and the latter stimulatory. The possible mechanisms of action of the two chemicals are discussed.

Topics: Adolescent; Alprostadil; Animals; Child; Cyclic AMP; Cyclic GMP; Female; Humans; Indomethacin; Lung Neoplasms; Male; Mice; Mice, Inbred C57BL; Neoplasm Metastasis; Neoplasm Transplantation

The present studies were undertaken to assess the effects of atrial natriuretic factor (ANF) on erythropoietin (Ep) secretion in Ep-producing renal carcinoma (RC) cells using a sensitive radioimmunoassay for Ep. Human ANF produced a significant dose-related increase in Ep secretion at concentrations of 10(-7) and 10(-6) M when compared with vehicle controls. ANF (greater than or equal to 10(-9) M) also significantly increased the intracellular guanosine 3',5'-cyclic monophosphate (cGMP) concentration after 5-min incubation with the RC cells. Scatchard analysis of the human 125I-labeled ANF binding data indicated that the RC cells contain a single class of binding sites with a dissociation constant (Kd) of 93 +/- 1 pM and a binding capacity of 2,190 +/- 750 sites/cell. Incubation of the RC cells with 8-bromo-cGMP in concentrations of 10(-7)-10(-5) M also produced a significant dose-related enhancement of Ep secretion. These findings suggest that the increase in Ep secretion in response to ANF can be attributed, at least in part, to activation of guanylate cyclase, which is coupled to specific ANF receptors on the RC cell.

Topics: Atrial Natriuretic Factor; Carcinoma, Renal Cell; Cyclic GMP; Erythropoietin; Humans; Kidney Neoplasms; Kinetics; Lung Neoplasms; Tumor Cells, Cultured

Prodigiozan and zymosan were shown to have different effects both on the intracellular content of cyclic nucleotides and pulmonary metastases formation in mice with Lewis' carcinoma. The authors believe that determination of cyclic nucleotide ratio in immunocompetent organs (thymus and spleen) may be used as an additional criterion for identification of new antitumour immunomodulators.

Topics: Animals; Cyclic AMP; Cyclic GMP; Lung; Lung Neoplasms; Male; Mice; Mice, Inbred C57BL; Neoplasm Transplantation; Phosphoric Diester Hydrolases; Polysaccharides, Bacterial; Prodigiozan; Spleen; Thymus Gland; Zymosan

Topics: Cyclic AMP; Cyclic GMP; Humans; Lung Neoplasms; Middle Aged

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

The activity of the phosphodiesterase enzyme(s) responsible for the degradation of cylic adenosine monophosphate (CA.M.P.) and cyclic guanosine monophosphate (CG.M.P. (in human normal and carcinomatous lung tissue has been investigated. Enzyme activities were 3-5 times greater in normal than in carcinomatous lung. This is compatible with the known higher concentrations of these cyclic nucleotides in normal tissues. It is suggested that cancer chemotherapy designed to block the phosphodiesterase activity, and thus promote accretion of CA.M.P and CG.M.P., may provide a means of normalising cancerous tissue. Both phosphodiesterase activities in both types of tissue were inhibited by methylxanthines at 10(-3) mol/l, but some enzyme potentiation was observed at lower concentration.

Topics: 2',3'-Cyclic-Nucleotide Phosphodiesterases; Caffeine; Carcinoma, Squamous Cell; Cyclic AMP; Cyclic GMP; Female; Humans; Lung; Lung Neoplasms; Middle Aged; Phosphoric Diester Hydrolases; Theophylline

Topics: Breast Neoplasms; Bucladesine; Cell Migration Inhibition; Colonic Neoplasms; Culture Media; Culture Techniques; Cyclic AMP; Cyclic GMP; Drug Synergism; Humans; Leukocytes; Lung Neoplasms; Neoplasms; Proteins; Theophylline; Tuberculin Test

Topics: Adult; Caffeine; Calcitonin; Calcium; Carcinoma, Bronchogenic; Circadian Rhythm; Cyclic AMP; Cyclic GMP; Diagnosis, Differential; Humans; Hypercalcemia; Hyperparathyroidism; Hypoparathyroidism; Lung Neoplasms; Middle Aged; Osteitis Deformans; Parathyroid Glands; Parathyroid Neoplasms; Physical Exertion; Sarcoidosis