RU 58841 (PSK-3841) is a specific androgen receptor antagonist with significant effects on hair regrowth.

In vitro Protein Kinase, PI3K, and mTOR Assays: PI3Kα, β, and δ proteins are composed of the iSH2 domain of p85 NH2-terminally fused to the full-length protein p110 protein, with the exception of α that also does not contain the last 20 amino acids. PI3Kγ is produced as full-length protein deleted for its first 144 amino acids. All constructs are fused to a COOH-terminal His tag for convenient purification and then cloned into the pBlue-Bac4.5 (for α, β, and δ isoforms) or pVL1393 (for γ isoform) plasmids. The different vectors are then cotransfected with BaculoGold WT genomic DNA using methods recommended by the vendor for production of the respective recombinant baculoviruses and proteins. BEZ235 are tested for their activity against PI3K using a Kinase-Glo assay. The kinase reaction is done in 384-well black plate. Each well is loaded with 50 μL of test items (in 90% DMSO) and 5 μL reaction buffer containing 10 μg/mL PI substrate (l-α-phosphatidylinositol; Avanti Polar Lipids; prepared in 3% octyl-glucoside) and the PI3K proteins (10, 25, 10, and 150 nM of p110α, p110β, p110δ, and p110γ, respectively) are then added to it. The reaction is started by the addition of 5 μL of 1 μM ATP prepared in the reaction buffer and is incubated for either 60 (for p110α, p110β, and p110δ) or 120 min (for p110γ). It is terminated by the addition of 10 μL Kinase-Glo buffer. The plates are then read in a Synergy 2 reader for luminescence detection.