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Objective To assess the long-term prevalence, natural history, progression, and incidence of radiographic first metatarsophalangeal (MTP) joint osteoarthritis (OA). Methods A longitudinal cohort design was used in which radiographic OA at the first MTP joint was investigated in participants from the Chingford 1,000 Women Study at year 6 (1995) and year 23 (2013-2015). Radiographic features of osteophytes (OPs) and/or joint space narrowing (JSN) at the first MTP joint were scored according to a validated foot atlas. Natural history was determined by the change in prevalence, incidence, progression, and worsening of OA in the first MTP joint. Results Complete case-matched foot radiographic data were available for 193 of the women currently enrolled in the study (mean ± SD age 75.7 ± 5.2 years [range 69-90 years]). At the level of the first MTP joint, prevalence of OA at year 6 was 21.76% in the left and 24.35% in the right; at year 23, it was 23.83% in the left and 32.64% in the right. Over the 19-year period, 13.5% of the women developed incident OA in the right first MTP joint and 8.3% in the left. Both progression and worsening of OA were more evident for OPs and in the right first MTP joints. Conclusion In this study of the natural history of radiographic first MTP joint OA, which to our knowledge is the longest study to date, the prevalence and incidence of first MTP joint OA increased over a 19-year period. Progression and/or worsening of OA at the first MTP joint over time appears to be driven by OP development rather than JSN, which suggests a biomechanical cause.

Background: Cervicovaginal inflammation has been linked to negative reproductive health outcomes including acquisition of HIV, other sexually transmitted infections, and cervical carcinogenesis. While changes to the vaginal microbiome have been linked to genital inflammation, the molecular relationships between the functional components of the microbiome with cervical immunology in the reproductive tract are understudied, limiting our understanding of mucosal biology that may be important for reproductive health.Results: In this study we used a multi’-omics approach to profile cervicovaginal samples collected from 43 Canadian women to characterize host, immune, functional microbiome and metabolome features of cervicovaginal inflammation. We demonstrate that inflammation is associated with lower amounts of L. crispatus and increased levels of cervical antigen presenting cells (APCs). Proteomic analysis showed an upregulation of pathways related to neutrophil degranulation, complement, and leukocyte migration, with decreased levels of cornified envelope and cell-cell adherens junctions. Functional microbiome analysis showed reductions to carbohydrate metabolism and lactic acid, with increases of xanthine and other metabolites. Bayesian network analysis linked L. crispatus with glycolytic and nucleotide metabolism, succinate and xanthine, and epithelial proteins SCEL and IVL as major molecular features associated with pro-inflammatory cytokines and increased APCs.Conclusions: This study identified key molecular and immunological relationships with cervicovaginal inflammation, including increased APCs, bacterial metabolism, and proteome alterations that underlie inflammation. As APCs are involved in HIV transmission, parturition, and cervical cancer progression, further studies are needed to explore the interactions between these cells, bacterial metabolism, mucosal immunity, and their relationship to reproductive health.

Animal models recapitulating features of chronic colitis, such as ulcerative colitis, Crohn’s disease, or HIV infection, are critical to study disease pathogenesis and test novel therapeutics. In this study, we used a proteomics approach to explore the molecular intestinal response in two rhesus macaque (RM) animal models of experimentally induced colitis using dextran sulfate sodium (DSS) and simian immunodeficiency virus (SIV) infection. Proteomic analysis detected more than 2500 proteins in colonic tissue collected from 30 RMs. Differential protein expression analysis revealed a protein expression pattern in DSS-treated RMs resembling the proteome of human ulcerative colitis. In a group of 12 DSS-treated RMs compared to 6 with no treatment, decrease in expression of proteins related to mitochondrial energy metabolism, including fatty acid metabolism was noted, while innate immune activation pathways, including complement and coagulation proteins were upregulated. SIV infection of RMs resulted in increased innate immune responses related to viral defense. Proteomic signatures of barrier damage were apparent in both DSS treatment or SIV infection. These results demonstrate that DSS treatment in a non-human primate model resembles features of human ulcerative colitis, making this a promising tool to study important immunological mechanisms in inflammatory bowel disease.

Vaccination and administration of monoclonal antibody cocktails are effective tools to control the progression of infectious diseases and to terminate pandemics such as COVID-19. However, the emergence of SARS-CoV-2 mutants with enhanced transmissibility and altered antigenicity requires broad-spectrum therapies. Here we developed a panel of SARS-CoV-2 specific mouse monoclonal antibodies (mAbs), and characterized them based on ELISA, Western immunoblot, isotyping, and virus neutralization. Six neutralizing mAbs that exhibited high-affinity binding to SARS-CoV-2 spike protein were identified, and their amino acid sequences were determined by mass spectrometry. Functional assays confirmed that three mAbs, F461G11, F461G15, and F461G16 neutralized four variants of concern (VOC): B.1.1.7 (alpha), B.1.351 (beta), P.1 (gamma) and B.1.617.2 (delta) These mAbs are promising candidates for COVID-19 therapy, and understanding their interactions with virus spike protein should support further vaccine and antibody development.

Label free quantitation by measurement of peptide fragment signal intensity (MS2 quantitation) is a technique that has seen limited use due to the stochastic nature of data dependent acquisition (DDA). However, data independent acquisition has the potential to make large scale MS2 quantitation a more viable technique. In this study we used an implementation of data independent acquisition--SWATH--to perform label free protein quantitation in a model bacterium Clostridium stercorarium. Four tryptic digests analyzed by SWATH were probed by an ion library containing information on peptide mass and retention time obtained from DDA experiments. Application of this ion library to SWATH data quantified 1030 proteins with at least two peptides quantified (∼ 40% of predicted proteins in the C. stercorarium genome) in each replicate. Quantitative results obtained were very consistent between biological replicates (R(2) ∼ 0.960). Protein quantitation by summation of peptide fragment signal intensities was also highly consistent between biological replicates (R(2) ∼ 0.930), indicating that this approach may have increased viability compared to recent applications in label free protein quantitation. SWATH based quantitation was able to consistently detect differences in relative protein quantity and it provided coverage for a number of proteins that were missed in some samples by DDA analysis.

Background: Ulnar collateral ligament (UCL) reconstruction of the elbow has become increasingly more frequent among elite overhead athletes. The purpose of this study was to conduct a systematic review comparing the clinical outcomes and biomechanical results of the Jobe, modified Jobe, docking, modified docking, Endobutton, and interference screw techniques for UCL reconstruction. Hypothesis: The docking technique will have significantly fewer complications and improved return-to-play rate. Study Design: Systematic review; Level of evidence, 4. Methods: Using the Medline PubMed, Cochrane, and EMBASE databases, a search was performed of all published articles, including randomized controlled trials, cohort studies, and case series, examining UCL reconstructions performed using one of the above noted techniques and excluding case reports and hybrid techniques. Statistical analysis was performed using a χ2 test of independence and 2-proportion Z test. Results: A total of 21 studies, 7 biomechanical and 14 clinical, met the inclusion criteria. There were 1368 patients. The overall complication rate was 18.6% (255/1368), further subdivided into 21 for the Jobe technique (29.2%), 203 for the modified Jobe technique (19.1%), 2 for the interference screw technique (10.0%), 2 (4.3%) for the modified docking technique, and 10 for the docking technique (6.0%). The most common complication across all studies was ulnar nerve neurapraxia in 176 patients (12.9%). The overall rate of return to play was 78.9%. Conclusion: Ulnar collateral ligament reconstruction utilizing the docking technique results in a significantly higher rate of return to play and a lower complication rate when compared with the Jobe and modified Jobe techniques. Clinical Relevance: A lower complication rate can lead to increased rates of return to play and better outcomes postoperatively.

Evaluation of: Stephanowitz H, Lange S, Lang D et al. Improved two-dimensional reversed phase–reversed phase LC-MS/MS approach for identification of peptide–protein interactions. J. Proteome Res. 11(2), 1175–1183 (2011).Recent developments in bottom-up proteomics have supplanted the use of gel-based approaches in favor of multidimensional chromatographic separations of peptide mixtures followed by mass spectrometry analysis. This trend is driven by the desire to eliminate labor-intensive in-gel digestion procedures and increase proteome coverage through better recovery of proteolytic fragments. Introduction of reversed-phase–reversed-phase 2D separation techniques is one of the major improvements that have made this possible. In this article, we review recent developments in 2D HPLC and highlight variations in reversed-phase HPLC separation selectivity that allow for superior peak capacity in peptide fractionation.

We have developed a real-time graphic-processor-unit-based search engine capable of high-quality peptide identifications in500 μs per spectrum. The steps of peptide/protein identification, in-silico prediction of all possible tryptic peptides from these proteins, and the prediction of their expected retention times and m/z values take less than 5 s per cycle over ∼3000 MS/MS spectra. This lays the foundation for information-dependent acquisition with exclusion lists generated on-the-fly, as the instrument continues to acquire data. While a complete evaluation of the dynamic exclusion system requires the participation from instrument vendors, we conducted a series of model experiments using a whole cell tryptic digestion of the bacterium Clostridium thermocellum. We ran a series of five iterative LC-MS/MS runs, adding a new exclusion list at each of four chromatographic "tripping points" - the elution times of the four standard peptides spiked into the sample. Retention times of these standard peptides were also used for real-time "chromatographic calibration." The dynamic exclusion approach gave a ≈ 5% increase in confident protein identification (for typical 2 h LC-MS/MS run), and reduced the average number of identified peptides per protein from 4.7 to 2.9. Its application to a two-times shorter gradient gave a ≈ 17% increase in proteins identified. Further improvements are possible for instruments with better mass accuracy, by employing a more accurate retention prediction algorithm and by developing better understanding of the possible chemical modifications and fragmentations produced during electrospray ionization.

Osteosarcoma is the most common primary bone malignancy, with a high propensity for local invasion, early metastasis and relapse. While the molecular mechanisms behind osteosarcoma development and metastasis have not yet been fully elucidated, research has highlighted an important role for Wnt signaling. Several Wnt ligands, receptors and coreceptors are highly expressed in osteosarcoma cell lines, while Wnt inhibitors are downregulated. As a result, research has begun to identify mechanisms with which to inhibit Wnt signaling. The use of Wnt pathway inhibitors and the targeting of c-Met, a Wnt regulated proto-oncogene, may be two possible mechanisms for treatment of osteosarcoma. In addition, as the Wnt signaling pathway is a regulator of stem cells, reagents that function as Wnt inhibitors are currently under investigation as inhibitors of cancer stem cell proliferation. Research involving the Wnt signaling pathway and cancer stem cells holds promise for novel treatment options in the future.

The human immunodeficiency virus type 1 (HIV-1) genome encodes 18 proteins and 2 peptides. Four of these proteins encode high-affinity calmodulin-binding sites for which direct interactions with calmodulin have already been described. In this study, the HIV-1 proteome is queried using an algorithm that predicts calmodulin-binding sites revealing seven new putative calmodulin-binding sites including residues 34-56 of the transactivator of transcription (Tat). Tat is a 101-residue intrinsically disordered RNA-binding protein that plays a central role in the regulation of HIV-1 replication. Interactions between a Tat peptide (residues 34-56), melittin, a well-characterized calmodulin-binding peptide, and calmodulin were examined by direct binding studies, mass spectrometry, and fluorescence. The Tat peptide binds to both calcium-saturated and apo-calmodulin with a low micromolar affinity. Conformational changes induced in the Tat peptide were determined by circular dichroism, and residues in calmodulin that interact with the peptide were identified by HSQC NMR spectroscopy. Multiple interactions between HIV-1 proteins and calmodulin, a highly promiscuous signal transduction hub protein, may be an important mechanism by which the virus controls cell physiology.

The mucosal surface of the female genital tract contains physiological, immunological, and microbial components that collectively comprise a functioning "mucosal system" that is critical for reproductive health. Alterations or imbalances to any of these components can have significant consequences for susceptibility to sexually transmitted infections, such as HIV. In recent years the advent of advanced systems biology technologies, such as metaproteomics, has provided new toolsets to studying mucosal systems. Studies have linked an altered mucosal proteome to many HIV risk factors including mucosal inflammation, bacterial vaginosis, hormonal contraceptives, and reduced efficacy of antiretroviral drugs for HIV prevention. Herein we will discuss how metaproteomics has been used to study mucosal system components, including epithelial barriers, inflammation, and the microbiome, with a focus on what alterations may contribute to increased HIV transmission risk in women.

Background: Musculoskeletal (MSK) disease is the major cause of years lived with disability in the UK. The UK is behind other comparable countries in confronting consequences of long-term diseases. One potentially effective approach is by educating people to become more health literate. Early life interventions relating to exercise and good MSK health practices may be an effective addition to traditional approaches. LifeLab is a science-based approach to improving teenagers’ health-related attitudes and behaviour. The LifeLab approach was developed at the University of Southampton and combines educationalists, scientists, clinical researchers and school children and has been effective in improving young peoples’ understanding of the nature of diseases and reasoning about health issues. However, no specific MSK health education components have previously been included in LifeLab. Methods: In 2014 the first MSK LifeLab workshop was designed with educationalists and researchers in biomechanics, occupational therapy, podiatry, and physiotherapy from the MSK Research Cluster at Southampton for year 8 (age 12-13) school students. The workshops aimed to promote young peoples’ health literacy in musculoskeletal health and integrated experiential learning using 3D motion analysis, real-time ultrasound scanning of muscles contracting; radiographs of normal and osteoarthritis foot joints; anatomy models and hand and hip joint implants. The workshops covered a) the impact of osteoarthritis joint disease on daily life b) capturing and illustrating joint movement using state of the art 3D motion analysis technology and c) an in-depth look at muscles using ultrasound imaging. Learning objectives included students being able to: 1. Identify key components of active healthy living for bones, muscles and joints 2. Observe patterns in how healthy joints can move and contrast patterns with injured joint movement 3. Discover what role muscles play in healthy joints 4. Compare healthy joint structures with arthritic joint structures Results: 58 students from 3 state secondary schools, attended a university widening participation outreach day within which the MSK LifeLab workshop was run. On the same day the students also attended workshops in Humanities and Oceanography. When asked which workshop of the outreach day was their favourite 43 % of the students identified the MSK workshops. Feedback on why the workshops were enjoyable included; “I enjoyed biomechanics because I like looking at how things work and move”; “Ostioarphritus. I'm into sports & find the body interesting”; “The bones because you got to find out about the body”. The interactive nature of the workshop with teenagers having hands on learning was also well received “My favourite was bones because they made it fun”; “The bones experiments because the technology involved was awesome.” Conclusions: Using interactive MSK workshops as part of LifeLab presents an exciting health literacy approach to encourage young people to start to engage in understanding their MSK health. Acknowledgements: These are not included in the abstract but will appear if we get a paper accepted. LifeLab, has been developed as a joint initiative, involving, in addition to the University of Southampton and the University Hospital Southampton NHS Foundation Trust; the MRC Lifecourse Epidemiology Unit, the University of Southampton (UoS) Faculty of Medicine and Southampton Education School, the Mathematics and Science Learning Centre (MSLC), the NIHR Southampton Biomedical Research Centre and the Garfield Weston Foundation. KWT is supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Centre Some facilities and personnel in the MSK Research Cluster are funded by Arthritis Research UK.

Background To report a case series of failures of bioabsorbable interference screws with possible identification of a novel failure mechanism. Methods A retrospective review of ACL reconstructions by the senior author utilizing BioComposite™ Interference Screws (Arthrex, Inc., Naples, FL) was performed. Complications related to screw placement, including fracture, breakage or bending were examined. Our rate and methods of failure were compared to those quoted in the current literature. Results Eighty-seven patients of average age 23.8 years met inclusion criteria. There were eight screw failures in six patients, with femoral failure in seven and tibial failure in one. The femoral screw fractured halfway between the tip and head in five, while the head of the screw broke in one and the screw bent in another. In the case of tibial interference screw fracture, failure occurred halfway between the tip and head. The insertion device that was used was replaced after recognition of material deformation and considered a potential contributor to the breakage risk as no further screw failures have occurred since. Conclusions We demonstrate a unique failure mechanism of bio-absorbable interference screws. In each case, the reconstruction was salvaged. Regular inspection of materials and implants can ensure optimal outcomes and decrease complications intra-operatively.

Background Neuropilin 2 (NRP2) isa multi-functional co-receptor to many receptors, including VEGF receptor, c-Met and others. NRP2 has recently been implicated in tumor angiogenesis, growth, and metastasis of many other cancers. However, its role in osteosarcoma remains poorly understood. Results NRP2 was overexpressed in osteosarcoma cell lines and tissues, and associated with poor survival of osteosarcoma patients. Knockdown of NRP2 expression by short-hairpin (Sh) RNA resulted in reduced tumor growth, metastasis, and blood vessel formation of osteosarcoma. Knockdown of NRP2 expression by ShRNA also inhibited the recruitment of HUVEC cells to osteosarcoma cells. Inhibition of Wnt signaling by overexpression of secreted Wnt antagonists soluble LRP5, Frzb, and WIF1 markedly down-regulated mRNA and protein expression of NRP2 in osteosarcoma cell lines. Conclusions Regulation of NRP2 receptor expression may represent a novel approach for treatment of osteosarcoma through retarding osteosarcoma growth, metastasis and blood vessel formation. In addition, down-regulation of NRP2 expression can be achieved by expression of secreted Wnt antagonists. Electronic supplementary material The online version of this article (doi:10.1186/s12943-015-0359-4) contains supplementary material, which is available to authorized users.

Osteosarcoma (OS) is the most common primary bone malignancy with a high propensity for local invasion and distant metastasis. Despite current multidisciplinary treatments, there has not been a drastic change in overall prognosis within the past 2 decades. Dickkopf-3 protein (Dkk-3/REIC) has been known to inhibit canonical Wnt/β-catenin pathway, and its expression has been shown to be downregulated in OS cell lines. Usingin vivoandin vitrostudies, we demonstrated that Dkk-3-transfected 143B cells inhibited tumorigenesis and metastasis in an orthotopic xenograft model of OS. Inoculation of Dkk-3-transfected 143B cell lines into nude mice showed significant decreased tumor growth and less metastatic pulmonary nodules (88.7%) compared to the control vector.In vitroexperiments examining cellular motility and viability demonstrated less anchorage-independent growth and decreased cellular motility for Dkk-3-transfected 143B and SaOS2 cell lines compared to the control vector. Downstream expressions of Met, MAPK, ALK, and S1004A were also downregulated in Dkk-3-transfected SaOS2 cells, suggesting the ability of Dkk-3 to inhibit tumorigenic potential of OS. Together, these data suggest that Dkk-3 has a negative impact on the progression of osteosarcoma. Reexpressing Dkk-3 in Dkk-3-deficient OS tumors may prove to be of benefit as a preventive or therapeutic strategy.

Background Clostridium thermocellum produces H2 and ethanol, as well as CO2, acetate, formate, and lactate, directly from cellulosic biomass. It is therefore an attractive model for biofuel production via consolidated bioprocessing. Optimization of end-product yields and titres is crucial for making biofuel production economically feasible. Relative protein expression profiles may provide targets for metabolic engineering, while understanding changes in protein expression and metabolism in response to carbon limitation, pH, and growth phase may aid in reactor optimization. We performed shotgun 2D-HPLC-MS/MS on closed-batch cellobiose-grown exponential phase C. thermocellum cell-free extracts to determine relative protein expression profiles of core metabolic proteins involved carbohydrate utilization, energy conservation, and end-product synthesis. iTRAQ (isobaric tag for relative and absolute quantitation) based protein quantitation was used to determine changes in core metabolic proteins in response to growth phase. Results Relative abundance profiles revealed differential levels of putative enzymes capable of catalyzing parallel pathways. The majority of proteins involved in pyruvate catabolism and end-product synthesis were detected with high abundance, with the exception of aldehyde dehydrogenase, ferredoxin-dependent Ech-type [NiFe]-hydrogenase, and RNF-type NADH:ferredoxin oxidoreductase. Using 4-plex 2D-HPLC-MS/MS, 24% of the 144 core metabolism proteins detected demonstrated moderate changes in expression during transition from exponential to stationary phase. Notably, proteins involved in pyruvate synthesis decreased in stationary phase, whereas proteins involved in glycogen metabolism, pyruvate catabolism, and end-product synthesis increased in stationary phase. Several proteins that may directly dictate end-product synthesis patterns, including pyruvate:ferredoxin oxidoreductases, alcohol dehydrogenases, and a putative bifurcating hydrogenase, demonstrated differential expression during transition from exponential to stationary phase. Conclusions Relative expression profiles demonstrate which proteins are likely utilized in carbohydrate utilization and end-product synthesis and suggest that H2 synthesis occurs via bifurcating hydrogenases while ethanol synthesis is predominantly catalyzed by a bifunctional aldehyde/alcohol dehydrogenase. Differences in expression profiles of core metabolic proteins in response to growth phase may dictate carbon and electron flux towards energy storage compounds and end-products. Combined knowledge of relative protein expression levels and their changes in response to physiological conditions may aid in targeted metabolic engineering strategies and optimization of fermentation conditions for improvement of biofuels production.

Background Growing interest in cellulolytic clostridia with potential for consolidated biofuels production is mitigated by low conversion of raw substrates to desired end products. Strategies to improve conversion are likely to benefit from emerging techniques to define molecular systems biology of these organisms. Clostridium stercorarium DSM8532T is an anaerobic thermophile with demonstrated high ethanol production on cellulose and hemicellulose. Although several lignocellulolytic enzymes in this organism have been well-characterized, details concerning carbohydrate transporters and central metabolism have not been described. Therefore, the goal of this study is to define an improved whole genome sequence (WGS) for this organism using in-depth molecular profiling by RNA-seq transcriptomics and tandem mass spectrometry-based proteomics. Results A paired-end Roche/454 WGS assembly was closed through application of an in silico algorithm designed to resolve repetitive sequence regions, resulting in a circular replicon with one gap and a region of 2 kilobases with 10 ambiguous bases. RNA-seq transcriptomics resulted in nearly complete coverage of the genome, identifying errors in homopolymer length attributable to 454 sequencing. Peptide sequences resulting from high-throughput tandem mass spectrometry of trypsin-digested protein extracts were mapped to 1,755 annotated proteins (68% of all protein-coding regions). Proteogenomic analysis confirmed the quality of annotation and improvement pipelines, identifying a missing gene and an alternative reading frame. Peptide coverage of genes hypothetically involved in substrate hydrolysis, transport and utilization confirmed multiple pathways for glycolysis, pyruvate conversion and recycling of intermediates. No sequences homologous to transaldolase, a central enzyme in the pentose phosphate pathway, were observed by any method, despite demonstrated growth of this organism on xylose and xylan hemicellulose. Conclusions Complementary omics techniques confirm the quality of genome sequence assembly, annotation and error-reporting. Nearly complete genome coverage by RNA-seq likely indicates background DNA in RNA extracts, however these preps resulted in WGS enhancement and transcriptome profiling in a single Illumina run. No detection of transaldolase by any method despite xylose utilization by this organism indicates an alternative pathway for sedoheptulose-7-phosphate degradation. This report combines next-generation omics techniques to elucidate previously undefined features of substrate transport and central metabolism for this organism and its potential for consolidated biofuels production from lignocellulose. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-567) contains supplementary material, which is available to authorized users.

Purpose of Study: To investigate the role of the Neuropilin-1 (NRP-1) in angiogenesis and regulation by Wnt-signaling pathway in osteosarcoma (OS) cell lines. Methods: In vitro tube formation assay using HUVEC cells to examine the effect of Frzb, WIF1, and DKK3 on angiogenesis. Microarray and real-time PCR to assess the mRNA level of NRP-1 in SaOS-2 cells transfected with Dominant Negative LRP5 (DNLRP5) and PcDNA vector control. Western blots were performed to evaluate the expression of NRP-1 in 8 OS cell lines and normal osteoblast (NHOst), as well as the effect of Wnt inhibitors (DNLPR5, Frzb, WIF-1, DKK3) on NRP-1 expression in OS cell lines (LM7, 143B, and 143.98.2) Results: In order to develop a new therapeutic target for OS, the most common primary malignant bone tumor, we examined the expression of NRP-1 and vascular endothelial growth factor (VEGF) in 8 established OS cell lines, as well as NHOst. Both VEGF and NRP-1 (a co-receptor of VEGF) were up-regulated in most OS cell lines compared with normal osteoblast, suggesting that VEGF and NRP-1 may be responsible for the excessive blood vessel formation in OS. Given our previous report that Wnt inhibitors Frzb, WIF1, DKK3, and DNLRP5, inhibited tumor growth and metastasis of OS, we hypothesize that one of the potential mechanisms may be through inhibition of tumor angiogenesis. When HUVEC assay was examined, DKK3, Frzb, WIF-1 condition medium significantly inhibited tube formation compared with control, suggesting that these Wnt inhibitors suppressed angiogenesis. Further microarray assay, real time PCR and western blots indicated that these Wnt inhibitors (DKK3, Frzb, WIF-1 and DNLRP5) dramatically down-regulated the expression of NRP-1, but VEGF level remained unchanged. These results show that inhibition of angiogenesis by Wnt signaling may be mediated by down-regulation of NRP-1 instead of VEGF. Discussion and Conclusions: Our study suggests that the Wnt-signaling reduces tumor growth and metastasis by inhibiting angiogenesis and by down-regulating NRP-1 expression in OS. We are further studying the role of NRP-1 in osteosarcoma by knockdown of NRP1 expression in OS cells to assess tumor proliferation, metastases and angiogenesis. This may represent a novel therapeutic strategy for osteosarcoma. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3963.