The performance of the non-iterative and iterative triples corrected EOMIP-CCSD in characterizing stationary points of excited state potential energy surfaces

textChemistry and BiochemistryChemistr

Mechanism and <i>In Vitro</i> Pharmacology of TAK1 Inhibition by (5<i>Z</i>)‑7-Oxozeaenol

Transforming growth factor-β activated kinase-1 (TAK1) is a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family that regulates several signaling pathways including NF-κB signal transduction and p38 activation. TAK1 deregulation has been implicated in human diseases including cancer and inflammation. Here, we show that, in addition to its kinase activity, TAK1 has intrinsic ATPase activity, that (5<i>Z</i>)-7-Oxozeaenol irreversibly inhibits TAK1, and that sensitivity to (5<i>Z</i>)-7-Oxozeaenol inhibition in hematological cancer cell lines is NRAS mutation status and TAK1 pathway dependent. X-ray crystallographic and mass spectrometric studies showed that (5<i>Z</i>)-7-Oxozeaenol forms a covalent complex with TAK1. Detailed biochemical characterization revealed that (5<i>Z</i>)-7-Oxozeaenol inhibited both the kinase and the ATPase activity of TAK1 following a bi-phase kinetics, consistent with the irreversible inhibition mechanism. In DoHH2 cells, (5<i>Z</i>)-7-Oxozeaenol potently inhibited the p38 phosphorylation driven by TAK1, and the inhibition lasted over 6 h after withdrawal of (5<i>Z</i>)-7-Oxozeaenol. Profiling (5<i>Z</i>)-7-Oxozeaenol in a panel of hematological cancer cells showed that sensitive cell lines tended to carry NRAS mutations and that genes in TAK1 regulated pathways were enriched in sensitive cell lines. Taken together, we have elucidated the molecular mechanism of a TAK1 irreversible inhibitor and laid the foundation for designing next generation TAK1 irreversible inhibitors. The NRAS-TAK1-Wnt signaling network discerned in our study may prove to be useful in patient selection for TAK1 targeted agents in hematological cancers

Essential role of TAK1 in regulating mantle cell lymphoma survival

TGF-β–activated kinase 1 (TAK1), a member of the MAPK kinase family, plays a key role in B-cell growth and development. In the present study, we examined the potential role of TAK1 as a therapeutic target for lymphoma. Here, we show that the active phosphorylated form of TAK1 is abundantly expressed in a panel of lymphoma cell lines, including mantle cell, anaplastic large cell, and Hodgkin lymphoma cell lines. Silencing TAK1 expression via the use of siRNA inhibited the activation of NF-κB and p38 and induced apoptosis in lymphoma cell lines. Moreover, submicromolar concentrations of AZ-TAK1, a novel ATP-competitive small molecule inhibitor of TAK1, dephosphorylated TAK1, p38, and IκB-α in lymphoma cell lines. These molecular events were associated with the release of cytochrome c into the cytosol, down-regulation of X-linked inhibitor of apoptosis, activation of caspase 9, and induction of apoptosis. We also demonstrate that primary lymphoma cells express TAK1 and pTAK1 and were sensitive to AZ-TAK1–mediated cell death. Collectively, our data demonstrate an essential role for TAK1 in regulating critical survival mechanisms in lymphoma and suggest that it may serve as a therapeutic target

Identification and Optimization of Benzimidazole Sulfonamides as Orally Bioavailable Sphingosine 1‑Phosphate Receptor 1 Antagonists with in Vivo Activity

We report here a novel series of benzimidazole sulfonamides that act as antagonists of the S1P₁ receptor, identified by exploiting an understanding of the pharmacophore of a high throughput screening (HTS)-derived series of compounds described previously. Lead compound <b>2</b> potently inhibits S1P-induced receptor internalization in a cell-based assay (EC₅₀ = 0.05 μM), but has poor physical properties and metabolic stability. Evolution of this compound through structure–activity relationship development and property optimization led to <i>in vivo</i> probes such as <b>4</b>. However, this compound was unexpectedly found to be a potent CYP3A inducer in human hepatocytes, and thus further chemistry efforts were directed at addressing this liability. By employing a pregnane X receptor (PXR) reporter gene assay to prioritize compounds for further testing in human hepatocytes, we identified lipophilicity as a key molecular property influencing the likelihood of P450 induction. Ultimately, we have identified compounds such as <b>46</b> and <b>47</b>, which demonstrate the desired S1P₁ antagonist activity while having greatly reduced risk of CYP3A induction in humans. These compounds have excellent oral bioavailability in preclinical species and exhibit pharmacodynamic effects of S1P₁ antagonism in several <i>in vivo</i> models following oral dosing. Relatively modest antitumor activity was observed in multiple xenograft models, however, suggesting that selective S1P₁ antagonists would have limited utility as anticancer therapeutics as single agents