Mcl-1, an antiapoptotic member of the Bcl-2 family of proteins, is a validated and attractive target for cancer therapy. Overexpression of Mcl-1 in many cancers results in disease progression and resistance to current chemotherapeutics. Utilizing high-throughput screening, compound 1 was identified as a selective Mcl-1 inhibitor and its binding to the BH3 binding groove of Mcl-1 was confirmed by several different, but complementary, biochemical and biophysical assays. Guided by structure-based drug design and supported by NMR experiments, comprehensive SAR studies were undertaken and a potent and selective inhibitor, compound 21, was designed which binds to Mcl-1 with a Ki of 180 nM. Biological characterization of 21 showed that it disrupts the interaction of endogenous Mcl-1 and biotinylated Noxa-BH3 peptide, causes cell death through a Bak/Bax-dependent mechanism, and selectively sensitizes Eμ-myc lymphomas overexpressing Mcl-1, but not Eμ-myc lymphoma cells overexpressing Bcl-2. Treatment of human leukemic cell lines with compound 21 resulted in cell death through activation of caspase-3 and induction of apoptosis.

Development of adventitious roots (ARs) at the base of the shoot is an important adaptation of plants to waterlogging stress; however, its physiological mechanisms remain unclear. Here, we investigated the regulation of AR formation under waterlogged conditions by hormones and reactive oxygen species (ROS) in Cucumis sativus L., an agriculturally and economically important crop in China. We found that ethylene, auxin, and ROS accumulated in the waterlogged cucumber plants. On the other hand, application of the ethylene receptor inhibitor 1-methylcyclopropene (1-MCP), the auxin transport inhibitor 1-naphthylphthalamic acid (NPA), or the NADPH oxidase inhibitor diphenyleneiodonium (DPI) decreased the number of ARs induced by waterlogging. Auxin enhanced the expression of ethylene biosynthesis genes, which led to ethylene entrapment in waterlogged plants. Both ethylene and auxin induced the generation of ROS. Auxin-induced AR formation was inhibited by 1-MCP, although ethylene-induced AR formation was not inhibited by NPA. Both ethylene-and auxin-induced AR formation were counteracted by DPI.These results indicate that auxin-induced AR formation is dependent on ethylene, whereas ethylene-induced AR formation is independent of auxin. They also show that ROS signals mediate both ethylene-and auxin-induced AR formation in cucumber plants.

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Ziziphi Spinosae Semen (ZSS), a traditional Chinese medicine, is used in clinics for the treatment of insomnia in China and other Asian countries. Herein, we described for the first time a comparative pharmacokinetics study of the six major compounds of ZSS in normal control (NC) and para -chlorophenylalanine (PCPA)-induced insomnia model (IM) rats that were orally administered the aqueous extract of ZSS. An ultra-high-performance liquid chromatography coupled with quadrupole orbitrap mass (UHPLC-Q-Orbitrap-MS) method was developed and validated for the simultaneous determination of coclaurine, magnoflorine, spinosin, 6 ‴ -feruloylspinosin, jujuboside A (JuA), and jujuboside B (JuB) in ZSS in rat plasma. The established approach was successfully applied to a comparative pharmacokinetic study. The systemic exposures of spinosin and 6 ‴ -feruloylspinosin were decreased in the IM group compared to the NC group, while plasma clearance (CL) was significantly increased. The T max values of JuA and JuB in IM rats were significantly lower than those in NC rats. The T 1/2 of JuA in the IM group was significantly accelerated. The pharmacokinetic parameters of coclaurine and magnoflorine were not evidently affected between the two groups. These results indicate that the pathological state of insomnia altered the plasma pharmacokinetics of spinosin, 6 ‴ -feruloylspinosin, JuA, and JuB in the ZSS aqueous extract, providing an experimental basis for the role of ZSS in insomnia treatment. The comparative pharmacokinetics-based UHPLC-Q-Orbitrap-MS using full-scan mode can therefore provide a reliable and suitable means for the screening of potentially effective substances applied as quality markers of ZSS.

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A seizure is one of the leading neurological disorders. NMDA receptor-mediated neuronal excitation has been thought to be essential for epileptogenesis. As an endogenous co-agonist of the NMDA receptor, D-serine has been suggested to play a role in epileptogenesis. However, the underlying mechanisms remain unclear. In the current study, we investigated the effects of antagonizing two key enzymes in D-serine metabolism on the development of seizures and the downstream signaling. Our results showed that serine racemase (SR), a key enzyme in regulating the L-to-D-serine conversion, was significantly up-regulated in hippocampal astrocytes in rats and patients who experienced seizure, in comparison with control rats and patients. L-aspartic acid β-hydroxamate (LaaβH), an inhibitor of SR, significantly prolonged the latencies of seizures, shortened the durations of seizures, and decreased the total EEG power in rats. In contrast, D-amino acid oxidase inhibitor 5-chlorobenzo[d]isoxazol-3-ol (CBIO), which can increase D-serine levels, showed the opposite effects. Furthermore, our data showed that LaaβH and CBIO significantly affected the phosphorylation of Extracellular Signal-regulated Kinase (ERK). Antagonizing or activating ERK could significantly block the effects of LaaβH/CBIO on the occurrence of seizures. In summary, our study revealed that D-serine is involved in the development of epileptic seizures, partially through ERK signaling, indicating that the metabolism of D-serine may be targeted for the treatment of epilepsy.

Background: MLL fusion proteins use similar strategy for leukemic transformation through DOT1L recruitment. Results: Ten amino acids in DOT1L were identified as essential for binding and transformation by MLL-AF9. Conclusion: Biochemical and functional results indicate that blocking DOT1L recruitment represents a promising therapeutic strategy for mixed lineage leukemia. Significance: Identified DOT1L peptide will lay a foundation toward discovery of chemical tools able to block DOT1L recruitment.