A targeted covalent inhibitor of p97 with proteome-wide selectivity

A resurging interest in targeted covalent inhibitors (TCIs) focus on compounds capable of irreversibly reacting with nucleophilic amino acids in a druggable target. p97 is an emerging protein target for cancer therapy, viral infections and neurodegenerative diseases. Extensive efforts were devoted to the development of p97 inhibitors. The most promising inhibitor of p97 was in phase 1 clinical trials, but failed due to the off-target-induced toxicity, suggesting the selective inhibitors of p97 are highly needed. We report herein a new type of TCIs (i.e., FL-18) that showed proteome-wide selectivity towards p97. Equipped with a Michael acceptor and a basic imidazole, FL-18 showed potent inhibition towards U87MG tumor cells, and in proteome-wide profiling, selectively modified endogenous p97 as confirmed by in situ fluorescence scanning, label-free quantitative proteomics and functional validations. FL-18 selectively modified cysteine residues located within the D2 ATP site of p97. This covalent labeling of cysteine residue in p97 was verified by LC‒MS/MS-based site-mapping and site-directed mutagenesis. Further structure-activity relationship (SAR) studies with FL-18 analogs were established. Collectively, FL-18 is the first known small-molecule TCI capable of covalent engagement of p97 with proteome-wide selectivity, thus providing a promising scaffold for cancer therapy.

3D-QSAR studies on thiazole derivatives as potent inhibitors of dihydroorotate dehydrogenase / 药物评价研究

Objective The three-dimensional quantitative structure activity relationship (3D-QSAR) method was applied to study thiazole derivatives as potent inhibitors ofdihydroorotate dehydrogenase,which provided useful guidance for more discovery of potent inhibitors of dihydroorotate dehydrogenase.Methods Molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) were applied to systematicly investigate 3D-QSAR of 38 hiazole derivatives as potent inhibitors of dihydroorotate dehydrogenase.Established models of CoMFA and CoMSIA and the predictive ability of models were validated.Three dimensional map was applied to analyzing the relationship between structure and activity of thiazole derivatives.Results The coefficients of cross validation q2 and non-cross validation r2 for CoMFA model were 0.796 and 0.978,and for CoMSIA model were 0.721 and 0.976 respectively.The prediction of activity of compound was close to the actual value of the two models.Effect of compound structure on its activity could be analyzed comprehensively and intuitively by three dimensional map.Conclusion The model reveals the relationship between the structure characteristics and the inhibitory activity,and has good predictive capability and stability to lay a good foundation for further development and research.

Angiogenesis of tissue engineered bone in the repair of rhesus tibia defects / 中国组织工程研究

BACKGROUND: Many experiments indicate that the angiogenesis of tissue engineered bone graft plays a key role in the osteogenesis.OBJECTIVE: An experimental pattern was set up designed to prepare a kind of vascularized engineered-bone graft for repairing rhesus tibia defects and analyze the relation of angiogenesis and osteogenesis in vivo by rontgenographic and morphological approaches.DESIGN: Random controlled animal experiment.SETTING: Department of Orthopaedics and Traumatology, Nanfang Hospital, Southern Medical University.MATERIALS: The composite graft was constructed by seeding the induced bone marrow stem cells (BMSCs) on to a beta-tricalcium phosphate(3-TCP) scaffold in vitro, a circular cylinder (20 mm × 8 mm diameter) with a slit (width 2 mm and length 3 mm ) open to both ends and slot. Porosity 60% and pore diameter 100-150 μm. Twenty-nine healthy rhesuses aged 4-5 years and weighted 3.5-5 kg were adopted without gender limitation.METHODS: The experiment was conducted in the Department of Orthopaedics and Traumatology, Nanfan Hospital, Southern Medical University from October 2003 to July 2005. ①Bone-periosteum defect of 20 mm was made in the middle part of right tibia of the 27 rhesuses, and randomly divided into 3 groups equally. ②The defect gaps in fascia-blood vessel group (A) were plugged with in vitro engineered composites constructed by bone marrow stem cells and 3-TCP scaffold, which were totally hugged by a sheet of pedicled deep fascia and additionally a corresponding portion of saphenous artery and veins. The gaps in fascia group (B) and control group(C), however, were inserted with fascia-coated tissue engineered bone and tissue engineered bone only, respectively. Furthermore, two rhesuses without filling materials on the defect were picked up as blanks fixed by steel pins. ③The angiogenesis and osteogenesis for each treatment was assessed by radioactive imaging, roentgenographic analyses, blocking density and vaso-area image analysis at time intervals of 4, 8 and 12 weeks postoperative.MAIN OUTCOME MEASURE: The score of radioactive imaging,roentgenographic, morphological and vaso-area image analyses RESULTS: Totally 29 rhesuses were involved in the result analysis.① General observation of samples: In group A, all the surfaces of the implanted material and the central part were wholly wrapped up or replaced by bonelike tissues which were hard and could not be broken. And 2/3 materials had been absorbed; In group B and C, partial materials of the medial surface and the front were not coated or replaced by bonelike tissues, which could be broken with force, and 1/3 material had been absorbed.②Histological observation of scaffolds: With time passing, the scaffold materials were absorbed to different degrees in group A, B and C, among which, group A was most significant; Under the microscope, the implanted materials at 12 weeks were completely coated with the bonelike tissues, while the blood vessels structures in the materials were mostly alveoli alike and multi-braches. In group B, most of the materials at 12 weeks were wrapped up by the new bone, and few blood vessels could be seen in the center of the materials. In group C, the implanted materials at 12 weeks were slightly absorbed. The new bone and the vascular structures were both increased a little, but still very few.③Analyses of vaso-area: The vaso-areas of both central and peripheral parts in group A were significantly bigger than those of group B and C (P ＜ 0.05). Furthermore, it tended to increase with the time.④X-rays observation: At 12 weeks, group A's images presented obviously decreased density which was lower than that of the normal bone in individual areas and the continual bony callus manifested. Whereas group B and C's images showed slightly decreased density and the continual bony callus appeared on the sections. ⑤The roentgenographic scores of bone defects: The results indicates that the scores of group A was better than those of group B and C at 4, 8 and 12 weeks, respectively (P ＜ 0.05).CONCLUSION: ①This study shows that a feasible and effective angiogenesis approach of tissue engineered bone can accelerate osteogenesis in vivo. ②The absorption level is positively related to local angiogenesis.

An experimental study of vascularization monitoring of tissue engineered bone in the rhesus / 中华创伤骨科杂志

Objective To compare four methods of monitoring vascularization of tissue engineered bone in the rhesus so as to find our the best. Methods Twenty-five lower limbs of 13 rhesuses were used in this study to make models of tibial diaphyseal defect of 20mm which were to be fixed with an AO reconstruction plate of 7 holes. The monkeys were randomly divided into five groups according to defect filling materials: group A:?-tricalcium phosphate (?-TCP) and bone marrow stromal cells (BMSCs) and blood vessel bundles; group B:?-TCP and blood vessel bundles; group C:?-TCP and BMSCs; group D:?-TCP; group E: blank. Perfusion weighted MR imaging (PWMR), X-ray, radionuclide imaging and histological examinations were carried out at weeks 4, 8, 12 postop- eratively. The maximum slope rates of the single intensity-time curve (SS_(max)) and values of baseline (Sl_(?))were calculated at the same time points. Transmittances of the X-ray films were assessed. Ratios between isotope counts in region of interest (ROI) were calculated. Chinese ink perfusion and calculation of blood vessel areas were done for histological examinations, Results Compared with other groups, the SS_(max) in group A was the highest at weeks 4, 8, 12 postoperatively. In group A, the SS_(max) at week eight was significantly higher than that at week four (P= 0. 003), and the SS_(max) and transmittance of X-ray were negatively related at week 12 after operation (rs=-0. 892, P=0. 042), but the SS_(max) and blood vessel area were positively related (rs=0. 894, P=0.041)Conclusions PWMR can be a sensitive, quantitative, noninvasive and non-radiant method to monitor vascularization of tissue engineered bone, because SS_(max) of the single intensity-time curve of PWMR can reflect the most accurately the process of vascularization of tissue engineered bone.