46 research outputs found

    In vivo imaging of microenvironmental and anti-PD-L1-mediated dynamics in cancer using S100A8/S100A9 as an imaging biomarker

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    Purpose: As a promotor of tumor invasion and tumor microenvironment (TME) formation, the protein complex S100A8/S100A9 is associated with poor prognosis. Our aim was to further evaluate its origin and regulatory effects, and to establish an imaging biomarker for TME activity. Methods: S100A9−/−cells (ko) were created from syngeneic murine breast cancer 4T1 (high malignancy) and 67NR (low malignancy) wildtype (wt) cell lines and implanted into either female BALB/c wildtype or S100A9−/− mice (n = 10 each). Anti-S100A9-Cy5.5-targeted fluorescence reflectance imaging was performed at 0 h and 24 h after injection. Potential early changes of S100A9-presence under immune checkpoint inhibition (anti-PD-L1, n = 7 vs. rat IgG2b as isotype control, n = 3) were evaluated. Results: In S100A9−/−mice contrast-to-noise-ratios were significantly reduced for wt and S100A9−/−tumors. No significant differences were detected for 4T1 ko and 67NR ko cells as compared to wildtype cells. Under anti-PD-L1 treatment S100A9 presence significantly decreased compared with the control group. Conclusion: Our results confirm a secretion of S100A8/S100A9 by the TME, while tumor cells do not apparently release the protein. Under immune checkpoint inhibition S100A9-imaging reports an early decrease of TME activity. Therefore, S100A9-specific imaging may serve as an imaging biomarker for TME formation and activity

    Enzymatic Late‐Stage Modifications: Better Late Than Never

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    From Wiley via Jisc Publications RouterHistory: received 2020-11-08, rev-recd 2021-01-15, pub-electronic 2021-03-08, pub-print 2021-07-26Article version: VoRPublication status: PublishedFunder: EPSRC; Grant(s): EP/S005226/1Funder: BBSRC; Grant(s): EP/S005226/1Funder: AstraZeneca plc; Id: http://dx.doi.org/10.13039/100004325; Grant(s): EP/S005226/1Funder: European Research Council; Id: http://dx.doi.org/10.13039/100010663; Grant(s): 742987-BIO-H-BORROW-ERC-2016-ADG, 788231-ProgrES-ERC-2017-ADGAbstract: Enzyme catalysis is gaining increasing importance in synthetic chemistry. Nowadays, the growing number of biocatalysts accessible by means of bioinformatics and enzyme engineering opens up an immense variety of selective reactions. Biocatalysis especially provides excellent opportunities for late‐stage modification often superior to conventional de novo synthesis. Enzymes have proven to be useful for direct introduction of functional groups into complex scaffolds, as well as for rapid diversification of compound libraries. Particularly important and highly topical are enzyme‐catalysed oxyfunctionalisations, halogenations, methylations, reductions, and amide bond formations due to the high prevalence of these motifs in pharmaceuticals. This Review gives an overview of the strengths and limitations of enzymatic late‐stage modifications using native and engineered enzymes in synthesis while focusing on important examples in drug development

    Enzymkatalysierte spÀte Modifizierungen: Besser spÀt als nie

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    From Wiley via Jisc Publications RouterHistory: received 2020-11-08, rev-recd 2021-01-15, pub-electronic 2021-03-08, pub-print 2021-07-26Article version: VoRPublication status: PublishedFunder: EPSRC; Grant(s): EP/S005226/1Funder: BBSRC; Grant(s): EP/S005226/1Funder: AstraZeneca plc; Id: http://dx.doi.org/10.13039/100004325; Grant(s): EP/S005226/1Funder: European Research Council; Id: http://dx.doi.org/10.13039/100010663; Grant(s): 742987-BIO-H-BORROW-ERC-2016-ADG, 788231-ProgrES-ERC-2017-AD

    Living GenoChemetics by hyphenating synthetic biology and synthetic chemistry in vivo

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    Marrying synthetic biology with synthetic chemistry provides a powerful approach toward natural product diversification, combining the best of both worlds: expediency and synthetic capability of biogenic pathways and chemical diversity enabled by organic synthesis. Biosynthetic pathway engineering can be employed to insert a chemically orthogonal tag into a complex natural scaffold affording the possibility of site-selective modification without employing protecting group strategies. Here we show that, by installing a sufficiently reactive handle (e.g., a C–Br bond) and developing compatible mild aqueous chemistries, synchronous biosynthesis of the tagged metabolite and its subsequent chemical modification in living culture can be achieved. This approach can potentially enable many new applications: for example, assay of directed evolution of enzymes catalyzing halo-metabolite biosynthesis in living cells or generating and following the fate of tagged metabolites and biomolecules in living systems. We report synthetic biological access to new-to-nature bromo-metabolites and the concomitant biorthogonal cross-coupling of halo-metabolites in living culture

    The proteolytic activity of the recombinant cryptic human fibronectin type IV collagenase from E-coli expression

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    Schnepel J, Tschesche H. The proteolytic activity of the recombinant cryptic human fibronectin type IV collagenase from E-coli expression. JOURNAL OF PROTEIN CHEMISTRY. 2000;19(8):685-692.Human plasma ftbronectin (pFN) contains a cryptic metalloprotease present in the collagen-binding domain. The enzyme could be generated and activated in the presence of Ca2+ from the purified 70-kDa pFN fragment produced by cathepsin D digestion. In this work we cloned and expressed the metalloprotease, designated FN type IV collagenase (FnColA), and a truncated variant (FnColB) in E. coli. The recombinant pFN protein fragment was isolated from inclusion bodies, and subjected to folding and autocatalytic degradation in the presence of Ca2+, and yielded an active enzyme capable of digesting gelatin, helical type II and type IV collagen, alpha- and beta -casein, insulin b-chain, and a synthetic Mca-peptide. In contrast, isolated plasma fibronectin, type I collagen, and the DNP-peptide were no substrates. Both catalytically active recombinant pFN fragments were efficiently inhibited by EDTA, and batimastat, and, in contrast to the glycosylated enzyme isolated from plasma fibronectin, were also inhibited by TIMP-2

    Recombinant cryptic human fibronectinase cleaves actin and myosin: Substrate specificity and possible role in muscular dystrophy

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    Schnepel J, Unger J, Tschesche H. Recombinant cryptic human fibronectinase cleaves actin and myosin: Substrate specificity and possible role in muscular dystrophy. BIOLOGICAL CHEMISTRY. 2001;382(12):1707-1714.The N-terminal heparin/fibrin binding domain of human plasma fibronectin (pFN) contains a cryptic proteinase. The enzyme could be generated and activated in the presence of Ca2+ from the purified 70 kDa pFN fragment produced by cathepsin D digestion of pFN. In this work we cloned and expressed the serine proteinase, designated fibronectinase (Fnase), in E. coli. The recombinant pFN protein fragment was isolated from inclusion bodies, subjected to folding and autocatalytic degradation in the presence of Ca2+, and yielded an active enzyme capable of digesting fibronectin. Cleavage of pFN and the synthetic peptides Ac-I-E-G-K-pNA and Bz-I-E-G-R-pNA demonstrated identical specificity of the recombinant and the isolated fibronectinase. Further investigations of the substrate specificity revealed for the first time the muscle proteins actin and myosin as being substrates of fibronectinase. The enzyme can be inhibited by alpha(1)-proteinase inhibitor. In the context of induced cathepsin D release, e. g. from granulocytes under inflammatory conditions, these results indicate an increase in specific proteolytic potential against muscular proteins in dystrophic diseases by the release of cryptic fibronectinase
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