Crystal Structures of Spleen Tyrosine Kinase in Complex with Two Novel 4-Aminopyrido[4,3-d] Pyrimidine Derivative Inhibitors.

Spleen tyrosine kinase (SYK) is a cytosolic non-receptor protein tyrosine kinase. Because SYK mediates key receptor signaling pathways involving the B cell receptor and Fc receptors, SYK is an attractive target for autoimmune disease and cancer treatments. To date, representative oral SYK inhibitors, including fostamatinib (R406 or R788), entospletinib (GS-9973), cerdulatinib (PRT062070), and TAK-659, have been assessed in clinical trials. Here, we report the crystal structures of SYK in complex with two newly developed inhibitors possessing 4-aminopyrido[4,3-D]pyrimidine moieties (SKI-G-618 and SKI-O-85). One SYK inhibitor (SKI-G-618) exhibited moderate inhibitory activity against SYK, whereas the other inhibitor (SKI-O-85) exhibited a low inhibitory profile against SYK. Binding mode analysis indicates that a highly potent SYK inhibitor might be developed by modifying and optimizing the functional groups that interact with Leu377, Gly378, and Val385 in the G-loop and the nearby region in SYK. In agreement with our structural analysis, one of our SYK inhibitor (SKI-G-618) shows strong inhibitory activities on the ß-hexosaminidase release and phosphorylation of SYK/Vav in RBL-2H3 cells. Taken together, our findings have important implications for the design of high affinity SYK inhibitors.

Heme oxygenase-1 (HO-1)/carbon monoxide (CO) axis suppresses RANKL-induced osteoclastic differentiation by inhibiting redox-sensitive NF-κB activation.

Heme oxygenase (HO-1) catalyzes heme to carbon monoxide (CO), biliverdin/bilirubin, and iron and is known to prevent the pathogenesis of several human diseases. We assessed the beneficial effect of heme degradation products on osteoclastogenesis induced by receptor activator of NF-κB ligand (RANKL). Treatment of RAW264.7 cells with CORM-2 (a CO donor) and bilirubin, but not with iron, decreased RANKL-induced osteoclastogenesis, with CORM-2 having a more potent anti-osteogenic effect. CORM-2 also inhibited RANKLinduced osteoclastogenesis and osteoclastic resorption activity in marrow-derived macrophages. Treatment with hemin, a HO-1 inducer, strongly inhibited RANKL-induced osteoclastogenesis in wild-type macrophages, but was ineffective in HO-1＋/- cells. CORM-2 reduced RANKL-induced NFATc1 expression by inhibiting IKK-dependent NF-κB activation and reactive oxygen species production. These results suggest that CO potently inhibits RANKL-induced osteoclastogenesis by inhibiting redox-sensitive NF-κB-mediated NFATc1 expression. Our findings indicate that HO-1/CO can act as an antiresorption agent and reduce bone loss by blocking osteoclast differentiation. [BMB Reports 2017; 50(2): 103-108].

Highly potent and selective pyrazolylpyrimidines as Syk kinase inhibitors.

A series of pyrazolylpyrimidine scaffold based Syk inhibitors were synthesized and evaluated for their biological activities and selectivity. Lead optimization efforts provided compounds with potent Syk inhibition in both enzymatic and TNF-α release assay.

Adjuvant revascularization of intracranial artery occlusion with angioplasty and/or stenting.

INTRODUCTION: In conjunction with intravenous and/or intra-arterial thrombolysis, adjuvant revascularization of intracranial artery occlusion by angioplasty vs. stenting remains controversial. We evaluated outcome in patients with intracranial occlusion after angioplasty and/or stenting. MATERIALS AND METHODS: Thirty-three patients who underwent angioplasty or stenting (17 stenting and 16 angioplasty) for intracranial arterial occlusion during the past 5 years were enrolled from prospective neurointerventional database. We compared recanalization rate [defined as thrombolysis in myocardial infarction (TIMI) grade II/III flow], adverse events, and clinical outcome [modified Rankin scale (mRS) at 1 and 6 months]. We also tried to determine independent variables associated with clinical outcome. RESULTS: Median initial National Institutes of Health Stroke Scale (NIHSS) was 13 and median time to treatment was 12 h from symptom onset. The successful recanalization rate was mean 79%. Symptomatic hemorrhage occurred in 15% (5/33). Events (27%, 9/33) at 1 month included four deaths, four major, and one minor stroke. Good outcome (mRS

Suppressive effects of young radish cultivated with sulfur on growth and metastasis of B16-F10 melanoma cells.

The oral administration of extracts of young radishes cultivated with sulfur after intravenous tumor cell injection achieved a marked reduction of pulmonary colonization in mice. Treatment of the mice with extracts of young radish cultivated with sulfur did not show any increase in the number of CD8+ or NK T cells in the spleen, indicating no influence on host immunity. Sulforaphane, which could be a candidate for an active compound from young radishes cultivated with sulfur, inhibited cell growth of B16-F10 melanoma cells. In addition, extracts of the young radish cultivated with sulfur-fed group showed enhanced quinine reductase (QR) activities in the liver and lung and a slight increase of glutathione S-transferase (GST) activity in the liver. These results suggested that the administration of extracts of young radishes cultivated with sulfur suppressed pulmonary tumorigenesis, possibly due to increased activity of detoxification enzymes in the liver and lung, and partly due to cell cytotoxicity.