- Email: [email protected]
Adenosine extracellular levels in human brain gliomas: an intraoperative microdialysis study
Neuroscience Letters 346 (2003) 93–96 www.elsevier.com/locate/neulet
Adenosine extracellular levels in human brain gliomas: an intraoperative microdialysis study Alessia Melania, Enrico De Michelib, Giampietro Pinnab, Alex Alfierib, Laura Della Cortea, Felicita Pedataa,* a
Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy b Department of Neurosurgery, Verona University Hospital, Piazzale Stefani 1, 37121 Verona, Italy Received 5 February 2003; received in revised form 8 May 2003; accepted 8 May 2003
Abstract Adenosine present in human brain glioma extracellular spaces is a marker of astrocyte purine metabolism. In this study, we evaluated adenosine levels in the extracellular fluid of 21 human gliomas of high-grade malignancy using brain microdialysis techniques coupled to high-performance liquid chromatography. The adenosine concentration (mean ^ SEM) within the control tissue was 2.99 ^ 0.37 mM and in the tumour tissue 1.56 ^ 0.46 mM. The reduction was statistically significant. It is concluded that the adenosine concentrations reached in the tumour tissue are sufficient to stimulate all adenosine receptor subtypes, suppress local anti-tumour immune responses and affect glial and endothelial cell proliferation. q 2003 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Adenosine; Glioma; Microdialysis; High-performance liquid chromatography; Brain tumour; Human
Adenosine present in the extracellular space of gliomas is a marker of astrocyte purine metabolism. Adenosine may exert a role in the development of cancer through several mechanisms mediated by its four receptor subtypes: the high affinity (low nM range) A1 and A2A receptors and the low affinity (mM range) A2b and A3 receptors [6]. Adenosine may suppress the anticancer immune response. It, in fact, inhibits adhesion of activated T-killer cells to mouse carcinoma cell targets [14] and the tumour necrosis factor (TNF) release [19], through A3 receptors located on lymphocytes and macrophages, respectively. A2A receptors are present on human T-lymphocytes and their expression increases in activated T-cells. A2A receptors may regulate T-lymphocyte cytokine production [11] and death [9]. Adenosine receptors were reported as mediators of both cell proliferation and cell death in human cancer cell lines [1, 16]. In particular, in human astrocytoma cells both a proliferative effect and apoptotic death have been described [1]. These effects may be mediated by A1, A2b [5] and A3 receptors [8] present on astrocytes. Furthermore, adenosine *
Corresponding author. Tel.: þ 39-055-4271262; fax: þ 39-0554271280. E-mail address: [email protected] (F. Pedata).
affects a number of steps involved in angiogenesis [4]. A proliferative action of retinal endothelial cells of bovine origin has been attributed to A2A adenosine receptors [20]. A2b receptors are expressed together with A2A receptors on human vascular endothelial cells and it was reported that A2b adenosine receptors mediate human retinal endothelial cell proliferation and vascular endothelial growth factor (VEGF) production [7]. The ectoenzyme 50 -nucleotidase, which converts nucleoside monophosphates (AMP, GMP, IMP) to adenosine, is densely distributed in the membranes of glioblastoma cells in vivo and in cell culture, and evidence exists that this enzyme is involved in the modulation of glioma cell proliferation [13]. The aim of this study was to measure, using microdialysis techniques, the extracellular concentrations of endogenous adenosine in human high-grade malignancy tumours, classified as grade III and IV gliomas. The study was performed at the Department of Neurosurgery, University of Verona, Italy. The study was approved by the Hospital Ethical Committee and complies with the European Community guiding policies and principles for experimental procedures. Informed consent was obtained for all
0304-3940/03/$ - see front matter q 2003 Elsevier Science Ireland Ltd. All rights reserved. doi:10.1016/S0304-3940(03)00596-2
94
A. Melani et al. / Neuroscience Letters 346 (2003) 93–96
patients. Twenty-one patients, nine males (mean age 48 ^ 5 years, ranging from 20 to 68 years) and 12 females (mean age 48 ^ 4 years, ranging from 28 to 76 years) due to undergo surgery for cortical glioma resection, and who had not previously undergone surgery, radiotherapy, chemotherapy, or cerebral biopsy, were included in this study. In all patients, diagnosis was confirmed by histopathology, according to the World Health Organization (WHO) classification [10]. During surgery for tumour resection, a flexible microdialysis catheter (CMA 70, CMA/Microdialysis, Solna, Sweden), with a 10 mm length of exposed membrane (cutoff 20 KD) and a 0.6 mm diameter, was inserted by freehand positioning to no more than 1 cm into the cortical area outside the proximity of the tumour, specifically at a 20 mm (far from tumour tissue) minimum distance from the edge of the tumour resection, utilizing pre-operative enhanced magnetic resonance imaging (MRI) and computed tomography (CT). After a 20 min equilibration period, one 20 min dialysis sample was collected, the probe was then moved to the cortical area of the tumour tissue and after a 20 min equilibration period, one 20 min sample was again collected. Dialysis catheters were perfused with artificial cerebral spinal fluid (CSF) containing 140 mM Naþ, 2.7 mM Kþ, 1.2 mM Ca2þ, 0.9 mM Mg2þ and 147 mM Cl2 at a constant flow rate of 2 ml/min, by means of a microperfusion pump (CMA 106, CMA/Microdialysis, Solna, Sweden). Samples were kept frozen at 2 80 8C until the assay. Adenosine content in the samples was analyzed using HPLC coupled to a spectrofluorimetric detector (LC-240, Perkin-Elmer, Norwalk, CT), according to the method described by Melani et al. [15]. In vitro experiments were carried out to evaluate the recovery of adenosine through the dialysis membrane. The dialysis probes were immersed in artificial CSF at 37 8C, containing known concentrations of adenosine. The probes were perfused at 2 ml/min and samples were collected every 20 min. The recovery rate calculated for six membranes was 43.4 ^ 5.1%. The adenosine concentration values reported in this paper were corrected for dialysis membrane recovery. Adenosine concentration data were analyzed using a paired Student’s t-test. Differences were considered statistically significant at P , 0:05. Table 1 summarizes the clinical features of the 21 patients with high-grade malignancy gliomas. Upon admission, all patients underwent barbiturate (100 mg per day) and dexamethasone (4 – 16 mg per day) therapy. In addition, all patients underwent pre-operative gadolinium-enhanced MRI and pre- and post-operative contrast-enhanced CT. The extracellular adenosine concentrations (mM) in the tumour (T) and far from the tumour (F) tissue of patients with cortical tumours of high-grade malignancy (n ¼ 21) are shown in Fig. 1. The mean adenosine concentration in T tissue (mean ^ SEM: 1.56 ^ 0.46 mM) was significantly reduced by 48%, as compared to F tissue (2.99 ^ 0.37 mM). A statistically significant difference, evaluated by the paired
Fig. 1. Adenosine extracellular concentrations in tumour (T, white bar) and far from tumour (F, black bar) tissue of patients with high-grade malignancy gliomas. Each bar represents the mean ^ SEM of 21 determinations performed in 21 patients. Paired Student’s t-test: *P , 0:01.
Student’s t-test, was found in adenosine levels between T and F tissue (P , 0:01). In the present study, it is the first time adenosine concentrations in the extracellular fluid of human brain gliomas have been measured. Furthermore, we report that the mean adenosine concentration is significantly reduced in the tumour tissue of gliomas when compared to the outside tissue. Since adenosine levels are reduced in the tumour tissue, we could infer that adenosine levels are not primarily determined by areas of hypoxia, which frequently develop in solid tumours [21]. The reduced adenosine extracellular concentration found in our study in the tumour area could reflect reduced purine metabolism. It is noteworthy that in highly malignant tumours, which are proliferative and therefore need DNA precursors, the rate of purine metabolism is decreased. In agreement with our results, quantification of high-energy phosphate compounds in brain tumours [12] and the observation by Pillwein et al. [18] that the total adenylate pool is significantly reduced in human glioblastoma in comparison to normal human brain suggest that human gliomas have lower metabolic rates than normal brain tissue [2]. From a methodological point of view, we are aware that adenosine levels collected immediately after probe implantation are higher than in the following hours [17], however, the same artefact, which is invariable under surgical conditions, occurs equally inside and outside the tumour. The difference in levels is so large and with no overlapping that it demonstrates a difference in adenosine metabolism, notwithstanding the adenosine increase due to the trauma of probe implantation. Adenosine concentrations reached in the microdialysates of gliomas are in the same range as that reported by Blay et al. [3] in murine MCA-38 colon carcinoma and human adenocarcinomas grown in nu/nu mice. Since this concentration approximates the EC50 of adenosine for inhibition of activated T-killer cell adhesion to mouse carcinoma cell targets [3], it appears sufficient to suppress the local antitumour immune response.
A. Melani et al. / Neuroscience Letters 346 (2003) 93–96
95
Table 1 Clinical data of patients with high-grade malignancy gliomas Case
Age (years)/sex
Tumour location
Neurological symptoms
Histology
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
64/M 46/M 20/M 43/M 28/F 68/M 57/F 59/M 56/F 57/F 35/F 57/M 57/F 43/F 47/F 32/F 35/M 41/M 76/F 48/F 37/F
R. frontal R. temporal L. frontoparietal L. temporal L. frontal L. temporo-insular R. temporo-occipital L. temporo-occipital R. parieto-occipital R. frontal L. parieto-occipital L. temporal L. temporal L. occipital L. temporo-occipital R. frontal R. temporal L. frontal R. frontal L. frontal L. frontal
Epilepsy Hemiparesthesia Epilepsy/paresthesia Epilepsy/paresthesia Confusion Dizziness Dizziness Reduced concentration Visual field deficit Confusion Epilepsy Apathia Epilepsy Visual field deficit Reduced concentration Epilepsy Epilepsy Epilepsy Paraparesthesia Epilepsy Epilepsy
Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Anaplastic astrocytoma III Anaplastic astrocytoma III Anaplastic astrocytoma III Anaplastic oligodendroglioma III Anaplastic oligodendroglioma III Anaplastic oligodendroglioma III
The age, sex, tumour location, neurological symptoms and histopathological diagnosis of 21 patients are reported. R., right cortex; L., left cortex.
In conclusion, the present study demonstrates that in the extracellular fluid of human brain gliomas adenosine is present at a concentration which can stimulate all its receptor subtypes, and might be sufficient to suppress a local anti-tumour immune response and affect the proliferation of glial and endothelial cells.
[7]
[8]
Acknowledgements This investigation was supported by a grant from the University of Florence, MURST 2001 and Ente Cassa di Risparmio di Firenze (Italy).
[9]
[10]
[11]
References [1] M.P. Abbracchio, S. Ceruti, R. Brambilla, D. Barbieri, A. Camurri, C. Franceschi, A.M. Giammarioli, K.A. Jacobson, F. Cattabeni, W. Malorni, Adenosine A3 receptors and viability of astrocytes, Drug Dev. Res. 45 (1998) 379 –386. [2] V. Bardot, A.M. Dutrillaux, J.Y. Delattre, F. Vega, M. Poisson, B. Dutrillaux, C. Luccioni, Purine and pyrimidine metabolism in human gliomas: relation to chromosomal aberrations, Br. J. Cancer 70 (1994) 212–218. [3] J. Blay, T.D. White, D.W. Hoskin, The extracellular fluid of solid carcinomas contains immunosuppressive concentrations of adenosine, Cancer Res. 57 (1997) 2602–2605. [4] M.F. Ethier, V. Chander, J.G.J. Dobson, Adenosine stimulates proliferation of human endothelial cells in culture, Am. J. Physiol. 265 (1993) H131–H138. [5] B. Fiebich, K. Biber, K. Lieb, D. van Calker, M. Berger, J. Bauer, P.J. Gebicke-Haerter, Cyclooxygenase-2 expression in rat microglia is induced by adenosine A2A-receptors, Glia 18 (1996) 152 –160. [6] B.B. Fredholm, M.P. Abbracchio, G. Burnstock, J.W. Daly, T.K.
[12]
[13]
[14]
[15]
Harden, K.A. Jacobson, P. Leff, M. Williams, Nomenclature and classification of purinoceptors, Pharmacol. Rev. 46 (1994) 143–156. M.B. Grant, W. Tarnuzzer, S. Caballero, M.J. Ozeck, M.I. Davis, P.E. Spoerri, I. Feoktistov, I. Biaggioni, J.C. Shryock, L. Belardinelli, Adenosine receptor activation induces vascular endothelial growth factor in human retinal endothelial cells, Circ. Res. 85 (1999) 699–706. K.A. Jacobson, Adenosine A3 receptors: novel ligand and paradoxical effects, Trends Pharmacol. Sci. 19 (1998) 184 –191. H. Kizaki, K. Suzuki, T. Tadakuma, Y. Ishimura, Adenosine receptormediated accumulation of cyclic AMP-induced T-lymphocyte death through internucleosomal DNA cleavage, J. Biol. Chem. 265 (1990) 5280– 5284. P. Kleihues, P.C. Burger, B.W. Scheithauer, Histological Typing of Tumours of the Central Nervous System, Springer-Verlag, Berlin, 1993. M. Koshiba, D.L. Rosin, N. Hayashi, J. Linden, M.V. Sitkovsky, Patterns of A2A extracellular adenosine receptor expression in different functional subsets of human peripheral T cells. Flow cytometric studies with anti-A2A receptor monoclonal antibodies, Mol. Pharmacol. 55 (1999) 614–624. O.H. Lowry, S.J. Berger, M.M.Y. Chi, G. Carter, A. Blackshaw, W. Outlaw, Diversity of metabolic patterns in human brain tumours. I. High energy phosphate compounds and basic composition, J. Neurochem. 29 (1977) 959 –977. H.C. Ludwig, S. Rausch, K. Schallock, E. Markakis, Expression of CD73 (ecto-50 -nucleotidase) in 165 glioblastomas by immunohistochemistry and electromicroscopic histochemistry, Anticancer Res. 19 (1999) 1747– 1752. W.M. MacKenzie, D.W. Hoskin, J. Blay, Adenosine inhibits the adhesion of anti-CD3-activated killer lymphocytes to adenocarcinoma cells through an A3 receptor, Br. J. Cancer 54 (1994) 3521–3526. A. Melani, L. Pantoni, C. Corsi, L. Bianchi, A. Monopoli, R. Bertorelli, G. Pepeu, F. Pedata, Striatal outflow of adenosine, excitatory amino acids, gamma-aminobutyric acid, and taurine in awake freely moving rats after middle cerebral artery occlusion. Correlations with neurological deficit and histopathological damage, Stroke 30 (1999) 2448– 2455.
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[16] S. Merighi, P. Mirandola, D. Milani, K. Varani, S. Gessi, K.N. Klotz, E. Leung, P.G. Baraldi, P.A. Borea, Adenosine receptors as mediators of both cell proliferation and cell death of cultured human melanoma cells, J. Invest. Dermatol. 119 (2002) 923 –933. [17] M. Pazzagli, F. Pedata, G. Pepeu, Effect of Kþ depolarization, tetrodotoxin, and NMDA receptor inhibition on extracellular adenosine levels in rat striatum, Eur. J. Pharmacol. 234 (1993) 61– 65. [18] K. Pillwein, P. Chiba, A. Knoflach, B. Czermak, K. Schuchter, E. Gersdorf, B. Ausserer, C. Murr, R. Goebl, G. Stockhammer, H. Maier, H. Kostron, Purine metabolism of human glioblastoma in vivo, Cancer Res. 50 (1990) 1576–1579.
[19] F.G. Sajjadi, K. Takabayashim, A.C. Foster, R.C. Domingo, G.S. Firestein, Inhibition of TNF-a expression by adenosine. Role of A3 adenosine receptors, J. Immunol. 156 (1996) 3435–3442. [20] H. Takagi, G.L. King, N. Ferrara, L.P. Aiello, Hypoxia regulates vascular endothelial growth factor receptor KDR/Flk gene expression through adenosine A2 receptors in retinal capillary endothelial cells, Invest. Ophthalmol. Vis. Sci. 37 (1996) 1311– 1321. [21] P. Vaupel, F. Kallinowski, P. Okunieff, Blood flow, oxygen and nutrient supply, and metabolic microenvironment of human tumours: a review, Cancer Res. 49 (1989) 6449–6465.
Adenosine extracellular levels in human brain gliomas: an intraoperative microdialysis study Alessia Melania, Enrico De Michelib, Giampietro Pinnab, Alex Alfierib, Laura Della Cortea, Felicita Pedataa,* a
Department of Preclinical and Clinical Pharmacology, University of Florence, Viale Pieraccini 6, 50139 Florence, Italy b Department of Neurosurgery, Verona University Hospital, Piazzale Stefani 1, 37121 Verona, Italy Received 5 February 2003; received in revised form 8 May 2003; accepted 8 May 2003
Abstract Adenosine present in human brain glioma extracellular spaces is a marker of astrocyte purine metabolism. In this study, we evaluated adenosine levels in the extracellular fluid of 21 human gliomas of high-grade malignancy using brain microdialysis techniques coupled to high-performance liquid chromatography. The adenosine concentration (mean ^ SEM) within the control tissue was 2.99 ^ 0.37 mM and in the tumour tissue 1.56 ^ 0.46 mM. The reduction was statistically significant. It is concluded that the adenosine concentrations reached in the tumour tissue are sufficient to stimulate all adenosine receptor subtypes, suppress local anti-tumour immune responses and affect glial and endothelial cell proliferation. q 2003 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Adenosine; Glioma; Microdialysis; High-performance liquid chromatography; Brain tumour; Human
Adenosine present in the extracellular space of gliomas is a marker of astrocyte purine metabolism. Adenosine may exert a role in the development of cancer through several mechanisms mediated by its four receptor subtypes: the high affinity (low nM range) A1 and A2A receptors and the low affinity (mM range) A2b and A3 receptors [6]. Adenosine may suppress the anticancer immune response. It, in fact, inhibits adhesion of activated T-killer cells to mouse carcinoma cell targets [14] and the tumour necrosis factor (TNF) release [19], through A3 receptors located on lymphocytes and macrophages, respectively. A2A receptors are present on human T-lymphocytes and their expression increases in activated T-cells. A2A receptors may regulate T-lymphocyte cytokine production [11] and death [9]. Adenosine receptors were reported as mediators of both cell proliferation and cell death in human cancer cell lines [1, 16]. In particular, in human astrocytoma cells both a proliferative effect and apoptotic death have been described [1]. These effects may be mediated by A1, A2b [5] and A3 receptors [8] present on astrocytes. Furthermore, adenosine *
Corresponding author. Tel.: þ 39-055-4271262; fax: þ 39-0554271280. E-mail address: [email protected] (F. Pedata).
affects a number of steps involved in angiogenesis [4]. A proliferative action of retinal endothelial cells of bovine origin has been attributed to A2A adenosine receptors [20]. A2b receptors are expressed together with A2A receptors on human vascular endothelial cells and it was reported that A2b adenosine receptors mediate human retinal endothelial cell proliferation and vascular endothelial growth factor (VEGF) production [7]. The ectoenzyme 50 -nucleotidase, which converts nucleoside monophosphates (AMP, GMP, IMP) to adenosine, is densely distributed in the membranes of glioblastoma cells in vivo and in cell culture, and evidence exists that this enzyme is involved in the modulation of glioma cell proliferation [13]. The aim of this study was to measure, using microdialysis techniques, the extracellular concentrations of endogenous adenosine in human high-grade malignancy tumours, classified as grade III and IV gliomas. The study was performed at the Department of Neurosurgery, University of Verona, Italy. The study was approved by the Hospital Ethical Committee and complies with the European Community guiding policies and principles for experimental procedures. Informed consent was obtained for all
0304-3940/03/$ - see front matter q 2003 Elsevier Science Ireland Ltd. All rights reserved. doi:10.1016/S0304-3940(03)00596-2
94
A. Melani et al. / Neuroscience Letters 346 (2003) 93–96
patients. Twenty-one patients, nine males (mean age 48 ^ 5 years, ranging from 20 to 68 years) and 12 females (mean age 48 ^ 4 years, ranging from 28 to 76 years) due to undergo surgery for cortical glioma resection, and who had not previously undergone surgery, radiotherapy, chemotherapy, or cerebral biopsy, were included in this study. In all patients, diagnosis was confirmed by histopathology, according to the World Health Organization (WHO) classification [10]. During surgery for tumour resection, a flexible microdialysis catheter (CMA 70, CMA/Microdialysis, Solna, Sweden), with a 10 mm length of exposed membrane (cutoff 20 KD) and a 0.6 mm diameter, was inserted by freehand positioning to no more than 1 cm into the cortical area outside the proximity of the tumour, specifically at a 20 mm (far from tumour tissue) minimum distance from the edge of the tumour resection, utilizing pre-operative enhanced magnetic resonance imaging (MRI) and computed tomography (CT). After a 20 min equilibration period, one 20 min dialysis sample was collected, the probe was then moved to the cortical area of the tumour tissue and after a 20 min equilibration period, one 20 min sample was again collected. Dialysis catheters were perfused with artificial cerebral spinal fluid (CSF) containing 140 mM Naþ, 2.7 mM Kþ, 1.2 mM Ca2þ, 0.9 mM Mg2þ and 147 mM Cl2 at a constant flow rate of 2 ml/min, by means of a microperfusion pump (CMA 106, CMA/Microdialysis, Solna, Sweden). Samples were kept frozen at 2 80 8C until the assay. Adenosine content in the samples was analyzed using HPLC coupled to a spectrofluorimetric detector (LC-240, Perkin-Elmer, Norwalk, CT), according to the method described by Melani et al. [15]. In vitro experiments were carried out to evaluate the recovery of adenosine through the dialysis membrane. The dialysis probes were immersed in artificial CSF at 37 8C, containing known concentrations of adenosine. The probes were perfused at 2 ml/min and samples were collected every 20 min. The recovery rate calculated for six membranes was 43.4 ^ 5.1%. The adenosine concentration values reported in this paper were corrected for dialysis membrane recovery. Adenosine concentration data were analyzed using a paired Student’s t-test. Differences were considered statistically significant at P , 0:05. Table 1 summarizes the clinical features of the 21 patients with high-grade malignancy gliomas. Upon admission, all patients underwent barbiturate (100 mg per day) and dexamethasone (4 – 16 mg per day) therapy. In addition, all patients underwent pre-operative gadolinium-enhanced MRI and pre- and post-operative contrast-enhanced CT. The extracellular adenosine concentrations (mM) in the tumour (T) and far from the tumour (F) tissue of patients with cortical tumours of high-grade malignancy (n ¼ 21) are shown in Fig. 1. The mean adenosine concentration in T tissue (mean ^ SEM: 1.56 ^ 0.46 mM) was significantly reduced by 48%, as compared to F tissue (2.99 ^ 0.37 mM). A statistically significant difference, evaluated by the paired
Fig. 1. Adenosine extracellular concentrations in tumour (T, white bar) and far from tumour (F, black bar) tissue of patients with high-grade malignancy gliomas. Each bar represents the mean ^ SEM of 21 determinations performed in 21 patients. Paired Student’s t-test: *P , 0:01.
Student’s t-test, was found in adenosine levels between T and F tissue (P , 0:01). In the present study, it is the first time adenosine concentrations in the extracellular fluid of human brain gliomas have been measured. Furthermore, we report that the mean adenosine concentration is significantly reduced in the tumour tissue of gliomas when compared to the outside tissue. Since adenosine levels are reduced in the tumour tissue, we could infer that adenosine levels are not primarily determined by areas of hypoxia, which frequently develop in solid tumours [21]. The reduced adenosine extracellular concentration found in our study in the tumour area could reflect reduced purine metabolism. It is noteworthy that in highly malignant tumours, which are proliferative and therefore need DNA precursors, the rate of purine metabolism is decreased. In agreement with our results, quantification of high-energy phosphate compounds in brain tumours [12] and the observation by Pillwein et al. [18] that the total adenylate pool is significantly reduced in human glioblastoma in comparison to normal human brain suggest that human gliomas have lower metabolic rates than normal brain tissue [2]. From a methodological point of view, we are aware that adenosine levels collected immediately after probe implantation are higher than in the following hours [17], however, the same artefact, which is invariable under surgical conditions, occurs equally inside and outside the tumour. The difference in levels is so large and with no overlapping that it demonstrates a difference in adenosine metabolism, notwithstanding the adenosine increase due to the trauma of probe implantation. Adenosine concentrations reached in the microdialysates of gliomas are in the same range as that reported by Blay et al. [3] in murine MCA-38 colon carcinoma and human adenocarcinomas grown in nu/nu mice. Since this concentration approximates the EC50 of adenosine for inhibition of activated T-killer cell adhesion to mouse carcinoma cell targets [3], it appears sufficient to suppress the local antitumour immune response.
A. Melani et al. / Neuroscience Letters 346 (2003) 93–96
95
Table 1 Clinical data of patients with high-grade malignancy gliomas Case
Age (years)/sex
Tumour location
Neurological symptoms
Histology
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
64/M 46/M 20/M 43/M 28/F 68/M 57/F 59/M 56/F 57/F 35/F 57/M 57/F 43/F 47/F 32/F 35/M 41/M 76/F 48/F 37/F
R. frontal R. temporal L. frontoparietal L. temporal L. frontal L. temporo-insular R. temporo-occipital L. temporo-occipital R. parieto-occipital R. frontal L. parieto-occipital L. temporal L. temporal L. occipital L. temporo-occipital R. frontal R. temporal L. frontal R. frontal L. frontal L. frontal
Epilepsy Hemiparesthesia Epilepsy/paresthesia Epilepsy/paresthesia Confusion Dizziness Dizziness Reduced concentration Visual field deficit Confusion Epilepsy Apathia Epilepsy Visual field deficit Reduced concentration Epilepsy Epilepsy Epilepsy Paraparesthesia Epilepsy Epilepsy
Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Glioblastoma IV Anaplastic astrocytoma III Anaplastic astrocytoma III Anaplastic astrocytoma III Anaplastic oligodendroglioma III Anaplastic oligodendroglioma III Anaplastic oligodendroglioma III
The age, sex, tumour location, neurological symptoms and histopathological diagnosis of 21 patients are reported. R., right cortex; L., left cortex.
In conclusion, the present study demonstrates that in the extracellular fluid of human brain gliomas adenosine is present at a concentration which can stimulate all its receptor subtypes, and might be sufficient to suppress a local anti-tumour immune response and affect the proliferation of glial and endothelial cells.
[7]
[8]
Acknowledgements This investigation was supported by a grant from the University of Florence, MURST 2001 and Ente Cassa di Risparmio di Firenze (Italy).
[9]
[10]
[11]
References [1] M.P. Abbracchio, S. Ceruti, R. Brambilla, D. Barbieri, A. Camurri, C. Franceschi, A.M. Giammarioli, K.A. Jacobson, F. Cattabeni, W. Malorni, Adenosine A3 receptors and viability of astrocytes, Drug Dev. Res. 45 (1998) 379 –386. [2] V. Bardot, A.M. Dutrillaux, J.Y. Delattre, F. Vega, M. Poisson, B. Dutrillaux, C. Luccioni, Purine and pyrimidine metabolism in human gliomas: relation to chromosomal aberrations, Br. J. Cancer 70 (1994) 212–218. [3] J. Blay, T.D. White, D.W. Hoskin, The extracellular fluid of solid carcinomas contains immunosuppressive concentrations of adenosine, Cancer Res. 57 (1997) 2602–2605. [4] M.F. Ethier, V. Chander, J.G.J. Dobson, Adenosine stimulates proliferation of human endothelial cells in culture, Am. J. Physiol. 265 (1993) H131–H138. [5] B. Fiebich, K. Biber, K. Lieb, D. van Calker, M. Berger, J. Bauer, P.J. Gebicke-Haerter, Cyclooxygenase-2 expression in rat microglia is induced by adenosine A2A-receptors, Glia 18 (1996) 152 –160. [6] B.B. Fredholm, M.P. Abbracchio, G. Burnstock, J.W. Daly, T.K.
[12]
[13]
[14]
[15]
Harden, K.A. Jacobson, P. Leff, M. Williams, Nomenclature and classification of purinoceptors, Pharmacol. Rev. 46 (1994) 143–156. M.B. Grant, W. Tarnuzzer, S. Caballero, M.J. Ozeck, M.I. Davis, P.E. Spoerri, I. Feoktistov, I. Biaggioni, J.C. Shryock, L. Belardinelli, Adenosine receptor activation induces vascular endothelial growth factor in human retinal endothelial cells, Circ. Res. 85 (1999) 699–706. K.A. Jacobson, Adenosine A3 receptors: novel ligand and paradoxical effects, Trends Pharmacol. Sci. 19 (1998) 184 –191. H. Kizaki, K. Suzuki, T. Tadakuma, Y. Ishimura, Adenosine receptormediated accumulation of cyclic AMP-induced T-lymphocyte death through internucleosomal DNA cleavage, J. Biol. Chem. 265 (1990) 5280– 5284. P. Kleihues, P.C. Burger, B.W. Scheithauer, Histological Typing of Tumours of the Central Nervous System, Springer-Verlag, Berlin, 1993. M. Koshiba, D.L. Rosin, N. Hayashi, J. Linden, M.V. Sitkovsky, Patterns of A2A extracellular adenosine receptor expression in different functional subsets of human peripheral T cells. Flow cytometric studies with anti-A2A receptor monoclonal antibodies, Mol. Pharmacol. 55 (1999) 614–624. O.H. Lowry, S.J. Berger, M.M.Y. Chi, G. Carter, A. Blackshaw, W. Outlaw, Diversity of metabolic patterns in human brain tumours. I. High energy phosphate compounds and basic composition, J. Neurochem. 29 (1977) 959 –977. H.C. Ludwig, S. Rausch, K. Schallock, E. Markakis, Expression of CD73 (ecto-50 -nucleotidase) in 165 glioblastomas by immunohistochemistry and electromicroscopic histochemistry, Anticancer Res. 19 (1999) 1747– 1752. W.M. MacKenzie, D.W. Hoskin, J. Blay, Adenosine inhibits the adhesion of anti-CD3-activated killer lymphocytes to adenocarcinoma cells through an A3 receptor, Br. J. Cancer 54 (1994) 3521–3526. A. Melani, L. Pantoni, C. Corsi, L. Bianchi, A. Monopoli, R. Bertorelli, G. Pepeu, F. Pedata, Striatal outflow of adenosine, excitatory amino acids, gamma-aminobutyric acid, and taurine in awake freely moving rats after middle cerebral artery occlusion. Correlations with neurological deficit and histopathological damage, Stroke 30 (1999) 2448– 2455.
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