Hypermethylation downregulates P2X 7 receptor expression in astrocytoma.

The present study investigated the altered expression of p2X purinoceptor (P2X7 R) in astrocytoma. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were used to determine the P2X7 R expression in glioblastoma (GBM) and surrounding normal brain tissue. DNA methylation levels of P2X7 R gene promoter in GBM were analyzed using a Sequenom MassARRAY® System. Immunohistochemistry (IHC) was used to detect the expression of P2X7 R in astrocytoma at different malignancy grades, including diffuse astrocytoma, anaplastic astrocytoma and GBM. P2X7 R mRNA and protein were significantly decreased in GBM compared with normal brain tissues. IHC results showed a negative correlation between P2X7 R expression and tumor grade. The decreased P2X7 R expression was mostly attributed to hypermethylation of its promoter. Therefore, P2X7 R was found to perform an important role in tumorigenesis and progression of astrocytoma.