Designed ankyrin repeat proteins (DARPins) are small engineered scaffold proteins that can be selected for binding to desirable molecular targets. High affinity and small size of DARPins render them ...promising probes for radionuclide molecular imaging. However, detailed knowledge on many factors influencing their imaging properties is still lacking. We have evaluated two human epidermal growth factor 2 (HER2)-specific DARPins with different size and binding properties. DARPins 9_29-H6 and G3-H6 were radiolabeled with iodine-125 and tricarbonyl technetium-99m and evaluated in vitro. A side-by-side comparison of biodistribution and tumor targeting was performed. HER2-specific tumor accumulation of G3-H6 was demonstrated. A combination of smaller size and higher affinity resulted in a higher tumor uptake of G3-H6 in comparison to 9_29-H6. Technetium-99m labeled G3-H6 demonstrated a better biodistribution profile than 9_29-H6, with several-fold lower uptake in liver. Radioiodinated G3-H6 showed the best tumor-to-organ ratios. The combined effect of affinity, molecular weight, scaffold composition, and nonresidualizing properties of iodine label provided radioiodinated G3-H6 with high clinical potential for imaging of HER2.
The effect of green bodies’ mesostructure on the porosity, optical properties and laser performance of reactive sintered Y3Al5O12:Nd3+ transparent ceramics was studied. Only minor changes in ...microstructure were revealed for green bodies without annealing and those annealed at 600, 800, 1000 °C, while average pore size increases to 140 nm for sample annealed at 1200 °C. Y3Al5O12:Nd3+ ceramics sintered at 1750 °C for 10 hours possess significant differences in the final porosity, optical and laser characteristics. Despite all green bodies exhibit a similar phase evolution and sintering behavior on heating, the differences appear in the final stage, when the latest percentage of porosity is removed. The green bodies annealed at 600 °C have an optimal mesostructure from the standpoint of uniform densification. Y3Al5O12:Nd3+ ceramics prepared using these green bodies exhibit porosity ≤0.001 vol% and yield efficient laser emission at 1.06 μm with slope efficiency as high as 67% in quasi-continuous pumping at 807 nm.
Abstract
Upregulation of the human epidermal growth factor receptor type 3 (HER3) is a common mechanism to bypass HER-targeted cancer therapy. Affibody-based molecular imaging has the potential for ...detecting and monitoring HER3 expression during treatment. In this study, we compared the imaging properties of newly generated
68
Ga-labeled anti-HER3 affibody molecules (HE)
3
-Z
HER3
-DOTA and (HE)
3
-Z
HER3
-DOTAGA with previously reported
68
GaGa-(HE)
3
-Z
HER3
-NODAGA. We hypothesized that increasing the negative charge of the gallium-68/chelator complex would reduce hepatic uptake, which could lead to improved contrast of anti-HER3 affibody-based PET-imaging of HER3 expression. (HE)
3
-Z
HER3
-X (X = DOTA, DOTAGA) were produced and labeled with gallium-68. Binding of the new conjugates was specific in HER3 expressing BxPC-3 and DU145 human cancer cells. Biodistribution and
in vivo
specificity was studied in BxPC-3 xenograft bearing Balb/c nu/nu mice 3 h pi. DOTA- and DOTAGA-containing conjugates had significantly higher concentration in blood than
68
GaGa-(HE)
3
-Z
HER3
-NODAGA. Presence of the negatively charged
68
Ga-DOTAGA complex reduced the unspecific hepatic uptake, but did not improve overall biodistribution of the conjugate.
68
GaGa-(HE)
3
-Z
HER3
-DOTAGA and
68
GaGa-(HE)
3
-Z
HER3
-NODAGA had similar tumor-to-liver ratios, but
68
GaGa-(HE)
3
-Z
HER3
-NODAGA had the highest tumor uptake and tumor-to-blood ratio among the tested conjugates. In conclusion,
68
GaGa-(HE)
3
-Z
HER3
-NODAGA remains the favorable variant for PET imaging of HER3 expression.
An fcc solid solution of cobalt in gold was synthesized under high-pressure torsion (shear) in air at room temperature and in liquid nitrogen. The mixture of Au and Co powders of 99.99 and 99.60% ...purities, respectively, was preliminarily consolidated under a pressure of 1–2 GPa. The obtained compact was subjected to high-pressure torsion at a pressure of 8 GPa under different temperature conditions. It has been shown that synthesis in liquid nitrogen not only enhances the solubility of Co in Au compared to that at room temperature, but also results in virtually no contamination of the alloy with anvil material. The morphology of the fracture surfaces of the samples synthesized at cryogenic temperature has been described. The main part of the fractures are in a region of brittle intergranular fracturing, which corresponds to an ultra-fine grain structure. It has been shown that the fraction of brittle intergranular fracturing and the sizes of regions with another morphology of the fracture surface change as a function of the true strain. The size of elements of the ultra-fine grain structure determined on the surface of fracture is no more than 50 nm.
Radionuclide molecular imaging of human epidermal growth factor receptor 3 (HER3) expression using affibody molecules could be used for patient stratification for HER3-targeted cancer therapeutics. ...We hypothesized that the properties of HER3-targeting affibody molecules might be improved through modification of the radiometal-chelator complex. Macrocyclic chelators NOTA (1,4,7-triazacyclononane-N,N',N''-triacetic acid), NODAGA (1-(1,3-carboxypropyl)-4,7-carboxymethyl-1,4,7-triazacyclononane), DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid), and DOTAGA (1,4,7,10-tetraazacyclododececane,1-(glutaric acid)-4,7,10-triacetic acid) were conjugated to the C-terminus of anti-HER3 affibody molecule Z
and conjugates were labeled with indium-111. All conjugates bound specifically and with picomolar affinity to HER3 in vitro. In mice bearing HER3-expressing xenografts, no significant difference in tumor uptake between the conjugates was observed. Presence of the negatively charged
In-DOTAGA-complex resulted in the lowest hepatic uptake and the highest tumor-to-liver ratio. In conclusion, the choice of chelator influences the biodistribution of indium-111 labeled anti-HER3 affibody molecules. Hepatic uptake of anti-HER3 affibody molecules could be reduced by the increase of negative charge of the radiometal-chelator complex on the C-terminus without significantly influencing the tumor uptake.
Ukrainian companies occupy an important niche in the global drug discovery process; however, before the Russian invasion, the role of Ukraine was not obvious. The biggest Ukrainian fine chemical ...supplier, Enamine Ltd, had to stop operation for more than a month, which significantly affected various early-stage drug discovery projects. The role of Enamine in drug discovery and the company’s past and future in the context of the Russian invasion are described in this Viewpoint.
We report on ion mobility (IM) separations achievable using traveling waves (TW) in a Structures for Lossless Ion Manipulations (SLIM) module having a 44 cm path length and 16 90° turns. The ...performance of the TW-SLIM module was evaluated for ion transmission and IM separations with different RF, TW parameters, and SLIM surface gaps in conjunction with mass spectrometry. In this work, TWs were created by the transient and dynamic application of DC potentials. The module demonstrated highly robust performance and, even with 16 closely spaced turns, achieving IM resolution performance and ion transmission comparable to a similar straight path module. We found an IM peak capacity of ∼31 and peak generation rate of 780 s−1 for TW speeds of ∼80 m/s using the current multi-turn TW-SLIM module. The separations achieved for isomers of peptides and tetrasaccharides were found to be comparable to those from a ∼0.9-m drift tube-based IM-MS platform operated at the same pressure (4 Torr). The combined attributes of flexible design, low voltage requirements and lossless ion transmission through multiple turns for the present TW-SLIM module provides a basis for SLIM devices capable of achieving much greater IM resolution via greatly extended ion path lengths and using compact serpentine designs.
Affibody® (affibody) ligands that are specific for the extracellular domain of human epidermal growth factor receptor 2 (HER2/neu) have been selected by phage display technology from a combinatorial ...protein library based on the 58 amino acid residue staphylococcal protein A-derived Z domain. The predominant variants from the phage selection were produced in Escherichia coli, purified by affinity chromatography, and characterized by biosensor analyses. Two affibody variants were shown to selectively bind to the extracellular domain of HER2/neu (HER2-ECD), but not to control proteins. One of the variants, denoted His6-ZHER2/neu:4, was demonstrated to bind with nanomolar affinity (∼50 nM) to the HER2-ECD molecule at a different site than the monoclonal antibody trastuzumab. Furthermore, radiolabeled His6-ZHER2/neu:4 affibody showed specific binding to native HER2/neu, overexpressed on the SKBR-3 tumor cell line. Such affibody ligands might be considered in tumor targeting applications for radionuclide diagnostics and therapy of adenocarcinomas such as breast and ovarian cancers.
The epidermal growth factor receptor 1 (EGFR) is overexpressed in various malignancies and is associated with a poor patient prognosis. A small, receptor-specific, high-affinity imaging agent would ...be a useful tool in diagnosing malignant tumors and in deciding upon treatment and assessing the response to treatment. We describe here the affinity maturation procedure for the generation of Affibody molecules binding with high affinity and specificity to EGFR. A library for affinity maturation was constructed by rerandomization of selected positions after the alignment of first-generation binding variants. New binders were selected with phage display technology, using a single oligonucleotide in a single-library effort, and the best second-generation binders had an approximately 30-fold improvement in affinity (
K
d
=
5–10 nM) for the soluble extracellular domain of EGFR in biospecific interaction analysis using Biacore. The dissociation equilibrium constant,
K
d, was also determined for the Affibody with highest affinity using EGFR-expressing A431 cells in flow cytometric analysis (
K
d
=
2.8 nM). A retained high specificity for EGFR was verified by a dot blot assay showing staining only of EGFR proteins among a panel of serum proteins and other EGFR family member proteins (HER2, HER3, and HER4). The EGFR-binding Affibody molecules were radiolabeled with indium-111, showing specific binding to EGFR-expressing A431 cells and successful targeting of the A431 tumor xenografts with 4–6% injected activity per gram accumulated in the tumor 4 h postinjection.
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