STUDY ON THE EXPRESSION OF P2X7 RECEPTOR AND ITS MEDIATION IN INTRACELLULAR CALCIUM RESPONSE IN HUMAN LEUKEMIC CELL LINES
人白血病细胞系P2X7受体的表达及其介导的细胞内钙浓度变化

The expression of ionotropic ATP-gated channel, P2X7 receptor, was studied at mRNA and protein level in human leukemia cell lines (U937, HL60 and Ramos) by semi-quantitative RT-PCR and flow cytometry. In order to confirm whether the expressed P2X7 receptor had biological function, cytosolic Ca2+ was measured using the fluorescent dye Fura-2/AM. Intracellular free Ca2+ concentration (i) increase in these cells induced by extracellular ATP and the more potent and specific agonist, 2',3'-O-(4-Benzoylbenzoyl)-ATP (BzATP), was determined by spectrophotometer. The results showed that expression of P2X7 receptor was founded at both mRNA and protein level in U937 and HL60 cells, but not in Ramos; ATP and BzATP could induce increase in i through ion channel in cells expressing P2X7 receptor (U937 and HL60, not Ramos); Furthermore, i couldn't be increased by ATP and BzATP in U937 and HL60 cells in the absence of extracellular Ca2+ . These results suggested that P2X7 receptor was expressed functionally in U937 and HL60 cells, but not in Ramos cells.