cyclic-gmp and Ovarian-Neoplasms

The usefulness of urine cyclic guanosine 3'-5'monophosphate (GMP (cGMP) as a cancer marker in ovarian cancer has been studied in two independent centres using specimens from 81 women. Serial specimens from 60 patients were monitored up to 2 years after the start of chemotherapy. Urine cGMP levels were significantly higher in those patients with poorly differentiated tumours. Levels were not associated with the tumour stage, histological type or residual tumour remaining after surgery. Pretreatment levels were of no value for predicting response to therapy or patient survival. During therapy, however, levels did confirm clinical observations and if a level was elevated then there was a 80-90% chance that the patient was not responding to therapy. Using serial measurements, it was possible to predict the recurrence of tumour in 16/25 patients prior to any other clinical signs.

Topics: Biomarkers, Tumor; Cyclic GMP; Female; Humans; Monitoring, Physiologic; Neoplasm Recurrence, Local; Ovarian Neoplasms

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

Dysregulated apoptosis plays a critical role in the development of a number of aberrant cellular processes, including tumorigenesis and chemoresistance. However, the mechanisms that govern the normal apoptotic program are not completely understood. Soluble guanylyl cyclase (sGC) and cyclic guanosine monophosphate (cGMP) promote mammalian cell viability via an unknown mechanism and p53 status is a key determinant of cell fate in human ovarian cancer cells. Whether an interaction exists between these two determinants of cell fate is unknown. We hypothesized that basal sGC activity reduces p53 content and attenuates p53-dependent apoptosis in human ovarian cancer cells. Suppression of sGC activity with the specific inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) lowered cGMP content, and increased p53 protein content and induced apoptosis in three ovarian cancer cell lines, effects which were attenuated by the cGMP analog 8-Br-cGMP and by Atrial Natriuretic Factor, an activator of particulate guanylyl cyclase, which circumvent the inhibition of sGC. ODQ prolonged p53 half-life, induced phosphorylation of p53 on Ser15, and upregulated the p53-dependent gene products p21, murine double minute-2, and the proapoptotic, p53-responsive gene product Bax. ODQ activated caspase-3, and ODQ-induced apoptosis was inhibited by overexpression of X-linked inhibitor of apoptosis Protein. Pretreatment with the specific p53 inhibitor pifithrin or downregulation of p53 using a specific small inhibitory RNA significantly attenuated ODQ-induced apoptosis. Moreover, ODQ-induced upregulation of p21 and Bax and ODQ-induced apoptosis were significantly reduced in a p53 mutant cell line relative to the wild-type parental cell line. Thus, the current study establishes that basal sGC/cGMP activity regulates p53 protein stability, content, and function, possibly by altering p53 phosphorylation and stabilization, and promotes cell survival in part through regulation of caspase-3 and p53.

Topics: Adenoviridae; Apoptosis; Atrial Natriuretic Factor; bcl-2-Associated X Protein; Benzothiazoles; Caspase 3; Caspases; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Cyclin-Dependent Kinase Inhibitor p21; Enzyme Activation; Enzyme Inhibitors; Female; Gene Expression Regulation, Neoplastic; Guanylate Cyclase; Half-Life; Humans; Mutation; Ovarian Neoplasms; Oxadiazoles; Phosphorylation; Proto-Oncogene Proteins c-mdm2; Quinoxalines; RNA, Small Interfering; Serine; Signal Transduction; Thiazoles; Toluene; Tumor Cells, Cultured; Tumor Suppressor Protein p53; X-Linked Inhibitor of Apoptosis Protein

The arginine vasopressin (AVP) gene is expressed in certain cancers such as breast cancer, where it is believed to act as an autocrine growth factor. However, little is known about the regulation of the AVP protein precursor (proAVP) or AVP-mediated signaling in breast cancer and this study was undertaken to address some of the basic issues. The cultured cell lines examined (Mcf7, Skbr3, BT474, ZR75, Mcf10a) and human breast cancer tissue extract were found to express proAVP mRNA. Western analysis revealed multiple forms of proAVP protein were present in cell lysates, corresponding to those detected in human hypothalamus extracts. Monoclonal antibodies directed against different regions of proAVP bound to intact live Mcf7 and Skbr3 cells. Dexamethasone increased the amount of proAVP-associated glycopeptide (VAG) secreted by Skbr3 cells and a combination of dexamethasone, IBMX and 8br-cAMP increased cellular levels of VAG. Exogenous AVP (1, 10, and 100 nM) elevated phospho-ERK1/2 levels, and increased cell proliferation was observed in the presence of 10 nM AVP. Concurrent treatment with the V1a receptor antagonist SR49059 reduced the effects of AVP on proliferation in Mcf7 cells, and abolished it in Skbr3 cells. Results here show that proAVP components are found at the surface of Skbr3 and Mcf7 cells and are also secreted from these cells. In addition, they show that AVP promotes cancer cell growth, apparently through a V1-type receptor-mediated pathway and subsequent ERK1/2 activation. Thus, strategies for targeting proAVP should be examined for their effectiveness in diagnosing and treating breast cancer.

Topics: 1-Methyl-3-isobutylxanthine; Anti-Inflammatory Agents; Antibodies, Monoclonal; Arginine Vasopressin; Blotting, Western; Breast Neoplasms; Cell Proliferation; Cyclic GMP; Dexamethasone; Female; Glycopeptides; Humans; Hypothalamus; Immunoenzyme Techniques; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Ovarian Neoplasms; Phosphodiesterase Inhibitors; Phosphorylation; Protein Precursors; Reverse Transcriptase Polymerase Chain Reaction

Urine contents of cyclic adenosine 3', 5' monophosphate (cAMP) and cyclic guanosine 3', 5' monophosphate (cGMP) were determined by radio-immunoassay in 150 patients. Fourty patients had malignant ovarian tumor (study group), 20 had other malignant tumors (control group 1), 40 benign tumors (control group 2) and 50 had no tumors whatever (normal control group). Urine content of cAMP was lower cGMP was higher in the study group than the other groups. Following effective treatment, the urine contact of cAMP and the ratio of cGMP/cAMP returned normal. The results indicate that determinations of cGMP and cAMP as well as their ratio are useful for diagnosis and predicting the therapeutic effect in malignant ovarian tumors.

Topics: Adult; Aged; Cyclic AMP; Cyclic GMP; Female; Humans; Middle Aged; Ovarian Neoplasms; Prognosis; Radioimmunoassay

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

Serial measurements of urinary cyclic guanosine monophosphate (cGMP) were performed in 47 patients with epithelial ovarian cancer. In 30 patients, the pre-chemotherapy cGMP level was above the range for normal controls (marker positive); the remainder were within the normal range. Marker positive patients demonstrated a 96% correlation of disease regression with a fall in marker level and a 75% correlation of disease progression with a rise in marker level. The corresponding correlations in the marker negative group were 41% and 39%. Marker positive patients also demonstrated a rise in marker before clinical recognition of disease progression in six of 11 instances whereas only one of nine instances in marker negative patients showed such a rise. Patients with evidence of static disease had normal and stable marker levels.

Topics: Chlorambucil; Cisplatin; Cyclic GMP; Female; Follow-Up Studies; Humans; Ovarian Neoplasms

Random urinary cyclic guanosine monophosphate (cyclic GMP) has been measured in a control group of 83 women and in 92 women with histologically proven epithelial ovarian cancer. Forty-eight cancer patients (53%) had levels greater than the mean +2SD of the control population. There was no correlation between urinary cyclic GMP and tumour histology, degree of differentiation or stage. Patients with gross residual disease after laparotomy had higher postoperative levels. This degree of sensitivity in addition to poor specificity for ovarian cancer renders this marker unsuitable for screening purposes. While residual disease state after surgery was found to be the best single predictor of survival, an elevated urinary cyclic GMP level before chemotherapy was found to be an independent adverse prognostic variable.

Topics: Adolescent; Adult; Aged; Cyclic GMP; Female; Humans; Middle Aged; Neoplasm Staging; Ovarian Neoplasms; Prognosis

Cyclic guanosine 3',5' monophosphate (cyclic GMP) and cyclic adenosine 3',5' monophosphate (cyclic AMP) have been determined in random urine specimens from 95 healthy individuals, 60 patients with non-cancerous conditions, 52 patients with benign tumours, and 74 patients with malignant tumours. Concentrations of cyclic GMP have also been determined in a number of other groups, including some undergoing cancer treatment. Ninety-three per cent of cancer patients had raised urinary cyclic GMP concentrations compared to the reference range for healthy subjects. For the non-cancerous and benign groups, 33% and 42% respectively had raised concentrations. The urine cyclic AMP concentrations were similar in all groups. Urine cyclic GMP appeared to rise early in the onset of malignant growth. Successful cancer treatment was accompanied by a dramatic fall in the urine cyclic GMP concentrations, whereas if the treatment was unsuccessful the level did not change. It is concluded that urine cyclic GMP may have important applications in the monitoring of cancer treatment.

Topics: Adolescent; Adult; Aged; Breast Neoplasms; Cyclic AMP; Cyclic GMP; Female; Humans; Male; Middle Aged; Neoplasms; Ovarian Neoplasms; Uterine Cervical Neoplasms; Uterine Prolapse

Guanosine 3':5'-phosphate (cycle GMP) in urine has been used to monitor the response of patients with ovarian cancer to treatment. Changes in the cyclic GMP level appear to correlate well with clinical status in that the disappearance of clinically detectable tumour is associated with a drop in the level whereas a tumour recurrence is associated with an elevation. Serially measured cyclic GMP is valuable for detecting a recurrence of tumour growth in patients in clinical remission and can predate any clinical signs by as much as 10 months. In patients who show no response to treatment, cyclic GMP levels in urine are elevated in the majority of specimens collected.

Topics: Creatinine; Cyclic GMP; Cyclophosphamide; Cystadenocarcinoma; Drug Therapy, Combination; Female; Gestonorone Caproate; Humans; Levamisole; Neoplasm Recurrence, Local; Ovarian Neoplasms

The biological activity of a protein growth factor is described. This factor was isolated from bovine pituitary tissue, and its activity was tested on cells of rat ovarian origin. Activity was assayed as growth-promoting potential measured by cell counts and is concentrationdependent. Similar growth stimulation was not produced by several cyclic nucleotides tested, neither was there crossreactivity between this growth factor and a chemically similar one produced by rat liver cells.

Topics: Animals; Bucladesine; Cattle; Cell Count; Cell Division; Cell Line; Chromatography; Cyclic GMP; DNA; Female; Fibroblasts; Growth Substances; Liver; Neoplasms, Experimental; Ovarian Neoplasms; Ovary; Pituitary Gland; Proteins; Rats; Thymidine; Tritium