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  • 1.
    Ahlgren, Sara
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Rosik, Daniel
    Affibody AB, Stockholm, Sweden.
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Sjöberg, Anna
    Affibody AB, Stockholm, Sweden.
    Baastrup, Barbro
    Affibody AB, Stockholm, Sweden.
    Widmark, Olof
    Affibody AB, Stockholm, Sweden.
    Fant, Gunilla
    Affibody AB, Stockholm, Sweden.
    Feldwisch, Joachim
    Affibody AB, Stockholm, Sweden.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Evaluation of maleimide derivative of DOTA for site-specific labeling of recombinant affibody molecules2008Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 19, nr 1, s. 235-243Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a new class of small (7 kDa) scaffold affinity proteins, which demonstrate promising properties as agents for in vivo radionuclide targeting. The Affibody scaffold is cysteine-free and therefore independent of disulfide bonds. Thus, a single thiol group can be engineered into the protein by introduction of one cysteine. Coupling of thiol-reactive bifunctional chelators can enable site-specific labeling of recombinantly produced Affibody molecules. In this study, the use of 1,4,7,10-tetraazacyclododecane-1,4,7-tris-acetic acid-10-maleimidoethylacetamide (MMA-DOTA) for 111 In-labeling of anti-HER2 Affibody molecules His 6-Z HER2:342-Cys and Z HER2:2395-Cys has been evaluated. The introduction of a cysteine residue did not affect the affinity of the proteins, which was 29 pM for His 6-Z HER2:342-Cys and 27 pM for Z HER2:2395-Cys, comparable with 22 pM for the parental Z HER2:342. MMA-DOTA was conjugated to DTT-reduced Affibody molecules with a coupling efficiency of 93% using a 1:1 molar ratio of chelator to protein. The conjugates were labeled with 111 In to a specific radioactivity of up to 7 GBq/mmol, with preserved binding for the target HER2. In vivo, the non-His-tagged variant 111 In-[MMA-DOTA-Cys61]-Z HER2:2395-Cys demonstrated appreciably lower liver uptake than its His-tag-containing counterpart. In mice bearing HER2-expressing LS174T xenografts, 111 In-[MMA-DOTA-Cys61]-Z HER2:2395-Cys showed specific and rapid tumor localization, and rapid clearance from blood and nonspecific compartments, leading to a tumor-to-blood-ratio of 18 +/- 8 already 1 h p.i. Four hours p.i., the tumor-to-blood ratio was 138 +/- 8. Xenografts were clearly visualized already 1 h p.i.

  • 2.
    Altai, Mohamed
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Strand, Joanna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Rosik, Daniel
    Selvaraju, Ram Kumar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Eriksson Karlström, Amelie
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Influence of Nuclides and Chelators on Imaging Using Affibody Molecules: Comparative Evaluation of Recombinant Affibody Molecules Site-Specifically Labeled with 68Ga and 111In via Maleimido Derivatives of DOTA and NODAGA2013Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 24, nr 6, s. 1102-1109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate detection of cancer-associated molecular abnormalities in tumors could make cancer treatment more personalized. Affibody molecules enable high contrast imaging of tumor-associated protein expression shortly after injection. The use of the generator-produced positron-emitting radionuclide 68Ga should increase sensitivity of HER2 imaging. The chemical nature of radionuclides and chelators influences the biodistribution of Affibody molecules, providing an opportunity to further increase the imaging contrast. The aim of the study was to compare maleimido derivatives of DOTA and NODAGA for site-specific labeling of a recombinant ZHER2:2395 HER2-binding Affibody molecule with 68Ga. DOTA and NODAGA were site-specifically conjugated to the ZHER2:2395 Affibody molecule having a C-terminal cysteine and labeled with 68Ga and 111In. All labeled conjugates retained specificity to HER2 in vitro. Most of the cell-associated activity was membrane-bound with a minor difference in internalization rate. All variants demonstrated specific targeting of xenografts and a high tumor uptake. The xenografts were clearly visualized using all conjugates. The influence of chelator on the biodistribution and targeting properties was much less pronounced for 68Ga than for 111In. The tumor uptake of 68Ga-NODAGA-ZHER2:2395 and 68Ga-DOTA-ZHER2:2395 and tumor-to-blood ratios at 2 h p.i. did not differ significantly. However, the tumor-to-liver ratio was significantly higher for 68Ga-NODAGA- ZHER2:2395 (8 ± 2 vs 5.0 ± 0.3) offering the advantage of better liver metastases visualization. In conclusion, influence of chelators on biodistribution of Affibody molecules depends on the radionuclides and reoptimization of labeling chemistry is required when a radionuclide label is changed.

  • 3. Beuttler, Julia
    et al.
    Rothdiener, Miriam
    Mueller, Dafne
    Frejd, Fredrik Y.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Kontermann, Roland E.
    Targeting of Epidermal Growth Factor Receptor (EGFR)-Expressing Tumor Cells with Sterically Stabilized Affibody Liposomes (SAL)2009Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 20, nr 6, s. 1201-1208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are small and stable antigen-binding molecules derived from the B domain of protein A. We applied a bivalent, high-affinity epidermal growth factor receptor (EGFR)-specific affibody molecule for the generation of targeted PEGylated liposomes. These sterically stabilized affibody liposomes (SAL) were produced by chemical coupling of the cysteine-modified affibody molecule to maleimide-PEG(2000)-DSPE and subsequent insertion into PEGylated liposomes. These SAL showed strong and selective binding to EGFR-expressing tumor cell lines. Binding was dependent on the amount of inserted affibody molecule-lipid conjugates and could be blocked by soluble EGF. Approximately 30% of binding activity was still retained after 6 days of incubation in human plasma at 37 degrees C. Binding of SAL to cells led to efficient internalization of the liposomes. Using mitoxantrone-loaded liposomes, we observed for SAL, compared to untargeted liposomes, an enhanced cytotoxicity toward EGFR-expressing cells. In summary, we show that SAL can be easily prepared from affibody molecules and thus may be suitable for the development of carrier systems for targeted delivery of drugs.

  • 4.
    Blom, Elisabeth
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Långström, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Velikyan, Irina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    68Ga-Labeling of Biotin Analogues and their Characterization2009Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 20, nr 6, s. 1146-1151Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biotin- and Ga-68-based tracers have been suggested as tools that could be used to monitor the survival of avidin-coated islets of Langerhans isolated from pancreas and used in transplantation, i.e., to liver. Three biotin analogues with various alkyl and poly(ethylene glycol) (PEG) chains coupled to DOTA were synthesized and labeled with Ga-68. The Ga-68 labeling was studied at room temperature as well as elevated temperature using either conventional or microwave heating. Radioactivity incorporation reached 95% within 5 and 2 min using the, respectively, conventional and microwave heating modes. The specific activity of the tracers was improved by preconcentration and purification of the generator eluate. The binding of the labeled and nonlabeled conjugates to avidin in solution was compared to the binding of native biotim. All compounds maintained good affinity for avidin, though introducing the linkers and chelator, especially the PEG-groups, somewhat decreased the binding affinity. The extent of binding of the labeled compounds to avidin was 54-91% after 5 min. Blocking experiments were performed confirming the specificity of the binding of biotin analogues to avidin. The stability of the three labeled compounds in human serum was studied. The stability of the biotin analogue 8 (65% within 30 min) and avidin-biotin complex (80% within 120 min) might be sufficient for the monitoring of the islets of Langerhans. The tracers will be evaluated in in vitro experiments of avidin-coated islets of Langerhans and in transplantation models in vivo.

  • 5.
    Bohl Kullberg, Erika
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Bergstrand, Nill
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Fysikalisk-kemiska institutionen.
    Carlsson, Jörgen
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Edwards, Katarina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Fysikalisk-kemiska institutionen.
    Johnsson, Markus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Fysikalisk-kemiska institutionen.
    Sjöberg, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi.
    Gedda, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Development of EGF-conjugated liposomes for targeted delivery of boronated DNA-binding agents2002Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 13, nr 4, s. 737-743Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Liposomes are of interest as drug delivery tools for therapy of cancer and infectious diseases. We investigated conjugation of epidermal growth factor, EGF, to liposomes using the micelle-transfer method. EGF was conjugated to the distal end of PEG−DSPE lipid molecules in a micellar solution and the EGF−PEG−DSPE lipids were then transferred to preformed liposomes, either empty or containing the DNA-binding compound, water soluble acridine, WSA. We found that the optimal transfer conditions were a 1-h incubation at 60 °C. The final conjugate, 125I-EGF−liposome−WSA, contained approximately 5 mol % PEG, 10−15 EGF molecules at the liposome surface, and 104 to 105 encapsulated WSA molecules could be loaded. The conjugate was shown to have EGF-receptor-specific cellular binding in cultured human glioma cells.

  • 6.
    Ekerljung, Lina
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Wållberg, Helena
    Division of Molecular Biotechnology, School of Biotechnology, Royal Institute of Technology (KTH).
    Sohrabian, Azita
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Andersson, Karl
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Friedman, Mikaela
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi.
    Frejd, Fredrik
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Ståhl, Stefan
    Division of Molecular Biotechnology, School of Biotechnology, Royal Institute of Technology (KTH).
    Gedda, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Generation and Evaluation of Bispecific Affibody Molecules for Simultaneous Targeting of EGFR and HER22012Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 23, nr 9, s. 1802-1811Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Co-expression of several ErbB receptors has been found in many cancers and has been linked with increased aggressiveness of tumors and a worse patient prognosis. This makes the simultaneous targeting of two surface receptors by using bispecific constructs an increasingly appreciated strategy. Here we have generated six such bispecific targeting proteins, which each comprising two monomeric affibody molecules with specific binding to either of the two human epidermal growth factor receptors, EGFR and HER2, respectively. The bispecific constructs were designed with (i) alternative positioning (N- or C-terminal) of the different affibody molecules, (ii) two alternative peptide linkers (Gly4Ser)3 or (Ser4Gly)3, and (iii) affibody molecules with different affinity (nanomolar or picomolar) for HER2. Using both Biacore technology and cell binding assays it was demonstrated that all six constructs could bind simultaneously to both their target proteins. N-terminal positioning of the monomeric affibody molecules was favorable to promote the binding to respective target. Interestingly, bispecific constructs containing the novel (Ser4Gly)3 linker displayed a higher affinity in cell binding, as compared to constructs containing the more conventional linker, (Gly4Ser)3. It could further be concluded that bispecific constructs (but not the monomeric affibody molecules) induced dimerization and phosphorylation of EGFR in SKBR3 cells, which express fairly high levels of both receptors. It was also investigated whether the bispecific binding would influence cell growth or sensitize cells for ionizing radiation, but no such effects were observed.

  • 7.
    Garousi, Javad
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Lindbo, Sarah
    Honarvar, Hadis
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Velletta, Justin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Bogdan, Mitran
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för Molekylär Avbildning.
    Altai, Mohamed
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för Molekylär Avbildning.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Hober, Sophia
    Influence of the N-Terminal Composition on Targeting Properties of Radiometal-Labeled Anti-HER2 Scaffold Protein ADAPT62016Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 27, nr 11, s. 2678-2688Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Radionuclide-imaging-based stratification of patients to targeted therapies makes cancer treatment more personalized and therefore more efficient. Albumin-binding domain derived affinity proteins (ADAPTs) constitute a novel group of imaging probes based on the scaffold of an albumin-binding domain (ABD). To evaluate how different compositions of the N-terminal sequence of ADAPTs influence their biodistribution, a series of human epidermal growth factor receptor type 2 (HER2)-binding ADAPT6 derivatives with different N-terminal sequences were created: GCH6DANS (2), GC(HE)3DANS (3), GCDEAVDANS (4), and GCVDANS(5). These were compared with the parental variant: GCSS(HE)3DEAVDANS (1). All variants were site-specifically conjugated with a maleimido-derivative of a DOTA chelator and labeled with (111)In. Binding to HER2-expressing cells in vitro, in vivo biodistribution as well as targeting properties of the new variants were compared with properties of the (111)In-labeled parental ADAPT variant 1 ((111)In-DOTA-1). The composition of the N-terminal sequence had an apparent influence on biodistribution of ADAPT6 in mice. The use of a hexahistidine tag in (111)In-DOTA-2 was associated with elevated hepatic uptake compared to the (HE)3-containing counterpart, (111)In-DOTA-3. All new variants without a hexahistidine tag demonstrated lower uptake in blood, lung, spleen, and muscle compared to uptake in the parental variant. The best new variants, (111)In-DOTA-3 and (111)In-DOTA-5, provided tumor uptakes of 14.6 ± 2.4 and 12.5 ± 1.3% ID/g at 4 h after injection, respectively. The tumor uptake of (111)In-DOTA-3 was significantly higher than the uptake of the parental (111)In-DOTA-1 (9.1 ± 2.0% ID/g). The tumor-to-blood ratios of 395 ± 75 and 419 ± 91 at 4 h after injection were obtained for (111)In-DOTA-5 and (111)In-DOTA-3, respectively. In conclusion, the N-terminal sequence composition affects the biodistribution and targeting properties of ADAPT-based imaging probes, and its optimization may improve imaging contrast.

  • 8. Justus, Eugen
    et al.
    Awad, Doaa
    Hohnholt, Michaela
    Schaffran, Tanja
    Edwards, Katarina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Fysikalisk kemi.
    Karlsson, Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för fysikalisk och analytisk kemi, Fysikalisk kemi.
    Damian, Luminita
    Gabel, Detlef
    Synthesis, liposomal preparation, and in vitro toxicity of two novel dodecaborate cluster lipids for boron neutron capture therapy2007Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 18, nr 4, s. 1287-1293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new class of lipids, contg. the closo-dodecaborate cluster, has been synthesized. Two lipids, S-(N, N-(2-dimyristoyloxyethyl)acetamido)thioundecahydro-closo-dodecaborate (2-) (B-6-14) and S-(N, N-(2-dipalmitoyloxyethyl)acetamido)thioundecahydro-closo-dodecaborate (2-) (B-6-16) are described. Both of them have a double-tailed lipophilic part and a headgroup carrying two neg. charges. Differential scanning calorimetry shows that B-6-14 and B-6-16 bilayers have main phase transition temps. of 18.8 and 37.9 DegC, resp. Above the transition temp. of 18.8 DegC, B-6-14 can form liposomal vesicles, representing the first boron-contg. lipid with this capability. Upon cooling below the transition temp., stiff bilayers are formed. When incorporated into liposomal formulations with equimolar amts. of distearoyl phosphatidylcholine (DSPC) and cholesterol, stable liposomes are obtained. The z-potential measurements indicate that both B-6-14- and B-6-16-contg. vesicles are neg. charged, with the most neg. potential described of any liposome so far. The liposomes are of high potential value as transporters of boron to tumor cells in treatments based on boron neutron capture therapy (BNCT). Liposomes prepd. from B-6-14 were slightly less toxic in V79 Chinese hamster cells (IC50 5.6 mM) than unformulated Na2B12H11SH (IC50 3.9 mM), while liposomes prepd. from B-6-16 were not toxic even at 30 mM.

  • 9.
    Kwiatkowski, Marek
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Struktur- och molekylärbiologi.
    Wang, Jinfan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Struktur- och molekylärbiologi.
    Forster, Anthony C.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för cell- och molekylärbiologi, Struktur- och molekylärbiologi.
    Facile Synthesis of N-Acyl-aminoacyl-pCpA for Preparation of Mischarged Fully Ribo tRNA2014Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 25, nr 11, s. 2086-2091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Chemical synthesis of N-acyl-aminoacyl-pdCpA and its ligation to tRNA(minus) CA is widely used for the preparation of unnatural aminoacyl-tRNA substrates for ribosomal translation. However, the presence of the unnatural deoxyribose can decrease incorporation yield in translation and there is no straightforward method for chemical synthesis of the natural ribo version. Here, we show that pCpA is surprisingly stable to treatment with strong organic bases provided that anhydrous conditions are used. This allowed development of a facile method for chemical aminoacylation of pCpA. Preparative synthesis of pCpA was also simplified by using t-butyl-dithiomethyl protecting group methodology, and a more reliable pCpA postpurification treatment method was developed. Such aminoacyl-pCpA analogues ligated to tRNA(minus) CA transcripts are highly active in a purified translation system, demonstrating utility of our synthetic method.

  • 10.
    Lindbo, Sarah
    et al.
    KTH Royal Inst Technol, Dept Prot Technol, SE-10691 Stockholm, Sweden.
    Garousi, Javad
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Åstrand, Mikael
    KTH Royal Inst Technol, Dept Prot Technol, SE-10691 Stockholm, Sweden.
    Honarvar, Hadis
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för Molekylär Avbildning.
    Hober, Sophia
    KTH Royal Inst Technol, Dept Prot Technol, SE-10691 Stockholm, Sweden.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Influence of Histidine-Containing Tags on the Biodistribution of ADAPT Scaffold Proteins.2016Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 27, nr 3, s. 716-726Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Engineered scaffold proteins (ESP) are high-affinity binders that can be used as probes for radionuclide imaging. Histidine-containing tags enable both efficient purification of ESP and radiolabeling with (99m)Tc(CO)3. Earlier studies demonstrated that the use of a histidine-glutamate-histidine-glutamate-histidine-glutamate (HE)3-tag instead of the commonly used hexahistidine (H6)-tag reduces hepatic uptake of radiolabeled ESP and short peptides. Here, we investigated the influence of histidine-containing tags on the biodistribution of a novel type of ESP, ADAPTs. A series of anti-HER2 ADAPT probes having H6- or (HE)3-tags in the N-termini were prepared. The constructs, (HE)3-ADAPT6 and H6-ADAPT6, were labeled with two different nuclides, (99m)Tc or (111)In. The labeling with (99m)Tc(CO)3 utilized the histidine-containing tags, while (111)In was attached through a maleimido derivative of DOTA conjugated to the N-terminus. For (111)In-labeled ADAPTs, the use of (HE)3 provided a significantly (p < 0.05) lower hepatic uptake at 1 h after injection, but there was no significant difference in hepatic uptake of (111)In-(HE)3-ADAPT6 and H6-ADAPT6 at later time points. Interestingly, in the case of (99m)Tc, (99m)Tc(CO)3-H6-ADAPT6 provided significantly (p < 0.05) lower uptake in a number of normal tissues and was more suitable as an imaging probe. Thus, the influence of histidine-containing tags on the biodistribution of the novel ADAPT scaffold proteins was different compared to its influence on other ESPs studied so far. Apparently, the effect of a histidine-containing tag on the biodistribution is highly dependent on the scaffold composition of the ESP.

  • 11.
    Mume, Eskender
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Larsson, Barbro
    Nilsson, Ann-Sofie
    Nilsson, Fredrik Y.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Sjöberg, Stefan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Kemiska institutionen. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi, Organisk kemi II.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Evaluation of ((4-Hydroxyphenyl)ethyl)maleimide for Site-Specific Radiobromination of Anti-HER2 Affibody2005Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 16, nr 6, s. 1547-1555Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a new class of small phage-display selected proteins using a scaffold domain of the bacterial receptor protein A. They can be selected for specific binding to a large variety of protein targets. An affibody molecule binidng with high affinity to a tumor antigen HER2 was recently developed for radionuclide diagnostics and therapy in vivo. The use of hte positron-emitting nuclide 76Br(T½ = 16.2 h) could imporve the sensitivity of detection of HER2-expressing tumors. A site-specific radiobromination o fa cysteine-containing variant of the anti-HER2 affibody, (ZHER2:4)2-Cys, using ((4-hydroxpyphenyl)ethyl)maleimide (HPEM), was evaluated in this study. It was found that HPEM can be radiobrominated with an efficiency of 83+0.4% and thereafter coupled to freshly reduced conjugate to exceed 97%. The label was stable against challenge with large excess of nonlabeled bromide and in a high molar strengt solution. In vitro cell tests demonstraded that radiobrominated affibody binds specifically to the HER2-expressing cel-line, SK-OV-3. Biodistribution studies in nude mice bearing SK-OV-3 xenografts have shown tumor accumulation of 4.8 ? 2.2% IA/g and good tumor-to-normal tissue ratios.

  • 12.
    Nestor, Marika
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Persson, Mikael
    Cheng, Junping
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Tolmachev, Vladimir
    van Dongen, Guus
    Anniko, Matti
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper.
    Kairemo, Kalevi
    Biodistribution of the chimeric monoclonal antibody U36 radioiodinated with a closo-dodecaborate-containing linker: Comparison with other radioiodination methods2003Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 14, nr 4, s. 805-10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have evaluated the applicability of the [(4-isothiocyanatobenzylammonio)undecahydro-closo-dodecaborate (1-)] (DABI) linker molecule for antibody radiohalogenation and compared it to radiohalogenation using the linker N-succinimidyl 4-iodobenzoate (PIB) and to direct radiohalogenation using Chloramine T. These studies were performed to assess the potential of DABI conjugates and to optimize the biological properties of halogen-labeled cMAb U36. The three conjugates were evaluated in vitro for their specificity and affinity and in vivo for their biodistribution patterns in normal mice at 1.5, 6, 24, and 96 h pi. Labeling efficiencies of direct CAT labeling, indirect PIB labeling, and indirect DABI labeling were 90-95%, 60%, and 68%, respectively. This resulted in a PIB:cMAb U36 molar ratio of 1.8-2.5 and a DABI:cMAb U36 molar ratio of 4.1. The in vitro data demonstrated specific binding for all conjugates and similar affinities with values around 1 x 10(8) M(-)(1). However, the in vivo data revealed accumulation of the radioiodine uptake in thyroid for the directly labeled conjugate, with a value 10 times higher than the indirectly labeled conjugates 96 h pi. Both the (125)I-PIB-cMAb U36 and (125)I-DABI-cMAb U36 conjugates yielded a low thyroid uptake with no accumulation, indicating different catabolites for these conjugates. This may favor the use of the indirectly labeled conjugates for future studies. Apart from the specific results obtained, these findings also demonstrate how the right linker molecule will provide additional opportunities to further improve the properties of an antibody-radionuclide conjugate.

  • 13. Perols, Anna
    et al.
    Honarvar, Hadis
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Strand, Joanna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Selvaraju, Ramkumar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Karlström, Amelie Eriksson
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Influence of DOTA Chelator Position on Biodistribution and Targeting Properties of In-111-Labeled Synthetic Anti-HER2 Affibody Molecules2012Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 23, nr 8, s. 1661-1670Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a class of affinity proteins. Their small size (7 kDa) in combination with the high (subnanomolar) affinity for a number of cancer-associated molecular targets makes them suitable for molecular imaging. Earlier studies demonstrated that the selection of radionuclide and chelator may substantially influence the tumor-targeting properties of affibody molecules. Moreover, the placement of chelators for labeling of affibody molecules with Tc-99m at different positions in affibody molecules influenced both blood clearance rate and uptake in healthy tissues. This introduces an opportunity to improve the contrast of affibody-mediated imaging. In this comparative study, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was conjugated to the synthetic affibody molecule Z(HER2:S1) at three different positions: DOTA-A1-Z(HER2:S1) (N-terminus), DOTA-K58-Z(HER2:S1) (C-terminus), and DOTA-K50-Z(HER2:S1) (middle of helix 3). The affinity for HER2 differed slightly among the variants and the K-D values were determined to be 133 pM, 107 pM and 94 pM for DOTA-A1-Z(HER2:S1), DOTA-K50-Z(HER2:S1), and DOTA-K58-Z(HER2:S1), respectively. Z(HER2:S1) K50-DOTA showed a slightly lower melting point (57 degrees C) compared to DOTA-A1-Z(HER2:S1) (64 degrees C) and DOTA-K5S-Z(HER2:S1) (62 degrees C), but all variants showed good refolding properties after heat treatment All conjugates were successfully labeled with In-III resulting in a radiochemical yield of 99% with preserved binding capacity. In vitro specificity studies using SKOV-3 and LS174T cell lines showed that the binding of the radiolabeled compounds was HER2 receptor mediated, which also was verified in vivo using BALB/C nu/nu mice with LS174T and Ramos lymphoma xenografts. The three conjugates all showed specific uptake in L5174T xenografts in nude mice, where DOTA-A1-Z(HER2:S1) and DOTA-K58-Z(HER2:S1) showed the highest uptake. Overall, DOTA-K58-Z(HER2:S1) provided the highest tumor-to-blood ratio, which is important for a high contrast imaging. In conclusion, the positioning of the DOTA chelator influences the cellular processing and the biodistribution pattern of radiolabeled affibody molecules, creating preconditions for imaging optimization.

  • 14. Ramapanicker, Ramesh
    et al.
    Sun, Xiaojiao
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Viljanen, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Baltzer, Lars
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - BMC, Fysikalisk-organisk kemi.
    Powerful binders for the D-dimer by conjugation of the GPRP peptide to polypeptides from a designed set: illustrating a general route to new binders for proteins2013Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 24, nr 1, s. 17-25Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthetic tetrapeptide GPRP based on the amino-terminal GPR sequence of the fibrin α-chain, binds the D-dimer protein with a dissociation constant KD of 25 μM. The D-dimer protein, a well-known biomarker for thrombosis, contains two cross-linked D fragments from the fibrinogen protein formed upon degradation of the fibrin gel, the core component of blood clots. In order to develop a specific high-affinity binder for the D-dimer protein, GPRP was conjugated via an aliphatic spacer to each member of a set of sixteen polypeptides designed for the development of binder molecules for proteins in general. The binders were individually characterised and ranked using surface plasmon resonance (SPR) analysis. The dissociation constant of the complex formed from the D-dimer and 4-D15L8-GPRP labelled with fluorescein was determined by fluorescense titration and found to be 3 nM, an affinity four orders of magnitude higher than that of free GPRP. According to SPR analysis binding was completely inhibited by free GPRP at mM concentrations and the polypeptide conjugate was therefore shown to bind specifically to the binding site of GPRP. Affinities were further enhanced by dimerisation of the polypeptide conjugates via a bifunctional linker resulting in dissociation constants that were further decreased (affinities increased) by factors of 2-4. The results suggest an efficient route to specific binders for proteins based on short peptides with affinites that need only to be modest, thus shortening the time of binder development dramatically.

  • 15. Rosik, Daniel
    et al.
    Thibblin, Alf
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Antoni, Gunnar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för onkologi.
    Honarvar, Hadis
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Strand, Joanna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Selvaraju, Ram Kumar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Altai, Mohamed
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Eriksson Karlström, Amelie
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Incorporation of a Triglutamyl Spacer Improves the Biodistribution of Synthetic Affibody Molecules Radiofluorinated at the N-Terminus via Oxime Formation with (18)F-4-Fluorobenzaldehyde2014Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 25, nr 1, s. 82-92Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a class of affinity agents for molecular imaging based on a non-immunoglobulin protein scaffold. Previous studies have demonstrated high contrast for in vivo imaging of cancer-associated molecular abnormalities using Affibody molecules. Using the radionuclide (18)F for labeling and PET as the imaging modality, the sensitivity of molecular imaging using Affibody molecules can be further increased. The use of oxime formation between an aminooxy-functionalized peptide and (18)F-fluorobenzaldehyde ((18)F-FBA) is a promising way of radiolabeling of targeting peptides. However, previous studies demonstrated that application of this method to Affibody molecules is associated with high liver uptake. We hypothesized that incorporation of a triglutamyl spacer between the aminooxy moiety and the N-terminus of a synthetic Affibody molecule would decrease the hepatic uptake of the (18)F-N-(4-fluorobenzylidine)oxime) ((18)F-FBO)-labeled tracer. To verify this, we have produced two variants of the HER2-targeting ZHER2:342 Affibody molecule by peptide synthesis: OA-PEP4313, where aminooxyacetic acid was conjugated directly to the N-terminal alanine, and OA-E3-PEP4313, where a triglutamyl spacer was introduced between the aminooxy moiety and the N-terminus. We have found that the use of the spacer is associated with a minor decrease of affinity, from KD = 49 pM to KD = 180 pM. Radiolabeled (18)F-FBO-E3-PEP4313 demonstrated specific binding to HER2-expressing ovarian carcinoma SKOV-3 cells and slow internalization. Biodistribution studies in mice demonstrated that the use of a triglutamyl linker decreased uptake of radioactivity in liver 2.7-fold at 2 h after injection. Interestingly, radioactivity uptake in kidneys was also reduced (2.4-fold). Experiments in BALB/C nu/nu mice bearing SKOV-3 xenografts demonstrated HER2-specific uptake of (18)F-FBO-E3-PEP4313 in tumors. At 2 h pi, the tumor uptake (20 ± 2% ID/g) exceeded uptake in liver 5-fold and uptake in kidneys 3.6-fold. The tumor-to-blood ratio was 21 ± 3. The microPET/CT imaging experiment confirmed the biodistribution data. In conclusion, the use of a triglutamyl spacer is a convenient way to improve the biodistribution profile of Affibody molecules labeled at the N-terminus using (18)F-FBA. It provides a tracer capable of producing high-contrast images of HER2-expressing tumors.

  • 16.
    Schoch, Juliane
    et al.
    Institute of Pharmacy and Molecular Biotechnology, Heidelberg University.
    Samanta, Ayan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Polymerkemi. Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany.
    Staudt, Markus
    Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany.
    Wiessler, Manfred
    German Cancer Research Center, Division of Medical Physics in Oncology E020, 69120 Heidelberg, Germany.
    Jäschke, Andres
    Institute of Pharmacy and Molecular Biotechnology, Heidelberg University, 69120 Heidelberg, Germany.
    Site-Specific One-Pot Dual Labeling of DNA by Orthogonal Cycloaddition Chemistry2012Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 23, nr 7, s. 1382-1386Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Bioorthogonal reactions are of high interest in biosciences as they allow the introduction of fluorescent dyes, affinity tags, or other unnatural moieties into biomolecules. The site-specific attachment of two or more different labels is particularly demanding and typically requires laborious multistep syntheses. Here, we report that the most popular cycloaddition in bioconjugation, the copper-catalyzed azide–alkyne click reaction (CuAAC), is fully orthogonal to the inverse electron-demand Diels–Alder reaction (DAinv). We demonstrate that both bioorthogonal reactions can be conducted concurrently in a one-pot reaction by just mixing all components. Orthogonality has been established even for highly reactive trans-cyclooctene-based dienophiles (with rate constants up to 380 000 M–1 s–1). These properties allow for the convenient site-specific one-step preparation of oligonucleotide FRET probes and related reporters needed in cellular biology and biophysical chemistry.

  • 17.
    Thuy, Tran
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Engfeldt, Torun
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Widström, Charles
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Avdelningen för sjukhusfysik.
    Bruskin, Alexander
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Eriksson Karlström, Amelie
    In Vivo Evaluation of Cysteine-Based Chelators for Attachment of 99mTc  to Tumor-Targeting Affibody Molecules2007Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 18, nr 2, s. 549-558Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules present a new class of affinity proteins, which utilizes a scaffold based on a 58-amino acid domain derived from protein A. The small (7 kDa) Affibody molecule can be selected to bind to cell-surface targets with high affinity. An Affibody molecule ZHER2:342 with a dissociation constant (Kd) of 22 pM for binding to the HER2 receptor has been reported earlier. Preclinical and pilot clinical studies have demonstrated the utilityof radiolabeled ZHER2:342 in imaging of HER2-expressing tumors. The small size and cysteine-free structure ofAffibody molecules enable complete peptide synthesis and direct incorporation of radionuclide chelators. The goal of this study was to evaluate if incorporation of the natural peptide sequences cysteine-diglycine (CGG) and cysteine-triglycine (CGGG) sequences would enable labeling of Affibody molecules with 99mTc. In a model monomeric form, the chelating sequences were incorporated by peptide synthesis. The HER2-binding affinity was 280 and 250 pM for CGG-ZHER2:342 and CGGG-ZHER2:342, respectively. Conjugates were directly labeled with 99mTc with 90% efficiency and preserved the capacity to bind specifically to HER2-expressing cells. The biodistribution in normal mice showed a rapid clearance from the blood and the majority of organs (except kidneys). In the mice bearing SKOV-3 xenografts, tumor uptake of 99mTc-CGG-ZHER2:342 was HER2-specific and a tumorto- blood ratio of 9.2 was obtained at 6 h postinjection. Gamma-camera imaging with 99mTc-CGG-ZHER2:342 clearly visualized tumors at 6 h postinjection. The results show that the use of a cysteine-based chelator enables 99mTclabeling of Affibody molecules for imaging.

  • 18.
    Tolmachev, Vladimir
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Altai, Mohamed
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för onkologi.
    Perols, Anna
    Karlström, Amelie Eriksson
    Boschetti, Frederic
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Evaluation of a Maleimido Derivative of NOTA for Site-Specific Labeling of Affibody Molecules2011Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 22, nr 5, s. 894-902Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Radionuclide molecular imaging has the potential to improve cancer treatment by selection of patients for targeted therapy. Affibody molecules are a class of small (7 kDa) high-affinity targeting proteins with appreciable potential as molecular imaging probes. The NOTA chelator forms stable complexes with a number of radionuclides suitable for SPECT or PET imaging. A maleimidoethylmonoamide NOTA (MMA-NOTA) has been prepared for site-specific labeling of Affibody molecules having a unique C-terminal cysteine. Coupling of the MMA-NOTA to the anti-HER2 Affibody molecule Z(HER2:239S) resulted in a conjugate with an affinity (dissociation constant) to HER2 of 72 pM. Labeling of [MMA-NOTA-Cys(61)]-Z(HER2:239S) with In-111 gave a yield of >95% after 20 min at 60 degrees C. In vitro cell tests demonstrated specific binding of [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) to HER2-expressing cell lines. In mice bearing prostate cancer DU-145 xenografts, the tumor uptake of [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) was 8.2 +/- 0.9% IA/g and the tumor-to-blood ratio was 31 +/- 1 (4 h postinjection). DU-145 xenografts were clearly visualized by a gamma camera. Direct in vivo comparison of [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) and [In-111-MMA-DOTA-Cys(61)]-Z(HER2:239S) demonstrated that both conjugates provided equal radioactivity uptake in tumors, but the tumor-to-organ ratios were better for [In-111-MMA-NOTA-Cys(61)]-Z(HER2:239S) due to more efficient clearance from normal tissues. In conclusion, coupling of MMA-NOTA to a cysteine-containing Affibody molecule resulted in a site-specifically labeled conjugate, which retains high affinity, can be efficiently labeled, and allows for high-contrast imaging.

  • 19.
    Tolmachev, Vladimir
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Hofström, Camilla
    Malmberg, Jennie
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Ahlgren, Sara
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Hosseinimehr, Seyed Jalal
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för onkologi.
    Abrahmsén, Lars
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Gräslund, Torbjörn
    HEHEHE-Tagged Affibody Molecule May Be Purified by IMAC, Is Conveniently Labeled with [Tc-99m(CO)(3)](+), and Shows Improved Biodistribution with Reduced Hepatic Radioactivity Accumulation2010Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 21, nr 11, s. 2013-2022Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a class of small (ca. 7 kDa) robust scaffold proteins suitable for radionuclide molecular imaging of therapeutic targets in vivo. A hexahistidine tag at the N-terminus streamlines development of new imaging probes by enabling facile purification using immobilized metal ion affinity chromatography (IMAC), as well as convenient [Tc-99m(CO)(3)](+)-labeling. However, previous studies in mice have demonstrated that Affibody molecules labeled by this method yield higher liver accumulation of radioactivity, compared to the same tracer lacking the hexahistidine tag and labeled by an alternative method. Two variants of the HER2-binding Affibody molecule Z(HER2:342) were made in an attempt to create a tagged tracer that could be purified by immobilized metal affinity chromatography, yet would not result in anomalous hepatic radioactivity accumulation following labeling with [Tc-99m(CO)(3)](+). In one construct, the hexahistidine tag was moved to the C-terminus. In the other construct, every second histidine residue in the hexahistidine tag was replaced by the more hydrophilic glutamate, resulting in a HEHEHE-tag. Both variants, denoted Z(HER2:342)-H-6 and (HE)(3)-Z(HER2:342), respectively, could be efficiently purified using IMAC and stably labeled with [Tc-99m(CO)(3)](+) and were subsequently compared with the parental H-6-Z(HER2:342) having an N-terminal hexahistidine tag. All three variants were demonstrated to specifically bind to HER2-expressing cells in vitro. The hepatic accumulation of radioactivity in a murine model was 2-fold lower with [Tc-99m(CO)(3)](+)-Z(HER2:342)-H-6 compared to [Tc-99m(CO)(3)](+)-H-6-Z(HER2:342), and more than 10-fold lower with [Tc-99m(CO)(3)](+)-(HE)(3)-Z(HER2:342). These differences translated into appreciably superior tumor-to-liver ratio for [Tc-99m(CO)(3)](+)-(HE)(3)-Z(HER2:342) compared to the alternative conjugates. This information might be useful for development of other scaffold-based molecular imaging probes.

  • 20.
    Tolmachev, Vladimir
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Koziorowski, Jacek
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Sivaev, Igor
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Lundqvist, Hans
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Carlsson, Jörgen
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Gedda, Lars
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Olsson, Pär
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Sjöberg, Stefan
    Sundin, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Closo-dodecaborate(2-) as a linker for iodination of macromolecules: Aspects on conjugation chemistry and biodistribution1999Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 10, nr 3, s. 338-45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Boron-containing compounds like closo-dodecaborate(2-) are in theory suitable for radioactive labeling with halogens. The boron-halogen bond is stronger than carbon-halogen bond and is not likely to be recognized by deiodinating enzymes in vivo. Peptides and proteins may be conjugated with various closo-dodecaborate(2-)-containing ligands, and thereafter, the conjugate can be iodinated. Since closo-dodecaborate(2-) is more avidly iodinated than tyrosine in moderately acidic media, such conjugates may be directly labeled on the boron part with radioisotopes of iodine using the standard Chloramine-T procedure. Mercapto-undecahydro-closo-dodecaborate(2-) (BSH) was reacted with the double bond of allyldextran to form a boronated dextran compound of the molecular size of about 70 kDa. This compound, in the text denoted as Dx-BS, and cesium dodecahydro-closo-dodecaborate(2-) were labeled using iodine-125. The two compounds were administered to rats in order to study their in vivo stability. The results indicate that iodinated Dx-BS is stable for about 20 h in vivo. The degradation rate, as indicated by thyroid uptake, was found low. [125I]Iodo-closo-dodecaborate(2-), which is a possible degradation product of [125I]Dx-BS-I, was rapidly excreted in urine without significant accumulation in any organ.

  • 21.
    Tolmachev, Vladimir
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Xu, Heng
    Wållberg, Helena
    KTH, Sthlm.
    Ahlgren, Sara
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Hjertman, Magnus
    Sjöberg, Anna
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Abrahmsén, Lars
    Affibody AB.
    Brechbiel, Martin W.
    NCI-NIH, USA.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Evaluation of a maleimido derivative of CHX-A'' DTPA for site-specific labeling of affibody molecules2008Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 19, nr 8, s. 1579-1587Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Affibody molecules are a new class of small targeting proteins based on a common three-helix bundle structure. Affibody molecules binding a desired target may be selected using phage-display technology. An Affibody molecule Z HER2:342 binding with subnanomolar affinity to the tumor antigen HER2 has recently been developed for radionuclide imaging in vivo. Introduction of a single cysteine into the cysteine-free Affibody scaffold provides a unique thiol group for site-specific labeling of recombinant Affibody molecules. The recently developed maleimido-CHX-A'' DTPA was site-specifically conjugated at the C-terminal cysteine of Z HER2:2395-C, a variant of Z HER2:342, providing a homogeneous conjugate with a dissociation constant of 56 pM. The yield of labeling with (111)In was >99% after 10 min at room temperature. In vitro cell tests demonstrated specific binding of (111)In-CHX-A'' DTPA-Z 2395-C to HER2-expressing cell-line SKOV-3 and good cellular retention of radioactivity. In normal mice, the conjugate demonstrated rapid clearance from all nonspecific organs except kidney. In mice bearing SKOV-3 xenografts, the tumor uptake of (111)In-CHX-A'' DTPA-Z 2395-C was 17.3 +/- 4.8% IA/g and the tumor-to-blood ratio 86 +/- 46 (4 h postinjection). HER2-expressing xenografts were clearly visualized 1 h postinjection. In conclusion, coupling of maleimido-CHX-A'' DTPA to cysteine-containing Affibody molecules provides a well-defined uniform conjugate, which can be rapidly labeled at room temperature and provides high-contrast imaging of molecular targets in vivo.

  • 22.
    Tran, Thuy
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Ekblad, Torun
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för onkologi.
    Feldwisch, Joachim
    Wennborg, Anders
    Abrahmsén, Lars
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Eriksson Karlström, Amelie
    Effects of lysine-containing mercaptoacetyl-based chelators on the biodistribution of 99mTc-labeled anti-HER2 Affibody molecules2008Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 19, nr 12, s. 2568-2576Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of polar (mercaptoacetyl-triseryl) and negatively charged (mercaptoacetyl-triglumatyl) chelators on the biodistribution of 99mTc-labeled anti-HER2 Affibody molecules were previously investigated. With glycine, serine, and glutamate, we demonstrated that substitution with a single amino acid in the chelator can significantly influence the biodistribution properties and the excretion pathways. Here, we have taken this investigation further, by analyzing the effects of introduction of a positive amino acid residue on the in vivo properties of the 99mTc-labeled Affibody molecule. The Affibody molecules with mercaptoacetyl-seryl-lysyl-seryl (maSKS) and mercaptoacetyl-trilysyl (maKKK) extensions were produced by peptide synthesis and labeled with 99mTc in alkaline conditions. A comparative biodistribution was performed in normal mice to evaluate the excretion pathway. A shift toward renal excretion was obtained when serine was substituted with lysine in the chelating sequence. The radioactivity in the gastrointestinal tract was reduced 3-fold for the 99mTc-maSKS-Z(HER2:342) and 99mTc-maKKK-Z(HER2: 342) in comparison with the 99mTc-maSSS-Z(HER2:342) conjugate 4 h post injection (p.i.). The radioactivity in the liver was elevated when a triple substitution of positively charged lysine was used. The tumor targeting properties of 99mTc-maSKS-Z(HER2:342) were further investigated in SKOV-3 xenografts. The tumor uptake of 99mTc-maSKS-Z(HER2: 342) was 17+/-7% IA/g 4 h p.i. Tumor xenografts were well-visualized by gamma scintigraphy. In conclusion, the substitution with one single lysine in the chelator results in better tumor imaging properties of the Affibody molecule Z(HER2:342) and is favorable for imaging of tumors and metastases in the abdominal area. Multiple lysine residues in the chelator are, however, undesirable due to elevated uptake both in the liver and kidneys.

  • 23.
    Tran, Thuy
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Engfeldt, Torun
    School of Biotechnology, Royal Institute of Technology, Stockholm, Sweden.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Feldwisch, Joachim
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi, Enheten för biomedicinsk strålningsvetenskap.
    Abrahmsén, Lars
    Wennborg, Anders
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper.
    Karlström, Amelie Eriksson
    School of Biotechnology, Royal Institute of Technology, Stockholm, Sweden.
    (99m)Tc-maEEE-Z(HER2:342), an Affibody molecule-based tracer for the detection of HER2 expression in malignant tumors2007Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 18, nr 6, s. 1956-1964Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Detection of HER2-overexpression in tumors and metastases is important for the selection of patients who will benefit from trastuzumab treatment. Earlier investigations showed successful imaging of HER2-positive tumors in patients using indium- or gallium-labeled Affibody molecules. The goal of this study was to evaluate the use of (99m)Tc-labeled Affibody molecules for the detection of HER2 expression. The Affibody molecule Z(HER2:342) with the chelator sequences mercaptoacetyl-Gly-Glu-Gly (maGEG) and mercaptoacetyl-Glu-Glu-Glu (maEEE) was synthesized by peptide synthesis and labeled with technetium-99m. Binding specificity, cellular retention, and in vitro stability were investigated. The biodistribution of (99m)Tc-maGEG-Z(HER2:342) and (99m)Tc-maEEE-Z(HER2:342) was compared with (99m)Tc-maGGG-Z(HER2:342) in normal mice, and the tumor targeting properties of (99m)Tc-maEEE-Z(HER2:342) were determined in SKOV-3 xenografted nude mice. The results showed that the Affibody molecules were efficiently labeled with technetium-99m. The labeled conjugates were highly stable in vitro with preserved HER2-binding capacity. The use of glutamic acid in the chelator sequences for (99m)Tc-labeling of Z(HER2:342) reduced the hepatobiliary excretion 3-fold with a single Gly-to-Glu substitution and 10-fold with three Gly-to-Glu substitutions. (99m)Tc-maEEE-Z(HER2:342) showed a receptor-specific tumor uptake of 7.9 +/- 1.0 %IA/g and a tumor-to-blood ratio of 38 at 4 h pi. Gamma-camera imaging with (99m)Tc-maEEE-Z(HER2:342) could detect HER2-expressing tumors in xenografts already at 1 h pi. It was concluded that peptide synthesis for the coupling of chelator sequences to Affibody molecules for (99m)Tc labeling is an efficient way to modify the in vivo kinetics. Increased hydrophilicity, combined with improved stability of the mercaptoacetyl-triglutamyl chelator, resulted in favorable biodistribution, making (99m)Tc-maEEE-Z(HER2:342) a promising tracer for clinical imaging of HER2 overexpression in tumors.

  • 24.
    Varasteh, Zohreh
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Velikyan, Irina
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Lindeberg, Gunnar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för organisk farmaceutisk kemi.
    Sörensen, Jens
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för nuklearmedicin och PET.
    Larhed, Mats
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Avdelningen för organisk farmaceutisk kemi.
    Sandström, Mattias
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för nuklearmedicin och PET.
    Selvaraju, Ram Kumar
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Malmberg, Jennie
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för radiologi, onkologi och strålningsvetenskap, Enheten för biomedicinsk strålningsvetenskap.
    Orlova, Anna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi, Plattformen för preklinisk PET.
    Synthesis and Characterization of a High-Affinity NOTA-Conjugated Bombesin Antagonist for GRPR-Targeted Tumor Imaging2013Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 24, nr 7, s. 1144-1153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The gastrin-releasing peptide receptor (GRPR/BB2) is a molecular target for the visualization of prostate cancer. This work focused on the development of high-affinity, hydrophilic, antagonistic, bombesin-based imaging agents for PET and SPECT. The bombesin antagonist analog D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 ([D-Phe(6),Sta(13),Leu(14)]-bombesin[6-14]) was synthesized and conjugated to 1,4,7-triazacyclononane-N,N',N ''-triacetic acid (NOTA) via a diethylene glycol (PEG(2)) linker. The resulting conjugate, NOTA-PEG(2)-[D-Phe(6),Sta(13),Leu(14)]bombesin[6-14] (NOTA-P2-RM26), was labeled with Ga-68 (T-1/2 = 68 min, positron emitter) and In-111 (T-1/2 = 2.8 days, gamma emitter). The labeling stability, specificity, inhibition efficiency (IC50), and dissociation constant (K-D) of both labeled compounds as well as their cellular retention and internalization were investigated. The pharmacokinetics of the dual isotope) (In-111/Ga-68)-labeled peptide in both normal NMRI mice and PC-3 tumor-bearing Balb/c nu/nu mice was also studied. NOTA-P2-RM26 was labeled with In-111 and Ga-68 at a radiochemical yield of >98%. Both conjugates were shown to have high specificity and binding affinity for GRPR. The K-D value was determined to be 23 +/- 13 pM for the In-111-labeled compound in a saturation binding experiment. In addition, In-nat- and Ga-nat-NOTA-P2-RM26 showed low nanomolar binding inhibition concentrations (IC50 = 1.24 +/- 0.29 nM and 0.91 +/- 0.19 nM, respectively) in a competitive binding assay. The internalization rate of the radiolabeled conjugates was slow. The radiometal-labeled tracers demonstrated rapid blood clearance via the kidney and GRPR-specific uptake in the pancreas in normal mice. Tumor targeting and biodistribution studies in mice bearing PC-3 xenografts displayed high and specific uptake in tumors (8.1 +/- 0.4%ID/g for Ga-68 and 5.7 +/- 0.3%ID/g for In-111) and high tumor-to-background ratios (tumor/blood: 12 +/- 1 for Ga-68 and 10 +/- 1 for In-111) after only 1 h pi of 45 pmol of peptide. The xenografts were visualized by gamma and microPET cameras shortly after injection. In conclusion, the antagonistic bombesin analog NOTA-PEG(2)-D-Phe-Gln-Trp-Ala-Val-Gly-His-Sta-Leu-NH2 (NOTA-P2-RM26) is a promisindg candidate for prostate cancer imaging using PET and SPECT/CT.

  • 25. Velikyan, I
    et al.
    Maecke, H
    Långström, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för biokemi och organisk kemi.
    Convenient preparation of 68Ga-based PET-radiopharmaceuticals at room temperature2008Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 19, nr 2, s. 569-573Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A straightforward labeling using generator produced positron emitting (68)Ga, which provides high quality images, may result in kit type production of PET radiopharmaceuticals and make PET examinations possible also at centers lacking accelerators. The introduction of macrocyclic bifunctional chelators that would provide fast (68)Ga-complexation at room temperature would simplify even further tracer preparation and open wide possibilities for (68)Ga-labeling of fragile and potent macromolecules. Gallium-68 has the potential to facilitate development of clinically practical PET and to promote PET technique for individualized medicine. The macrocyclic chelator, 1,4,7-triazacyclononanetriacetic acid (NOTA), and its derivative coupled to an eight amino acid residue peptide (NODAGA-TATE, [NODAGA (0), Tyr(3)]Octreotate) were labeled with (68)Ge/(68)Ga-generator produced positron emitting (68)Ga. Formation kinetics of (68)Ga-NOTA was studied as a function of pH and formation kinetics of (68)Ga-NODAGA-TATE was studied as a function of the bioconjugate concentration. The nearly quantitative radioactivity incorporation (RAI>95%) for (68)Ga-NOTA was achieved within less than 10 min at room temperature and pH 3.5. The concentrations of NODAGA-TATE required for RAI of >90% and >95% were, respectively, 2-5 and 10 microM. In both cases the purification of the (68)Ga-labeled products was not necessary since the radiochemical purity was >95% and the preparation buffer, 4-(2-hydroxyethyl) piperazine-1-ethanesulfonic acid (HEPES) is suitable for human use. In order to confirm the identity of the products, complexes comprising (nat)Ga were synthesized and analyzed by mass spectrometry. The complex was found to be stable in the reaction mixture, phosphate buffer, and human plasma during 4.5 h incubation. Free and peptide conjugated NOTA formed stable complexes with (68)Ga at room temperature within 10 min. This might be of special interest for the labeling of fragile and potent macromolecules and allow for kit type preparation of (68)Ga-based radiopharmaceuticals.

  • 26. Westerlund, Kristina
    et al.
    Honarvar, Hadis
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi, Medicinsk strålningsvetenskap.
    Eriksson Karlström, Amelie
    Design, Preparation, and Characterization of PNA-Based Hybridization Probes for Affibody-Molecule-Mediated Pretargeting2015Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 26, nr 8, s. 1724-1736Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In radioimmunotherapy, the contrast between tumor and normal tissue can be improved by using a pretargeting strategy with a primary targeting agent, which is conjugated to a recognition tag, and a secondary radiolabeled molecule binding specifically to the recognition tag. The secondary molecule is injected after the targeting agent has accumulated in the tumor and is designed to have a favorable biodistribution profile, with fast clearance from blood and low uptake in normal tissues. In this study, we have designed and evaluated two complementary peptide nucleic acid (PNA)-based probes for specific and high-affinity association in vivo. An anti-HER2 Affibody-PNA chimera, ZHER2:342-SR-HP1, was produced by a semisynthetic approach using sortase A catalyzed ligation of a recombinantly produced Affibody molecule to a PNA-based HP1-probe assembled using solid-phase chemistry. A complementary HP2 probe carrying a DOTA chelator and a tyrosine for dual radiolabeling was prepared by solid-phase synthesis. Circular dichroism (CD) spectroscopy and UV thermal melts showed that the probes can hybridize to form a structured duplex with a very high melting temperature (Tm), both in HP1:HP2 and in ZHER2:342-SR-HP1:HP2 (Tm = 86-88 °C), and the high binding affinity between ZHER2:342-SR-HP1 and HP2 was confirmed in a surface plasmon resonance (SPR)-based binding study. Following a moderately fast association (1.7 × 10(5) M(-1) s(-1)), the dissociation of the probes was extremely slow and <5% dissociation was observed after 17 h. The equilibrium dissociation constant (KD) for ZHER2:342-SR-HP1:HP2 binding to HER2 was estimated by SPR to be 212 pM, suggesting that the conjugation to PNA does not impair Affibody binding to HER2. The biodistribution profiles of (111)In- and (125)I-labeled HP2 were measured in NMRI mice, showing very fast blood clearance rates and low accumulation of radioactivity in kidneys and other organs. The measured radioactivity in blood was 0.63 ± 0.15 and 0.41 ± 0.15%ID/g for (125)I- and (111)In-HP2, respectively, at 1 h p.i., and at 4 h p.i., the kidney accumulation of radioactivity was 0.17 ± 0.04%ID/g for (125)I-HP2 and 3.83 ± 0.39%ID/g for (111)In-HP2. Taken together, the results suggest that a PNA-based system has suitable biophysical and in vivo properties and is a promising approach for pretargeting of Affibody molecules.

  • 27.
    Zhao, Qinghai
    et al.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Tolmachev, Vladimir
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Carlsson, Jörgen
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Lundqvist, Hans
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Sundin, Johanna
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Janson, Jan-Christer
    Sundin, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för onkologi, radiologi och klinisk immunologi.
    Effects of dextranation on the pharmacokinetics of short peptides: A PETstudy on mEGF1999Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 10, nr 6, s. 938-946Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of dextranation on the biodistribution of mouse epidermal growth factor (mEGF, 6 kDa) were assessed. By reductive amination, mEGF was coupled to 13 and 46 kDa dextran. The two dextranated conjugates and free mEGF were labeled with the positron-emitting nuclide (76)Br (T(1/2) = 16 h). After intravenous administration to Sprague Dawley rats, the radioactivity biodistribution was evaluated by positron emission tomography (PET) and by measurements of dissected tissues. The dextranation prolonged the retention time in blood, especially when the dextran chain was long. [(76)Br]mEGF-dextran conjugates were shown to have significantly, more than 5 times, lower kidney accumulation than the nonconjugated [(76)Br]mEGF. In conclusion, dextranation affects the biodistribution of mEGF in vivo giving a prolonged circulation time, a decreased uptake in kidney, and an increased spleen accumulation.

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