Gdc 0941

The chemical SYK inhibitor, R406, was a gift from Rigel Pharmaceuticals (San Francisco, CA, USA). R406 was dissolved in DMSO at a concentration of 10 mM and stored at −80°C. For immediate inhibition, cells were incubated with 1 μM R406 or vehicle alone (in PBS) in a 37°C water bath for 2 hours (h). For long-term inhibition, R406 was added to cell culture medium at a final concentration of 1 μM and cells were maintained in an incubator at 37°C for 24 h. The chemical pan-PI3K inhibitor, LY294002, was purchased from Sigma-Aldrich (Saint Louis, MO, USA), The chemical SYK inhibitor, GS-9973 (entospletinib), the PI3K isoform-predominant inhibitors, GDC-0941 (pictilisib, PI3K α/δ>β/γ), CAL101 (idelalisib, d) and IPI145 (duvelisib, δ/γ) and the BTK inhibitor, PCI-32765 (ibrutinib) were purchased from Selleckchem (Houston, TX, USA). DLBCL cell lines were treated with GS-9973 (2 μM), LY294002 (10 μM), GDC-0941 (0.5 μM), CAL101 (2 μM), IPI145 (1 μM), PC1-32765 (0.1 μM) or vehicle (DMSO) for 24 h as previously described.^{9 (link)} The doses of SYK, PI3K and BTK inhibitors used in these studies were determined based on prior analyses of the respective agent EC50s of these agents;^{9 (link)} the LY294002 dose was chosen based on previously reported studies.^{3 (link),16 (link)} Following treatment with chemical SYK, PI3K or BTK inhibitors, cells were harvested for additional analyses (below).