Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Glutamate release by primary brain tumors induces epileptic activity


Epileptic seizures are a common and poorly understood comorbidity for individuals with primary brain tumors. To investigate peritumoral seizure etiology, we implanted human-derived glioma cells into severe combined immunodeficient mice. Within 14–18 d, glioma-bearing mice developed spontaneous and recurring abnormal electroencephalogram events consistent with progressive epileptic activity. Acute brain slices from these mice showed marked glutamate release from the tumor mediated by the system xc cystine-glutamate transporter (encoded by Slc7a11). Biophysical and optical recordings showed glutamatergic epileptiform hyperexcitability that spread into adjacent brain tissue. We inhibited glutamate release from the tumor and the ensuing hyperexcitability by sulfasalazine (SAS), a US Food and Drug Administration–approved drug that blocks system xc. We found that acute administration of SAS at concentrations equivalent to those used to treat Crohn's disease in humans reduced epileptic event frequency in tumor-bearing mice compared with untreated controls. SAS should be considered as an adjuvant treatment to ameliorate peritumoral seizures associated with glioma in humans.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Tumor-bearing mice show abnormal spontaneous EEG events indicative of epileptic activity.
Figure 2: Acute cortical slices from tumor-bearing mice show spontaneous epileptiform activity.
Figure 3: Acute cortical slices from tumor-bearing mice are hyperexcitable.
Figure 4: Cortical slices from glioma-bearing mice show increased cortical network activity and hyperexcitable layer 2 and 3 peritumoral pyramidal cells.
Figure 5: SAS application reduces epileptiform activity in cortical slices from glioma-bearing mice.
Figure 6: Sulfasalazine reduces frequency of epileptic activity in tumor-bearing mice.


  1. Moots, P.L. et al. The course of seizure disorders in patients with malignant gliomas. Arch. Neurol. 52, 717–724 (1995).

    Article  CAS  Google Scholar 

  2. van Breemen, M.S. et al. Efficacy of anti-epileptic drugs in patients with gliomas and seizures. J. Neurol. 256, 1519–1526 (2009).

    Article  Google Scholar 

  3. Hauser, W.A., Annegers, J.F. & Kurland, L.T. Incidence of epilepsy and unprovoked seizures in Rochester, Minnesota: 1935–1984. Epilepsia 34, 453–468 (1993).

    Article  CAS  Google Scholar 

  4. During, M.J. & Spencer, D.D. Extracellular hippocampal glutamate and spontaneous seizure in the conscious human brain. Lancet 341, 1607–1610 (1993).

    Article  CAS  Google Scholar 

  5. Patt, S. et al. Source localization and possible causes of interictal epileptic activity in tumor-associated epilepsy. Neurobiol. Dis. 7, 260–269 (2000).

    Article  CAS  Google Scholar 

  6. Senner, V. et al. A new neurophysiological/neuropathological ex vivo model localizes the origin of glioma-associated epileptogenesis in the invasion area. Acta Neuropathol. 107, 1–7 (2004).

    Article  Google Scholar 

  7. Köhling, R., Senner, V., Paulus, W. & Speckmann, E.J. Epileptiform activity preferentially arises outside tumor invasion zone in glioma xenotransplants. Neurobiol. Dis. 22, 64–75 (2006).

    Article  Google Scholar 

  8. Marcus, H.J., Carpenter, K.L., Price, S.J. & Hutchinson, P.J. In vivo assessment of high-grade glioma biochemistry using microdialysis: a study of energy-related molecules, growth factors and cytokines. J. Neurooncol. 97, 11–23 (2010).

    Article  CAS  Google Scholar 

  9. Ye, Z.C. & Sontheimer, H. Glioma cells release excitotoxic concentrations of glutamate. Cancer Res. 59, 4383–4391 (1999).

    CAS  Google Scholar 

  10. Ye, Z.C., Rothstein, J.D. & Sontheimer, H. Compromised glutamate transport in human glioma cells: reduction- mislocalization of sodium-dependent glutamate transporters and enhanced activity of cystine-glutamate exchange. J. Neurosci. 19, 10767–10777 (1999).

    Article  CAS  Google Scholar 

  11. Lyons, S.A., Chung, W.J., Weaver, A.K., Ogunrinu, T. & Sontheimer, H. Autocrine glutamate signaling promotes glioma cell invasion. Cancer Res. 67, 9463–9471 (2007).

    Article  CAS  Google Scholar 

  12. Kim, J.Y. et al. Human cystine/glutamate transporter: cDNA cloning and upregulation by oxidative stress in glioma cells. Biochim. Biophys. Acta 1512, 335–344 (2001).

    Article  CAS  Google Scholar 

  13. Chung, W.J. et al. Inhibition of cystine uptake disrupts the growth of primary brain tumors. J. Neurosci. 25, 7101–7110 (2005).

    Article  CAS  Google Scholar 

  14. Sato, H., Tamba, M., Ishii, T. & Bannai, S. Cloning and expression of a plasma membrane cystine/glutamate exchange transporter composed of two distinct proteins. J. Biol. Chem. 274, 11455–11458 (1999).

    Article  CAS  Google Scholar 

  15. de Vries, N.A., Beijnen, J.H. & van Tellingen, O. High-grade glioma mouse models and their applicability for preclinical testing. Cancer Treat. Rev. 35, 714–723 (2009).

    Article  CAS  Google Scholar 

  16. Fomchenko, E.I. & Holland, E.C. Mouse models of brain tumors and their applications in preclinical trials. Clin. Cancer Res. 12, 5288–5297 (2006).

    Article  CAS  Google Scholar 

  17. Giannini, C. et al. Patient tumor EGFR and PDGFRA gene amplifications retained in an invasive intracranial xenograft model of glioblastoma multiforme. Neuro-oncol. 7, 164–176 (2005).

    Article  CAS  Google Scholar 

  18. Sarkaria, J.N. et al. Identification of molecular characteristics correlated with glioblastoma sensitivity to EGFR kinase inhibition through use of an intracranial xenograft test panel. Mol. Cancer Ther. 6, 1167–1174 (2007).

    Article  CAS  Google Scholar 

  19. D'Ambrosio, R. et al. Functional definition of seizure provides new insight into post-traumatic epileptogenesis. Brain 132, 2805–2821 (2009).

    Article  Google Scholar 

  20. Mody, I., Lambert, J.D. & Heinemann, U. Low extracellular magnesium induces epileptiform activity and spreading depression in rat hippocampal slices. J. Neurophysiol. 57, 869–888 (1987).

    Article  CAS  Google Scholar 

  21. Jones, R.S. Ictal epileptiform events induced by removal of extracellular magnesium in slices of entorhinal cortex are blocked by baclofen. Exp. Neurol. 104, 155–161 (1989).

    Article  CAS  Google Scholar 

  22. DeFazio, R.A. & Hablitz, J.J. Horizontal spread of activity in neocortical inhibitory networks. Brain Res. Dev. Brain Res. 157, 83–92 (2005).

    Article  CAS  Google Scholar 

  23. Gutnick, M.J., Connors, B.W. & Prince, D.A. Mechanisms of neocortical epileptogenesis in vitro. J. Neurophysiol. 48, 1321–1335 (1982).

    Article  CAS  Google Scholar 

  24. Zheng, W., Winter, S.M., Mayersohn, M., Bishop, J.B. & Sipes, I.G. Toxicokinetics of sulfasalazine (salicylazosulfapyridine) and its metabolites in B6C3F1 mice. Drug Metab. Dispos. 21, 1091–1097 (1993).

    CAS  Google Scholar 

  25. Herman, M.A. & Jahr, C.E. Extracellular glutamate concentration in hippocampal slice. J. Neurosci. 27, 9736–9741 (2007).

    Article  CAS  Google Scholar 

  26. Danbolt, N.C. Glutamate uptake. Prog. Neurobiol. 65, 1–105 (2001).

    Article  CAS  Google Scholar 

  27. Rothstein, J.D. et al. Knockout of glutamate transporters reveals a major role for astroglial transport in excitotoxicity and clearance of glutamate. Neuron 16, 675–686 (1996).

    Article  CAS  Google Scholar 

  28. Meldrum, B.S. The role of glutamate in epilepsy and other CNS disorders. Neurology 44, S14–S23 (1994).

    CAS  Google Scholar 

  29. Tanaka, K. et al. Epilepsy and exacerbation of brain injury in mice lacking the glutamate transporter glt-1. Science 276, 1699–1702 (1997).

    Article  CAS  Google Scholar 

  30. Behrens, P.F., Langemann, H., Strohschein, R., Draeger, J. & Hennig, J. Extracellular glutamate and other metabolites in and around RG2 rat glioma: an intracerebral microdialysis study. J. Neurooncol. 47, 11–22 (2000).

    Article  CAS  Google Scholar 

  31. Takano, T. et al. Glutamate release promotes growth of malignant gliomas. Nat. Med. 7, 1010–1015 (2001).

    Article  CAS  Google Scholar 

  32. Savaskan, N.E. et al. Small interfering RNA-mediated xCT silencing in gliomas inhibits neurodegeneration and alleviates brain edema. Nat. Med. 14, 629–632 (2008).

    Article  CAS  Google Scholar 

  33. Engelhorn, T. et al. Cellular characterization of the peritumoral edema zone in malignant brain tumors. Cancer Sci. 100, 1856–1862 (2009).

    Article  CAS  Google Scholar 

  34. Robe, P.A. et al. Early termination of ISRCTN45828668, a phase 1/2 prospective, randomized study of sulfasalazine for the treatment of progressing malignant gliomas in adults. BMC Cancer 9, 372 (2009).

    Article  Google Scholar 

  35. Soroceanu, L., Gillespie, Y., Khazaeli, M.B. & Sontheimer, H. Use of chlorotoxin for targeting of primary brain tumors. Cancer Res. 58, 4871–4879 (1998).

    CAS  Google Scholar 

  36. Buck, K., Voehringer, P. & Ferger, B. Rapid analysis of GABA and glutamate in microdialysis samples using high-performance liquid chromatography and tandem mass spectrometry. J. Neurosci. Methods 182, 78–84 (2009).

    Article  CAS  Google Scholar 

Download references


The authors would like to thank J. Hablitz and A. Albertson for technical assistance with diode array recordings; A. Margolies for help with histology; C. Langford for orthotopic xenografts; V. Cuddapah for editorial advice; M. McFerrin for technical support, and E. Dudek and K. Wilson at the University of Utah for training in EEG acquisition. We conducted glutamate measurements at the University of Alabama at Birmingham Targeted Metabolomics and Proteomics Facility (funded by the National Center for Research Resources grant S10 RR19231 and US National Institutes of Health grants U54 CA 100949, P50 AT00477, P30 DK079337 and P30 AR50948). We obtained bioluminescence imaging and some field electrode recordings in the Neuroscience Blueprint Core facility (Neuroscience Blueprint Core Grant NS57098). We obtained U251-MG cells from Y. Gillespie (University of Alabama at Birmingham) and U251-MGffluc cells from M. Jensen (City of Hope National Medical Center); GBM12 and GBM22 tumors were obtained from J. Sarkaria (Mayo Clinic) and provided by the University of Alabama at Birmingham Brain Tumor Animal Models Core (UAB SPORE P50-CA097247). This work was supported by US National Institutes of Health grants 2R01-NS052634, 5R01-NS036692 and 5T32NS048039-03.

Author information

Authors and Affiliations



S.C.B. and S.L.C. acquired the majority of the data presented. B.R.H. was instrumental in mouse surgeries and statistical analyses of data. V.M. (supported by an American Brain Tumor Association Basic Research Fellowship) carried out glutamate release assays. S.R. assisted in electrophysiological recordings. T.O. did western blotting and glutamate uptake assays. H.S. designed experiments, supervised all research and co-wrote the manuscript.

Corresponding author

Correspondence to Harald Sontheimer.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–5 and Supplementary Methods (PDF 1779 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Buckingham, S., Campbell, S., Haas, B. et al. Glutamate release by primary brain tumors induces epileptic activity. Nat Med 17, 1269–1274 (2011).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing: Cancer

Sign up for the Nature Briefing: Cancer newsletter — what matters in cancer research, free to your inbox weekly.

Get what matters in cancer research, free to your inbox weekly. Sign up for Nature Briefing: Cancer