Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.2 (guanylate cyclase)
8,497 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In squamous cell carcinoma, the levels of nitric oxide (NO) derived from inducible NO synthase (iNOS) and prostaglandin E2 (PGE2) derived from cyclooxygenase-2 (COX-2) originated from tumor cells or tumor-associated inflammatory cells have been reported to correlate with tumor growth, metastasis, and angiogenesis. The present study examined the role of the iNOS signaling pathway in PGE2-mediated tumor invasiveness and proliferation in squamous cell carcinoma, A431, and SCC-9 cells. Cell invasion and proliferation promoted by PGE2 were blocked by iNOS silencing RNA or iNOS/guanylate cyclase (GC) pharmacological inhibition. Consistently, iNOS-GC pathway inhibitors blocked mitogen-activated protein kinase-ERK1/2 phosphorylation, which was required to mediate PGE2 functions. In vivo, in A431 cells implanted in nude mice, GC inhibition also decreased the tumor proliferation index and ERK1/2 activation. PGE2 effects were confined to the selective stimulation of the EP2 receptor subtype, leading to epidermal growth factor receptor (EGFR) transactivation via protein kinase A (PKA) and c-Src activation. EP2-mediated ERK1/2 activation and cell functions were abolished by inhibitors of PKA, c-Src, and EGFR, as well as by inhibiting iNOS pathway. Silencing of iNOS also impaired EGFR-induced ERK1/2 phosphorylation. These results indicate that iNOS/GC signaling is a downstream player in the control of EP2/EGFR-mediated tumor cell proliferation and invasion.
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PMID:EP2 prostanoid receptor promotes squamous cell carcinoma growth through epidermal growth factor receptor transactivation and iNOS and ERK1/2 pathways. 1738 45

The lymphatic vascular system regulates tissue fluid homeostasis and the afferent phase of the immune response, and it is also involved in tumor metastasis. There is increasing evidence that lymphatic vessels also mediate acute and chronic inflammation. However, the mechanisms and functional consequences of lymphangiogenesis under inflammatory conditions are largely unknown. Here, we show that lymphatic endothelial cells (LECs) specifically express the alpha1beta1 isoform of soluble guanylate cyclase (sGC), that vascular endothelial growth factor-A potently induces sGCalpha1beta1, and that nitric oxide (NO) -induced LEC proliferation, migration, and cGMP production in LECs are specifically dependent on sGCalpha1beta1. Moreover, the specific sGC inhibitor NS-2028 completely prevents ultraviolet B-irradiation-induced lymphatic vessel enlargement, edema formation, and skin inflammation in vivo. These findings identify a crucial role of the NO/sGCalpha1beta1/cGMP pathway in modulating lymphatic vessel function. The blockade of sGCalpha1beta1 signaling might serve as a novel therapeutic strategy for inhibiting lymphangiogenesis and inflammation, in addition to its effects on the blood vasculature.
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PMID:Nitric oxide mediates lymphatic vessel activation via soluble guanylate cyclase alpha1beta1-impact on inflammation. 1785 21

Sonodynamic therapy (SDT) is a novel tumor therapy method. We investigated membrane fluidity, activity of the enzymes and membrane morphology in vitro post hematoporphyrin-SDT treatment. Furthermore, the potential mechanisms behind the changes in membrane fluidity and enzymic activity were discussed. Tumor cells were exposed to ultrasound at 1.75 MHz for up to 3 min in the presence and absence of hematoporphyrin. Fluorescence polarization, contents of Malonaldehyde, and levels of free fatty acid were assessed. Activity of enzymes was checked by the plumbic nitrate detection method. For the morphologic study, a scanning electron microscope was used to observe the cellular surface. Ultrasonically induced cell damage increased in the presence of HPD (from 15% to 24%). Compared with ultrasound treatment alone, the fluidity decreased from 5.037 to 3.908, malonaldehyde content and free fatty acid level increased from 0.743 nmol/mL to 0.97 9 nmol/mL and from 237.180 micromol/L to 730.769 micromol/L, respectively, post ultrasound combined with HPD treatment. Inactivity of adenylate cyclase and guanylate cyclase and significant deformation of the cellular surface were also observed post SDT treatment. Our results suggested that alterations in membrane modality and lipid composition played important roles in SDT-mediated inhibition of tumor growth, even inducing tumor cell death, which might be attributed to a sono-chemical activation mechanism.
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PMID:Membrane fluidity altering and enzyme inactivating in sarcoma 180 cells post the exposure to sonoactivated hematoporphyrin in vitro. 1808 37

Ultrasonically induced effects of hematoporphyrin (HPD) on cell damage and membrane protein alteration of S180 isolated tumor cells in vitro were investigated, and the potential mechanisms of sonodynamic therapy (SDT) inhibiting tumor growth were discussed. Tumor cells suspended in air-saturated PBS (pH 7.2) were exposed to ultrasound at 1.8 MHz for up to 180s in the presence and absence of HPD. The viability of cells was determined by a trypan blue exclusion test. To estimate the damage effects of SDT on plasma membrane of tumor cells primarily, membrane integral proteins (EGFR, Ras, Fas, FasL) and cell proliferation associated enzymes (adenylate cyclase and guanylate cyclase) were checked with immunochemical methods. The results indicated that the intensity threshold for ultrasonically induced cell damage at 1.8 MHz was 3 W/cm2. At this condition, the expression of the integral proteins was obviously inhibited and the activity of the enzymes was decreased post ultrasound treatment in the presence of 20 microg/ml HPD. Loss of the membrane proteins and inactivity of AC and GC post SDT was time-dependent. This paper reveals SDT can cause the loss of tumor cell membrane integral proteins and inactivity of the enzymes associated with cell proliferation which might be attributed to a sonochemical activation mechanism. The mechanisms by that tumor growth is inhibited by SDT can be understood as that the growth signaling pathway is partially interdicted and the resistance of tumor cells to the specifically activated immune cells is weakened.
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PMID:Ultrasound exposure in the presence of hematoporphyrin induced loss of membrane integral proteins and inactivity of cell proliferation associated enzymes in sarcoma 180 cells in vitro. 1827 19

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.
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PMID:Inhibition of non-small cell lung cancer cell migration by grape seed proanthocyanidins is mediated through the inhibition of nitric oxide, guanylate cyclase, and ERK1/2. 1868 Jan 2

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.
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PMID:EGCG inhibits mammary cancer cell migration through inhibition of nitric oxide synthase and guanylate cyclase. 1869 79

Colorectal cancer immunotherapy is limited by the paucity of available target antigens fulfilling the necessary criteria of tumor-specificity, sufficient immunogenicity and universal association with disease. A novel class of immune targets, cancer mucosa antigens (CMAs), whose expression normally is confined to mucosae but maintained during neoplastic transformation, promises to overcome these imitations, enjoying the advantage of immune compartmentalization, preventing autoimmune disease, while permitting therapeutic anti-tumor responses. Indeed, therapeutic immunization against the model CMA guanylyl cyclase c (GCC) extends survival in mouse models of established parenchymal colorectal cancer metastases with antitumor efficacy superior to currently available antigens. Here adjuvanation of therapeutic antitumor immunity to GCC was explored employing the cytokines IL-2 and GM-CSF in a mouse model of metastatic colorectal cancer. Combining plasmids expressing murine IL-2 or GM-CSF with recombinant viral vector immunization to GCC enhanced antitumor efficacy beyond viral vector immunization alone. These studies support the incorporation of IL-2 and GM-CSF in CMA-targeted immunization regimens for established colorectal cancer metastases.
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PMID:Cytokine adjuvanation of therapeutic anti-tumor immunity targeted to cancer mucosa antigens. 1995 76

Sulindac displays promising antineoplastic activity, but toxicities from cyclooxygenase inhibition limit its use for chemoprevention. Previous reports suggest that its anticancer properties may be attributed to a cyclooxygenase-independent mechanism, although alternative targets have not been well defined. Here, we show that sulindac sulfide (SS) induces apoptosis and inhibits the growth of human breast tumor cells with IC50 values of 60 to 85 micromol/L. Within the same concentration range, SS inhibited cyclic GMP (cGMP) hydrolysis in tumor cell lysates but did not affect cyclic AMP hydrolysis. SS did not induce apoptosis of normal human mammary epithelial cells (HMEC) nor did it inhibit phosphodiesterase (PDE) activity in HMEC lysates. SS increased intracellular cGMP levels and activated protein kinase G in breast tumor cells but not HMEC. The guanylyl cyclase (GC) activator, NOR-3, and cGMP PDE inhibitors, trequinsin and MY5445, displayed similar growth-inhibitory activity as SS, but the adenylyl cyclase activator, forskolin, and other PDE inhibitors had no effect. Moreover, GC activation increased the sensitivity of tumor cells to SS, whereas GC inhibition reduced sensitivity. By comparing PDE isozyme profiles in breast tumor cells with HMEC and determining the sensitivity of recombinant PDE isozymes to SS, PDE5 was found to be overexpressed in breast tumor cells and selectively inhibited by SS. The mechanism of SS binding to the catalytic domain of PDE5 was revealed by molecular modeling. These data suggest that PDE5 inhibition is responsible for the breast tumor cell growth-inhibitory and apoptosis-inducing activity of SS and may contribute to the chemopreventive properties of sulindac.
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PMID:Sulindac sulfide selectively inhibits growth and induces apoptosis of human breast tumor cells by phosphodiesterase 5 inhibition, elevation of cyclic GMP, and activation of protein kinase G. 1999 73

The benzoquinone derivative embelin is a multifunctional drug that not only induces apoptosis by inhibiting XIAP, the X chromosome-linked inhibitor of apoptosis protein, but also blocks nuclear factor-kappaB signaling pathways, thereby leading to down-regulation of a variety of gene products involved in tumor cell survival, proliferation, invasion, angiogenesis, and inflammation. Here, we report that embelin activates and modulates l-arginine/nitric oxide/cyclic GMP signaling in cultured endothelial cells. Embelin elicited a rapid increase of intracellular free Ca(2+), leading to activation of endothelial nitric oxide synthase (eNOS) and NO-induced cGMP accumulation. While the cGMP response was comparable to that caused by other Ca(2+)-mobilizing agents, the stimulatory effect of embelin on l-citrulline formation (approximately 4-fold) was substantially lower than that observed upon activation of eNOS with the Ca(2+) ionophore A23187 (approximately 18-fold), the receptor agonist ATP (approximately 16-fold) or the sarco-endoplasmic reticulum Ca(2+)-ATPase inhibitor thapsigargin (approximately 14-fold). The apparent discrepancy between NO/cGMP and l-citrulline formation in embelin-treated cells was not due to enhanced metabolism and/or efflux of l-citrulline, increased NO bioavailability, inhibition of cGMP hydrolysis, sensitization of soluble guanylate cyclase (sGC) to NO, or enhanced formation of a sGC/eNOS complex. Our puzzling observations suggest that embelin improves coupling of endothelial NO synthesis to sGC activation through mobilization of an as yet unrecognized signaling pathway.
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PMID:Activation of endothelial nitric oxide synthase by the pro-apoptotic drug embelin: Striking discrepancy between nitric oxide-mediated cyclic GMP accumulation and L-citrulline formation. 2014 27

Analogues of the E. coli heat-stable enterotoxin (STh) are currently under study as both imaging and therapeutic agents for colorectal cancer. Studies have shown that the guanylate cyclase C (GC-C) receptor is commonly expressed in colorectal cancers. It has also been shown that STh peptides inhibit the growth of tumor cells expressing GC-C. The ability to determine GC-C status of tumor tissue using in vivo molecular imaging techniques would provide a useful tool for the optimization of GC-C-targeted therapeutics. In this work, we have compared receptor binding affinities, internalization/efflux rates, and in vivo biodistribution patterns of an STh analogue linked to N-terminal DOTA, TETA, and NOTA chelating moieties and radiolabeled with Cu-64. The peptide F(19)-STh(2-19) was N-terminally labeled with three different chelating groups via NHS ester activation and characterized by RP-HPLC, ESI-MS, and GC-C receptor binding assays. The purified conjugates were radiolabeled with Cu-64 and used for in vitro internalization/efflux, in vivo biodistribution, and in vivo PET imaging studies. In vivo experiments were carried out using SCID mice bearing T84 human colorectal cancer tumor xenografts. Incorporation of DOTA-, TETA-, and NOTA-chelators at the N-terminus of the peptide F(19)-STh(2-19) resulted in IC(50)s between 1.2 and 3.2 nM. In vivo, tumor localization was similar for all three compounds, with 1.2-1.3%ID/g at 1 h pi and 0.58-0.83%ID/g at 4 h pi. The principal difference between the three compounds related to uptake in nontarget tissues, principally kidney and liver. At 1 h pi, (64)Cu-NOTA-F(19)-STh(2-19) demonstrated significantly (p < 0.05) lower uptake in liver than (64)Cu-DOTA-F(19)-STh(2-19) (0.36 +/- 0.13 vs 1.21 +/- 0.65%ID/g) and significantly (p < 0.05) lower uptake in kidney than (64)Cu-TETA-F(19)-STh(2-19) (3.67 +/- 1.60 vs 11.36 +/- 2.85%ID/g). Use of the NOTA chelator for coordination of Cu-64 in the context of E. coli heat-stable enterotoxin analogues results in higher tumor/nontarget tissue ratios at 1 h pi than either DOTA or TETA macrocycles. Heat-stable enterotoxin-based radiopharmaceuticals such as these provide a means of noninvasively determining GC-C receptor status in colorectal cancers by PET.
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PMID:Comparative evaluation of three 64Cu-labeled E. coli heat-stable enterotoxin analogues for PET imaging of colorectal cancer. 2053 42


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