Data presented here is consistent with a model where intrace

Data presented here is consistent with a model where intracellular accumulation and retention of TKIs in vivo also translates into significantly higher intracellular TKI concentrations as compared to the extracellular medium. It is conceivable that in the setting of high-dose pulse therapy this may then CC-10004 result in prolonged intracellular TKI exposure significantly exceeding plasma halflife of a given TKI. In conclusion, we show that dramatic intracellular TKI accumulation and retention result in prolonged target inhibition which appears to be the sole underlying molecular mechanism in HD-TKI pulse-exposure mediated induction of apoptosis in vitro. Moreover, the data illustrate that potent but transient kinase inhibition per se is not sufficient to irreversibly commit oncogene transformed cells to apoptosis. As we have observed intracellular TKI accumulation and retention in other oncogenic kinase models such as FLT3-ITD and JAK2- V617F, the mechanism described here may indicate a general pharmacokinetic feature of TKIs. However, this point clearly requires further investigation. Based on our data presented here, monitoring both, plasma and intracellular drug levels of imatinib and S-(1,2-Dichlorovinyl)-L-cysteine dasatinib in vivo will provide pharmacokinetic data which may prove useful to optimize dosing schedules in upcoming clinical trials. We speculate that either the design of inhibitors that accumulate and are retained in target cells or, alternatively, co-administration of drugs which result in intracellular enrichment of specific TKIs may improve TKI therapy in the future. The IKK family of kinases consists of four family members, the canonical IKKa and IKKb, as well as two noncanonical family members, IKKe and TBK1. Together, this family of kinases regulates a myriad of critical cellular processes including inflammation, survival, proliferation, senescence, and autophagy. Consistent with these numerous functions, aberrant IKK signaling can result in susceptibility to diseases such as inflammatory disorders and cancer. The canonical IKK complex, which consists of IKKa, IKKb, and a regulatory subunit, NEMO, is a point of convergence for a variety of stimuli. Upon activation, the canonical IKKs, primarily IKKb, phosphorylate IkBa, the inhibitor of NF-kB, which promotes the ubiquitinatio