The epidermal growth factor receptor is associated with phospholipase C-gamma 1 in meningiomas.
In this study we evaluated phospholipase C-gamma 1 (PLC-gamma 1) expression, activity, and association with the epidermal growth factor (EGF) receptor in a series of human meningiomas as well as cultured meningioma cells. Phospholipase C-gamma 1 was detectable by immunoblot and immunohistochemistry in 13 of 13 meningioma specimens. Epidermal growth factor receptors were detected by immunoblot in six of nine meningiomas (67%) and by immunohistochemistry in 13 of 19 meningiomas (68%) but not in normal leptomeningeal cells. In two of three meningiomas EGF receptors and/or a 170-kd phosphotyrosine band precipitated with a PLC-gamma 1 antiserum. Both PLC-gamma 1 and EGF receptors also exhibited the same pattern of immunostaining on meningioma tissue sections. Phospholipase C-gamma 1 catalytic activity, measured in a PIP2 hydrolysis assay, was higher in nine EGF receptor-positive meningiomas than in six EGF receptor-negative meningiomas (P = .05; t test). Finally, treatment of cultured meningioma cells with transforming growth factor-alpha induced a 78% increase in PLC-gamma 1 catalytic activity. Thus, these data are consistent with the possibility that the EGF receptor tyrosine kinase regulates PLC-gamma 1 activity in native meningioma tissue.
Johnson
M D
MD
Nashville Veterans Administration Medical Center, TN.
Horiba
M
M
Winnier
A R
AR
Arteaga
C L
CL
D000328:Adult; D000368:Aged; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D008297:Male; D008577:Meningeal Neoplasms / Q000378:metabolism*; D008578:Meninges / Q000378:metabolism; D008579:Meningioma / Q000378:metabolism*; D008875:Middle Aged; D010766:Phosphorylation; D014407:Tumor Cells, Cultured / Q000378:metabolism; D010738:Type C Phospholipases / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
D014443:Tyrosine; D066246:ErbB Receptors; D010738:Type C Phospholipases