cyclic-gmp and Glioblastoma

Since the discovery of phosphodiesterase-5 (PDE5) enzyme overexpression in the central nervous system (CNS) malignancies, investigations have explored the potential capacity of current PDE5 inhibitor drugs for repositioning in the treatment of brain tumors, notably glioblastoma multiforme (GBM). It has now been recognized that these drugs increase brain tumors permeability and enhance standard chemotherapeutics effectiveness. More importantly, studies have highlighted the promising antitumor functions of PDE5 inhibitors, e.g., triggering apoptosis, suppressing tumor cell growth and invasion, and reversing tumor microenvironment (TME) immunosuppression in the brain. However, contradictory reports have suggested a pro-oncogenic role for neuronal cyclic guanosine monophosphate (cGMP), indicating the beneficial function of PDE5 in the brain of GBM patients. Unfortunately, due to the inconsistent preclinical findings, only a few clinical trials are evaluating the therapeutic value of PDE5 inhibitors in GBM treatment. Accordingly, additional studies should be conducted to shed light on the precise effect of PDE5 inhibitors in GBM biology regarding the existing molecular heterogeneities among individuals. Here, we highlighted and discussed the previously investigated mechanisms underlying the impacts of PDE5 inhibitors in cancers, focusing on GBM to provide an overview of current knowledge necessary for future studies.

Topics: Brain Neoplasms; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 5; Glioblastoma; Humans; Phosphodiesterase 5 Inhibitors; Tumor Microenvironment

Topics: Apoptosis; beta Catenin; Cyclic GMP; Glioblastoma; Humans; Signal Transduction; Steroids

The paucity of currently available therapies for glioblastoma multiforme requires novel approaches to the treatment of this brain tumour. Disrupting cyclic nucleotide-signalling through phosphodiesterase (PDE) inhibition may be a promising way of suppressing glioblastoma growth. Here, we examined the effects of 28 PDE inhibitors, covering all the major PDE classes, on the proliferation of the human U87MG, A172 and T98G glioblastoma cells. The PDE10A inhibitors PF-2545920, PQ10 and papaverine, the PDE3/4 inhibitor trequinsin and the putative PDE5 inhibitor MY-5445 potently decreased glioblastoma cell proliferation. The synergistic suppression of glioblastoma cell proliferation was achieved by combining PF-2545920 and MY-5445. Furthermore, a co-incubation with drugs that block the activity of the multidrug resistance-associated protein 1 (MRP1) augmented these effects. In particular, a combination comprising the MRP1 inhibitor reversan, PF-2545920 and MY-5445, all at low micromolar concentrations, afforded nearly complete inhibition of glioblastoma cell growth. Thus, the potent suppression of glioblastoma cell viability may be achieved by combining MRP1 inhibitors with PDE inhibitors at a lower toxicity than that of the standard chemotherapeutic agents, thereby providing a new combination therapy for this challenging malignancy.

Topics: Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclic AMP; Cyclic GMP; Drug Synergism; Glioblastoma; Humans; Multidrug Resistance-Associated Proteins; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Pyrazoles; Quinolines

The high mortality associated with glioblastoma multiforme (GBM) is attributed to its invasive nature, hypoxic core, resistant cell subpopulations and a highly immunosuppressive tumor microenvironment (TME). To support adaptive immune function and establish a more robust antitumor immune response, we boosted the local innate immune compartment of GBM using an immunostimulatory mesoporous silica nanoparticle, termed immuno-MSN. The immuno-MSN was specifically designed for systemic and proficient delivery of a potent innate immune agonist to dysfunctional antigen-presenting cells (APCs) in the brain TME. The cargo of the immuno-MSN was cyclic diguanylate monophosphate (cdGMP), a Stimulator of Interferon Gene (STING) agonist. Studies showed the immuno-MSN promoted the uptake of STING agonist by APCs in vitro and the subsequent release of the pro-inflammatory cytokine interferon β, 6-fold greater than free agonist. In an orthotopic GBM mouse model, systemically administered immuno-MSN particles were taken up by APCs in the near-perivascular regions of the brain tumor with striking efficiency. The immuno-MSNs facilitated the recruitment of dendritic cells and macrophages to the TME while sparing healthy brain tissue and peripheral organs, resulting in elevated circulating CD8

Topics: Animals; Antigen-Presenting Cells; Antineoplastic Agents; Brain Neoplasms; CD8-Positive T-Lymphocytes; Cyclic GMP; Dendritic Cells; Female; Glioblastoma; Immunity, Innate; Immunologic Factors; Immunotherapy; Interferon Type I; Macrophages; Mice; Mice, Inbred C57BL; Nanoparticles; Porosity; RAW 264.7 Cells; Silicon Dioxide; Tumor Microenvironment

Cyclic nucleotides (cAMP & cGMP) are critical intracellular second messengers involved in the transduction of a diverse array of stimuli and their catabolism is mediated by phosphodiesterases (PDEs). We previously detected focal genomic amplification of PDE1C in >90 glioblastoma multiforme (GBM) cells suggesting a potential as a novel therapeutic target in these cells. In this report, we show that genomic gain of PDE1C was associated with increased expression in low passage GBM-derived cell cultures. We demonstrate that PDE1C is essential in driving cell proliferation, migration and invasion in GBM cultures since silencing of this gene significantly mitigates these functions. We also define the mechanistic basis of this functional effect through whole genome expression analysis by identifying down-stream gene effectors of PDE1C which are involved in cell cycle and cell adhesion regulation. In addition, we also demonstrate that Vinpocetine, a general PDE1 inhibitor, can also attenuate proliferation with no effect on invasion/migration. Up-regulation of at least one of this gene set (IL8, CXCL2, FOSB, NFE2L3, SUB1, SORBS2, WNT5A, and MMP1) in TCGA GBM cohorts is associated with worse outcome and PDE1C silencing down-regulated their expression, thus also indicating potential to influence patient survival. Therefore we conclude that proliferation, migration, and invasion of GBM cells could also be regulated downstream of PDE1C.

Topics: Brain; Brain Neoplasms; Cell Movement; Cell Proliferation; Cyclic AMP; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 1; Gene Expression Regulation, Neoplastic; Glioblastoma; Humans; Neoplasm Invasiveness; Up-Regulation

The nitric oxide (NO) donor JS-K is specifically activated by glutathione S-transferases (GSTs) in GST-overexpressing cells. We have shown the induction of cell death in glioblastoma multiforme (GBM) cells at high JS-K doses but the mechanism remains unclear. The aim of this study was to determine whether NO-induced cell death is triggered by induction of apoptotic or necrotic pathways. For the first time, we demonstrate that NO induces cell death via mitotic catastrophe (MC) with non-apoptotic mechanisms in GBM cells. Moreover, the level of morphological changes indicating MC correlates with increased necrosis. Therefore, we conclude that MC is the main mechanism by which GBM cells undergo cell death after treatment with JS-K associated with necrosis rather than apoptosis. In addition, we show that PARP1 is not an exclusive marker for late apoptosis but is also involved in MC. Activating an alternative way of cell death can be useful for the multimodal cancer therapy of GBM known for its strong anti-apoptotic mechanisms and drug resistance.

Topics: Adenosine Triphosphate; Apoptosis; Azo Compounds; Blotting, Western; Caspases; Cell Line, Tumor; Cyclic GMP; Enzyme Activation; Flow Cytometry; Glioblastoma; Humans; In Situ Nick-End Labeling; Mitosis; Necrosis; Nitric Oxide; Piperazines; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-akt; Time Factors

Peroxizome proliferator-activated receptor gamma (PPARγ) is highly expressed in the central nervous system where it modulates numerous gene transcriptions. Nitric oxide synthase (NOS) expression could be modified by simulation of PPARγ which in turn activates nitric oxide (NO)/soluble guanylyl-cyclase (sGC)/cyclic guanosine mono phosphate (cGMP) pathway. It is well known that NO/cGMP pathway possesses pivotal role in the development of opioid dependence and this study is aimed to investigate the effect of PPARγ stimulation on opioid dependence in mice as well as human glioblastoma cell line. Pioglitazone potentiated naloxone-induced withdrawal syndrome in morphine dependent mice in vivo. While selective inhibition of PPARγ, neuronal NOS or GC could reverse the pioglitazone-induced potentiation of morphine withdrawal signs; sildenafil, a phosphodiesterase-5 inhibitor amplified its effect. We also showed that nitrite levels in the hippocampus were significantly elevated in pioglitazone-treated morphine dependent mice. In the human glioblastoma (U87) cell line, rendered dependent to morphine, cAMP levels did not show any alteration after chronic pioglitazone administration while cGMP measurement revealed a significant rise. We were unable to show a significant alteration in neuronal NOS mRNA expressions by pioglitazone in mice hippocampus or U87 cells. Our results suggest that pioglitazone has the ability to enhance morphine-dependence and to augment morphine withdrawal signs. The possible pathway underlying this effect is through activation of NO/GC/cGMP pathway.

Topics: Animals; Cell Line, Tumor; Cyclic AMP; Cyclic GMP; Disease Models, Animal; Enzyme Inhibitors; Glioblastoma; Hippocampus; Humans; Hypoglycemic Agents; Male; Mice; Morphine Dependence; Naloxone; Narcotic Antagonists; Nitric Oxide; Nitric Oxide Synthase; Pioglitazone; PPAR gamma; RNA, Messenger; Signal Transduction; Substance Withdrawal Syndrome; Thiazolidinediones; Transfection

Endostatin is a 20 kDa carboxyl-terminal fragment of collagen XVIII that, when added exogenously, inhibits endothelial proliferation and migration in vitro and angiogenesis and tumor growth in vivo. Previous results showed endostatin/collagen XVIII labeling in few endothelial cells in human glioblastoma multiforme. We have now observed constitutive release of endostatin from one of four endothelial cell lines. Induction of endostatin release was observed after H2O2, an in vitro model of cell stress, CoCl2, a model of hypoxia, and by IFN-gamma challenge. Endostatin expression and release was reduced by the nitric oxide synthase inhibitors aminoguanidine and L-NAME and induced by the NO synthase-independent NO donors sodium nitroprusside (SNP) and spermine-NONO-ate. SNP-mediated endostatin induction was abrogated by the soluble guanylate cyclase inhibitor 1H-(1.2.4) oxadiazolo (4,3-A) quinoxalin-1-one. Adenoviral endostatin transduction resulted in the release of endostatin from endothelial cells and in down-regulation of iNOS (NOS2) and eNOS (NOS3), and surprisingly in a 10% induction of PCNA. These results describe the modulation of endostatin release by the NO signaling cascade and provide important new pharmacological information for the systemic induction of endogenous endostatin release by common NO donor pharmacotherapy.

Topics: Adult; Aged; Animals; Brain; Brain Neoplasms; Cell Hypoxia; Cell Line; Collagen; Collagen Type XVIII; Cyclic GMP; Endostatins; Endothelium; Enzyme Inhibitors; Female; Glioblastoma; Guanylate Cyclase; Humans; Hydrogen Peroxide; Interferon-gamma; Male; Mice; Middle Aged; Nitric Oxide; Nitric Oxide Donors; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Nitric Oxide Synthase Type III; Oxidants; Peptide Fragments; Rats; Signal Transduction; Tumor Cells, Cultured; Up-Regulation

Angiogenesis is a prerequisite for tumour progression and is highly regulated by growth factors and cytokines a number of which also stimulate the production of nitric oxide. Asymmetric dimethylarginine is an endogenous inhibitor of nitric oxide synthesis. Asymmetric dimethylarginine is metabolised by dimethylarginine dimethylaminohydrolase. To study the effect of dimethylarginine dimethylaminohydrolase on tumour growth and vascular development, the rat C6 glioma cell line was manipulated to overexpress the rat gene for dimethylarginine dimethylaminohydrolase I. Enhanced expression of dimethylarginine dimethylaminohydrolase I increased nitric oxide synthesis (as indicated by a two-fold increase in the production of cGMP), expression and secretion of vascular endothelial cell growth factor, and induced angiogenesis in vitro. Tumours derived from these cells grew more rapidly in vivo than cells with normal dimethylarginine dimethylaminohydrolase I expression. Immunohistochemical and magnetic resonance imaging measurements were consistent with increased tumour vascular development. Furthermore, dimethylarginine dimethylaminohydrolase activity was detected in a series of human tumours. This data demonstrates that dimethylarginine dimethylaminohydrolase plays a pivotal role in tumour growth and the development of the tumour vasculature by regulating the concentration of nitric oxide and altering vascular endothelial cell growth factor production.

Topics: Amidohydrolases; Animals; Astrocytoma; Blotting, Northern; Blotting, Western; Brain Neoplasms; Cell Division; Cell Movement; Cells, Cultured; Cyclic GMP; DNA Primers; Endothelial Growth Factors; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Female; Glioblastoma; Glioma; Humans; Lymphokines; Mice; Mice, Nude; Neoplasm Transplantation; Neoplasms, Experimental; Neovascularization, Pathologic; Nitric Oxide; Rats; Reverse Transcriptase Polymerase Chain Reaction; Transfection; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factors

Topics: Astrocytoma; Brain Neoplasms; Cyclic AMP; Cyclic GMP; Glioblastoma; Glioma; Humans; Meningeal Neoplasms; Meningioma

Studies on the level of cyclic nucleotides (cAMP and cGMP) in human and animal glial tumours showed that the content of both nucleotides, especially that of cAMP, decreases in all the tumours. The cAMP/cGMP ratio also drops down. Concurrently it appears to be the most consistent parameter of nucleotide metabolism both in brain tissue and in human or animal glial tumours. The growing tumour affects cAMP and cGMP metabolism not only in the involved but also in the other hemisphere. No principal differences between human and animal tumours have been revealed in the content of cyclic nucleotides and its variation in tumour tissue.

Topics: Animals; Astrocytoma; Cerebellar Cortex; Cerebral Cortex; Cyclic AMP; Cyclic GMP; Glioblastoma; Humans; Neoplasms, Experimental; Rabbits; Rats; Species Specificity

Topics: Adult; Animals; Brain; Chromatography, Ion Exchange; Cyclic AMP; Cyclic GMP; Glioblastoma; Humans; Hydrogen-Ion Concentration; Kinetics; Magnesium; Male; Methods; Middle Aged; Parkinson Disease; Phosphodiesterase Inhibitors; Phosphoric Diester Hydrolases; Rabbits; Rats; Resins, Plant; Snakes; Temperature; Theophylline; Time Factors; Tritium; Venoms