Interação entre o receptor purinérgico P2X7 e a interleucina-17 em linhagens de glioma humano

• Autor(a) principal: Gehring, Marina Petersen
• Data de Publicação: 2012
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/5434
• topic: BIOLOGIA MOLECULAR; BIOLOGIA CELULAR; GLIOMA; NEOPLASIAS; RADIOTERAPIA; QUIMIOTERAPIA; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL

Glioblastoma multiforme (GBM) is the most aggressive tumor of the CNS and most deadly primary tumors. Despite the malignant gliomas are generally treated with radiotherapy, often they exhibit a significant radioresistance that limits the treatment success. It can be postulated that molecular changes commonly observed in these tumors contribute to this resistance. The nucleotide ATP is an important signaling molecule in CNS and it is a selective P2X7 purinergic receptor (P2X7R) ligand at high concentrations. Some studies have reported that P2X7R is responsible for ATP-induced cell death in various cell types, but some human glioma cells were resistant to death induced by ATP. In addition to ATP resistance, patients with GBM develop spontaneous antitumor immune responses. These studies show the requirement for an exogenous induction of the immune system to generate an antitumor response. IL-17 is a pro-inflammatory cytokine and its role in cancer is already unknown. Herein, we first aimed to characterize a radiosensitive human glioma cell line for sensitivity to ATP and to investigate whether activation of the P2X7R could be involved in the death of this cell line. Furthermore, aimed to elucidate the IL-17 receptor susceptibility to irradiation, as well as, elucidate the effect of IL-17 and a possible interaction between this cytokine and P2X7R in human glioma cells. The human glioma cell lines U-138 MG and U-251 MG were resistant to death when treated with either ATP (5 mM) or BzATP (100 μM), a selective P2X7R agonist, whereas in the radiosensitive M059J glioma cell line, the high ATP (5 mM) or BzATP (100 μM), significantly diminished the cell viability (32.4% ± 4.1 and 24.6% ± 4.0, respectively). The M059J lineage expresses significantly higher 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 in all lineages. Additionally, the selective P2X7R antagonist A740003 (10 µM) significantly decreased the cell death caused by irradiation. We provided novel evidence indicating that M059J human glioma cell line is ATP-P2X7R sensitive, pointing out the relevance of the purinergic P2X7R in glioma radiosensitivity. The IL-17 receptor was significantly more expressed after irradiation (2 Gy), showing a possible participation of the IL-17/R on the irradiation susceptibility. The treatment with IL-17 (10 ng/ml) diminished approximately 62% the human glioma cell lines viability. Other preliminary result showed that the P2X7R antagonist was able to partially reverse the toxicity caused by IL-17 in these cell lines. Our data show an antitumor role of this cytokine and corroborate to the idea of a possible interaction between IL-17/P2X7R. This work prospects for studies to be conducted to better understanding the action of IL-17 in gliomas and interaction IL-17/P2X7R