Pharmacological blockade of group II metabotropic glutamate receptors reduces the growth of glioma cells in vivo

Neuro Oncol. 2005 Jul;7(3):236-45. doi: 10.1215/S1152851704000961.


U87MG human glioma cells in cultures expressed metabotropic glutamate (mGlu) receptors mGlu2 and mGlu3. Addition of the mGlu2/3 receptor antagonist LY341495 to the cultures reduced cell growth, expression of cyclin D1/2, and activation of the MAP kinase and phosphatidylinositol-3-kinase pathways. This is in line with the evidence that activation of mGlu2/3 receptors sustains glioma cell proliferation. U87MG cells were either implanted under the skin (1x10(6) cells/0.5 ml) or infused into the caudate nucleus (0.5x10(6) cells/5 microl) of nude mice. Animals were treated for 28 days with mGlu receptor antagonists by means of subcutaneous osmotic minipumps. Treatments with LY341495 or (2S)-alpha-ethylglutamate (both infused at a rate of 1 mg/kg per day) reduced the size of tumors growing under the skin. Infusion of LY341495 (10 mg/kg per day) also reduced the growth of brain tumors, as assessed by magnetic resonance imaging analysis carried out every seven days. The effect of drug treatment was particularly evident during the exponential phase of tumor growth, that is, between the third and the fourth week following cell implantation. Immunohistochemical analysis showed that U87MG cells retained the expression of mGlu2/3 receptors when implanted into the brain of nude mice. These data suggest that mGlu2/3 receptor antagonists are of potential use in the experimental treatment of malignant gliomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / pharmacology*
  • Animals
  • Blotting, Western
  • Brain Neoplasms / drug therapy*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cyclin D1 / biosynthesis
  • Cyclin D1 / drug effects
  • Cyclin D2
  • Cyclins / biosynthesis
  • Cyclins / drug effects
  • Enzyme Activation / drug effects
  • Excitatory Amino Acid Antagonists / pharmacology*
  • Glioma / drug therapy*
  • Humans
  • Immunohistochemistry
  • Ki-67 Antigen / drug effects
  • Ki-67 Antigen / metabolism
  • MAP Kinase Signaling System / drug effects
  • Magnetic Resonance Imaging
  • Mice
  • Mice, Nude
  • Phosphatidylinositol 3-Kinases / drug effects
  • Receptors, Metabotropic Glutamate / antagonists & inhibitors*
  • Receptors, Metabotropic Glutamate / drug effects
  • Reverse Transcriptase Polymerase Chain Reaction
  • Xanthenes / pharmacology*


  • Amino Acids
  • CCND2 protein, human
  • Cyclin D2
  • Cyclins
  • Excitatory Amino Acid Antagonists
  • Ki-67 Antigen
  • LY 341495
  • Receptors, Metabotropic Glutamate
  • Xanthenes
  • metabotropic glutamate receptor 2
  • Cyclin D1
  • Phosphatidylinositol 3-Kinases