The Aurora kinases play critical roles in the regulation of mitosis and are frequently overexpressed or amplified in human tumors. Selective inhibitors may provide a new therapy for the treatment of ...tumors with Aurora kinase amplification. Herein we describe our lead optimization efforts within a 7-azaindole-based series culminating in the identification of GSK1070916 (17k). Key to the advancement of the series was the introduction of a 2-aryl group containing a basic amine onto the azaindole leading to significantly improved cellular activity. Compound 17k is a potent and selective ATP-competitive inhibitor of Aurora B and C with K i* values of 0.38 ± 0.29 and 1.5 ± 0.4 nM, respectively, and is >250-fold selective over Aurora A. Biochemical characterization revealed that compound 17k has an extremely slow dissociation half-life from Aurora B (>480 min), distinguishing it from clinical compounds 1 and 2. In vitro treatment of A549 human lung cancer cells with compound 17k results in a potent antiproliferative effect (EC50 = 7 nM). Intraperitoneal administration of 17k in mice bearing human tumor xenografts leads to inhibition of histone H3 phosphorylation at serine 10 in human colon cancer (Colo205) and tumor regression in human leukemia (HL-60). Compound 17k is being progressed to human clinical trials.
The protein kinases, Aurora A, B, and C have critical roles in the regulation of mitosis and are frequently overexpressed
or amplified in human tumors. GSK1070916, is a novel ATP competitive ...inhibitor that is highly potent and selective for Aurora
B/C kinases. Human tumor cells treated with GSK1070916 show dose-dependent inhibition of phosphorylation on serine 10 of Histone
H3, a substrate specific for Aurora B kinase. Moreover, GSK1070916 inhibits the proliferation of tumor cells with EC 50 values of <10 nmol/L in over 100 cell lines spanning a broad range of tumor types. Although GSK1070916 has potent activity
against proliferating cells, a dramatic shift in potency is observed in primary, nondividing, normal human vein endothelial
cells, consistent with the proposed mechanism. We further determined that treated cells do not arrest in mitosis but instead
fail to divide and become polyploid, ultimately leading to apoptosis. GSK1070916 shows dose-dependent inhibition of phosphorylation
of an Aurora B–specific substrate in mice and consistent with its broad cellular activity, has antitumor effects in 10 human
tumor xenograft models including breast, colon, lung, and two leukemia models. These results show that GSK1070916 is a potent
Aurora B/C kinase inhibitor that has the potential for antitumor activity in a wide range of human cancers. Mol Cancer Ther
2009;8(7):1808–17
Perfluoroalkyl and polyfluoroalkyl substances (PFASs) have been frequently detected in groundwater globally. With the phase-out of perfluorooctane sulfonate (PFOS) and perfluorooctanate (PFOA) due to ...their risk to the ecosystem and human population, various novel PFASs have been used as replacements and detected in groundwater. In order to summarize the current understanding and knowledge gaps on PFASs in groundwater, we reviewed the studies about environmental occurrence, transport, and risk of legacy and novel PFASs in groundwater published from 1999 to 2021. Our review suggests that PFOS and PFOA could still be detected in groundwater due to the long residence time and the retention in the soil-groundwater system. Firefighting training sites, industrial parks, and landfills were commonly hotspots of PFASs in groundwater. More novel PFASs have been detected via nontarget analysis using high-resolution mass spectrometry. Some novel PFASs had concentrations comparable to that of PFOS and PFOA. Both legacy and novel PFASs can pose a risk to human population who rely on contaminated groundwater as drinking water. Transport of PFASs to groundwater is influenced by various factors, i.e., the compound structure, the hydrochemical condition, and terrain. The exchange of PFASs between groundwater and surface water needs to be better characterized. Field monitoring, isotope tracing, nontarget screening, and modeling are useful approaches and should be integrated to get a comprehensive understanding of PFASs sources and behaviors in groundwater.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Live virus vaccine (LVV) purification, employing chromatography, can be challenged by low binding capacities and elution yields. Alternatively, processes relying solely on enzymatic digestion steps ...and size‐based membrane separations can be limited by suboptimal reduction of process related impurities and poorly scalable unit operations. Here, we demonstrate that the combination of flowthrough mode chromatography and an ultrafiltration/diafiltration (UF/DF) unit operation delivers a purification process for two different LVV candidates, V590 and Measles, expressed in adherent Vero cells. For V590, chromatography with mixed mode cation exchange resins returned final product yields of ∼50% and logarithmic reduction values (LRVs) of 1.7–>3.4 and 2.5–3.0 for host cell DNA (hcDNA) and host cell proteins (HCPs), respectively. For Measles, chromatography with mixed mode anion exchange resins returned final product yields of ∼50% and LRVs of 1.6 and 2.2 for hcDNA and HCPs, respectively. For both V590 and Measles processing, the employed resins cleared a key HCP, fibronectin, which could foul the UF/DF unit operation, and thusly enabling it to further reduce HCPs and to formulate the final LVV products. This integrated purification process utilizes the complementary action of the two unit operations and its applicability across LVVs supports its consideration for their processing.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Experimental evidence suggests that a tetramer of integrase (IN) is the protagonist of the concerted strand transfer reaction, whereby both ends of retroviral DNA are inserted into a host cell ...chromosome. Herein we present two crystal structures containing the N-terminal and the catalytic core domains of maedi-visna virus IN in complex with the IN binding domain of the common lentiviral integration co-factor LEDGF. The structures reveal that the dimer-of-dimers architecture of the IN tetramer is stabilized by swapping N-terminal domains between the inner pair of monomers poised to execute catalytic function. Comparison of four independent IN tetramers in our crystal structures elucidate the basis for the closure of the highly flexible dimer-dimer interface, allowing us to model how a pair of active sites become situated for concerted integration. Using a range of complementary approaches, we demonstrate that the dimer-dimer interface is essential for HIV-1 IN tetramerization, concerted integration in vitro, and virus infectivity. Our structures moreover highlight adaptable changes at the interfaces of individual IN dimers that allow divergent lentiviruses to utilize a highly-conserved, common integration co-factor.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Homeostasis under hypoxic conditions is maintained through a coordinated transcriptional response mediated by the hypoxia-inducible factor (HIF) pathway and requires coactivation by the CBP and p300 ...transcriptional coactivators. Through a target-based high-throughput screen, we identified chetomin as a disrupter of HIF binding to p300. At a molecular level, chetomin disrupts the structure of the CH1 domain of p300 and precludes its interaction with HIF, thereby attenuating hypoxia-inducible transcription. Systemic administration of chetomin inhibited hypoxia-inducible transcription within tumors and inhibited tumor growth. These results demonstrate a therapeutic window for pharmacological attenuation of HIF activity and further establish the feasibility of disrupting a signal transduction pathway by targeting the function of a transcriptional coactivator with a small molecule.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Oxidative stress has been implicated in protein phosphorylation and dephosphorylation in cells. In our current studies, H2O2 was shown to reversibly inhibit protein tyrosine phosphatase (PTPase) ...activity in HER14 cells. H2O2 (150 mM) resulted in 40% inhibition of PTPase activity by 15 min and recovery from inhibition was nearly complete by 60 min. H2O2-induced inhibition or recovery of PTPase activity was not affected by cycloheximide, a protein synthesis inhibitor. L-Buthionine-S,R-sulfoximine (BSO), an inhibitor of glutathione synthesis, had no effect on H2O2-induced inhibition of PTPase activity but retarded the recovery of activity. Epidermal growth factor (EGF) and EGTA, a Ca2+ chelator, did not influence H2O2-induced inhibition or recovery of PTPase activity. These results suggest that at least 40% of fibroblast PTPase activity can be regulated by cellular redox activity.
Abstract
The phosphoinositide 3-kinase (PI3K) pathway is among the most commonly activated pathways in human cancer. The biological role of PI3K in growth and survival of cancer cells and the ...prevalence of activating mutations in human cancers are well documented and a significant proportion of tumors would be predicted to benefit from inhibition of this pathway. Here we report on the characterization of the pan-PI3K pyridylsulfonamide inhibitor GSK2126458: a very potent (PI3K app Ki = 19 pM), reversible, ATP-competitive inhibitor of wild-type PI3K and the ‘hotspot’ activating mutants of p110 found in human cancer. GSK2126458 demonstrated good selectivity for the PI3K family of enzymes including the mTORC1 and mTORC2 complexes, when evaluated in a large panel of protein kinases. Consistent with potent PI3K enzyme inhibition, GSK2126458 decreased the cellular levels of phosphorylated AKT, p70S6K, PRAS40 and ERK in a concentration and time dependent manner, the IC50 for pAKT in the HCC1954 breast carcinoma cell line was 2 nM. GSK2126458 induced the nuclear translocation of the FOXO3a transcription factor in a concentration dependent manner that mechanistically appeared bimodal. Growth inhibition was time and concentration dependent with a 3 day exposure resulting in a growth IC50 (gIC50) of 9 nM in HCC1954 cells with evidence of cell death. Cell death correlated with induction of caspase 3 and 7 activity suggesting apoptosis was the mechanism of cell death. GSK2126458 had a breadth of activity for potent cell growth inhibition and induction of cell death in a variety of human cancer cells. GSK2126458 demonstrated robust, dose dependent in vivo pharmacodynamic activity as measured by inhibition of phospho-AKT in advanced BT474 breast cancer cell xenograft tumors. Inhibition of AKT phosphorylation was rapid and lasted for several hours after a single oral administration of GSK2126458. Transient increases in plasma insulin and blood glucose were observed. Evaluation of in vivo tumor growth effects of GSK2126458 in xenograft models demonstrated dose dependent tumor growth delay in several models of diverse tumor lineage and tumor regression in a breast cancer xenograft. The biological profile of GSK2126458 supports the clinical advancement of this compound and GSK2126458 has entered Phase I human clinical trials.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C63.
The purpose of this study was to determine the role of reducing agents in maintaining the integrity of vitamin E-deficient red cells. Three groups of one-month-old male Wistar rats were fed a basal ...vitamin E-deficient diet supplemented with either 0, 10 or 100 mg d, 1-α-tocopheryl acetate per kg diet for up to 12 weeks. Washed red blood cells (5%) were resuspended in saline-phosphate buffer, pH 7.4, and were incubated at 37°C with or without containing 12.5 mM 2,Z'-azobis (2amino- propane) dihydrochloride (AAPH), 2.8 mM glucose, 1 mM ascorbic acid, 10 mM hydrogen peroxide (H2O2), 250 μM dimethylsulfoxide (DMSO) or 2.8 mM deoxyribose (DR) for up to 20 hours. Addition of either glucose, AAPH, ascorbic acid or H2O2 markedly accelerated the rates of hemolysis and lipid peroxidation in the red cells of vitamin E-deficient rats. On the contrary, both glucose and ascorbic acid were protective against oxidative damage to the red cells of vitamin E-supplemented rats in a dose-dependent manner. Also, vitamin E-supplemented red cells were more resistant to AAPH and H2O2 than the deficient cells. DMSO or DR had no significant effects on the rates of hemolysis or lipid peroxidation. Glucose, but not others, maintained or slowed down the loss of glutathione (GSH) during incubation. The results obtained suggest a dual role of ascorbic acid and GSH in the function of vitamin E in maintaining red cell integrity: these reducing agents may exert antioxidant function by participating in vitamin E regeneration when certain levels of vitamin E is maintained, but promote oxidative damage by enhancing free radical generation when vitamin E is low or depleted.
IgA nephropathy (IgAN) is a common cause of renal failure worldwide. Treatment is limited because of a complex pathogenesis, including unknown factors favoring IgA1 deposition in the glomerular ...mesangium. IgA receptor abnormalities are implicated, including circulating IgA-soluble CD89 (sCD89) complexes and overexpression of the mesangial IgA1 receptor, TfR1 (transferrin receptor 1). Herein, we show that although mice expressing both human IgA1 and CD89 displayed circulating and mesangial deposits of IgA1-sCD89 complexes resulting in kidney inflammation, hematuria, and proteinuria, mice expressing IgA1 only displayed endocapillary IgA1 deposition but neither mesangial injury nor kidney dysfunction. sCD89 injection into IgA1-expressing mouse recipients induced mesangial IgA1 deposits. sCD89 was also detected in patient and mouse mesangium. IgA1 deposition involved a direct binding of sCD89 to mesangial TfR1 resulting in TfR1 up-regulation. sCD89-TfR1 interaction induced mesangial surface expression of TGase2 (transglutaminase 2), which in turn up-regulated TfR1 expression. In the absence of TGase2, IgA1-sCD89 deposits were dramatically impaired. These data reveal a cooperation between IgA1, sCD89, TfR1, and TGase2 on mesangial cells needed for disease development. They demonstrate that TGase2 is responsible for a pathogenic amplification loop facilitating IgA1-sCD89 deposition and mesangial cell activation, thus identifying TGase2 as a target for therapeutic intervention in this disease.
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