MicroRNA-645 promotes metastasis of osteosarcoma via targeting tumor suppressor NM23 nucleoside diphosphate kinase 2.

Osteosarcoma is the most common non-hematological primary bony malignancy in children and young adults with tumor metastasis being a common event at diagnosis. Understanding the pathogenesis of metastatic osteosarcoma may help identify potential therapeutic targets. In this study, we found that the level of microRNA-645 (miR-645) in osteosarcoma tumor tissues was significantly increased compared with their paired non-tumorous tissues, and was associated with histologic grade, TNM staging, lymph metastasis and distant metastasis. Knockdown of miR-645 caused a remarkable inhibition of migration of osteosarcoma U2OS cells. Furthermore, miR-645 inhibited NME2 (nucleoside diphosphate kinase 2) expression through directly binding to its 3' untranslated region. In human osteosarcoma tissues, we also found that NME2 was significantly decreased in tumor tissues, and its level was negatively correlated with miR-645. In addition, silencing NME2 attenuated the decreased cell migration by knockdown of miR-645, suggesting that it was involved in the miR-645 induced cell migration of osteosarcoma cells. Taken together, we found that miR-645 was up-regulated in osteosarcoma tissues and could promote osteosarcoma cell migration through directly inhibiting the tumor suppressor NME2. Our data provide novel insight into the role of miR-645 in osteosarcoma and indicate that miR-645 might be a potential therapeutic target of osteosarcoma.

Studies on [5,6]-Fused Bicyclic Scaffolds Derivatives as Potent Dual B-RafV600E/KDR Inhibitors Using Docking and 3D-QSAR Approaches.

Research and development of multi-target inhibitors has attracted increasing attention as anticancer therapeutics. B-RafV600E synergistically works with vascular endothelial growth factor receptor 2 (KDR) to promote the occurrence and progression of cancers, and the development of dual-target drugs simultaneously against these two kinds of kinase may offer a better treatment advantage. In this paper, docking and three-dimensional quantitative structure activity relationship (3D-QSAR) studies were performed on a series of dual B-Raf/KDR inhibitors with a novel hinge-binding group, [5,6]-fused bicyclic scaffold. Docking studies revealed optimal binding conformations of these compounds interacting with both B-Raf and KDR. Based on these conformations, comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA) 3D-QSAR models were constructed, and the best CoMFA (q²=0.542, r²=0.989 for B-Raf; q²=0.768, r²=0.991 for KDR) and CoMSIA models (q²=0.519, r²=0.992 for B-Raf; q²=0.849, r²=0.993 for KDR) were generated. Further external validations confirmed their predictability, yielding satisfactory correlation coefficients (r²pred=0.764 (CoMFA), r²pred=0.841 (CoMSIA) for B-Raf, r²pred=0.912 (CoMFA), r²pred=0.846 (CoMSIA) for KDR, respectively). Through graphical analysis and comparison on docking results and 3D-QSAR contour maps, key amino acids that affect the ligand-receptor interactions were identified and structural features influencing the activities were discussed. New potent derivatives were designed, and subjected to preliminary pharmacological evaluation. The study may offer useful references for the modification and development of novel dual B-Raf/KDR inhibitors.

[Targeting the substrate binding domain of polo-like kinase 1: advances in the study of PBD1 inhibitors].

Polo-box domain 1 (PBD1) is a characteristic domain of polo-like kinase 1 (PLK1), which locates in C-terminal and can influence the catalytic activity and specific subcellular locations of PLK1. At present, most PLK1 inhibitors are developed to occupy the ATP pocket or its close sites. However, this kind of PLK1 inhibitors is difficult to pursue target selectivity and may encounter cross drug resistance with other kinase inhibitors due to the conserved sequence of ATP pocket. Recently, PBD1, with aberrant specificity in sequence and structure, has attracted enormous interests as the alternative target to the discovery of corresponding inhibitors for anti-tumor drugs. The structure and function of PBD1 as well as the advances of its inhibitors are reviewed in this paper.

Hepatic Artery Injection of 131I-Metuximab Combined with Transcatheter Arterial Chemoembolization for Unresectable Hepatocellular Carcinoma: A Prospective Nonrandomized, Multicenter Clinical Trial.

This prospective nonrandomized, multicenter clinical trial was performed to investigate the efficacy and safety of 131I-labeled metuximab in adjuvant treatment of unresectable hepatocellular carcinoma. Methods: Patients were assigned to treatment with transcatheter arterial chemoembolization (TACE) combined with 131I-metuximab or TACE alone. The primary outcome was overall tumor recurrence. The secondary outcomes were safety and overall survival. Results: The median time to tumor recurrence was 6 mo in the TACE + 131I-metuximab group (n = 160) and 3 mo in the TACE group (n = 160) (hazard ratio, 0.55; 95% CI, 0.43-0.70; P < 0.001). The median overall survival was 28 mo in the TACE + 131I-metuximab group and 19 mo in the TACE group (hazard ratio, 0.62; 95% CI, 0.47-0.82; P = 0.001). Conclusion: TACE + 131I-metuximab showed a greater antirecurrence benefit, significantly improved the 5-y survival of patients with advanced hepatocellular carcinoma, and was well tolerated by patients.

Combined pharmacophore modeling, docking, and 3D-QSAR studies of PLK1 inhibitors.

Polo-like kinase 1, an important enzyme with diverse biological actions in cell mitosis, is a promising target for developing novel anticancer drugs. A combined molecular docking, structure-based pharmacophore modeling and three-dimensional quantitative structure-activity relationship (3D-QSAR) study was performed on a set of 4,5-dihydro-1H-pyrazolo[4,3-h]quinazoline derivatives as PLK1 inhibitors. The common substructure, molecular docking and pharmacophore-based alignment were used to develop different 3D-QSAR models. The comparative molecular field analysis (CoMFA) and comparative molecule similarity indices analysis (CoMSIA) models gave statistically significant results. These models showed good q(2) and r(2) (pred) values and revealed a good response to test set validation. All of the structural insights obtained from the 3D-QSAR contour maps are consistent with the available crystal structure of PLK1. The contour maps obtained from the 3D-QSAR models in combination with the structure based pharmacophore model help to better interpret the structure-activity relationship. These satisfactory results may aid the design of novel PLK1 inhibitors. This is the first report on 3D-QSAR study of PLK1 inhibitors.

Protective effect of hyperoside against hydrogen peroxide-induced dysfunction and oxidative stress in osteoblastic MC3T3-E1 cells.

Oxidative stress can induce apoptosis and decrease activities of osteoblasts. Hyperoside (HYP) is a potent antioxidant derived from Chinese herb. This study aims to evaluate the protective effects provided by HYP to osteoblastic MC3T3-E1 cells. MC3T3-E1 cells were pre-treated with HYP for 24 h before being treated with 0.3 mM hydrogen peroxide (H2O2) for 24 h. Cell viability, flow cytometric analysis and mRNA expression of alkaline phosphatase (ALP), collagen I (COL-I) and osteocalcin (OCN) in MC3T3-E1 cells were examined. We next examined apoptosis-related and mitogen-activated protein kinase (MAPK) related proteins in HYP and H2O2 groups. HYP over the dose of 40 µmol/L could obviously increase the MC3T3-E1 cell viability at 24 h and 48 h (p < .05). HYP significantly (p < .05) increased mRNA expression of ALP, COL-I and OCN than H2O2 group. Moreover, HYP decreased the apoptosis rate and apoptosis-related proteins that induced by H2O2. In addition, HYP decreased the production of phosphorylated Jun N-terminal kinase (JNK) and p38 levels of osteoblastic MC3T3-E1 cells induced by H2O2. These results demonstrated that the protective effect provided by HYP to osteoblastic MC3T3-E1 cells was mediated, at least in part, via inhibition of MAPK signalling pathway and oxidative damage of the cells.

Degradation of refuse in hybrid bioreactor landfill.

OBJECTIVE: To explore the process of refuse decomposition in hybrid bioreactor landfill. METHODS: The bioreactor landfill was operated in sequencing of facultative-anaerobic and aerobic conditions with leachate recirculation, pH, COD, and ammonia in the leachate and pH, biodegradable organic matter (BDM), and cation exchange capacity (CEC) in refuse were detected. RESULTS: CEC increased gradually with the degradation of refuse, which was negatively correlated with BDM. COD and ammonia in the leachate was declined to 399.2 mg L(-1) and 20.6 mg N L(-1), respectively, during the 357-day operation. The respective concentrations of ammonia and COD were below the second and the third levels of current discharge standards in China. CONCLUSION: The refuse is relatively stable at the end of hybrid bioreactor landfill operation. Most of the readily biodegradable organic matter is mineralized in the initial phase of refuse degradation, whereas the hard-biodegradable organic matter is mainly humidified in the maturity phase of refuse degradation.

Virtual Screening Strategy Combined Bayesian Classification Model, Molecular Docking for Acetyl-CoA Carboxylases Inhibitors.

INTRODUCTION: Acetyl-CoA Carboxylases (ACC) have been an important target for the therapy of metabolic syndrome, such as obesity, hepatic steatosis, insulin resistance, dyslipidemia, non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), type 2 diabetes (T2DM), and some other diseases. METHODS: In this study, virtual screening strategy combined with Bayesian categorization modeling, molecular docking and binding site analysis with protein ligand interaction fingerprint (PLIF) was adopted to validate some potent ACC inhibitors. First, the best Bayesian model with an excellent value of Area Under Curve (AUC) value (training set AUC: 0.972, test set AUC: 0.955) was used to screen compounds of validation library. Then the compounds screened by best Bayesian model were further screened by molecule docking again. RESULTS: Finally, the hit compounds evaluated with four percentages (1%, 2%, 5%, 10%) were verified to reveal enrichment rates for the compounds. The combination of the ligandbased Bayesian model and structure-based virtual screening resulted in the identification of top four compounds which exhibited excellent IC 50 values against ACC in top 1% of the validation library. CONCLUSION: In summary, the whole strategy is of high efficiency, and would be helpful for the discovery of ACC inhibitors and some other target inhibitors.

TIMP-1 suppressed by miR-138 participates in endoplasmic reticulum stress-induced osteoblast apoptosis in osteoporosis.

The aim of this study was to investigate the role of miR-138 in osteoporosis and its underlying mechanism. Hydrogen peroxide (H2O2) was used to induce osteoporotic injury of osteoblasts. The cell viability and apoptosis of MC3T3-E1 cells was assessed using MTT assay and flow cytometry, respectively. The cell transfection was carried out to modulate the expression levels of miR-138 and TIMP-1 in MC3T3-E1 cells. Luciferase reporter gene assay was performed to determine the interaction between miR-138 and TIMP-1 3'UTR. In the present study, H2O2 inhibited osteoblasts growth and induced intracellular endoplasmic reticulum (ER) stress accompanied by high expression of miR-138. We also confirmed that miR-138 promoted osteoblasts apoptosis in vitro and in vivo. MiR-138 was further indicated to inhibit osteoblast survival via negative regulating TIMP-1 expression. Moreover, the downregulated TIMP-1 also mediated the ER stress-induced apoptosis of osteoblasts. We confirmed that miR-138 and ER stress were induced in osteoporosis and then promoted the apoptosis of osteoblasts, at least in part, through TIMP-1.

Three-dimensional QSAR of HPPD inhibitors, PSA inhibitors, and anxiolytic agents: effect of tautomerism on the CoMFA models.

The present study was design to examine the effect of tautomerism upon the CoMFA results. Three selected data sets involving protropic tautomerism, which are 21 p-hydroxyphenylpyruvate dioxygenase (HPPD) inhibitors, 35 inhibitors of puromycin-sensitive aminopeptidase (PSA), and 67 anxiolytic agents, were used for this purpose. Atom-by-atom alignment technique was adopted to superimpose the molecules in the data sets onto a template. The structural alignments using different tautomeric forms had no significant difference except the atoms involved in tautomerism, which ensures, to a great extent, that the differences of the CoMFA results result primarily from the tautomerism. All-orientation and all-placement search (AOS-APS) based CoMFA models, in addition to the conventional ones, were derived for each system and proved to be capable of yielding much improved statistical results. In the cases of the data sets of HPPD inhibitors and PSA inhibitors, excellent AOS-APS CoMFA models (q2>0.8 with four components for the former and q2>0.7 with seven components for the latter) were obtained, and almost no significant difference in statistical quality was observed when using different tautomeric forms to derive the models. However, it was not the case when treating the data set of anxiolytic agents. The keto tautomer, which was the active form of the PBI type inhibitors, produced measurably better results (q2=0.54 with eight components) than that the enol one (q2=0.37 with five components), indicating the importance of selecting proper tautomer in the CoMFA studies. Furthermore, there existed some substantial differences of the electrostatic field contours between the two different tautomeric forms for all of the three systems considered, whereas the differences in the steric field contour maps were limited. This implies that the resulting new potent ligands may be quite different if one utilizes the CoMFA models of different tautomeric forms for guiding further structural refinements.

Phenotypic changes of Schwann cells on the proximal stump of injured peripheral nerve during repair using small gap conduit tube.

Dedifferentiation of Schwann cells is an important feature of the response to peripheral nerve injury and specific negative myelination regulators are considered to have a major role in this process. However, most experiments have focused on the distal nerve stump, where the Notch signaling pathway is strongly associated with Schwann cell dedifferentiation and repair of the nerve. We observed the phenotypic changes of Schwann cells and changes of active Notch signaling on the proximal stump during peripheral nerve repair using small gap conduit tubulization. Eighty rats, with right sciatic nerve section of 4 mm, were randomly assigned to conduit bridging group and control group (epineurium suture). Glial fibrillary acidic protein expression, in myelinating Schwann cells on the proximal stump, began to up-regulate at 1 day after injury and was still evident at 5 days. Compared with the control group, Notch1 mRNA was expressed at a higher level in the conduit bridging group during the first week on the proximal stump. Hes1 mRNA levels in the conduit bridging group significantly increased compared with the control group at 3, 5, 7 and 14 days post-surgery. The change of the Notch intracellular domain shared a similar trend as Hes1 mRNA expression. Our results confirmed that phenotypic changes of Schwann cells occurred in the proximal stump. The differences in these changes between the conduit tubulization and epineurium suture groups correlate with changes in Notch signaling. This suggests that active Notch signaling might be a key mechanism during the early stage of neural regeneration in the proximal nerve stump.

Chemical Space of FLT3 Inhibitors as Potential Anti-AML Drugs.

BACKGROUND: FLT3 is a member of receptor tyrosine kinase III family, mainly expressed in hematopoietic cells. The aberrant expression and function of FLT3 are strongly related to leukemia, especially acute myeloid leukemia. Its varieties of amino-acid residues mutations, such as FLT3-ITDs and -TKDs, can induce constant proliferation of hematological tumor cells with poor prognosis. Hence FLT3 serves as a promising target in AML chemotherapy. OBJECTIVE: This review focused on the progress of FLT3 inhibitors study including those that have entered clinical trials or were reported in numerous patents all over the world. Thus, we provided a useful reference for the development of new anti-leukemia drugs. METHOD: Through a comprehensive retrospective study, FLT3 inhibitors in several patent applications were identified and classified into five categories, including quinolone-related, indole-related, ureas, pyrimidines and other compounds. RESULTS: For each category of compounds, the structural feature, SAR, biological activity and current research status were thoroughly reviewed and analyzed. CONCLUSION: Although some of those compounds expressed potent bioactivities and have reached the advanced clinical trials for the treatment of leukemia, there are still several problems need to be faced before they enter the market eventually, especially the drug resistance issue. The improvement of therapeutic potency for FLT3 inhibitors might depend on the useful combination therapy and further refinement of the intrinsic properties of FLT3 inhibitors.

Role of recombinant plasmid pEGFP-N1-IGF-1 transfection in alleviating osteoporosis in ovariectomized rats.

Decreased levels of serum insulin-like growth factor-1 (IGF-1) have been proven to cause osteoporosis. Gene transfer of IGF-1 offers an attractive technology to treat skeletal metabolic disorders including osteoporosis, but the viral vectors are limited by their high antigenicity and immune response. Our purpose was to investigate the expression of a non-invasive vector, recombinant plasmid enhanced green fluorescent protein-N1 (pEGFP-N1) that transferred IGF-1 gene into ovariectomized (OVX) rats in vivo and evaluate the effect of this therapy on osteoporosis. OVX or sham operations were performed in 60 female, 7-month-old unmated SD rats. 12 weeks after OVX operation, the vectors were transfected to the 10-month-old rats and experimental data were detected from 48 h to 7 week after transfection. Our results showed that remarkable expression of fluorescence and serum IGF-1 was observed in the rats transfected by recombinant plasmids, indicating that IGF-1 gene was successfully transferred to OVX rats by injecting the vector through hydrodynamic method via the tail vein. The bone metabolism index including serum alkaline phosphatase, the histomorphometric parameters of lumbar vertebra including trabecular area percentage, trabecular thickness, trabecular number and trabecular separation, and the bone mineral density (BMD) and biomechanical parameters of lumbar vertebra including BMD, maximum condensing force, crushing strength in OVX rats transfected by pEGFP-N1-IGF-1 were improved remarkably compared with OVX+pEGFP-N1 rats, indicating that the transfection of recombinant plasmid pEGFP-N1-IGF-1 played a significant role in alleviating osteoporosis in rats induced by OVX. This encouraged a potential approach of IGF-1 gene therapy to the treatment of osteoporosis.

Management of lumbosacropelvic fracture-dislocation using lumbo-iliac internal fixation.

OBJECTIVE: Traumatic lumbosacropelvic fracture-dislocation is a rare but potentially serious injury. Conventional methods like lumbosacral fixation used to treat such injuries often result in suboptimal outcome secondary to complications like pseudoarthroses, sagittal imbalance and hardware failure. In this study, we retrospectively analysed the clinical features and management for this trauma using lumbo-iliac fixation. METHODS: Eight patients (6 male, 2 female; 21-52 years old, mean: 38.4) with traumatic lumbosacropelvic fracture-dislocation were surgically managed by lumbo-iliac internal fixation after lumbosacral decompression. Patients were followed up for 24-40 months (mean: 31.6). American Spine Injury Association (ASIA) scores were measured before surgery and at the last follow-up, and statistically analysed. RESULTS: After surgery, all patients experienced improved sensory and motor performance. Six patients showed recovery of bowel and bladder functions. Immediately after lumbo-iliac fixation, all patients could turn in bed without assistance. Lumbosacral alignment was restored immediately after surgery and no dislocation was observed during follow-up. Radiography indicated excellent integration between the autograft and the vertebrae. After surgery, no patient experienced neurological deterioration. CONCLUSION: Our experience with these cases suggests that early surgical decompression and posterior lumbo-iliac internal fixation can effectively restore spinal alignment, stabilise the spine, and improve neurological symptoms for this complex trauma.

Identification of novel polo-like kinase 1 inhibitors by a hybrid virtual screening.

Polo-like kinase 1 is an important and attractive oncological target that plays a key role in mitosis and cytokinesis. A combined pharmacophore- and docking-based virtual screening was performed to identify novel polo-like kinase 1 inhibitors. A total of 34 hit compounds were selected and tested in vitro, and some compounds showed inhibition of polo-like kinase 1 and human tumor cell growth. The most potent compound (66) inhibited polo-like kinase 1 with an IC(50) value of 6.99 µm. The docked binding models of two hit compounds were discussed in detail. These compounds contained novel chemical scaffolds and may be used as foundations for the development of novel classes of polo-like kinase 1 inhibitors.

Structure-based and shape-complemented pharmacophore modeling for the discovery of novel checkpoint kinase 1 inhibitors.

Checkpoint kinase 1 (Chk1), a member of the serine/threonine kinase family, is an attractive therapeutic target for anticancer combination therapy. A structure-based modeling approach complemented with shape components was pursued to develop a reliable pharmacophore model for ATP-competitive Chk1 inhibitors. Common chemical features of the pharmacophore model were derived by clustering multiple structure-based pharmacophore features from different Chk1-ligand complexes in comparable binding modes. The final model consisted of one hydrogen bond acceptor (HBA), one hydrogen bond donor (HBD), two hydrophobic (HY) features, several excluded volumes and shape constraints. In the validation study, this feature-shape query yielded an enrichment factor of 9.196 and performed fairly well at distinguishing active from inactive compounds, suggesting that the pharmacophore model can serve as a reliable tool for virtual screening to facilitate the discovery of novel Chk1 inhibitors. Besides, these pharmacophore features were assumed to be essential for Chk1 inhibitors, which might be useful for the identification of potential Chk1 inhibitors.

Recent advances in the research and development of B-Raf inhibitors.

Oncogenic B-Raf has been identified in a variety of cancers with high incidence, especially in malignant melanoma and thyroid cancer. Most B-Raf mutations elicit elevated kinase activity and the constitutive activation of Ras/Raf/MEK/ERK pathway, which induces proliferation and promotes malignant transformation. Therefore, B-Raf inhibitors, targeting B-Raf or mutated B-Raf, have received increasing momentum in oncology drug discovery arena. This review focuses on the diverse small-molecule inhibitors of B-Raf kinase recently reported in the literature, including those currently in clinical and preclinical phase. They are described as two categories, type I or type II kinase inhibitors, based on their different mechanism of action with active or inactive conformations of the B-Raf kinase derived from the available crystal structures or molecular docking analysis. A particular emphasis is placed on their binding modes and the structure-activity relationship (SAR) of each chemical structure class.

Ab initio study of the complexes of halogen-containing molecules RX (X=Cl, Br, and I) and NH3: towards understanding the nature of halogen bonding and the electron-accepting propensities of covalently bonded halogen atoms.

Ab initio calculations have been performed on a series of complexes formed between halogen-containing molecules and ammonia to gain a deeper insight into the nature of halogen bonding. It appears that the dihalogen molecules form the strongest halogen-bonded complexes with ammonia, followed by HOX; the charge-transfer-type contribution has been demonstrated to dominate the halogen bonding in these complexes. For the complexes involving carbon-bound halogen molecules, our calculations clearly indicate that electrostatic interactions are mainly responsible for their binding energies. Whereas the halogen-bond strength is significantly enhanced by progressive fluorine substitution, the substitution of a hydrogen atom by a methyl group in the CH(3)X...NH(3) complex weakened the halogen bonding. Moreover, remote substituent effects have also been noted in the complexes of halobenzenes with different para substituents. The influence of the hybridization state of the carbon atom bonded to the halogen atom has also been examined and the results reveal that halogen-bond strengths decrease in the order HC triple bond CX > H(2)C=CHX approximately O=CHX approximately C(6)H(5)X > CH(3)X. In addition, several excellent linear correlations have been established between the interaction energies and both the amount of charge transfer and the electrostatic potentials corresponding to an electron density of 0.002 au along the R-X axis; these correlations provide good models with which to evaluate the electron-accepting abilities of the covalently bonded halogen atoms. Finally, some positively charged halogen-bonded systems have been investigated and the effect of the charge has been discussed.