Selective NTPDase2 expression modulates in vivo rat glioma growth.
The ectonucleoside triphosphate diphosphohydrolases (E-NTPDases) are a family of ectoenzymes that hydrolyze extracellular nucleotides, thereby modulating purinergic signaling. Gliomas have low expression of all E-NTPDases, particularly NTPDase2, when compared to astrocytes in culture. Nucleotides induce glioma proliferation and ATP, although potentially neurotoxic, does not evoke cytotoxic action on the majority of glioma cultures. We have previously shown that the co-injection of apyrase with gliomas decreases glioma progression. Here, we tested whether selective re-establishment of NTPDase2 expression would affect glioma growth. NTPDase2 overexpression in C6 glioma cells had no effect on in vitro proliferation but dramatically increased tumor growth and malignant characteristics in vivo. Additionally, a sizable platelet sequestration in the tumor area and an increase in CD31 or platelet/endothelial cell adhesion molecule-1 (PECAM-1), vascular endothelial growth factor and OX-42 immunostaining were observed in C6-Enhanced Yellow Fluorescent Protein (EYFP)/NTPDase2-derived gliomas when compared to controls. Treatment with clopidogrel, a P2Y(12) antagonist with anti-platelet properties, decreased these parameters to control levels. These data suggest that the ADP derived from NTPDase2 activity stimulates platelet migration to the tumor area and that NTPDase2, by regulating angiogenesis and inflammation, seems to play an important role in tumor progression. In conclusion, our results point to the involvement of purinergic signaling in glioma progression.
Braganhol
Elizandra
E
Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Morrone
Fernanda B
FB
Bernardi
Andressa
A
Huppes
Daiane
D
Meurer
Luise
L
Edelweiss
Maria Isabel A
MI
Lenz
Guido
G
Wink
Márcia R
MR
Robson
Simon C
SC
Battastini
Ana Maria O
AM
D000251:Adenosine Triphosphatases / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001081:Apyrase / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D004396:Coloring Agents / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D005910:Glioma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D008164:Luminescent Proteins / Q000378:metabolism; D008954:Models, Biological; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000378:metabolism; D051381:Rats; D012680:Sensitivity and Specificity; D013778:Tetrazolium Salts / Q000378:metabolism; D013844:Thiazoles / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D001426:Bacterial Proteins; D004396:Coloring Agents; D005456:Fluorescent Dyes; D008164:Luminescent Proteins; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D013778:Tetrazolium Salts; D013844:Thiazoles; D042461:Vascular Endothelial Growth Factor A; C054562:yellow fluorescent protein, Bacteria; D000251:Adenosine Triphosphatases; C027201:ectoATPase; D001081:Apyrase; C022616:thiazolyl blue