Reagent Preparation for PI3K Inhibition

FR900359 was isolated as described previously (Schrage et al., 2015 (link)). Salts and drugs have been purchased from Sigma-Aldrich (Germany) with the exception of PTX and TGX 221, which were obtained from Merck Millipore (Calbiochem) (Germany) and PI-103 from Enzo Life Sciences. The PI3K inhibitors TGX-221, AS-252424, and PI-103 were administered at submaximal concentrations to achieve biological effects (Ali et al., 2008 (link); Tsvetkov et al., 2016a (link)). All drugs were freshly dissolved on the day of the experiment according to the material sheet. The relaxin peptides have been purchased from Sigma-Aldrich (Germany). Relaxins were dissolved in water. The following concentrations were used: relaxin-1 at 10 pM or at 100 pM, relaxin-2 at 10 pM or at 100 pM or from 1 pM to 10 nM, relaxin-3 at 10 pM or at 100 pM.