| 1. |
- Berggrund, Malin, et al.
(författare)
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Identification of candidate plasma protein biomarkers for cervical cancer using the multiplex proximity extension assay
- 2019
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 18:4, s. 735-743
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Tidskriftsartikel (refereegranskat)abstract
- Human papillomavirus (HPV) is recommended as the primary test in cervical cancer screening, with co-testing by cytology for HPV-positive women to identify cervical lesions. Cytology has low sensitivity and there is a need to identify biomarkers that could identify dysplasia that are likely to progress to cancer. We searched for plasma proteins that could identify women with cervical cancer using the multiplex proximity extension assay (PEA). The abundance of 100 proteins were measured in plasma collected at the time of diagnosis of patients with invasive cervical cancer and in population controls using the Olink Multiplex panels CVD II, INF I, and ONC II. Eighty proteins showed increased levels in cases compared to controls. We identified a signature of 11 proteins (PTX3, ITGB1BP2, AXIN1, STAMPB, SRC, SIRT2, 4E-BP1, PAPPA, HB-EGF, NEMO and IL27) that distinguished cases and controls with a sensitivity of 0.96 at a specificity of 1.0. This signature was evaluated in a prospective replication cohort with samples collected before, at or after diagnosis and achieved a sensitivity of 0.78 and a specificity 0.56 separating samples collected at the time of diagnosis of invasive cancer from samples collected prior to diagnosis. No difference in abundance was seen between samples collected prior to diagnosis or after treatment as compared to population controls, indicating that this protein signature is mainly informative close to time of diagnosis. Further studies are needed to determine the optimal window in time prior to diagnosis for these biomarker candidates.
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| 2. |
- Björkesten, Johan, et al.
(författare)
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Stability of Proteins in Dried Blood Spot Biobanks.
- 2017
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 16:7, s. 1286-1296
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Tidskriftsartikel (refereegranskat)abstract
- An important motivation for the construction of biobanks is to discover biomarkers that identify diseases at early, potentially curable stages. This will require biobanks from large numbers of individuals, preferably sampled repeatedly, where the samples are collected and stored under conditions that preserve potential biomarkers. Dried blood samples are attractive for biobanking because of the ease and low cost of collection and storage. Here we have investigated their suitability for protein measurements. 92 proteins with relevance for oncology were analyzed using multiplex proximity extension assays (PEA) in dried blood spots collected on paper and stored for up to 30 years at either +4°C or -24°C. Our main findings were that 1) the act of drying only slightly influenced detection of blood proteins (average correlation of 0.970), and in a reproducible manner (correlation of 0.999), 2) detection of some proteins was not significantly affected by storage over the full range of three decades (34% and 76% of the analyzed proteins at +4°C and -24°C, respectively), while levels of others decreased slowly during storage with half-lives in the range of 10 to 50 years, and 3) detectability of proteins was less affected in dried samples stored at -24°C compared to at +4°C, as the median protein abundance had decreased to 80% and 93% of starting levels after 10 years of storage at +4°C or -24°C, respectively. The results of our study are encouraging as they suggest an inexpensive means to collect large numbers of blood samples, even by the donors themselves, and to transport, and store biobanked samples as spots of whole blood dried on paper. Combined with emerging means to measure hundreds or thousands of protein, such biobanks could prove of great medical value by greatly enhancing discovery as well as routine analysis of blood biomarkers.
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| 3. |
- Blokzijl, Andries, et al.
(författare)
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Single Chain Antibodies as Tools to Study transforming growth factor--Regulated SMAD Proteins in Proximity Ligation-Based Pharmacological Screens
- 2016
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 15:6, s. 1848-1856
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Tidskriftsartikel (refereegranskat)abstract
- The cellular heterogeneity seen in tumors, with subpopulations of cells capable of resisting different treatments, renders single-treatment regimens generally ineffective. Accordingly, there is a great need to increase the repertoire of drug treatments from which combinations may be selected to efficiently target sets of pathological processes, while suppressing the emergence of resistance mutations. In this regard, members of the TGF- signaling pathway may furnish new, valuable therapeutic targets. In the present work, we developed in situ proximity ligation assays (isPLA) to monitor the state of the TGF- signaling pathway. Moreover, we extended the range of suitable affinity reagents for this analysis by developing a set of in-vitro-derived human antibody fragments (single chain fragment variable, scFv) that bind SMAD2 (Mothers against decapentaplegic 2), 3, 4, and 7 using phage display. These four proteins are all intracellular mediators of TGF- signaling. We also developed an scFv specific for SMAD3 phosphorylated in the linker domain 3 (p179 SMAD3). This phosphorylation has been shown to inactivate the tumor suppressor function of SMAD3. The single chain affinity reagents developed in the study were fused tocrystallizable antibody fragments (Fc-portions) and expressed as dimeric IgG-like molecules having Fc domains (Yumabs), and we show that they represent valuable reagents for isPLA. Using these novel assays, we demonstrate that p179 SMAD3 forms a complex with SMAD4 at increased frequency during division and that pharmacological inhibition of cyclin-dependent kinase 4 (CDK4)(1) reduces the levels of p179SMAD3 in tumor cells. We further show that the p179SMAD3-SMAD4 complex is bound for degradation by the proteasome. Finally, we developed a chemical screening strategy for compounds that reduce the levels of p179SMAD3 in tumor cells with isPLA as a read-out, using the p179SMAD3 scFv SH544-IIC4. The screen identified two kinase inhibitors, known inhibitors of the insulin receptor, which decreased levels of p179SMAD3/SMAD4 complexes, thereby demonstrating the suitability of the recombinant affinity reagents applied in isPLA in screening for inhibitors of cell signaling.
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| 4. |
- Boulund, Fredrik, 1985, et al.
(författare)
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Typing and Characterization of Bacteria Using Bottom-up Tandem Mass Spectrometry Proteomics
- 2017
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 16:6, s. 1052-1063
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Tidskriftsartikel (refereegranskat)abstract
- Methods for rapid and reliable microbial identification are essential in modern healthcare. The ability to detect and correctly identify pathogenic species and their resistance phenotype is necessary for accurate diagnosis and efficient treatment of infectious diseases. Bottom-up tandem mass spectrometry (MS) proteomics enables rapid characterization of large parts of the expressed genes of microorganisms. However, the generated data are highly fragmented, making downstream analyses complex. Here we present TCUP, a new computational method for typing and characterizing bacteria using proteomics data from bottom-up tandem MS. TCUP compares the generated protein sequence data to reference databases and automatically finds peptides suitable for characterization of taxonomic composition and identification of expressed antimicrobial resistance genes. TCUP was evaluated using several clinically relevant bacterial species (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae), using both simulated data generated by in silico peptide digestion and experimental proteomics data generated by liquid chromatography-tandem mass spectrometry (MS/MS). The results showed that TCUP performs correct peptide classifications at rates between 90.3 and 98.5% at the species level. The method was also able to estimate the relative abundances of individual species in mixed cultures. Furthermore, TCUP could identify expressed beta-lactamases in an extended spectrum beta-lactamase-producing (ESBL) E.coli strain, even when the strain was cultivated in the absence of antibiotics. Finally, TCUP is computationally efficient, easy to integrate in existing bioinformatics workflows, and freely available under an open source license for both Windows and Linux environments.
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| 5. |
- Dubois, Louise, et al.
(författare)
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Proteomic profiling of detergent resistant membranes (lipid rafts) of prostasomes
- 2015
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 14:11, s. 3015-3022
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Tidskriftsartikel (refereegranskat)abstract
- Prostasomes are exosomes derived from prostate epithelial cells through exocytosis by multivesicular bodies. Prostasomes have a bilayered membrane and readily interact with sperm. The membrane lipid composition is unusual with a high contribution of sphingomyelin at the expense of phosphatidylcholine and saturated and monounsaturated fatty acids are dominant. Lipid rafts are liquid-ordered domains that are more tightly packed than the surrounding non-raft phase of the bilayer. Lipid rafts are proposed to be highly dynamic, submicroscopic assemblies that float freely within the liquid disordered membrane bilayer and some proteins preferentially partition into the ordered raft domains. We asked the question whether lipid rafts do exist in prostasomes and, if so, which proteins might be associated with them. Prostasomes of density range 1.13-1.19g/mL were subjected to density gradient ultracentrifugation in sucrose fabricated by phosphate buffered saline (PBS) containing 1% Triton X-100 with capacity for banding at 1.10g/mL, i.e. the classical density of lipid rafts. Prepared prostasomal lipid rafts (by gradient ultracentrifugation) were analyzed by mass spectrometry and electron microscopy. The clearly visible band on top of 1.10g/mL sucrose in the Triton X-100 containing gradient was subjected to LC-MS/MS and more than 370 lipid raft associated proteins were identified. Several of them were involved in intraluminal vesicle formation, e.g. tetraspanins, ESCRTs and Ras-related proteins. This is the first comprehensive LC-MS/MS profiling of proteins in lipid rafts derived from exosomes. Data are available via ProteomeXchange with identifier PXD002163.
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| 6. |
- El-Rami, Fadi E., et al.
(författare)
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Quantitative proteomics of the 2016 WHO Neisseria gonorrhoeae reference strains surveys vaccine candidates and antimicrobial resistance determinants
- 2019
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Ingår i: Molecular & Cellular Proteomics. - : American Society for Biochemistry and Molecular Biology. - 1535-9476 .- 1535-9484. ; 18:1, s. 127-150
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Tidskriftsartikel (refereegranskat)abstract
- The sexually transmitted disease gonorrhea (causative agent: Neisseria gonorrhoeae) remains an urgent public health threat globally due to its reproductive health repercussions, high incidence, widespread antimicrobial resistance (AMR), and absence of a vaccine. To mine gonorrhea antigens and enhance our understanding of gonococcal AMR at the proteome level, we performed the first large-scale proteomic profiling of a diverse panel (n=15) of gonococcal strains, including the 2016 World Health Organization (WHO) reference strains. These strains show all existing AMR profiles - established through phenotypic characterization and reference genome publication - and are intended for quality assurance in laboratory investigations. Herein, these isolates were subjected to subcellular fractionation and labeling with tandem mass tags coupled to mass spectrometry and multi-combinatorial bioinformatics. Our analyses detected 904 and 723 common proteins in cell envelope and cytoplasmic subproteomes, respectively. We identified nine novel gonorrhea vaccine candidates. Expression and conservation of new and previously selected antigens were investigated. In addition, established gonococcal AMR determinants were evaluated for the first time using quantitative proteomics. Six new proteins, WHO_F_00238, WHO_F_00635c, WHO_F_00745, WHO_F_01139, WHO_F_01144c, and WHO_F_01126, were differentially expressed in all strains, suggesting that they represent global proteomic AMR markers, indicate a predisposition toward developing or compensating gonococcal AMR, and/or act as new antimicrobial targets. Finally, phenotypic clustering based on the isolates' defined antibiograms and common differentially expressed proteins yielded seven matching clusters between established and proteome-derived AMR signatures. Together, our investigations provide a reference proteomics databank for gonococcal vaccine and AMR research endeavors, which enables microbiological, clinical, or epidemiological projects and enhances the utility of the WHO reference strains.
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| 7. |
- Erdem, Cemal, et al.
(författare)
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Proteomic screening and lasso regression reveal differential signaling in insulin and insulin-like growth factor I (IGF1) pathways
- 2016
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Ingår i: Molecular & Cellular Proteomics. - : Elsevier. - 1535-9476 .- 1535-9484. ; 15:9, s. 3045-3057
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Tidskriftsartikel (refereegranskat)abstract
- Insulin and insulin-like growth factor I (IGF1) influence cancer risk and progression through poorly understood mechanisms. To better understand the roles of insulin and IGF1 signaling in breast cancer, we combined proteomic screening with computational network inference to uncover differences in IGF1 and insulin induced signaling. Using reverse phase protein array, we measured the levels of 134 proteins in 21 breast cancer cell lines stimulated with IGF1 or insulin for up to 48 h. We then constructed directed protein expression networks using three separate methods: (i) lasso regression, (ii) conventional matrix inversion, and (iii) entropy maximization. These networks, named here as the time translation models, were analyzed and the inferred interactions were ranked by differential magnitude to identify pathway differences. The two top candidates, chosen for experimental validation, were shown to regulate IGF1/insulin induced phosphorylation events. First, acetyl-CoA carboxylase (ACC) knock-down was shown to increase the level of mitogen-activated protein kinase (MAPK) phosphorylation. Second, stable knock-down of E-Cadherin increased the phospho-Akt protein levels. Both of the knock-down perturbations incurred phosphorylation responses stronger in IGF1 stimulated cells compared with insulin. Overall, the time-translation modeling coupled to wet-lab experiments has proven to be powerful in inferring differential interactions downstream of IGF1 and insulin signaling, in vitro.
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| 8. |
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| 9. |
- Götzke, Hansjörg, et al.
(författare)
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Identification of Putative Substrates for the Periplasmic Chaperone YfgM in Escherichia coli Using Quantitative Proteomics
- 2015
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 14:1, s. 216-226
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Tidskriftsartikel (refereegranskat)abstract
- How proteins are trafficked, folded, and assembled into functional units in the cell envelope of Gram-negative bacteria is of significant interest. A number of chaperones have been identified, however, the molecular roles of these chaperones are often enigmatic because it has been challenging to assign substrates. Recently we discovered a novel periplasmic chaperone, called YfgM, which associates with PpiD and the SecYEG translocon and operates in a network that contains Skp and SurA. The aim of the study presented here was to identify putative substrates of YfgM. We reasoned that substrates would be incorrectly folded or trafficked when YfgM was absent from the cell, and thus more prone to proteolysis (the loss-of-function rationale). We therefore used a comparative proteomic approach to identify cell envelope proteins that were lower in abundance in a strain lacking yfgM, and strains lacking yfgM together with either skp or surA. Sixteen putative substrates were identified. The list contained nine inner membrane proteins (CusS, EvgS, MalF, OsmC, TdcB, TdcC, WrbA, YfhB, and YtfH) and seven periplasmic proteins (HdeA, HdeB, AnsB, Ggt, MalE, YcgK, and YnjE), but it did not include any lipoproteins or outer membrane proteins. Significantly, AnsB (an asparaginase) and HdeB (a protein involved in the acid stress response), were lower in abundance in all three strains lacking yfgM. For both genes, we ruled out the possibility that they were transcriptionally down-regulated, so it is highly likely that the corresponding proteins are misfolded/mistargeted and turned-over in the absence of YfgM. For HdeB we validated this conclusion in a pulse-chase experiment. The identification of HdeB and other cell envelope proteins as potential substrates will be a valuable resource for follow-up experiments that aim to delineate molecular the function of YfgM.
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| 10. |
- Hober, Andreas, et al.
(författare)
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Absolute Quantification of Apolipoproteins Following Treatment with Omega-3 Carboxylic Acids and Fenofibrate Using a High Precision Stable Isotope-labeled Recombinant Protein Fragments Based SRM Assay
- 2019
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Ingår i: Molecular & Cellular Proteomics. - : AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC. - 1535-9476 .- 1535-9484. ; 18:12, s. 2433-2446
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Tidskriftsartikel (refereegranskat)abstract
- Stable isotope-labeled standard (SIS) peptides are used as internal standards in targeted proteomics to provide robust protein quantification, which is required in clinical settings. However, SIS peptides are typically added post trypsin digestion and, as the digestion efficiency can vary significantly between peptides within a protein, the accuracy and precision of the assay may be compromised. These drawbacks can be remedied by a new class of internal standards introduced by the Human Protein Atlas project, which are based on SIS recombinant protein fragments called SIS PrESTs. SIS PrESTs are added initially to the sample and SIS peptides are released on trypsin digestion. The SIS PrEST technology is promising for absolute quantification of protein biomarkers but has not previously been evaluated in a clinical setting. An automated and scalable solid phase extraction workflow for desalting and enrichment of plasma digests was established enabling simultaneous preparation of up to 96 samples. Robust high-precision quantification of 13 apolipoproteins was achieved using a novel multiplex SIS PrEST-based LC-SRM/MS Tier 2 assay in non-depleted human plasma. The assay exhibited inter-day coefficients of variation between 1.5% and 14.5% (median = 3.5%) and was subsequently used to investigate the effects of omega-3 carboxylic acids (OM3-CA) and fenofibrate on these 13 apolipoproteins in human plasma samples from a randomized placebo-controlled trial, EFFECT I (NCT02354976). No significant changes were observed in the OM3-CA arm, whereas treatment with fenofibrate significantly increased apoAII and reduced apoB, apoCI, apoE and apoCIV levels. The reduction in apoCIV following fenofibrate treatment is a novel finding. The study demonstrates that SIS PrESTs can facilitate the generation of robust multiplexed biomarker Tier 2 assays for absolute quantification of proteins in clinical studies. Applications of LC-SRM in clinical research are still limited. SIS PrEST are a novel class of standards added prior to trypsinization. We have developed a semi-automated sample preparation workflow and a SIS PrEST LC-SRM/MS Tier 2 assay for absolute quantification of 13 apolipoproteins in human plasma and applied it on clinical samples from the EFFECT I study. We demonstrate, for the first time, that SIS PrEST can be applied for exploratory biomarker research in clinical settings and capture drug effects.
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