Growth of cultured human glioma tumour cells can be regulated with histamine and histamine antagonists

Biological basis and clinical study of glycogen synthase kinase- 3β-targeted therapy by drug repositioning for glioblastoma

Background

Glycogen synthase kinase (GSK)-3β has emerged as an appealing therapeutic target for glioblastoma (GBM). Here, we investigated the therapeutic effect of the current approved drugs against GBM via inhibition of GSK3β activity both, in experimental setting and in a clinical study for recurrent GBM patients by repositioning existent drugs in combination with temozolomide (TMZ).

Materials and Methods

Progression-free and overall survival rates were compared between patients with low or high expression of active GSK3β in the primary tumor. GBM cells and a mouse model were examined for the effects of GSK3β-inhibitory drugs, cimetidine, lithium, olanzapine, and valproate. The safety and efficacy of the cocktail of these drugs (CLOVA cocktail) in combination with TMZ were tested in the mouse model and in a clinical study for recurrent GBM patients.

Results

Activation of GSK3β in the tumor inversely correlated with patient survival as an independent prognostic factor. CLOVA cocktail significantly inhibited cell invasion and proliferation. The patients treated with CLOVA cocktail in combination with TMZ showed increased survival compared to the control group treated with TMZ alone.

Conclusions

Repositioning of the GSK3β-inhibitory drugs improved the prognosis of refractory GBM patients with active GSK3β in tumors. Combination of CLOVA cocktail and TMZ is a promising approach for recurrent GBM.

Histamine hyperpolarizes human glioblastoma cells by activating the intermediate-conductance Ca2+-activated K+ channel

The effects of histamine on the membrane potential and currents of human glioblastoma (GL-15) cells were investigated. In perforated whole cell configuration, short (3 s) applications of histamine (100 microM) hyperpolarized the membrane by activating a K(+)-selective current. The response involved the activation of the pyrilamine-sensitive H(1) receptor and Ca(2+) release from thapsigargin-sensitive intracellular stores. The histamine-activated current was insensitive to tetraethylammonium (3 mM), iberiotoxin (100 nM), and d-tubocurarine (100 microM) but was markedly inhibited by charybdotoxin (100 nM), clotrimazole (1 microM), and 1-[(2-chlorophenyl)diphenylmethyl]-1H-pyrazole (TRAM-34, 1 microM), a pharmacological profile congruent with the intermediate conductance Ca(2+)-activated K(+) (IK(Ca)) channel. Cell-attached recordings confirmed that histamine activated a K(+) channel with properties congruent with the IK(Ca) channel (voltage independence, 22 pS unitary conductance and slight inward rectification in symmetrical 140 mM K(+)). More prolonged histamine applications (2-3 min) often evoked a sustained IK(Ca) channel activity, which depended on a La(2+) (10 microM)-sensitive Ca(2+) influx. Intracellular Ca(2+) measurements revealed that the sustained IK(Ca) channel activity enhanced the histamine-induced Ca(2+) signal, most likely by a hyperpolarization-induced increase in the driving force for Ca(2+) influx. In virtually all cells examined we also observed the expression of the large conductance Ca(2+)-activated K(+) (BK(Ca)) channel, with a unitary conductance of ca. 230 pS in symmetrical 140 mM K(+), and a Ca(2+) dissociation constant [K(D(Ca))] of ca. 3 microM, at -40 mV. Notably in no instance was the BK(Ca) channel activated by histamine under physiological conditions. The most parsimonious explanation based on the different K(D(Ca)) for the two K(Ca) channels is provided.

The influence of mast cell mediators on migration of SW756 cervical carcinoma cells

The role of mast cell mediators on cervical cancer cell migration was assessed using an in vitro assay of scratch wound healing onto monolayers of HPV18-positive cervical carcinoma cells (SW756). Migration of SW756 cells was accelerated by co-culture with the mast cell line LAD2. This effect was inhibited by the H1R antagonist pyrilamine and the cannabinoid agonists 2-arachidonylglycerol (2AG) and Win 55,212-2. Therefore, the specific effects of histamine and cannabinoids on SW756 migration and LAD2 activation were analyzed. Histamine added to the in vitro assay of scratch wound healing either increased or inhibited SW756 migration rate by acting either on H1R or H4R, respectively. Cannabinoids acted on CB1 receptors to inhibit SW756 migration. Supernatants from SW756 cells stimulated LAD2 cell degranulation, which in turn was inhibited by cannabinoids acting via CB2 receptors. RT-PCR showed that SW756 expressed mRNA for CB1, CB2, H1R, H2R, and H4R. On the other hand, LAD2 expressed mRNA for all four HRs and CB2. The results suggest that mast cells could be contributing to cervical cancer cell invasion and spreading by the release of histamine and cannabinoids. Therefore, therapeutic modulation of specific mast cell mediators may be beneficial for cervical cancer treatment.

Direct effects of nitric oxide on histamine release from rat enterochromaffin-like cells

The direct effects of nitric oxide (NO) on enterochromaffin-like (ECL) cells have not yet been demonstrated. In this study we investigated the direct effects of NO donors on rat ECL cells. The NO donor, NOR3 (10 and 100 microM), decreased gastrin-induced histamine release. 100 microM NOR3 increased cGMP levels and reduced gastrin-induced calcium influx. ODQ, an inhibitor of guanylate cyclase, completely blocked NOR3-induced inhibition of histamine release. These results suggest that NO inhibits gastric acid secretion via suppression of gastrin-induced histamine release through a pathway in which NO activates guanylate cyclase, in addition to increasing cGMP levels and reducing gastrin-induced calcium influx. The use of NO as a new type of gastric acid inhibitor that decreases histamine levels in the stomach would be beneficial as increased histamine levels resulting from use of a histamine H2 receptor antagonist or proton pump inhibitor have various effects on tumors and immunological functions.

Direct effects of proton pump inhibitors on histamine release from rat enterochromaffin-like cells

Enterochromaffin-like (ECL) cells play a central role in the regulation of gastric acid secretion. Previous studies have shown that proton pump inhibitors accelerate histamine release from ECL cells through the effects of gastrin. However, direct effects of proton pump inhibitors on ECL cells have not been demonstrated to date because the indirect effects of gastrin are difficult to suppress. We investigated the direct effects of proton pump inhibitors medication on ECL cells using an elutriation system. ECL cells were stimulated with gastrin or rabeprazole, and histamine release from ECL cells was measured. Rabeprazole increased histamine release through a pathway that differed from that of gastrin. The histamine increase was likely due to an acceleration of vesicular monoamine transporter 2 (VMAT2). Rabeprazole increased histamine release from ECL cells directly via VMAT2, but did not affect the total amount of histamine in the cells. The results suggest that patients receiving proton pump inhibitors for extended periods must be monitored extensively because gastric tumor proliferation may be promoted by increased histamine release from ECL cells.

Determination of histamine in the whole blood of colon cancer patients

The aim of the present work is to investigate whether histamine assay could be useful in detecting the presence of primary cancer. The high-performance liquid chromatographic (HPLC)-based o-phthalaldialdehyde (OPA) histamine derivatization assay was investigated with respect to several variables, dramatization reagent concentration, organic solvent requirement, derivatization time and counter-ion effect on chromatographic separation. The OPA histamine assay, in the absence of added -SH groups, was found to detect histamine in whole blood samples with relative standard deviations <14% and recoveries not less than 90%. The assay showed high selectivity towards other aminic-containing compounds and a detection limit of 18 nM of histamine was evaluated. Calibration curves in the range 50-500 nM were obtained by using histamine standards in 0.1 M HCl with a regression coefficient value (r(2)) of 0.9969. In order to assess the usefulness of this assay in primary tumor monitoring, two groups of individuals, 29 controls and 29 colon cancer patients were selected, and serum levels of histamine, carcinogen embrionary antigen (CEA), carcinogen antigen 19.9 (CA19.9), and tumor staging, were determined. A significant histamine reduction (P=0.028) between controls (180.12+/-70.4 nM) and patients (134.5+/-90.3 nM) was found, and a cut-off value of 157.5 nM was extrapolated as intercept point of sensitivity and specificity curves. Fifty percent of patients showed a histamine value below the cut-off, while 45.8 and 8.3% of patients were positive for CEA and CA19.9, respectively. No correlation was found between Tumor Node Metastasis staging and histamine amount, indicating that this marker is not related to the tumor mass. Our data suggest that histamine level, together with other classical tumor markers, could be a potentially interesting tumor marker in colon cancer monitoring.

Pd(II)- and Pt(II)-cimetidine complexes. Crystal structure of trans-[Pt(N,S-cimetidine)(2)]Cl(2)(*)12H(2)O

The influence of cimetidine on patients under cisplatin treatment for cancer is controversial. It has moderate or no effects on several types of cancer and its effects on the nephrotoxicity induced by cisplatin are uncertain. To examine the binding properties and antiproliferative effects of the known anticancer noble metals, cimetidine (cim) was complexed to platinum(II) and palladium(II). The crystal structure of the Pt-cim compound shows two molecules of cimetidine coordinated to the metal through thioether sulfur and imidazolic nitrogen whereas spectroscopic studies in solution for Pd-cim reveal that the ratio of the metal to cimetidine is 1:1 with identical coordination environments. To determine the antitumor activity of the drugs, the interaction of the metallic complexes and free cimetidine with DNA was assessed. Their cytotoxic activity was compared with that of cisplatin.

Histamine H1 receptor activation stimulates mitogenesis in human astrocytoma U373 MG cells

In human astrocytoma U373 MG cells that express histamine H1 receptors (180 +/- 6 fmol/mg protein) but not H2 or H3 receptors, histamine stimulated mitogenesis as assessed by [3H]-thymidine incorporation (173 +/- 2% of basal; EC50, 2.5 +/- 0.4 microM). The effect of 100 microM histamine was fully blocked by the selective H1 antagonist mepyramine (1 microM) and was markedly reduced (93 +/- 4% inhibition) by the phospholipase C inhibitor U73122 (10 microM). The activator of protein kinase C (PKC) phorbol 12-tetradecanoyl-13-acetate (TPA, 100nM) stimulated [3H]-thymidine incorporation (270 +/- 8% of basal), and this response was not additive with that to 100 microM histamine. The incorporation of [3H]-thymidine induced by 100 microM histamine was partially reduced by the PKC inhibitor Ro 31-8220 (57 +/- 7% inhibition at 300 nM) and by the compound PD 098,059 (30 microM, 62 +/- 14% inhibition), an inhibitor of the mitogen-activated kinase (MAPK) kinases MEK1/MEK2. These results show that histamine H1 receptor activation stimulates the proliferation of human astrocytoma U373 MG cells. The action of histamine appears to be partially mediated by PKC stimulation and MAPK activation.

Histidine decarboxylase expression in human melanoma

Histamine has been implicated as one of the mediators involved in regulation of proliferation in both normal and neoplastic tissues. Histidine decarboxylase, the only enzyme that catalyzes the formation of histamine from L-histidine, is an essential regulator of histamine levels. In this study, we investigated the gene and protein expression of histidine decarboxylase in melanoma. Reverse transcriptase polymerase chain reaction and in situ hybridization studies of WM-35, WM-983/B, HT-168, and M1 human melanoma cell lines both resulted in positive signals for histidine decarboxylase messenger RNA. A polyclonal chicken antibody was developed against human histidine decarboxylase and protein expression was confirmed by western blot analysis of the cell lysates, revealing a predominant immunoreactive band at approximately 54 kDa corresponding to monomeric histidine decarboxylase. Protein expression of histidine decarboxylase was also shown by flow cytometric analysis and strong punctate cytoplasmic staining of melanoma cell lines. Moreover, both primary and metastatic human melanoma tissues were brightly stained for histidine decarboxylase. When compared with the very weak or no reactions on cultivated human melanocytes both western blot and immunohistochemical studies showed much stronger histidine decarboxylase expression in melanoma cells. These findings suggest that expression of histidine decarboxylase is elevated in human melanoma.

Histamine in brain development and tumors

Histamine is found in developing mammalian brain in both neurons and mast cells. Under normal conditions, histamine H1 and H2 receptors are found in neural, glial and endothelial cells, and H3 receptors at least on neurons. Experimental brain tumors display both H1 and H2 receptors, and histamine increases permeability in the tumors and in the neighboring areas. Many studies have addressed histaminergic signalling mechanisms in cell lines originating from brain tumors. However, the role of histamine in normal development of brain structures, proliferation and differentiation of neurons and glial cells, and growth of malignant tumors in situ is still poorly understood.

Histamine as an autocrine growth factor: an unusual role for a widespread mediator

The involvement of histamine in cancer growth represents an old controversy and direct experimental evidence proving this hypothesis is not still available. In this paper we review the most relevant mechanisms referring to the role of histamine receptors, histidine decarboxylase and histamine release in the onset of an autocrine loop, that enables histamine to act as an autocrine growth factor. We postulate that this autocrine loop, that has been studied in an experimental mammary carcinoma model induced in rats, may be present in different human neoplasias. Therefore, the better understanding of this novel regulatory pathway that is controlled by histamine may contribute to identifying new therapeutic targets.

Kappa-opioid receptor binding varies inversely with tumor grade in human gliomas

BACKGROUND

Opioid agonists can inhibit cell proliferation in various neural tumor cell lines, including rat gliomas. Because opioid antimitogenic effects are mediated by opioid receptors, it was of interest to the authors to determine opioid receptor levels in human brain tumors.

METHODS

Specimens obtained at craniotomy from 30 patients with glioma and nonneoplastic brain disorders were evaluated for their kappa-opioid receptor binding. Kd and Bmax values were estimated from homologous competition binding curves with the kappa1-selective radioligand [3H]U69,593.

RESULTS

Receptor binding density was greatest in nonneoplastic brain tissue, less in Grade 2 and 3 astrocytoma, and least in glioblastoma multiforme.

CONCLUSIONS

These results suggest that opioid receptor-based stratification of grade may have clinical utility in distinguishing glioblastoma multiforme from lower grade astrocytomas, and thereby may facilitate diagnosis and treatment.

The growth of brown adipose tissue in cold-acclimatized rats after depletion of mast cell histamine by compound 48/80

Cold acclimatization (4-5 degree C) is accompanied by 2-3 fold increase of brown adipose tissue (BAT). This rapid growth of interscapular BAT was studied after histamine depletion. In control rats maintained at room temperature (28 +/- 2 degree C) the BAT histamine content was 23.4 +/- 5.9 (mean +/- SD) microgram/g of tissue and cold acclimatization (5 +/- 1 degree C) produced a significant increase of BAT weight, but reduced the histamine content to 8.4 +/- 1.9 microgram/g. The total weight of BAT after 20 days of acclimatization was unaffected by depletion of histamine due to compound 48/80. The low level of histamine in BAT of cold acclimatized rats could be due to a fast rate of amine utilization; alternatively an altered synthesis or storage process may occur during acclimatization.

Neuroligand-triggered calcium signalling in cultured human glioma cells

Cells from primary cultures of four glioblastomas (GB), three low-grade astrocytomas (A), and four low-grade oligodendrogliomas (O) were tested for the presence of neuroligand receptors linked to Ca2+ signalling by calcium imaging. Cells of days 3 to 21 in culture were incubated with 5 microM fluo-3-acetomethylester in a bath solution and stimulated with 0.1 mM ATP, 0.01 mM angiotensin II, bradykinin, histamine, norepinephrine, serotonin, and substance P for 15 s, with 0.01 mM glutamate and 50 mM K+ for 30 s. Changes in the Ca2+ concentration were measured with a confocal laser scanning microscope. In all glioma subtypes, the majority of cells showed Ca2+ responses after application of histamine (60% of cells tested in GB, 67% in A, 86% in O), bradykinin (66% in GB, 29% in A, 55% in O) and ATP (48% in GB, 70% in A, 47% in O). The other stimuli induced Ca2+ transients in a smaller proportion (between 33% and 2%) of the cells. Our study demonstrates that histamine, bradykinin and ATP are potent inducers of [Ca2+]i signals in gliomas.

Effect of histamine and the H2 antagonist cimetidine on the growth and migration of human neoplastic glia

Histamine is known to act, at least in part, as a growth factor, as production of this neurotransmitter has been found to accelerate the rate of tissue proliferation in wound repair, embryogenesis and malignant growth. Histamine favours in vivo tumour cell proliferation via H2 receptors. Cimetidine is an H2 blocker and has been shown to inhibit tumour cell growth. In the present study, the growth modulating effects of histamine and cimetidine were assessed on five cell lines derived from human brain tumours of different histological types and grades of malignancy. Each cell line was treated with either cimetidine or histamine for 24 h before kinetic analyses, with PCNA, or motility assays, using Transwell migration chambers incorporating a microporous membrane, were carried out. Cimetidine significantly inhibited cell proliferation in three out of the five cell lines, which may indicate the dependence of proliferation of these cell lines on stimulation of the H2 receptor. With regard to migration, it was observed that in the majority of cell lines, cimetidine induced migration whilst histamine inhibited it. It was concluded that the link between effects of histamine on proliferation and its effects on migration must be clarified using a larger sample of cell lines.

Effects of histamine and 5-hydroxytryptamine on the growth rate of xenografted human bronchogenic carcinomas

1. The influence of histamine and 5-hydroxytryptamine (5-HT) antagonists and agonists on the volume doubling times (Td) of human bronchogenic carcinomas propagated as s.c. xenografts in immunosuppressed mice was examined. 2. The H2-receptor antagonists, cimetidine and ranitidine, increased Td. 3. Treatment with the H2-receptor agonist, 4-methyl histamine, had no effect on Td. 4. Co-administration of 4-methyl histamine and cimetidine abolished the effects of cimetidine. 5. The 5-HT2-receptor antagonists, cinanserin and ketanserin, both increased Td. 6. Treatment with the 5-HT1/2-receptor agonist quipazine (0.1 mg/kg, reflecting 5-HT2 agonist activity) decreased Td, while a higher dose (10.0 mg/kg) had no effect. 7. The 5-HT1/2-receptor antagonist, methiothepin, decreased Td. 8. The 5-HT uptake inhibitor, fluoxetine, increased Td in one tumour line but not in another, while the 5-HT releaser/depletor, fenfluramine, increased Td. 9. Histamine may stimulate tumour growth through the histamine H2-receptor, while the dominant effect of 5-HT is 5-HT1-receptor inhibition. 10. Tumour growth in some bronchogenic carcinomas may involve 5-HT uptake mechanisms.

Acetylcholine as a mitogen: muscarinic receptor-mediated proliferation of rat astrocytes and human astrocytoma cells

The mitogenic effect of muscarinic receptor agonists in glial cells has been characterized in rat cortical astrocytes and human 132 1N1 astrocytoma cells. The muscarinic receptor agonist carbachol caused a dose- and time-dependent increase in proliferation, as measured by [3H]thymidine incorporation. The mitogenic effect was mimicked by several muscarinic, but not nicotinic receptor agonists, and was blocked by muscarinic receptor antagonists. Reverse transcription-polymerase chain reaction (RT-PCR) experiments indicated the presence of m2, m3 and to a lesser degree, m5 muscarinic receptor mRNA in both astrocytes and astrocytoma cells. Proliferation experiments with subtype-specific muscarinic receptor antagonists suggest that carbachol-induced proliferation is due to activation of muscarinic M3 receptors. The phorbol ester 12-O-tetradecanoyl-phorbol 13-acetate (TPA) also stimulated glial cell proliferation. Down-regulation of protein kinase C, or the protein kinase C antagonist 1,5-(isoquinolynsulfanyl)-2-methylpiperazine dihydrochloride (H7) blocked proliferation induced by either TPA or carbachol. Of other neurotransmitters tested, histamine caused glial cell proliferation, norepinephrine and gamma-aminobutyric acid were ineffective, while serotonin and glutamate inhibited basal or serum-stimulated proliferation.