P2X7 receptor activation leads to increased cell death in a radiosensitive human glioma cell line.
Gliomas are the most lethal tumors of central nervous system. ATP is an important signaling molecule in CNS and it is a selective P2X7 purinergic receptor ligand at high concentrations. Herein, we investigated whether the activation of P2X7R might be implicated in death of a radiosensitive human glioma lineage. The effects of P2X7R agonists (ATP and BzATP) and irradiation (2 Gy) on glioma cells were analyzed by MTT assay and annexin-V/PI determination, whereas mRNA and protein P2X7R expression was assessed by qRT-PCR and flow cytometry, respectively. P2X7R pore formation was functionality examined by analyzing ethidium bromide uptake. The human glioma cells U-138 MG and U-251 MG were resistant to death when treated with either ATP (5 mM) or BzATP (100 μM), but the radiosensitive M059J glioma cells displayed a significant decrease of cell viability (32.4 ± 4.1 % and 25.6 ± 3.3 %, respectively). The M059J lineage expresses significantly higher mRNA P2X7R levels when compared to the U-138 MG and U-251 cell lines (0.40 ± 0.00; 0.28 ± 0.01, and 0.31 ± 0.01, respectively), and irradiation upregulated P2X7R expression (0.55 ± 0.08) in this lineage. Noteworthy, P2X7R protein doubled after irradiation on M059J lineage, and increased in 50 % and 42.6 % when comparing M059J-irradiated to irradiated U-138 MG and U-251 MG cells, respectively. Ethidium bromide uptake was significantly increased in 104 % and 77.8 % when comparing M059J to U-138 MG and U-251MG, respectively. Finally, the selective P2X7R antagonist A740003 significantly decreased the cell death caused by irradiation. We provide novel evidence indicating that M059J human glioma cell line is ATP-P2X7R sensitive, pointing out the relevance of the purinergic P2X7R on glioma radiosensitivity.
Laboratório de Farmacologia Aplicada, PUCRS, Av. Ipiranga, 6681, Prédio 12C, Sala 148, Partenon, Porto Alegre, RS, Brazil.
Marina Petersen
MP
Gehring
Talita Carneiro Brandão
TC
Pereira
Rafael Fernandes
RF
Zanin
Magali Carvalho
MC
Borges
Aroldo
A
Braga Filho
Ana Maria Oliveira
AM
Battastini
Maurício Reis
MR
Bogo
Guido
G
Lenz
Maria Martha
MM
Campos
Fernanda Bueno
FB
Morrone
D000255:Adenosine Triphosphate / Q000378:metabolism; D016923:Cell Death / Q000528:radiation effects; D045744:Cell Line, Tumor; D005910:Glioma / Q000378:metabolism / Q000532:radiotherapy*; D006801:Humans; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism*; D015854:Up-Regulation / Q000528:radiation effects
D058486:Receptors, Purinergic P2X7; D000255:Adenosine Triphosphate