Assay Method Information

Assay Name:  Measurement of A2A and A2B Antagonism in cAMP Cell-Based Assay
Description:  The ability of compounds to antagonize human A2A and A2B adenosine receptors was determined using a kit to measure changes in intracellular cyclic AMP levels (LANCE cAMP 384 Kit, Perkin Elmer, Cat. No. AD0264). HEK293 cells recombinantly expressing either human A2A or A2B receptors, previously frozen in Recovery Medium (Life Technologies, Cat. No. 12648-010) were thawed and diluted into stimulation buffer (HBSS (Hyclone SH 30268.01), 5 mM HEPES (Gibco 15630-106), 200 nM rolipram (Tocris, Cat. No. 0905), and 1.5% (V/v) BSA stabilizer (kit component). The cell suspension was centrifuged at 200×g for 10 min and then resuspended in stimulation buffer, supplemented with a 1:10 000 dilution of Alexa Fluor 647 anti-cAMP antibody, to a density of 6.0×105 cells/mL. A Labcyte Echo 550 acoustic dispenser was used to transfer up to 25 nL of test compound dissolved in DMSO into the wells of a dry Optiplate-384 plate (Perkin Elmer, Cat. No. 6008289). All subsequent liquid additions were performed using a multichannel pipettor. Next, 5 μL of the cell suspension was added to the wells of the Optiplate-384 and incubated for 30 min. at 37° C. and 5% CO2 in a humidified environment. After this time 5 μL of either 300 nM or 600 nM adenosine (Sigma Cat. No. A9251) for A2A and A2B respectively was added and incubated for 30 minutes at 37° C. and 5% CO2 in a humidified environment. At this time detection mix was prepared by combining the LANCE Eu-W8044 labeled streptavidin and Biotin-cAMP in detection buffer according to the manufacturers protocol. 10 μL of the detection mix was added to each well of the Optiplate-384 which was covered with a plate seal and incubated under ambient conditions for 2 hours prior to reading the plate using an Envision (Perkin Elmer, Waltham, Mass.) multimode plate reader. Data was normalized by defining minimal effect as stimulation in the presence of 0.25% (v/v) DMSO and maximal effect as stimulation in the presence of 1 μM ZM241385 (Cayman, Cat. No. 1036). Curve fitting of the percent effect data versus the log of compound concentration used a 4-parameter concentration response curve fitting algorithm to calculate IC50 values.
Affinity data for this assay
 

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