These results conclusively establish the existence and identity of an 8-oxoguanine DNA glycosylase/lyase in human and murine cells, completing the triad of proteins that together protect mammals from the genotoxic effects of guanine oxidation. The observation that at least one allele of hOGG1 is commonly deleted in cancer cells suggests that such cells may possess a reduced capacity to counter the mutagenic effects of reactive oxygen species, a deficiency that could increase their overall genomic instability. This speculation is fueled by recent observations that cells constitutively active for the Ras/Raf pathway constitutively produce high levels of superoxide, a known generator of OG.

No abstract

This study provides the first direct identification of the active-site amine for any DNA glycosylase/lyase belonging to the BER superfamily, members of which are characterized by the presence of a helix-hairpin-helix-Gly/Pro-Asp active-site motif. The critical lysine residue identified here is conserved in all members of the BER superfamily that exhibit robust glycosylase/lyase activity. The ability to trigger the catalytic activity of the Lys249-->Cys mutant of hOgg1 by treatment with the chemical inducer 2-bromoethylamine may permit snapshots to be taken of the enzyme acting on its substrate and could represent a novel strategy for conditional activation of catalysis by hOgg1 in cells.

IntroductionAn array of chronic inflammatory diseases, including Crohn disease, psoriasis, rheumatoid arthritis, and multiple sclerosis, cause widespread and severe health problems. These and other immune diseases can be considered to have a predominantly T helper cell type 1 (Th1) bias. Although injectable biologic treatments such as antibodies and soluble protein that block TNF-␣ have provided significant clinical benefit, there is still a high unmet medical need, particularly for a safe targeted drug that can be taken orally.Interleukin-12 (IL-12) is a heterodimeric cytokine (p70) composed of 2 independently regulated protein subunits, p35 and p40. IL-12 plays a central role in the immune response by bridging innate resistance and antigen-specific adaptive immunity. 1 It is produced from phagocytic cells and antigen-presenting cells, in particular macrophages and dendritic cells, upon stimulation with bacteria, bacterial products such as lipopolysaccharide (LPS), and intracellular parasites. 2,3 The well-documented biologic functions of IL-12 are the induction of interferon-␥ (IFN-␥) expression from T and natural killer (NK) cells 4,5 and the differentiation of naive T cells toward a Th1-cell type. 6,7 IL-12 also appears to be critical in the expansion and maintenance of the Th1 phenotype. [8][9][10] IL-23, a more recently discovered member of the IL-12 family, also promotes Th1 response, but has distinct functions from IL-12. IL-23 is required for the generation of effector memory T cells. 11 IL-23 is also needed for the generation of IL-17-producing T cells, which play a significant role in the inflammatory response. 12 Through these activities, IL-23 plays a critical role in chronic inflammatory diseases.Although the inflammatory effector function of Th1 is essential for the clearance of intracellular pathogens, the excessive production of proinflammatory cytokines leads to serious tissue damage typical of organ-specific autoimmunity, 13,14 including type 1 diabetes, 15 multiple sclerosis, 16,17 rheumatoid arthritis, 18,19 inflammatory bowel disease, 20 psoriasis, 21 and sepsis. 22 IL-12/IL-23 has been validated as an attractive clinical target by a number of studies. Mice lacking the gene encoding the p40 subunit shared by IL-12 and IL-23 or lacking the IL-23-specific subunit p19 have proven the integral role of IL-12/IL-23 to the pathogenesis of these disorders, implying that blockade of the cytokines could be effective in the treatment of a variety of autoimmune diseases. 21,[23][24][25][26][27][28] Monoclonal antibodies to the IL-12/23 p40 subunit have been shown to be effective in human clinical trials in patients with Crohn disease and psoriasis. 29,30 While antibodies against IL-12/IL-23 could provide significant medical benefit, a small-molecule IL-12/IL-23 inhibitor that could be administered orally would be highly desirable. Although some compounds weakly or nonselectively inhibit IL-12, there are no potent and selective small-molecule IL-12 inhibitors. To find an effective inhibitor against the...

A series of novel indolizine 2-oxoacetamides were designed and synthesized as PDE4 inhibitors. Preliminary SAR of this new class of compounds revealed key structural features required for high potency. Compounds 1ab and 2a are among the most potent inhibitors of PDE4 with low single nM IC 50 . Cellular activity was demonstrated by the inhibition of TNFa production from human PBMC with IC 50 ranging from 14 to 72 nM. Docking analyses suggest the OH group in 1ab enhance the binding via an H-bond interaction with the PDE4 enzyme.

Matrix high-throughput screening (HTS) methods are increasingly employed to rapidly define potential therapeutic drug combinations. We used combination HTS to identify compounds showing synergistic anti-proliferative activity with ibrutinib, an irreversible, small-molecule inhibitor of Bruton's tyrosine kinase. The goal was to identify ibrutinib combinations with maximum synergistic effects in heme malignancy lines, particularly in non-Hodgkin lymphoma including diffuse large B-cell lymphoma (DLBCL). Growth inhibition (GI) was used to measure cell viability; synergy scores characterized strength of synergistic interaction. Single-agent ibrutinib demonstrated varying degrees of activity across 30 cell lines evaluated. In DLBCL lines, TMD8 was the most sensitive to ibrutinib (GI = 0.001); combinations with BCL-2 inhibitor ABT-199, and PI3K inhibitors IPI-145 and GDC-0941 showed the strongest synergistic activity. Anti-proliferative synergies were also observed with BET bromodomain inhibitor (+)-JQ1, XPO1 inhibitor selinexor, and IRAK4 inhibitor, and confirmed using apoptosis assay. These findings are intended to inform and advance treatment of B-cell malignancies.