| 1. |
- Garousi, Javad, et al.
(författare)
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Experimental HER2-Targeted Therapy Using ADAPT6-ABD-mcDM1 in Mice Bearing SKOV3 Ovarian Cancer Xenografts : Efficacy and Selection of Companion Imaging Counterpart
- 2022
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Ingår i: Pharmaceutics. - : MDPI. - 1999-4923. ; 14:8
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Garousi, Javad, et al.
(författare)
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Radionuclide therapy using ABD-fused ADAPT scaffold protein : Proof of Principle
- 2021
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Ingår i: Biomaterials. - : Elsevier. - 0142-9612 .- 1878-5905. ; 266
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Tidskriftsartikel (refereegranskat)abstract
- Molecular recognition in targeted therapeutics is typically based on immunoglobulins. Development of engineered scaffold proteins (ESPs) has provided additional opportunities for the development of targeted therapies. ESPs offer inexpensive production in prokaryotic hosts, high stability and convenient approaches to modify their biodistribution. In this study, we demonstrated successful modification of the biodistribution of an ESP known as ADAPT (Albumin-binding domain Derived Affinity ProTein). ADAPTs are selected from a library based on the scaffold of ABD (Albumin Binding Domain) of protein G. A particular ADAPT, the ADAPT6, binds to human epidermal growth factor receptor type 2 (HER2) with high affinity. Preclinical and early clinical studies have demonstrated that radiolabeled ADAPT6 can image HER2-expression in tumors with high contrast. However, its rapid glomerular filtration and high renal reabsorption have prevented its use in radionuclide therapy. To modify the biodistribution, ADAPT6 was genetically fused to an ABD. The non-covalent binding to the host's albumin resulted in a 14-fold reduction of renal uptake and appreciable increase of tumor uptake for the best variant, 177Lu-DOTA-ADAPT6-ABD035. Experimental therapy in mice bearing HER2-expressing xenografts demonstrated more than two-fold increase of median survival even after a single injection of 18 MBq 177Lu-DOTA-ADAPT6-ABD035. Thus, a fusion with ABD and optimization of the molecular design provides ADAPT derivatives with attractive targeting properties for radionuclide therapy.
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| 3. |
- Garousi, Javad, et al.
(författare)
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Radionuclide Therapy Using ABD-fused ADAPT Scaffold Protein: Proof of Principle
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The molecular recognition characteristics of targeted therapeutics is typically attributed to immunoglobulins. However, recent development of engineered scaffold proteins (ESPs) has provided additional opportunities for the improvement of these targeted therapies. ESPs offer inexpensive production in prokaryotic hosts and high molecular stability as well as convenient approaches to modify the biodistribution. In this study, we have demonstrated successful modification of the biodistribution of a particular ESP known as ADAPT (Albumin-binding domain Derived Affinity ProTein). These ADAPTs are generated through screening of combinatorial libraries based on the rigid scaffold of ABD (Albumin Binding Domain) of protein G. As one of these ADAPTs, ADAPT6 binds to human epidermal growth factor type 2 (HER2) with high affinity. Preclinical and early clinical studies have demonstrated that radiolabeled ADAPT6 can image HER2-expression in tumors with high contrast. However, its rapid glomerular filtration and high renal re-absorption have prevented its use in radionuclide therapy. To modify the biodistribution of ADAPT6 and allow for a therapeutic use, we present here an ADAPT6 genetically fused to ABD. The non-covalent binding of this fusion protein to the host albumin resulted in a 14-fold reduction of renal uptake and appreciable increase of tumor uptake for the best variant, 177Lu-DOTA-ADAPT6-ABD035. Experimental therapy in mice bearing HER2-expressing xenografts demonstrated more than two-fold increase of median survival even after a single injection of 18 MBq 177Lu-DOTA-ADAPT6-ABD035. The injections were not associated with any observable toxicity. Thus, a fusion with ABD and optimization of the molecular design provides ADAPT derivatives with attractive targeting properties for radionuclide therapy.
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| 4. |
- Vorobyeva, Anzhelika, et al.
(författare)
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Radionuclide Molecular Imaging of EpCAM Expression in Triple-Negative Breast Cancer Using the Scaffold Protein DARPin Ec1
- 2020
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 25:20
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Tidskriftsartikel (refereegranskat)abstract
- Efficient treatment of disseminated triple-negative breast cancer (TNBC) remains an unmet clinical need. The epithelial cell adhesion molecule (EpCAM) is often overexpressed on the surface of TNBC cells, which makes EpCAM a potential therapeutic target. Radionuclide molecular imaging of EpCAM expression might permit selection of patients for EpCAM-targeting therapies. In this study, we evaluated a scaffold protein, designed ankyrin repeat protein (DARPin) Ec1, for imaging of EpCAM in TNBC. DARPin Ec1 was labeled with a non-residualizing [I-125]I-para-iodobenzoate (PIB) label and a residualizing [Tc-99m]Tc(CO)(3) label. Both imaging probes retained high binding specificity and affinity to EpCAM-expressing MDA-MB-468 TNBC cells after labeling. Internalization studies showed that Ec1 was retained on the surface of MDA-MB-468 cells to a high degree up to 24 h. Biodistribution in Balb/c nu/nu mice bearing MDA-MB-468 xenografts demonstrated specific uptake of both [I-125]I-PIB-Ec1 and [Tc-99m]Tc(CO)(3)-Ec1 in TNBC tumors. [I-125]I-PIB-Ec1 had appreciably lower uptake in normal organs compared with [Tc-99m]Tc(CO)(3)-Ec1, which resulted in significantly (p < 0.05) higher tumor-to-organ ratios. The biodistribution data were confirmed by micro-Single-Photon Emission Computed Tomography/Computed Tomography (microSPECT/CT) imaging. In conclusion, an indirectly radioiodinated Ec1 is the preferable probe for imaging of EpCAM in TNBC.
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