| 1. |
- Adrian Meredith, Jenny, 1971-, et al.
(author)
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Design and Synthesis of BACE-1 Inhibitors Containing a New Hydroxyethylene (HE) Scaffold: Potent activities in a cellular assay
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Other publication (other academic/artistic)abstract
- In a preceding report from our group we disclosed the development of a novel HE transition state isostere with a difluorophenoxymethyl side chain in the P1 position and a methoxy group in the P1’ position furnishing highly potent inhibitors of BACE-1 (i.e. lead compound 1), which moreover exhibit very promising selectivity over cathepsin D. In a continuation of this work with the aim at improving on the cell-based activity and pharmacokinetic properties, we have further developed the SAR for the P1 side chain of inhibitor 1 whereby the P1 side chain oxygen has been substituted for an amine, a carbon or a bond. The chemistry developed for the previous HE inhibitor structure 1 has now been extended to readily accommodate the introduction of new P1 side chains into this new HE scaffold. These modifications have given rise to several highly potent inhibitors where the most potent displayed a BACE-1 Ki value of 0.2 nM and a cell-based Aβ40 IC50 value of 9 nM. Thus, regarding the enzyme inhibition in the cell assay a more than 600-fold improvement compared to compound 1 was achieved via minor structural alterations.
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| 2. |
- Adrian Meredith, Jenny, 1971-, et al.
(author)
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P2 '-truncated BACE-1 inhibitors with a novel hydroxethylene-like core
- 2010
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In: European Journal of Medicinal Chemistry. - : Elsevier BV. - 0223-5234 .- 1768-3254. ; 45:2, s. 542-554
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Journal article (peer-reviewed)abstract
- Highly potent BACE-1 protease inhibitors derived from a novel hydroxyethylene-like core structure were recently developed by our group using X-ray crystal structure data and molecular modelling. In a continuation of this work guided by molecular modelling we have explored a truncated core motif where the P2' amide group is replaced by an ether linkage resulting in a set of alkoxy, aryloxy and alkylaryl groups, with the overall aim to reduce molecular weight and the number of amide bonds to increase permeability and bestow the inhibitors with drug-like features. The most potent of these inhibitors displayed a BACE-I IC50 value of 140 nM. The synthesis of these BACE-I inhibitors utilizes readily available starting materials, furnishing the target compounds in good overall yields.
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| 3. |
- Calitz, Carlemi, et al.
(author)
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A Biomimetic Model for Liver Cancer to Study Tumor-Stroma Interactions in a 3D Environment with Tunable Bio-Physical Properties
- 2020
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In: Journal of Visualized Experiments. - : JOURNAL OF VISUALIZED EXPERIMENTS. - 1940-087X. ; :162
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Journal article (peer-reviewed)abstract
- Hepatocellular carcinoma (HCC) is a primary liver tumor developing in the wake of chronic liver disease. Chronic liver disease and inflammation leads to a fibrotic environment actively supporting and driving hepatocarcinogenesis. Insight into hepatocarcinogenesis in terms of the interplay between the tumor stroma microenvironment and tumor cells is thus of considerable importance. Three-dimensional (3D) cell culture models are proposed as the missing link between current in vitro 2D cell culture models and in vivo animal models. Our aim was to design a novel 3D biomimetic HCC model with accompanying fibrotic stromal compartment and vasculature. Physiologically relevant hydrogels such as collagen and fibrinogen were incorporated to mimic the bio-physical properties of the tumor ECM. In this model LX2 and HepG2 cells embedded in a hydrogel matrix were seeded onto the inverted transmembrane insert. HUVEC cells were then seeded onto the opposite side of the membrane. Three formulations consisting of ECM-hydrogels embedded with cells were prepared and the bio-physical properties were determined by rheology. Cell viability was determined by a cell viability assay over 21 days. The effect of the chemotherapeutic drug doxorubicin was evaluated in both 2D co-culture and our 3D model for a period of 72h. Rheology results show that bio-physical properties of a fibrotic, cirrhotic and HCC liver can be successfully mimicked. Overall, results indicate that this 3D model is more representative of the in vivo situation compared to traditional 2D cultures. Our 3D tumor model showed a decreased response to chemotherapeutics, mimicking drug resistance typically seen in HCC patients.
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| 4. |
- Calitz, Carlemi, et al.
(author)
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Influence of extracellular matrix composition on tumour cell behaviour in a biomimetic in vitro model for hepatocellular carcinoma
- 2023
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In: Scientific Reports. - : NATURE PORTFOLIO. - 2045-2322. ; 13:1
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Journal article (peer-reviewed)abstract
- The tumor micro-environment (TME) of hepatocellular carcinoma (HCC) consists out of cirrhotic liver tissue and is characterized by an extensive deposition of extracellular matrix proteins (ECM). The evolution from a reversible fibrotic state to end-stage of liver disease, namely cirrhosis, is characterized by an increased deposition of ECM, as well as changes in the exact ECM composition, which both contribute to an increased liver stiffness and can alter tumor phenotype. The goal of this study was to assess how changes in matrix composition and stiffness influence tumor behavior. HCC-cell lines were grown in a biomimetic hydrogel model resembling the stiffness and composition of a fibrotic or cirrhotic liver. When HCC-cells were grown in a matrix resembling a cirrhotic liver, they increased proliferation and protein content, compared to those grown in a fibrotic environment. Tumour nodules spontaneously formed outside the gels, which appeared earlier in cirrhotic conditions and were significantly larger compared to those found outside fibrotic gels. These tumor nodules had an increased expression of markers related to epithelial-to-mesenchymal transition (EMT), when comparing cirrhotic to fibrotic gels. HCC-cells grown in cirrhotic gels were also more resistant to doxorubicin compared with those grown in fibrotic gels or in 2D. Therefore, altering ECM composition affects tumor behavior, for instance by increasing pro-metastatic potential, inducing EMT and reducing response to chemotherapy.
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| 5. |
- Martinelli, Silvia, et al.
(author)
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ANGPT2 promoter methylation is strongly associated with gene expression and prognosis in chronic lymphocytic leukemia
- 2013
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In: Epigenetics. - : Informa UK Limited. - 1559-2294 .- 1559-2308. ; 8:7, s. 720-729
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Journal article (peer-reviewed)abstract
- Increasing evidence suggests a key role for angiopoietin-2 (ANGPT2) in influencing the aggressiveness of chronic lymphocytic leukemia (CLL). In the presence of vascular endothelial growth factor (VEGF), ANGPT2 causes vessel destabilization leading to neoangiogenesis. Accordingly, high expression levels of ANGPT2 and high degree of angiogenesis have consistently been associated with poor prognosis in CLL; however, the molecular mechanisms behind the variability in ANGPT2 expression are still to be discovered. Here, for the first time, we investigated the DNA methylation status of the ANGPT2 promoter in a large CLL cohort (n = 88) using pyrosequencing and correlated methylation data with ANGPT2 expression levels, prognostic factors and outcome. Importantly, methylation levels of the ANGPT2 gene correlated inversely with its mRNA expression levels (p < 0.001). Moreover, low ANGPT2 methylation status was highly associated with adverse prognostic markers, shorter time to first treatment and overall survival. Finally, treatment with methyl inhibitors induced re-expression of ANGPT2 in two B-cell lymphoma cell lines, underscoring the importance of DNA methylation in regulating transcriptional silencing of this gene. In conclusion, we believe that the known variability in ANGPT2 expression among CLL patients could be explained by differential promoter DNA methylation and that low methylation levels of the ANGPT2 promoter have an adverse prognostic impact in CLL.
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| 6. |
- Pupkaite, Justina, 1988-, et al.
(author)
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Injectable Shape-Holding Collagen Hydrogel for Cell Encapsulation and Delivery Cross-linked Using Thiol-Michael Addition Click Reaction
- 2019
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In: Biomacromolecules. - : American Chemical Society. - 1525-7797 .- 1526-4602. ; 20:9, s. 3475-3484
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Journal article (peer-reviewed)abstract
- Injectable hydrogels based on extracellular matrix-derived polymers show much promise in the field of tissue engineering and regenerative medicine. However, the hydrogels reported to date have at least one characteristic that limits their potential for clinical use, such as excessive swelling, complicated and potentially toxic cross-linking process, or lack of shear thinning and self-healing properties. We hypothesized that a collagen hydrogel cross-linked using thiol-Michael addition click reaction would be able to overcome these limitations. To this end, collagen was modified to introduce thiol groups, and hydrogels were prepared by cross-linking with 8-arm polyethylene glycol-maleimide. Rheological measurements on the hydrogels revealed excellent shear-thinning and self-healing properties. Additionally, only minimal swelling (6%) was observed over a period of 1 month in an aqueous buffer solution. Finally, tests using mesenchymal stromal cells and endothelial cells showed that the hydrogels are cell-compatible and suitable for cell encapsulation and delivery. Thus, the reported thiolated-collagen hydrogel cross-linked using thiol-Michael addition click reaction overcomes most of the challenges in the injectable hydrogel design and is an excellent candidate for cell delivery in regenerative medicine and tissue engineering applications. The hydrogel reported here is the first example of a self-healing hydrogel containing covalent cross-links.
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| 7. |
- Rosenquist, Jenny, et al.
(author)
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An Injectable, Shape-Retaining Collagen Hydrogel Cross-linked Using Thiol-Maleimide Click Chemistry for Sealing Corneal Perforations
- 2023
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In: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 15:29, s. 34407-34418
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Journal article (peer-reviewed)abstract
- Injectable hydrogels show great promise in developingnovel regenerativemedicine solutions and present advantages for minimally invasive applications.Hydrogels based on extracellular matrix components, such as collagen,have the benefits of cell adhesiveness, biocompatibility, and degradabilityby enzymes. However, to date, reported collagen hydrogels possesssevere shortcomings, such as nonbiocompatible cross-linking chemistry,significant swelling, limited range of mechanical properties, or gelationkinetics unsuitable for in vivo injection. To solvethese issues, we report the design and characterization of an injectablecollagen hydrogel based on covalently modified acetyl thiol collagencross-linked using thiol-maleimide click chemistry. The hydrogel isinjectable for up to 72 h after preparation, shows no noticeable swelling,is transparent, can be molded in situ, and retainsits shape in solution for at least one year. Notably, the hydrogelmechanical properties can be fine-tuned by simply adjusting the reactantstoichiometries, which to date was only reported for synthetic polymerhydrogels. The biocompatibility of the hydrogel is demonstrated in vitro using human corneal epithelial cells, which maintainviability and proliferation on the hydrogels for at least seven days.Furthermore, the developed hydrogel showed an adhesion strength onsoft tissues similar to fibrin glue. Additionally, the developed hydrogelcan be used as a sealant for repairing corneal perforations and canpotentially alleviate the off-label use of cyanoacrylate tissue adhesivefor repairing corneal perforations. Taken together, these characteristicsshow the potential of the thiol collagen hydrogel for future use asa prefabricated implant, injectable filler, or as sealant for cornealrepair and regeneration.
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| 8. |
- Smith, Laura B., et al.
(author)
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Psychological manifestations of celiac disease autoimmunity in young children
- 2017
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In: Pediatrics. - : American Academy of Pediatrics (AAP). - 0031-4005 .- 1098-4275. ; 139:3
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Journal article (peer-reviewed)abstract
- BACKGROUND AND OBJECTIVES: Psychological symptoms can be associated with celiac disease; abstract however, this association has not been studied prospectively in a pediatric cohort. We examined mother report of psychological functioning in children persistently positive for tissue transglutaminase autoantibodies (tTGA), defined as celiac disease autoimmunity (CDA), compared with children without CDA in a screening population of genetically at-risk children. We also investigated differences in psychological symptoms based on mothers' awareness of their child's CDA status. METHODS: The Environmental Determinants of Diabetes in the Young study followed 8676 children to identify triggers of type 1 diabetes and celiac disease. Children were tested for tTGA beginning at 2 years of age. The Achenbach Child Behavior Checklist assessed child psychological functioning at 3.5 and 4.5 years of age. RESULTS: At 3.5 years, 66 mothers unaware their child had CDA reported more child anxiety and depression, aggressive behavior, and sleep problems than 3651 mothers of children without CDA (all Ps ≤ .03). Unaware-CDA mothers also reported more child anxiety and depression, withdrawn behavior, aggressive behavior, and sleep problems than 440 mothers aware of their child's CDA status (all Ps ≤.04). At 4.5 years, there were no differences. CONCLUSIONS: In 3.5-year-old children, CDA is associated with increased reports of child depression and anxiety, aggressive behavior, and sleep problems when mothers are unaware of their child's CDA status. Mothers' knowledge of their child's CDA status is associated with fewer reports of psychological symptoms, suggesting that awareness of the child's tTGA test results affects reporting of symptoms.
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| 9. |
- Törn, Carina, et al.
(author)
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Complement gene variants in relation to autoantibodies to beta cell specific antigens and type 1 diabetes in the TEDDY Study
- 2016
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Journal article (peer-reviewed)abstract
- A total of 15 SNPs within complement genes and present on the ImmunoChip were analyzed in The Environmental Determinants of Diabetes in the Young (TEDDY) study. A total of 5474 subjects were followed from three months of age until islet autoimmunity (IA: n = 413) and the subsequent onset of type 1 diabetes (n = 115) for a median of 73 months (IQR 54-91). Three SNPs within ITGAM were nominally associated (p < 0.05) with IA: rs1143678 [Hazard ratio; HR 0.80; 95% CI 0.66-0.98; p = 0.032], rs1143683 [HR 0.80; 95% CI 0.65-0.98; p = 0.030] and rs4597342 [HR 1.16; 95% CI 1.01-1.32; p = 0.041]. When type 1 diabetes was the outcome, in DR3/4 subjects, there was nominal significance for two SNPs: rs17615 in CD21 [HR 1.52; 95% CI 1.05-2.20; p = 0.025] and rs4844573 in C4BPA [HR 0.63; 95% CI 0.43-0.92; p = 0.017]. Among DR4/4 subjects, rs2230199 in C3 was significantly associated [HR 3.20; 95% CI 1.75-5.85; p = 0.0002, uncorrected] a significance that withstood Bonferroni correction since it was less than 0.000833 (0.05/60) in the HLA-specific analyses. SNPs within the complement genes may contribute to IA, the first step to type 1 diabetes, with at least one SNP in C3 significantly associated with clinically diagnosed type 1 diabetes.
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| 10. |
- Öhrngren, Per, et al.
(author)
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Hiv-1 Protease Inhibitors with a Tertiary Alcohol Containing a Transition-State Mimic and Various P2/P1´ Substituents
- 2011
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In: MedChemComm. - : Royal Society of Chemistry (RSC). - 2040-2503 .- 2040-2511. ; 2:8, s. 701-709
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Journal article (peer-reviewed)abstract
- Two series, including in total 18 novel HIV-1 protease inhibitors, comprising a tertiary alcohol as thetransition-state mimic have been synthesised and evaluated. Replacement of the previously used, butmetabolically unstable, indanol amide group with amino acid derived aliphatic P2–P3 moietiesprovided potent inhibitors with low Ki- and EC50-values (2.7 nM and 2.0 mM, respectively). The P10subunit was varied using 10 different aromatic and heteroaromatic substituents furnishing thecorresponding inhibitors with retained activity. Permeability and stability studies showed examples inthe same range as Atazanavir. X-Ray crystallographic analysis of two selected inhibitor enzyme cocomplexes(9a and 9d) supplied detailed structural information. The binding modes were compared tothose of Atazanavir and a previously reported indanol amide containing inhibitor (14). The novelinhibitors with an elongated P1' side chain enabled a previously unexploited edge-on interaction withPhe53/153. Exchange of the previously used indanol amide P2 moiety, with a tert-leucine derived P2–P3side chain, furnished small main chain displacements in the S2–S3 pocket. The methyl amide in the P3 position caused a 2 Å shift of the Arg8/108 in comparison to 14, indicating the flexibility of the proteaseactive site.
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