| 1. |
- Abouzayed, Ayman, et al.
(author)
-
177Lu-labeled PSMA targeting therapeutic with optimized linker for treatment of disseminated prostate cancer; evaluation of biodistribution and dosimetry
- 2023
-
In: Frontiers in Oncology. - : Frontiers Media S.A.. - 2234-943X. ; 13
-
Journal article (peer-reviewed)abstract
- Introduction: Prostate specific membrane antigen (PSMA), highly expressed in metastatic castration-resistant prostate cancer (mCRPC), is an established therapeutic target. Theranostic PSMA-targeting agents are widely used in patient management and has shown improved outcomes for mCRPC patients. Earlier, we optimized a urea-based probe for radionuclide visualization of PSMA-expression in vivo using computer modeling. With the purpose to develop a targeting agent equally suitable for radionuclide imaging and therapy, the agent containing DOTA chelator was designed (BQ7876). The aim of the study was to test the hypothesis that Lu-177-labeled BQ7876 possesses target binding and biodistribution properties potentially enabling its use for radiotherapy.Methods: BQ7876 was synthesized and labeled with Lu-177. Specificity and affinity of [Lu-177]Lu-BQ7876 to PSMA-expressing PC3-pip cells was evaluated and its processing after binding to cells was studied. Animal studies in mice were performed to assess its biodistribution in vivo, target specificity and dosimetry. [Lu-177]Lu-PSMA-617 was simultaneously evaluated for comparison.Results: BQ7876 was labeled with Lu-177 with radiochemical yield >99%. Its binding to PSMA was specific in vitro and in vivo when tested in antigen saturation conditions as well as in PSMA-negative PC-3 tumors. The binding of [Lu-177]Lu-BQ7876 to living cells was characterized by rapid association, while the dissociation included a rapid and a slow phase with affinities K-D1 = 3.8 nM and K-D2 = 25 nM. The half-maximal inhibitory concentration for Lu-nat-BQ7876 was 59 nM that is equal to 61 nM for Lu-nat-PSMA-617. Cellular processing of [Lu-177]Lu-BQ7876 was accompanied by slow internalization. [Lu-177]Lu-BQ7876 was cleared from blood and normal tissues rapidly. Initial elevated uptake in kidneys decreased rapidly, and by 3 h post injection, the renal uptake (13 +/- 3%ID/g) did not differ significantly from tumor uptake (9 +/- 3%ID/g). Tumor uptake was stable between 1 and 3 h followed by a slow decline. The highest absorbed dose was in kidneys, followed by organs and tissues in abdomen.Discussion: Biodistribution studies in mice demonstrated that targeting properties of [Lu-177]Lu-BQ7876 are not inferior to properties of [Lu-177]Lu-PSMA-617, but do not offer any decisive advantages.
|
|
| 2. |
- Garousi, Javad, et al.
(author)
-
Experimental HER2-Targeted Therapy Using ADAPT6-ABD-mcDM1 in Mice Bearing SKOV3 Ovarian Cancer Xenografts : Efficacy and Selection of Companion Imaging Counterpart
- 2022
-
In: Pharmaceutics. - : MDPI. - 1999-4923. ; 14:8
-
Journal article (peer-reviewed)abstract
- Overexpression of the human epidermal growth factor receptor 2 (HER2) in breast and gastric cancer is exploited for targeted therapy using monoclonal antibodies and antibody-drug conjugates. Small engineered scaffold proteins, such as the albumin binding domain (ABD) derived affinity proteins (ADAPTs), are a promising new format of targeting probes for development of drug conjugates with well-defined structure and tunable pharmacokinetics. Radiolabeled ADAPT6 has shown excellent tumor-targeting properties in clinical trials. Recently, we developed a drug conjugate based on the HER2-targeting ADAPT6 fused to an albumin binding domain (ABD) for increased bioavailability and conjugated to DM1 for cytotoxic action, designated as ADAPT6-ABD-mcDM1. In this study, we investigated the therapeutic efficacy of this conjugate in mice bearing HER2-expressing SKOV3 ovarian cancer xenografts. A secondary aim was to evaluate several formats of imaging probes for visualization of HER2 expression in tumors. Administration of ADAPT6-ABD-mcDM1 provided a significant delay of tumor growth and increased the median survival of the mice, in comparison with both a non-targeting homologous construct (ADAPT(Neg)-ABD-mcDM1) and the vehicle-treated groups, without inducing toxicity to liver or kidneys. Moreover, the evaluation of imaging probes showed that small scaffold proteins, such as Tc-99m(CO)(3)-ADAPT6 or the affibody molecule Tc-99m-Z(HER2:41071), are well suited as diagnostic companions for potential stratification of patients for ADAPT6-ABD-mcDM1-based therapy.
|
|
| 3. |
- Machulkin, Aleksei E., et al.
(author)
-
Synthesis and Preclinical Evaluation of Urea-Based Prostate-Specific Membrane Antigen-Targeted Conjugates Labeled with 177Lu
- 2024
-
In: ACS Pharmacology & Translational Science. - : American Chemical Society (ACS). - 2575-9108. ; 7:5, s. 1457-1473
-
Journal article (peer-reviewed)abstract
- 177Lu-labeled small-molecule prostate-specific membrane antigen (PSMA) targeted tracers are therapeutic agents for metastatic castration-resistant prostate cancer. Optimizing molecular design holds the potential to further enhance the pharmacokinetic properties of PSMA-targeted agents while preserving their potent therapeutic effects. In this study, six novel N-[N-[(S)-1,3-dicarboxypropyl]carbamoyl]-(S)-l-lysine (DCL) urea-based PSMA ligand 2,2′,2″,2‴-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetraacetic acid conjugates were synthesized. These conjugates feature polypeptide linkers containing the Phe-Phe peptide sequence and an aromatic fragment at the ε-NH-Lys group of the DCL fragment. The synthesis yielded products with satisfactory yields ranging from 60% to 72%, paving the way for their preclinical evaluation. The labeling of the new variants of urea-based PSMA inhibitors provided a radiochemical yield of over 95%. The 177Lu-labeled conjugates demonstrated specific and moderate affinity binding to PSMA-expressing human cancer cells PC3-pip in vitro and specific accumulation in PSMA-expressing xenografts in vivo. Based on the results, both the lipophilicity and the type of substituent in the linker significantly influence the binding properties of the PSMA inhibitor and its biodistribution profile. Specifically, the studied variants containing a bromine substituent or a hydroxyl group introduced into the aromatic fragment of the phenylalanyl residue in DCL exhibit higher affinities to PSMA compared to variants with only a chlorine-substituted aromatic fragment or variants without any substituents. The [177Lu]Lu-13C with the bromine substituent was characterized by the highest activity accumulation in blood, salivary glands, muscle, bone, and gastrointestinal tract and had inasmuch as an unfavorable pharmacokinetic profile. The negative charge of the carboxyl group in the phenyl moiety of the [177Lu]Lu-13A variant has demonstrated a positive effect on reducing the retention of activity in the liver and the kidneys (the ratio of tumor to kidneys was 1.3-fold). Low accumulation in normal tissues in vivo indicates that this novel PSMA-targeting inhibitor is a promising radioligand.
|
|
| 4. |
- Nordling, Sofia, 1985-, et al.
(author)
-
Enhanced protection of the renal vascular endothelium improves early outcome in kidney transplantation : Preclinical investigations in pig and mouse
- 2018
-
In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 8
-
Journal article (peer-reviewed)abstract
- Ischemia reperfusion injury is one of the major complications responsible for delayed graft function in kidney transplantation. Applications to reduce reperfusion injury are essential due to the widespread use of kidneys from deceased organ donors where the risk for delayed graft function is especially prominent. We have recently shown that coating of inflamed or damaged endothelial cells with a unique heparin conjugate reduces thrombosis and leukocyte recruitment. In this study we evaluated the binding capacity of the heparin conjugate to cultured human endothelial cells, to kidneys from brain-dead porcine donors, and to murine kidneys during static cold storage. The heparin conjugate was able to stably bind cultured endothelial cells with high avidity, and to the renal vasculature of explanted kidneys from pigs and mice. Treatment of murine kidneys prior to transplantation reduced platelet deposition and leukocyte infiltration 24 hours post-transplantation, and significantly improved graft function. The present study thus shows the benefits of enhanced protection of the renal vasculature during cold storage, whereby increasing the antithrombotic and anti-adhesive properties of the vascular endothelium yields improved renal function early after transplantation.
|
|
| 5. |
- Oroujeni, Maryam, PhD, 1982-, et al.
(author)
-
Evaluation of affinity matured Affibody molecules for imaging of the immune checkpoint protein B7-H3
- 2023
-
In: Nuclear Medicine and Biology. - : Elsevier BV. - 0969-8051 .- 1872-9614. ; 124-125
-
Journal article (peer-reviewed)abstract
- B7-H3 (CD276), an immune checkpoint protein, is a promising molecular target for immune therapy of malignant tumours. Sufficient B7-H3 expression level is a precondition for successful therapy. Radionuclide molecular imaging is a powerful technique for visualization of expression levels of molecular targets in vivo. Use of small radiolabelled targeting proteins would enable high-contrast radionuclide imaging of molecular targets if adequate binding affinity and specificity of an imaging probe could be provided. Affibody molecules, small engineered affinity proteins based on a non-immunoglobulin scaffold, have demonstrated an appreciable potential in radionuclide imaging. Proof-of principle of radionuclide visualization of expression levels of B7-H3 in vivo was demonstrated using the [99mTc]Tc-AC12-GGGC Affibody molecule. We performed an affinity maturation of AC12, enabling selection of clones with higher affinity. Three most promising clones were expressed with a -GGGC (triglycine-cysteine) chelating sequence at the C-terminus and labelled with technetium-99m (99mTc). 99mTc-labelled conjugates bound to B7-H3-expressing cells specifically in vitro and in vivo. Biodistribution in mice bearing B7-H3-expressing SKOV-3 xenografts demonstrated improved imaging properties of the new conjugates compared with the parental variant [99mTc]Tc-AC12-GGGC. [99mTc]Tc-SYNT-179 provided the strongest improvement of tumour-to-organ ratios. Thus, affinity maturation of B7-H3 Affibody molecules could improve biodistribution and targeting properties for imaging of B7-H3-expressing tumours.
|
|
| 6. |
- Rinne, Sara Sophie
(author)
-
Affibody-Based Molecular Imaging and Targeted Therapy of HER3-Expressing Cancer
- 2022
-
Doctoral thesis (other academic/artistic)abstract
- The human epidermal growth factor receptor type 3 (HER3) is overexpressed in different types of cancer and is a known contributor to disease progression and resistance to cancer therapy. This thesis is based on five original articles, which aimed to improve the diagnostic and therapeutic potential of affibody-based agents for management of HER3-expressing cancers. Papers I-III focused on the development and optimization of radiolabeled affibody molecules for radionuclide molecular imaging of HER3 expression. In particular, they investigated the influence of different radiometal/chelator complexes and hydrophilicity on the biodistribution and imaging properties of the HER3-targeting affibody molecule ZHER3. Paper IV compared the optimized ZHER3-based radiotracer with antibody and antibody-fragment based radiotracers for PET imaging of HER3 expression. In Paper V, a preclinical therapy study was conducted to investigate the efficacy of different monomeric and dimeric HER3-targeting affibody constructs for treatment of HER3-expressing cancer.It was shown that by optimizing the radiometal/chelator complex and incorporation of a hydrophilic (HE)3-tag the imaging properties of ZHER3-based radiotracers could be improved (Papers I-III). Generally, replacing a positively charged radiometal/chelator complex with a neutral or negatively charged complex improved the image contrast by reducing the normal organ uptake, especially in the liver. Further, it was demonstrated that the optimized affibody-based tracer [68Ga]Ga-(HE)3-ZHER3-NODAGA could provide higher contrast PET images of HER3 expression than the 89Zr-labeled antibody seribantumab and a seribantumab-derived F(ab’)2 fragment (Paper IV). The therapy study showed that the arrangement of the molecular building blocks affected the therapeutic efficacy of ZHER3-based affibody constructs. The monomeric and dimeric ABD-conjugated affibody constructs 3A and 3A3 showed the best therapeutic efficacy among the tested constructs and were able to delay tumor growth and prolong survival with the same efficacy as the therapeutic HER3-targeting antibody seribantumab (Paper V).In conclusion, the results described in this thesis show that HER3-targeting affibody-based agents could be well-suited for molecular imaging of HER3 expression and HER3-targeted therapy in cancer. Careful optimization of the molecular design could improve the imaging properties and therapeutic efficacy of HER3-targeting affibody molecules. Most importantly, it was demonstrated that HER3-targeting affibody molecules could provide superior diagnostic images and similar therapeutic effect than more traditional approaches for management of HER3-expressing cancer.
|
|
| 7. |
- Westerlund, Kristina, et al.
(author)
-
Design, Preparation, and Characterization of PNA-Based Hybridization Probes for Affibody-Molecule-Mediated Pretargeting
- 2015
-
In: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 26:8, s. 1724-1736
-
Journal article (peer-reviewed)abstract
- 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 × 105 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 111In- and 125I-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 125I- and 111In-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 125I-HP2 and 3.83 ± 0.39%ID/g for 111In-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.
|
|
| 8. |
- Yin, Wen, 1993-, et al.
(author)
-
The Influence of Domain Permutations of an Albumin-Binding Domain-Fused HER2-Targeting Affibody-Based Drug Conjugate on Tumor Cell Proliferation and Therapy Efficacy
- 2021
-
In: Pharmaceutics. - : MDPI AG. - 1999-4923. ; 13:11, s. 1974-1974
-
Journal article (peer-reviewed)abstract
- Human epidermal growth factor receptor 2 (HER2) is a clinically validated target for breast cancer therapy. Previously, a drug-fused HER2-targeting affinity protein construct successfully extended the survival of mice bearing HER2-expressing xenografts. The aim of this study was to evaluate the influence of the number and positioning of the protein domains in the drug conjugate. Seven HER2-targeting affibody-based constructs, including one or two affibody molecules (Z) with or without an albumin-binding domain (ABD), namely Z, Z-ABD, ABD-Z, Z-Z, Z-Z-ABD, Z-ABD-Z, and ABD-Z-Z, were evaluated on their effects on cell growth, in vivo targeting, and biodistribution. The biodistribution study demonstrated that the monomeric constructs had longer blood retention and lower hepatic uptake than the dimeric ones. A dimeric construct, specifically ABD-Z-Z, could stimulate the proliferation of HER2 expressing SKOV-3 cells in vitro and the growth of tumors in vivo, whereas the monomeric construct Z-ABD could not. These two constructs demonstrated a therapeutic effect when coupled to mcDM1; however, the effect was more pronounced for the non-stimulating Z-ABD. The median survival of the mice treated with Z-ABD-mcDM1 was 63 days compared to the 37 days for those treated with ABD-Z-Z-mcDM1 or for the control animals. Domain permutation of an ABD-fused HER2-targeting affibody-based drug conjugate significantly influences tumor cell proliferation and therapy efficacy. The monomeric conjugate Z-ABD is the most promising format for targeted delivery of the cytotoxic drug DM1.
|
|
| 9. |
|
|
| 10. |
- Altai, Mohamed, et al.
(author)
-
Feasibility of Affibody-Based Bioorthogonal Chemistry Mediated Radionuclide Pretargeting
- 2016
-
In: Journal of Nuclear Medicine. - : SOC NUCLEAR MEDICINE. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 57:3, s. 431-436
-
Journal article (peer-reviewed)abstract
- Affibody molecules constitute a new class of probes for radionuclide tumor targeting. The small size of Affibody molecules is favorable for rapid localization in tumors and clearance from circulation. However, high renal reabsorption of Affibody molecules prevents the use of residualizing radiometals, including several promising low-energy (beta- and alpha-emitters, for radionuclide therapy. We tested a hypothesis that Affibody-based pretargeting mediated by a bioorthogonal interaction between trans-cyclooctene (TCO) and tetrazine would provide higher accumulation of radiometals in tumor xenografts than in the kidneys. Methods: TCO was conjugated to the anti-human epidermal growth factor receptor 2 (HER2) Affibody molecule Z(2395). DOTA-tetrazine was labeled with In-111 and Lu-177. In vitro pretargeting was studied in HER2-expressing SKOV-3 and BT474 cell lines. In vivo studies were performed on BALB/C nu/nu mice bearing SKOV-3 xenografts. Results: I-125-Z(2395)-TCO bound specifically to HER2-expressing cells in vitro with an affinity of 45 +/- 16 pM. In-111-tetrazine bound specifically and selectively to Z(2325)-TCO pretreated cells. In vivo studies demonstrated HER2-specific I-125-Z(2395)-TCO accumulation in xenografts. TCO-mediated In-111-tetrazine localization was shown in tumors, when the radiolabeled tracer was injected 4 h after an injection of Z(2395)-TCO. At 1 h after injection, the tumor uptake of In-111-tetrazine and Lu-177-tetrazine was approximately 2-fold higher than the renal uptake. Pretargeting provided more than a 56-fold reduction of renal uptake of In-111 in comparison with direct targeting. Conclusion: The feasibility of Affibody-based bioorthogonal chemistry-mediated pretargeting was demonstrated. The use of pre-targeting provides a substantial reduction of radiometal accumulation in kidneys, creating preconditions for palliative radionuclide therapy.
|
|
