References 1 Hollmann, M, Heinemann, S. Cloned glutamate receptors. Annu Rev Neurosci 1994, 17:31–108. 2 Skerry, TM, Genever, PG. Glutamate signalling in non‐neuronal tissues. Trends Pharmacol Sci 2001, 22:174–181. 3 Frati, C, Marchese, C, Fisichella, G, Copani, A, Nasca, MR, Storto, M, Nicoletti, F. Expression of functional mGlu5 metabotropic glutamate receptors in human melanocytes. J Cell Physiol 2000, 183:364–372. 4 Genever, PG, Maxfield, SJ, Kennovin, GD, Maltman, J, Bowgen, CJ, Raxworthy, MJ, Skerry, TM. Evidence for a novel glutamate‐mediated signaling pathway in keratinocytes. J Invest Dermatol 1999, 112:337–342. 5 Gill, SS, Pulido, OM, Mueller, RW, McGuire, PF. Immunochemical localization of the metabotropic glutamate receptors in the rat heart. Brain Res Bull 1999, 48:143–146. 6 Melchiorri, D, Cappuccio, I, Ciceroni, C, Spinsanti P, Mosillo P, Sarichelou I, Sale P, Nicoletti F. Metabotropic glutamate receptors in stem/progenitor cells. Neuropharmacology 2007, 53:473–480. 7 Morimoto, R, Uehara, S, Yatsushiro, S, Juge, N, Hua, Z, Senoh, S, Echigo, N, Hayashi, M, Mizoguchi, T, Ninomiya, T, et al. Secretion of L‐glutamate from osteoclasts through transcytosis. EMBO J 2006, 20:4175–4186. 8 Storto, M, Capobianco, L, Battaglia, G, Molinaro, G, Gradini, R, Riozzi, B, Di Mambro, A, Mitchell, KJ, Bruno, V, Vairetti, MP, et al. Insulin secretion is controlled by mGlu5 metabotropic glutamate receptors. Mol Pharmacol 2006, 69:1234–1241. 9 Storto, M, de Grazia, U, Knopfel, T, Canonico, PL, Copani, A, Richelmi, P, Nicoletti, F, Vairetti, M. Selective blockade of mGlu5 metabotropic glutamate receptors protects rat hepatocytes against hypoxic damage. Hepatology 2000, 31:649–655. 10 Hollmann, M, O`Shea‐Greenfield, A, Rogers, SW, Heinemann, S. Cloning by functional expression of a member of the glutamate receptor family. Nature 1989, 342:643–648. 11 Traynelis, SF, Wollmuth, LP, McBain, CJ, Menniti, FS, Vance, KM, Ogden, KK, Hansen, KB, Yuan, H, Myers, SJ, Dingledine, R. Glutamate receptor ion channels: structure, regulation, and function. Pharmacol Rev 2010, 62:405–496. 12 Hermans, E, Challiss, RA. Structural, signalling and regulatory properties of the group I metabotropic glutamate receptors: prototypic family C G‐protein‐coupled receptors. Biochem J 2001, 1(Pt 3 ):465–484. 13 Marinissen, MJ, Gutkind, JS. G‐protein‐coupled receptors and signaling networks: emerging paradigms. Trends Pharmacol Sci 2001, 22:368–376. 14 Dorsam, RT, Gutkind, JS. G‐protein‐coupled receptors and cancer. Nat Rev Cancer 2007, 7:79–94. 15 Sladeczek, F, Pin, JP, Recasens, M, Bockaert, J, Weiss, S. Glutamate stimulates inositol phosphate formation in striatal neurones. Nature 1985, 317:24–30. 16 Masu, M, Tanabe, Y, Tsuchida, K, Shigemoto, R, Nakanishi, S. Sequence and expression of a metabotropic glutamate receptor. Nature 1991, 28:760–765. 17 Niswender, CM, Conn, PJ. Metabotropic glutamate receptors: physiology, pharmacology, and disease. Annu Rev Pharmacol Toxicol 2010, 50:295–322. 18 Aiba, A, Kano, M, Chen, C, Stanton, ME, Fox, GD, Herrup, K, Zwingman, TA, Tonegawa, S. Deficient cerebellar long‐term depression and impaired motor learning in mGluR1 mutant mice. Cell 1994, 21:377–388. 19 Levenes, C, Daniel, H, Jaillard, D, Conquet, F, Crepel, F. Incomplete regression of multiple climbing fibre innervation of cerebellar Purkinje cells in mGLuR1 mutant mice. Neuroreport 1997, 8:571–574. 20 Higgins, GA, Ballard, TM, Kew, JN, Richards, JG, Kemp, JA, Adam, G, Woltering, T, Nakanishi, S, Mutel, V. Pharmacological manipulation of mGlu2 receptors influences cognitive performance in the rodent. Neuropharmacology 2004, 46:907–917. 21 Corti, C, Battaglia, G, Molinaro, G, Riozzi, B, Pittaluga, A, Corsi, M, Mugnaini, M, Nicoletti, F, Bruno, V. The use of knock‐out mice unravels distinct roles for mGlu2 and mGlu3 metabotropic glutamate receptors in mechanisms of neurodegeneration/neuroprotection. J Neurosci 2007, 1:8297–8308. 22 Yoneda, Y, Ogita, K. [3H]glutamate binding sites in the rat pituitary. Neurosci Res 1986, 3:430–435. 23 Yoneda, Y, Ogita, K. Localization of [3H]glutamate binding sites in rat adrenal medulla. Brain Res 1986, 24:387–391. 24 Gu, Y, Publicover, SJ. Expression of functional metabotropic glutamate receptors in primary cultured rat osteoblasts. Cross‐talk with N‐methyl‐D‐aspartate receptors. J Biol Chem 2000, 3:34252–34259. 25 Stepulak, A, Luksch, H, Gebhardt, C, Uckermann, O, Marzahn, J, Sifringer, M, Rzeski, W, Staufner, C, Brocke, KS, Turski, L, et al. Expression of glutamate receptor subunits in human cancers. Histochem Cell Biol 2009, 132:435–445. 26 Brocke, KS, Staufner, C, Luksch, H, Geiger, KD, Stepulak, A, Marzahn, J, Schacker, G, Temme, A, Ikonomidou, C. Glutamate receptors in pediatric tumors of the central nervous system. Cancer Biol Ther 2010, 9:455–468. 27 Seidlitz, EP, Sharma, MK, Saikali, Z, Ghert, M, Singh, G. Cancer cell lines release glutamate into the extracellular environment. Clin Exp Metastasis 2009, 26:781–787. 28 Sharma, MK, Seidlitz, EP, Singh, G. Cancer cells release glutamate via the cystine/glutamate antiporter. Biochem Biophys Res Commun 2010, 391:91–95. 29 Seidlitz, EP, Sharma, MK, Singh, G. Extracellular glutamate alters mature osteoclast and osteoblast functions. Can J Physiol Pharmacol 2010, 88:929–936. 30 Pollock, PM, Cohen‐Solal, K, Sood, R, Namkoong, J, Martino, JJ, Koganti, A, Zhu, H, Robbins, C, Makalowska, I, Shin, SS, et al. Melanoma mouse model implicates metabotropic glutamate signaling in melanocytic neoplasia. Nat Genet 2003, 34:108–112. 31 Speyer, CL, Smith, JS, Banda, M, Devries, JA, Mekani, T, Gorski, DH. Metabotropic glutamate receptor‐1: a potential therapeutic target for the treatment of breast cancer. Breast Cancer Res Treat 2011. 32 Park, SY, Lee, SA, Han, IH, et al. Clinical significance of metabotropic glutamate receptor 5 expression in oral squamous cell carcinoma. Oncol Rep 2007, 17:81–87. 33 Kalariti, N, Lembessis, P, Papageorgiou, E, Pissimissis, N, Koutsilieris, M. Regulation of the mGluR5, EAAT1 and GS expression by glucocorticoids in MG‐63 osteoblast‐like osteosarcoma cells. J Musculoskelet Neuronal Interact 2007, 7:113–118. 34 Pissimissis, N, Papageorgiou, E, Lembessis, P, Armakolas, A, Koutsilieris, M. The glutamatergic system expression in human PC‐3 and LNCaP prostate cancer cells. Anticancer Res 2009, 29:371–377. 35 Aleman, MMA, Harsch, KM, Detore, N, Klein, E, Heston, WDW. Expression of metabotropic glutamate receptors in human prostate cancers and its potential signaling through prostate specific membrane antigen. Proc Am Assoc Cancer Res 2004, 45:1196. 36 D`Onofrio, M, Arcella, A, Bruno, V, Ngomba, RT, Battaglia, G, Lombari, V, Ragona, G, Calogero, A, Nicoletti, F. Pharmacological blockade of mGlu2/3 metabotropic glutamate receptors reduces cell proliferation in cultured human glioma cells. J Neurochem 2003, 84:1288–1295. 37 Arcella, A, Carpinelli, G, Battaglia, G, D`Onofrio, M, Santoro, F, Ngomba, RT, Bruno, V, Casolini, P, Giangaspero, F, Nicoletti, F. Pharmacological blockade of group II metabotropic glutamate receptors reduces the growth of glioma cells in vivo . Neuro Oncol 2005, 7:236–245. 38 Ciceroni, C, Arcella, A, Mosillo, P, Battaglia, G, Mastrantoni, E, Oliva, MA, Carpinelli, G, Santoro, F, Sale, P, Ricci‐Vitiani, L, et al. Type‐3 metabotropic glutamate receptors negatively modulate bone morphogenetic protein receptor signaling and support the tumourigenic potential of glioma‐initiating cells. Neuropharmacology 2008, 55:568–576. 39 Chang, HJ, Yoo, BC, Lim, SB, Jeong, SY, Kim, WH, Park, JG. Metabotropic glutamate receptor 4 expression in colorectal carcinoma and its prognostic significance. Clin Cancer Res 2005, 1:3288–3295. 40 Iacovelli, L, Arcella, A, Battaglia, G, Pazzaglia, S, Aronica, E, Spinsanti, P, Caruso, A, De Smaele, E, Saran, A, Gulino, A, et al. Pharmacological activation of mGlu4 metabotropic glutamate receptors inhibits the growth of medulloblastomas. J Neurosci 2006, 9:8388–8397. 41 Chen, S, Teicher, LC, Kazim, D, Pollack, RE, Wise, LS. Commitment of mouse fibroblasts to adipocyte differentiation by DNA transfection. Science 1989, 5:582–585. 42 Chen, S, Zhu, H, Wetzel, WJ, Philbert, MA. Spontaneous melanocytosis in transgenic mice. J Invest Dermatol 1996, 106:1145–1151. 43 Zhu, H, Reuhl, K, Zhang, X, Botha, R, Ryan, K, Wei, J, Chen, S. Development of heritable melanoma in transgenic mice. J Invest Dermatol 1998, 110:247–252. 44 Marin, YE, Namkoong, J, Shin, SS, Raines, J, Degenhardt, K, White, E, Chen, S. Grm5 expression is not required for the oncogenic role of Grm1 in melanocytes. Neuropharmacology 2005, 49(suppl 1 ):70–79. 45 Ohtani, Y, Harada, T, Funasaka, Y, Nakao, K, Takahara, C, Abdel‐Daim, M, Saka, N, Saito, N, Nishigori, C, Aiba, A. Metabotropic glutamate receptor subtype‐1 is essential for in vivo growth of melanoma. Oncogene 2008, 27:7162–7170. 46 Julius, D, Livelli, TJ, Jessell, TM, Axel, R. Ectopic expression of the serotonin 1c receptor and the triggering of malignant transformation. Science 1989, 244:1057–1062. 47 Gutkind, JS. Cell growth control by G protein‐coupled receptors: from signal transduction to signal integration. Oncogene 1998, 17:1331–1342. 48 Allen, LF, Lefkowitz, RJ, Caron, MG, Cotecchia, S. G‐protein‐coupled receptor genes as protooncogenes: constitutively activating mutation of the α 1B‐adrenergic receptor enhances mitogenesis and tumorigenicity. Proc Natl Acad Sci U S A 1991, 88:11354–11358. 49 Bais, C, Santomasso, B, Coso, O, Arvanitakis, L, Raaka, EG, Gutkind, JS, Asch, S, Cesarman, E, Gershengorn, MC, Mesri, EA. G‐protein‐coupled receptor of Kaposi`s sarcoma‐associated herpesvirus is a viral oncogene and angiogenesis activator. Nature 1998, 391:86–89. 50 Dhanasekaran, N, Tsim, ST, Dermott, JM, Onesime, D. Regulation of cell proliferation by G proteins. Oncogene 1998, 17:1383–1394. 51 Hermouet, S, Aznavoorian, S, Spiegel, AM. In vitro and in vivo growth inhibition of murine melanoma K‐1735 cell by a dominant negative mutant α subunit of the Gi2 protein. Cell Signal 1996, 8:159–166. 52 Montaner, S, Sodhi, A, Molinolo, A, Bugge, TH, Sawai, ET, He, Y, Li, Y, Ray, PE, Gutkind, JS. Endothelial infection with KSHV genes in vivo reveals that vGPCR initiates Kaposi`s sarcomagenesis and can promote the tumorigenic potential of viral latent genes. Cancer Cell 2003, 3:23–36. 53 Namkoong, J, Shin, SS, Lee, HJ, Marin, YE, Wall, BA, Goydos, JS, Chen, S. Metabotropic glutamate receptor 1 and glutamate signaling in human melanoma. Cancer Res 2007, 67:2298–2305. 54 Funasaka, YHT, Aiba, A, Nishigori, C. Expression of metabotropic glutamate receptor 1 and phosphorylated extracellular signal‐regulated kinase 1/2 proteins in human melanocytic lesions. Pigment Cell Melanoma Res 2006, 19:656. 55 Shin, SS, Namkoong, J, Wall, BA, Gleason, R, Lee, HJ, Chen, S. Oncogenic activities of metabotropic glutamate receptor 1 (Grm1) in melanocyte transformation. Pigment Cell Melanoma Res 2008, 21:368–378. 56 Shin, SS, Wall, BA, Goydos, JS, Chen, S. AKT2 is a downstream target of metabotropic glutamate receptor 1 (Grm1). Pigment Cell Melanoma Res 2010, 23:103–111. 57 Stahl, JM, Sharma, A, Cheung, M, Zimmerman, M, Cheng, JQ, Bosenberg, MW, Kester, M, Sandirasegarane, L, Robertson, GP. Deregulated Akt3 activity promotes development of malignant melanoma. Cancer Res 2004, 1:7002–7010. 58 Nogueira, C, Kim, KH, Sung, H, Paraiso, KH, Dannenberg, JH, Bosenberg, M, Chin, L, Kim, M. Cooperative interactions of PTEN deficiency and RAS activation in melanoma metastasis. Oncogene 2010, 25:6222–6232. 59 Cheah, BC, Vucic, S, Krishnan, AV, Kiernan, MC. Riluzole, neuroprotection and amyotrophic lateral sclerosis. Curr Med Chem 2010, 17:1942–1199. 60 Yip, D, Le, MN, Chan, JL, Lee, JH, Mehnert, JA, Yudd, A, Kempf, J, Shih, WJ, Chen, S, Goydos, JS. A phase 0 trial of riluzole in patients with resectable stage III and IV melanoma. Clin Cancer Res 2009, 15:3896–3902. 61 Biechele, TL, Camp, ND, Fass, DM, Kulikauskas, RM, Robin, NC, White, BD, Taraska, CM, Moore, EC, Muster, J, Karmacharya, R, et al. Chemical‐genetic screen identifies riluzole as an enhancer of Wnt/β ‐catenin signaling in melanoma. Chem Biol 2010, 24:1177–1182. 62 Chien, AJ, Moore, EC, Lonsdorf, AS, Kulikauskas, RM, Rothberg, BG, Berger, AJ, Major, MB, Hwang, ST, Rimm, DL, Moon, RT. Activated Wnt/β ‐catenin signaling in melanoma is associated with decreased proliferation in patient tumors and a murine melanoma model. Proc Natl Acad Sci U S A 2009, 106:1193–1198. 63 Degenhardt, K, White, E. A mouse model system to genetically dissect the molecular mechanisms regulating tumorigenesis. Clin Cancer Res 2006, 15:5298–5304. 64 Louis, DN, Ohgaki, H, Wiestler, OD, Cavenee, WK, Burger, PC, Jouvet, A, Scheithauer, BW, Kleihues, P. The 2007 WHO classification of tumours of the central nervous system. Acta Neuropathol 2007, 114:97–109. 65 Ye, ZC, Sontheimer, H. Glioma cells release excitotoxic concentrations of glutamate. Cancer Res 1999, 1:4383–4391. 66 Denysenko, T, Gennero, L, Roos, MA, Melcarne, A, Juenemann, C, Faccani, G, Morra, I, Cavallo, G, Reguzzi, S, Pescarmona, G, et al. Glioblastoma cancer stem cells: heterogeneity, microenvironment and related therapeutic strategies. Cell Biochem Funct 2010, 28:343–351. 67 Gomes, WA, Mehler, MF, Kessler, JA. Transgenic overexpression of BMP4 increases astroglial and decreases oligodendroglial lineage commitment. Dev Biol 2003, 255:164–177. 68 Huse, JT, Holland, EC. Targeting brain cancer: advances in the molecular pathology of malignant glioma and medulloblastoma. Nat Rev Cancer 2010, 10:319–331. 69 Canudas, AM, Di Giorgi‐Gerevini, V, Iacovelli, L, Nano, G, D`Onofrio, M, Arcella, A, Giangaspero, F, Busceti, C, Ricci‐Vitiani, L, Battaglia, G, et al. PHCCC, a specific enhancer of type 4 metabotropic glutamate receptors, reduces proliferation and promotes differentiation of cerebellar granule cell neuroprecursors. J Neurosci 2004, 17:10343–10352. 70 Ye, P, Xing, Y, Dai, Z, D`Ercole, AJ. In vivo actions of insulin‐like growth factor‐I (IGF‐I) on cerebellum development in transgenic mice: evidence that IGF‐I increases proliferation of granule cell progenitors. Brain Res Dev Brain Res 1996, 20:44–54. 71 Dahmane, N, Ruiz i Altaba, A. Sonic hedgehog regulates the growth and patterning of the cerebellum. Development 1999, 126:3089–3100. 72 Yokota, N, Nishizawa, S, Ohta, S, Date, H, Sugimura, H, Namba, H, Maekawa, M. Role of Wnt pathway in medulloblastoma oncogenesis. Int J Cancer 2002, 10:198–201. 73 Gilbertson, RJ. Medulloblastoma: signalling a change in treatment. Lancet Oncol 2004, 5:209–218. 74 Pazzaglia, S, Mancuso, M, Atkinson, MJ, Tanori, M, Rebessi, S, Majo, VD, Covelli, V, Hahn, H, Saran, A. High incidence of medulloblastoma following X‐ray‐irradiation of newborn Ptc1 heterozygous mice. Oncogene 2002, 24:7580–7584. 75 Hopkins, CR, Lindsley, CW, Niswender, CM. mGluR4‐positive allosteric modulation as potential treatment for Parkinson`s disease. Future Med Chem 2009, 1:501–513. 76 Yoo, BC, Jeon, E, Hong, SH, Shin, YK, Chang, HJ, Park, JG. Metabotropic glutamate receptor 4‐mediated 5‐fluorouracil resistance in a human colon cancer cell line. Clin Cancer Res 2004, 10(12 Pt 1 ):4176–4184. 77 Shin, SS, Martino, JJ, Chen, S. Metabotropic glutamate receptors (mGlus) and cellular transformation. Neuropharmacology 2008, 55:396–402. 78 Cappuccio, I, Spinsanti, P, Porcellini, A, Desiderati, F, De Vita, T, Storto, M, Capobianco, L, Battaglia, G, Nicoletti, F, Melchiorri, D. Endogenous activation of mGlu5 metabotropic glutamate receptors supports self‐renewal of cultured mouse embryonic stem cells. Neuropharmacology 2005, 49(suppl 1 ):196–205. 79 Spinsanti, P, De Vita, T, Di Castro, S, Storto, M, Formisano, P, Nicoletti, F, Melchiorri, D. Endogenously activated mGlu5 metabotropic glutamate receptors sustain the increase in c‐Myc expression induced by leukaemia inhibitory factor in cultured mouse embryonic stem cells. J Neurochem 2006, 99:299–307. 80 Kalariti, N, Lembessis, P, Koutsilieris, M. Characterization of the glutametergic system in MG‐63 osteoblast‐like osteosarcoma cells. Anticancer Res 2004, 24:3923–3929. 81 Taylor, AF. Osteoblastic glutamate receptor function regulates bone formation and resorption. J Musculoskelet Neuronal Interact 2002, 2:285–290. 82 Wei, X, Walia, V, Lin, JC, Teer, JK, Prickett, TD, Gartner, J, Davis, S, Stemke‐Hale, K, Davies, MA, Gershenwald, JE, et al. Exome sequencing identifies GRIN2A as frequently mutated in melanoma. Nat Genet 2011, 43:442–446.