Galanin and galanin receptors in human gliomas.
Galanin-like immunoreactivity (GAL-LI) and specific GAL binding sites have been shown to be widely distributed in the central nervous system (CNS) and in CNS tumors. GAL and its receptors have also been shown to be present in glial cells, but to date it is still unknown whether human gliomas produce GAL and express GAL receptors. In this study 20 brain tumors consisting of 15 glioblastomas, 4 meningiomas and 1 gliosarcoma were investigated for the presence of GAL-LI and GAL receptors. Immunofluorescence analysis revealed a dense network of GAL-LI positive cellular processes and cell bodies in 18 of the 20 tumors. In contrast, in vitro (125)I-labeled GAL receptor autoradiography showed substantial GAL binding in only 6 glioblastoma tissues. Reverse transcription-PCR analysis detected mRNA of all three known galanin receptors in the tumor tissues, with most tumors expressing multiple receptor subtypes. Pharmacological analysis of tumor membrane homogenates with GAL and the specific GAL receptor GalR2 agonist, AR-M1896, revealed that the GAL receptor GalR1 is most likely the receptor responsible for the observed GAL binding in the glioblastomas. No correlation could be found between GAL-LI, the level of GAL binding and proliferative activity as determined by immunostaining with the cell proliferation marker Ki-67.
Department of Pediatrics, General Hospital, Muellner Hauptstrasse 48, 5020, Salzburg, Austria.
Alexandra
A
Berger
Radmila
R
Santic
Dietmar
D
Almer
Cornelia
C
Hauser-Kronberger
Michael
M
Huemer
Christian
C
Humpel
Günther
G
Stockhammer
Wolfgang
W
Sperl
Barbara
B
Kofler
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001345:Autoradiography / Q000379:methods; D001665:Binding Sites / Q000502:physiology; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology; D002490:Central Nervous System / Q000378:metabolism* / Q000473:pathology; D005260:Female; D019004:Galanin / Q000378:metabolism*; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D007456:Iodine Isotopes / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000096:biosynthesis; D044088:Receptors, Galanin; D018013:Receptors, Neuropeptide / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods
D007456:Iodine Isotopes; D012333:RNA, Messenger; D044088:Receptors, Galanin; D018013:Receptors, Neuropeptide; D019004:Galanin