CHEMBL5732756

AlphaScreen (Amplified Luminescent Proximity Homogeneous Assay, ALPHA, Perkin Elmer) is a non-radioactive bead-based proximity assay technology to study biomolecular interactions in a homogenous microtiter plate format. The brand name SureFire denotes AlphaScreen assays that are adapted to quantify the phosphorylation of endogenous cellular proteins in cell lysates, by using matched antibody pairs, which consist of an anti-phospho-kinase and an anti-kinase antibody. The assay allows characterization of kinase signaling in cells as well as measurement of kinase inhibitor effects. The AlphaScreen technology provides several advantages over standard assay techniques such as ELISA, as it avoids time-consuming washing procedures and reduces plate handling. Furthermore, it is miniaturizable at least to a 384-well format and provides sensitivity down to the femtomolar range, dependent on the affinity of the antibodies included in the individual AlphaScreen SureFire assay kit. High sensitivity is reached by an intrinsic amplification mechanism, which involves production of singlet oxygen molecules. SureFire assay kits are commercially available for specific targets and include pairs of validated antibodies (PerkinElmer). This report describes common procedures applied for AlphaScreen SureFire assays and respective semi-automated steps for routine kinase inhibitor profiling in cell-based assays.The Rat-1 cell lines stably overexpressing activated PI3K class I isoforms Rat-1 pBABEpuro Myr-HA-hp110 delta (Rat-1_PI3Kdelta) and Rat-1 pBABEpuro Myr-HA-hp110alpha (Rat-1_PI3Kalpha) and Rat-1 pBABEpuro Myr-HA-hp110 beta (Rat-1_PI3beta) were prepared as described (Maira S M, Stauffer F, Brueggen J, Furet P, Schnell C, Fritsch C, Brachmann S, Chène P, de Pover A, Schoemaker K, Fabbro D, Gabriel D, Simonen M, Murphy L, Finan P, Sellers W, Garcia-Echeverria C (2008), Mol Cancer Ther. 7:1851-63 and Maira S M, Pecchi S, Brueggen J, Huh K, Schnell C, Fritsch C, Nagel T, Wiesmann M, Brachmann S, Dorsch M, Chène P, Schoemaker K, De Pover A, Menezes D, Fabbro D, Sellers W, Garcia-Echeverria C, Voliva CF (2011), Mol. Cancer Ther., accepted). All cell lines were cultivated in complete growth medium (DMEM high glucose, 10% (v/v) fetal bovine serum, 1% (v/v) MEM NEAA, 10 mM HEPES, 2 mM L-glutamine, puromycin (10 μg/mL for Rat-1_PI3Kdelta and Rat-1_PI3Kalpha, 4 ug/mL for Rat-1_PI3beta), 1% (v/v) Pen/Strep) to 90% confluency at 37° C./5% CO2/90% humidity in a humidified CO2 incubator and were split twice a week.The following materials were used for p-AKT(5473) detection in Rat-1 cell lysates: Dulbecco's modified Eagle's medium (DMEM) high glucose (Gibco Invitrogen, Basel, Switzerland, Cat. No. 41965), Heat Inactivated Fetal Bovine Serum, Qualified (HI FBS; Gibco Invitrogen, Basel, Switzerland, Lot. No. 16140), MEM non essential amino acids (NEAA; Gibco Invitrogen, Basel, Switzerland, Cat. No. 11140), HEPES (Gibco Invitrogen, Basel, Switzerland, Cat. No. 15630), Penicillin/Streptomycin (Pen/Strep, 100x; Gibco Invitrogen, Basel, Switzerland, Cat. No. 15140-122), L-Glutamine (Gibco Invitrogen, Basel, Switzerland, Cat. No. 25030), Puromycin (Sigma Aldrich, Buchs, Switzerland, Cat. No. P9620), DMSO (MERCK, Dietikon, Switzerland, Cat. No. 8.02912.2500), H2O, MilliQ-H2O unless otherwise stated (MILLIPORE QGARDOOR1, Millipore, Zug, Switzerland), Bovine serum albumine (BSA; Sigma Aldrich, Buchs, Switzerland Cat. No. A8412), SureFire p-Akt ½ (Ser473) Assay Kit (PerkinElmer, Schwerzenbach, Switzerland, Cat. No. TGRAS50K).The p-Akt(5473) SureFire assay measures the phosphorylation of endogenous cellular Akt ½ at Ser473 in cell lysates. Using Rat-1 cells stably expressing myr-HA-tagged versions of the human PI3Kdelta, PI3Kalpha, or PI3Kbeta p110 catalytic subunit isoforms, the assay was developed as a two-plate protocol in a 384-well format. For compound testing, the cells were seeded at a density of 4000 (Rat-1_PI3Kdelta), 7500 (Rat-1_PI3Kalpha).