Indomethacin stimulates activity and expression of ecto-5′-nucleotidase/CD73 in glioma cell lines

Gliomas are the most common and devastating primary tumors of the central nervous system. Ecto-NTPDases and ecto-5′-nucleotidase/CD73 can control extracellular ATP/adenosine levels, which have been described as proliferation factors. Here, we investigate the influence of indomethacin on the enzyme cascade that catalyses the interconversion of purine nucleotides in U138-MG and C6 glioma cell lines. Exposure of glioma cells to 100 μM indomethacin for 48 h caused increases of 52% (P < 0.05) and 62% (P < 0.05) in the AMP hydrolysis rate in C6 and U138-MG cell lines, respectively. Indomethacin treatments also increased ATP hydrolysis. Significant increase in ecto-5′-nucleotidase/CD73 mRNA and protein levels were observed after treatment with indomethacin. Pretreatment of glioma cells with a specific antagonist of the adenosine A3 receptor, MRS1220 (1 μM; 9-Chloro-2-(2-furanyl)-5-((phenylacetyl)amino)-[1,2,4]triazolo[1,5-c]quinazoline), significantly reduced the inhibition of cell proliferation induced by indomethacin. In addition, a significant increase in mRNA levels of the adenosine A3 receptor was observed after treatment with indomethacin. In conclusion, our data indicate that adenosine A3 receptors and the enzyme, ecto-5′-nucleotidase/CD73, are involved in the anti-proliferative effect of indomethacin in glioma cells.