| 1. |
- Abouzayed, Ayman, et al.
(författare)
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Synthesis and Preclinical Evaluation of Radio-Iodinated GRPR/PSMA Bispecific Heterodimers for the Theranostics Application in Prostate Cancer
- 2019
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Ingår i: Pharmaceutics. - : MDPI AG. - 1999-4923. ; 11:7
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Tidskriftsartikel (refereegranskat)abstract
- Gastrin-releasing peptide receptor (GRPR) and prostate-specific membrane antigen (PSMA) are overexpressed in most prostate cancers. GRPR expression is higher in early stages while PSMA expression increases with progression. The possibility of targeting both markers with a single theranostics radiotracer could improve patient management. Three GRPR/PSMA-targeting bispecific heterodimers (urea derivative PSMA-617 and bombesin-based antagonist RM26 linked via X-triazolyl-Tyr-PEG2, X = PEG2 (BO530), (CH2)(8) (BO535), none (BO536)) were synthesized by solid-phase peptide synthesis. Peptides were radio-iodinated and evaluated in vitro for binding specificity, cellular retention, and affinity. In vivo specificity for all heterodimers was studied in PC-3 (GRPR-positive) and LNCaP (PSMA-positive) xenografts. [I-125]I-BO530 was evaluated in PC-3pip (GRPR/PSMA-positive) xenografts. Micro single-photon emission computed tomography/computed tomography (microSPECT/CT) scans were acquired. The heterodimers were radiolabeled with high radiochemical yields, bound specifically to both targets, and demonstrated high degree of activity retention in PC-3pip cells. Only [I-125]I-BO530 demonstrated in vivo specificity to both targets. A biodistribution study of [I-125]I-BO530 in PC-3pip xenografted mice showed high tumor activity uptake (30%-35%ID/g at 3 h post injection (pi)). Activity uptake in tumors was stable and exceeded all other organs 24 h pi. Activity uptake decreased only two-fold 72 h pi. The GRPR/PSMA-targeting heterodimer [I-125]I-BO530 is a promising agent for theranostics application in prostate cancer.
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| 2. |
- Abouzayed, Ayman, 1992-
(författare)
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Theranostic Targeting of GRPR and PSMA in Prostate Cancer
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis is based on five original articles that investigated the theranostics of prostate cancer by gastrin-releasing peptide receptor (GRPR) and prostate-specific membrane antigen (PSMA) targeting. GRPR and PSMA are two extensively evaluated prostate cancer cell markers due to their overexpression in the majority of prostate cancer samples. Theranostic targeting of GRPR and PSMA is an attractive strategy to improve the management of prostate cancer patients.Papers I and II focused on the dual targeting of GRPR and PSMA. The effect of linker modification on the affinity for GRPR and PSMA and the pharmacokinetic profile was evaluated. In Paper III, the effect of the GRPR antagonist RM26 conjugation to an albumin-binding domain on the pharmacokinetic profile and its potential use in therapy was investigated. Paper IV focused on developing a GRPR antagonist that was suitable for single-photon emission computed tomography (SPECT) using technetium-99m. In Paper V, the GRPR antagonist developed in Paper IV was translated into a phase I clinical trial to assess safety and dosimetry.Modifying the linkers in GRPR and PSMA heterodimers can largely impact the affinity for both targets. This modification influenced the in vivo targeting specificity and biodistribution, with [125I]I-BO530 in Paper I and [111In]In-BQ7812 in Paper II outperforming other analogues. Our findings in Paper III indicated that the conjugation of an albumin-binding domain to RM26 increased the blood concentration of the radiotracer. This increase led to elevated and stable tumour uptake of [111In]In-DOTA-ABD-RM26 after several days of injection. However, [111In]In-DOTA-ABD-RM26 was also increasingly taken up by various healthy organs. The GRPR antagonist [99mTc]Tc-maSSS-PEG2-RM26, studied in Paper IV, showed high specificity and affinity for GRPR. This resulted in elevated GRPR-mediated uptake. Additionally, maSSS-PEG2-RM26 could be radiolabelled via a straightforward radiolabelling protocol. Clinical evaluation of [99mTc]Tc-maSSS-PEG2-RM26 in prostate and breast cancer patients (Paper V) demonstrated the safety and tolerability of the radiotracer, with favourable dosimetry and no side effects.In conclusion, this thesis evaluated different tools for the theranostic targeting of GRPR and PSMA. The findings warrant further investigation to optimise the reported radiotracers.
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| 3. |
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| 4. |
- Altai, Mohamed, et al.
(författare)
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Affibody-derived drug conjugates : Potent cytotoxic molecules for treatment of HER2 over-expressing tumors
- 2018
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Ingår i: Journal of Controlled Release. - : Elsevier B.V.. - 0168-3659 .- 1873-4995. ; 288, s. 84-95
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Tidskriftsartikel (refereegranskat)abstract
- Patients with HER2-positive tumors often suffer resistance to therapy, warranting development of novel treatment modalities. Affibody molecules are small affinity proteins which can be engineered to bind to desired targets. They have in recent years been found to allow precise targeting of cancer specific molecular signatures such as the HER2 receptor. In this study, we have investigated the potential of an affibody molecule targeting HER2, ZHER2:2891, conjugated with the cytotoxic maytansine derivate MC-DM1, for targeted cancer therapy. ZHER2:2891 was expressed as a monomer (ZHER2:2891), dimer ((ZHER2:2891)2) and dimer with an albumin binding domain (ABD) for half-life extension ((ZHER2:2891)2-ABD). All proteins had a unique C-terminal cysteine that could be used for efficient and site-specific conjugation with MC-DM1. The resulting affibody drug conjugates were potent cytotoxic molecules for human cells over-expressing HER2, with sub-nanomolar IC50-values similar to trastuzumab emtansine, and did not affect cells with low HER2 expression. A biodistribution study of a radiolabeled version of (ZHER2:2891)2-ABD-MC-DM1, showed that it was taken up by the tumor. The major site of off-target uptake was the kidneys and to some extent the liver. (ZHER2:2891)2-ABD-MC-DM1 was found to have a half-life in circulation of 14 h. The compound was tolerated well by mice at 8.5 mg/kg and was shown to extend survival of mice bearing HER2 over-expressing tumors. The findings in this study show that affibody molecules are a promising class of engineered affinity proteins to specifically deliver small molecular drugs to cancer cells and that such conjugates are potential candidates for clinical evaluation on HER2-overexpressing cancers.
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| 5. |
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| 6. |
- Altai, Mohamed, et al.
(författare)
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Evaluation of affibody molecule-based PNA-mediated radionuclide pretargeting : Development of an optimized conjugation protocol and 177Lu labeling
- 2017
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Ingår i: Nuclear Medicine and Biology. - : Elsevier. - 0969-8051 .- 1872-9614. ; 54, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Introduction We have previously developed a pretargeting approach for affibody-mediated cancer therapy based on PNA–PNA hybridization. In this article we have further developed this approach by optimizing the production of the primary agent, ZHER2:342-SR-HP1, and labeling the secondary agent, HP2, with the therapeutic radionuclide 177Lu. We also studied the biodistribution profile of 177Lu-HP2 in mice, and evaluated pretargeting with 177Lu-HP2 in vitro and in vivo. Methods The biodistribution profile of 177Lu-HP2 was evaluated in NMRI mice and compared to the previously studied 111In-HP2. Pretargeting using 177Lu-HP2 was studied in vitro using the HER2-expressing cell lines BT‐474 and SKOV-3, and in vivo in mice bearing SKOV-3 xenografts. Results and conclusion Using an optimized production protocol for ZHER2:342-SR-HP1 the ligation time was reduced from 15 h to 30 min, and the yield increased from 45% to 70%. 177Lu-labeled HP2 binds specifically in vitro to BT474 and SKOV-3 cells pre-treated with ZHER2:342-SR-HP1. 177Lu-HP2 was shown to have a more rapid blood clearance compared to 111In-HP2 in NMRI mice, and the measured radioactivity in blood was 0.22 ± 0.1 and 0.68 ± 0.07%ID/g for 177Lu- and 111In-HP2, respectively, at 1 h p.i. In contrast, no significant difference in kidney uptake was observed (4.47 ± 1.17 and 3.94 ± 0.58%ID/g for 177Lu- and 111In-HP2, respectively, at 1 h p.i.). Co-injection with either Gelofusine or lysine significantly reduced the kidney uptake for 177Lu-HP2 (1.0 ± 0.1 and 1.6 ± 0.2, respectively, vs. 2.97 ± 0.87%ID/g in controls at 4 h p.i.). 177Lu-HP2 accumulated in SKOV-3 xenografts in BALB/C nu/nu mice when administered after injection of ZHER2:342-SR-HP1. Without pre-injection of ZHER2:342-SR-HP1, the uptake of 177Lu-HP2 was about 90-fold lower in tumor (0.23 ± 0.08 vs. 20.7 ± 3.5%ID/g). The tumor-to-kidney radioactivity accumulation ratio was almost 5-fold higher in the group of mice pre-injected with ZHER2:342-SR-HP1. In conclusion, 177Lu-HP2 was shown to be a promising secondary agent for affibody-mediated tumor pretargeting in vivo.
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| 7. |
- Altai, Mohamed, et al.
(författare)
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Feasibility of Affibody-Based Bioorthogonal Chemistry Mediated Radionuclide Pretargeting
- 2016
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Ingår i: Journal of Nuclear Medicine. - : SOC NUCLEAR MEDICINE. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 57:3, s. 431-436
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Tidskriftsartikel (refereegranskat)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.
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| 8. |
- Andersson, Ken G., et al.
(författare)
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Feasibility of imaging of epidermal growth factor receptor expression with ZEGFR:2377 affibody molecule labeled with Tc-99m using a peptide-based cysteine-containing chelator
- 2016
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Ingår i: International Journal of Oncology. - : SPANDIDOS. - 1019-6439 .- 1791-2423. ; 49:6, s. 2285-2293
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Tidskriftsartikel (refereegranskat)abstract
- The epidermal growth factor receptor (EGFR) is overexpressed in a number of malignant tumors and is a molecular target for several specific anticancer antibodies and tyrosine kinase inhibitors. The overexpression of EGFR is a predictive biomarker for response to several therapy regimens. Radionuclide molecular imaging might enable detection of EGFR overexpression by a non-invasive procedure and could be used repeatedly. Affibody molecules are engineered scaffold proteins, which could be selected to have a high affinity and selectivity to predetermined targets. The anti-EGFR ZEGFR:2377 affibody molecule is a potential imaging probe for EGFR detection. The use of the generator-produced radionuclide Tc-99m should facilitate clinical translation of an imaging probe due to its low price, availability and favorable dosimetry of the radionuclide. In the present study, we evaluated feasibility of ZEGFR:2377 labeling with Tc-99m using a peptide-based cysteine-containing chelator expressed at the C-terminus of ZEGFR:2377. The label was stable in vitro under cysteine challenge. In addition, Tc-99m-ZEGFR:2377 was capable of specific binding to EGFR-expressing cells with high affinity (274 pM). Studies in BALB/C nu/nu mice bearing A431 xenografts demonstrated that Tc-99m-ZEGFR:2377 accumulates in tumors in an EGFR-specific manner. The tumor uptake values were 3.6 1 and 2.5 0.4% ID/g at 3 and 24 h after injection, respectively. The corresponding tumor-to-blood ratios were 1.8 0.4 and 8 3. The xenografts were clearly visualized at both time-points. This study demonstrated the potential of Tc-99m-labeled ZEGFR:2377 for imaging of EGFR in vivo.
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| 9. |
- Bass, Tarek, et al.
(författare)
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In vivo evaluation of a novel format of a bivalent HER3-targeting and albumin- binding therapeutic affibody construct
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Overexpression of human epidermal growth factor receptor 3 (HER3) is involved in resistance to several therapies for malignant tumours. Currently, several anti-HER3 monoclonal antibodies are under clinical development. We introduce an alternative approach to HER3-targeted therapy based on engineered scaffold proteins, i.e. affibody molecules. We designed a small construct (22.5 kDa, denoted 3A3), consisting of two high-affinity anti-HER3 affibody molecules flanking an albumin-binding domain ABD, which was introduced for prolonged residence in circulation. In vitro, 3A3 efficiently inhibited growth of HER3-expressing BxPC-3 cells. Biodistribution in mice was measured using 3A3 that was site-specifically labelled with In-111 via a DOTA chelator. The residence time of In-111-DOTA-3A3 in blood was extended when compared with the monomeric affibody molecule. In-111-DOTA-3A3 accumulated specifically in HER3-expressing BxPC-3 xenografts in mice. However, In-111-DOTA-3A3 cleared more rapidly from blood than a size-matched control construct In-111-DOTA-TAT, most likely due to sequestering of 3A3 by mErbB3, the murine counterpart of HER3. Repeated dosing and increase of injected protein dose decreased uptake of In-111-DOTA-3A3 in mErbB3-expressing tissues. Encouragingly, growth of BxPC-3 xenografts in mice was delayed in an experimental (pilot-scale) therapy study using 3A3. We conclude that the 3A3 affibody format seems promising for treatment of HER3-overexpressing tumours.
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| 10. |
- Baun, Christina, et al.
(författare)
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Preclinical Evaluation of the Copper-64 Labeled GRPR-Antagonist RM26 in Comparison with the Cobalt-55 Labeled Counterpart for PET-Imaging of Prostate Cancer
- 2020
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Ingår i: Molecules. - : MDPI AG. - 1431-5157 .- 1420-3049. ; 25:24
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Tidskriftsartikel (refereegranskat)abstract
- Gastrin-releasing peptide receptor (GRPR) is overexpressed in the majority of prostate cancers. This study aimed to investigate the potential of 64Cu (radionuclide for late time-point PET-imaging) for imaging of GRPR expression using NOTA-PEG2-RM26 and NODAGA-PEG2-RM26. Methods: NOTA/NODAGA-PEG2-RM26 were labeled with 64Cu and evaluated in GRPR-expressing PC-3 cells. Biodistribution of [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 was studied in PC-3 xenografted mice and compared to the biodistribution of [57Co]Co-NOTA/NODAGA-PEG2-RM26 at 3 and 24 h p.i. Preclinical PET/CT imaging was performed in tumor-bearing mice. NOTA/NODAGA-PEG2-RM26 were stably labeled with 64Cu with quantitative yields. In vitro, binding of [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 was rapid and GRPR-specific with slow internalization. In vivo, [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 bound specifically to GRPR-expressing tumors with fast clearance from blood and normal organs and displayed generally comparable biodistribution profiles to [57Co]Co-NOTA/NODAGA-PEG2-RM26; tumor uptake exceeded normal tissue uptake 3 h p.i.. Tumor-to-organ ratios did not increase significantly with time. [64Cu]Cu-NOTA-PEG2-RM26 had a significantly higher liver and pancreas uptake compared to other agents. 57Co-labeled radioconjugates showed overall higher tumor-to-non-tumor ratios, compared to the 64Cu-labeled counterparts. [64Cu]Cu-NOTA/NODAGA-PEG2-RM26 was able to visualize GRPR-expression in a murine PC model using PET. However, [55/57Co]Co-NOTA/NODAGA-PEG2-RM26 provided better in vivo stability and overall higher tumor-to-non-tumor ratios compared with the 64Cu-labeled conjugates.
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| 11. |
- Dahlsson Leitao, Charles, et al.
(författare)
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Molecular Design of HER3-Targeting Affibody Molecules : Influence of Chelator and Presence of HEHEHE-Tag on Biodistribution of 68Ga-Labeled Tracers
- 2019
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 20:5
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Tidskriftsartikel (refereegranskat)abstract
- Affibody-based imaging of HER3 is a promising approach for patient stratification. We investigated the influence of a hydrophilic HEHEHE-tag ((HE)3-tag) and two different gallium-68/chelator-complexes on the biodistribution of Z08698 with the aim to improve the tracer for PET imaging. Affibody molecules (HE)3-Z08698-X and Z08698-X (X = NOTA, NODAGA) were produced and labeled with gallium-68. Binding specificity and cellular processing were studied in HER3-expressing human cancer cell lines BxPC-3 and DU145. Biodistribution was studied 3 h p.i. in Balb/c nu/nu mice bearing BxPC-3 xenografts. Mice were imaged 3 h p.i. using microPET/CT. Conjugates were stably labeled with gallium-68 and bound specifically to HER3 in vitro and in vivo. Association to cells was rapid but internalization was slow. Uptake in tissues, including tumors, was lower for (HE)3-Z08698-X than for non-tagged variants. The neutral [68Ga]Ga-NODAGA complex reduced the hepatic uptake of Z08698 compared to positively charged [68Ga]Ga-NOTA-conjugated variants. The influence of the chelator was more pronounced in variants without (HE)3-tag. In conclusion, hydrophilic (HE)3-tag and neutral charge of the [68Ga]Ga-NODAGA complex promoted blood clearance and lowered hepatic uptake of Z08698. [68Ga]Ga-(HE)3-Z08698-NODAGA was considered most promising, providing the lowest blood and hepatic uptake and the best imaging contrast among the tested variants.
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| 12. |
- Deyev, S., et al.
(författare)
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Comparative Evaluation of Two DARPin Variants : Effect of Affinity, Size, and Label on Tumor Targeting Properties
- 2019
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 16:3, s. 995-1008
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Tidskriftsartikel (refereegranskat)abstract
- Designed ankyrin repeat proteins (DARPins) are small engineered scaffold proteins that can be selected for binding to desirable molecular targets. High affinity and small size of DARPins render them promising probes for radionuclide molecular imaging. However, detailed knowledge on many factors influencing their imaging properties is still lacking. We have evaluated two human epidermal growth factor 2 (HER2)-specific DARPins with different size and binding properties. DARPins 9-29-H 6 and G3-H 6 were radiolabeled with iodine-125 and tricarbonyl technetium-99m and evaluated in vitro. A side-by-side comparison of biodistribution and tumor targeting was performed. HER2-specific tumor accumulation of G3-H 6 was demonstrated. A combination of smaller size and higher affinity resulted in a higher tumor uptake of G3-H 6 in comparison to 9-29-H 6 . Technetium-99m labeled G3-H 6 demonstrated a better biodistribution profile than 9-29-H 6 , with several-fold lower uptake in liver. Radioiodinated G3-H 6 showed the best tumor-to-organ ratios. The combined effect of affinity, molecular weight, scaffold composition, and nonresidualizing properties of iodine label provided radioiodinated G3-H 6 with high clinical potential for imaging of HER2.
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| 13. |
- Garousi, Javad, et al.
(författare)
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Comparative evaluation of affibody- and antibody fragments-based CAIX imaging probes in mice bearing renal cell carcinoma xenografts
- 2019
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Carbonic anhydrase IX (CAIX) is a cancer-associated molecular target for several classes of therapeutics. CAIX is overexpressed in a large fraction of renal cell carcinomas (RCC). Radionuclide molecular imaging of CAIX-expression might offer a non-invasive methodology for stratification of patients with disseminated RCC for CAIX-targeting therapeutics. Radiolabeled monoclonal antibodies and their fragments are actively investigated for imaging of CAIX expression. Promising alternatives are small non-immunoglobulin scaffold proteins, such as affibody molecules. A CAIX-targeting affibody ZCAIX:2 was re-designed with the aim to decrease off-target interactions and increase imaging contrast. The new tracer, DOTA-HE3-ZCAIX:2, was labeled with In-111 and characterized in vitro. Tumor-targeting properties of [In-111]In-DOTA-HE3-ZCAIX:2 were compared head-to-head with properties of the parental variant, [(99)mTc]Tc(CO)(3)-HE3-ZCAIX:2, and the most promising antibody fragment-based tracer, [In-111]In-DTPA-G250(Fab')(2), in the same batch of nude mice bearing CAIX-expressing RCC xenografts. Compared to the (99)mTc-labeled parental variant, [In-111]In-DOTA-HE3-ZCAIX:2 provides significantly higher tumor-to-lung, tumor-to-bone and tumor-to-liver ratios, which is essential for imaging of CAIX expression in the major metastatic sites of RCC. [In-111]In-DOTA-HE3-ZCAIX:2 offers significantly higher tumor-to-organ ratios compared with [In-111]In-G250(Fab']2. In conclusion, [In-111]In-DOTA-HE3-ZCAIX:2 can be considered as a highly promising tracer for imaging of CAIX expression in RCC metastases based on our results and literature data.
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| 14. |
- Garousi, Javad, et al.
(författare)
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Comparative Evaluation of Affibody Molecules for Radionuclide Imaging of in Vivo Expression of Carbonic Anhydrase IX
- 2016
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 13:11, s. 3676-3687
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Tidskriftsartikel (refereegranskat)abstract
- Overexpression of the enzyme carbonic anhydrase IX (CAIX) is documented for chronically hypoxic malignant tumors as well as for normoxic renal cell carcinoma. Radionuclide molecular imaging of CAIX would be useful for detection of hypoxic areas in malignant tumors, for patients' stratification for CAIX-targeted therapies, and for discrimination of primary malignant and benign renal tumors. Earlier, we have reported feasibility of in vivo radionuclide based imaging of CAIX expressing tumors using Affibody molecules, small affinity proteins based on a non-immunoglobulin scaffold. In this study, we compared imaging properties of several anti-CAIX Affibody molecules having identical scaffold parts and competing for the same epitope on CAIX, but having different binding paratopes. Four variants were labeled using residualizing Tc-99m and nonresidualizing I-125 labels. All radiolabeled variants demonstrated high affinity detection of CAIX-expressing cell line SK-RC-52 in vitro and specific accumulation in SK-RC-52 xenografts in vivo. I-125-labeled conjugates demonstrated much lower radioactivity uptake in kidneys but higher radioactivity concentration in blood compared with Tc-99m-labeled counterparts. Although all variants cleared rapidly from blood and nonspecific compartments, there was noticeable difference in their biodistribution. The best variant for imaging of expression of CAIX in disseminated cancer was Tc-99m-(HE)(3)-ZCAIX:2 providing tumor uptake of 16.3 +/- 0.9% ID/g and tumor-to-blood ratio of 44 +/- 7 at 4 h after injection. For primary renal cell carcinoma, the most promising imaging candidate was I-125-ZCAIX:4 providing tumor-kidney ratio of 2.1 0.5. In conclusion, several clones of scaffold proteins should be evaluated to select the best variant for development of an imaging probe with optimal sensitivity for the intended application.
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| 15. |
- Garousi, Javad, et al.
(författare)
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Comparative evaluation of dimeric and monomeric forms of ADAPT scaffold protein for targeting of HER2-expressing tumours
- 2019
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Ingår i: European journal of pharmaceutics and biopharmaceutics. - : ELSEVIER SCIENCE BV. - 0939-6411 .- 1873-3441. ; 134, s. 37-48
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Tidskriftsartikel (refereegranskat)abstract
- ADAPTs are small engineered non-immunoglobulin scaffold proteins, which have demonstrated very promising features as vectors for radionuclide tumour targeting. Radionuclide imaging of human epidermal growth factor 2 (HER2) expression in vivo might be used for stratification of patients for HER2-targeting therapies. ADAPT6, which specifically binds to HER2, has earlier been shown to have very promising features for in vivo targeting of HER2 expressing tumours. In this study we tested the hypothesis that dimerization of ADAPT6 would increase the apparent affinity to HER2 and accordingly improve tumour targeting. To find an optimal molecular design of dimers, a series of ADAPT dimers with different linkers, -SSSG- (DiADAPT6L1), -(SSSG)(2)- (DiADAPT6L2), and -(SSSG)(3)- (DiADAPT6L3) was evaluated. Dimers in combination with optimal linker lengths demonstrated increased apparent affinity to HER2. The best variants, DiADAPT6L2 and DiADAPT6L3 were site-specifically labelled with In-111 and I-125, and compared with a monomeric ADAPT6 in mice bearing HER2-expressing tumours. Despite higher affinity, both dimers had lower tumour uptake and lower tumour-to-organ ratios compared to the monomer. We conclude that improved affinity of a dimeric form of ADAPT does not compensate the disadvantage of increased size. Therefore, increase of affinity should be obtained by affinity maturation and not by dimerization.
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| 16. |
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| 17. |
- Garousi, Javad, et al.
(författare)
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Comparative evaluation of tumor targeting using the anti-HER2 ADAPT scaffold protein labeled at the C-terminus with indium-111 or technetium-99m
- 2017
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- ABD-Derived Affinity Proteins (ADAPTs) is a novel class of engineered scaffold proteins derived from an albumin-binding domain of protein G. The use of ADAPT6 derivatives as targeting moiety have provided excellent preclinical radionuclide imaging of human epidermal growth factor 2 (HER2) tumor xenografts. Previous studies have demonstrated that selection of nuclide and chelator for its conjugation has an appreciable effect on imaging properties of scaffold proteins. In this study we performed a comparative evaluation of the anti-HER2 ADAPT having an aspartate-glutamate-alanine-valine-aspartate-alanine-asparagine-serine (DEAVDANS) N-terminal sequence and labeled at C-terminus with (99)mTc using a cysteine-containing peptide based chelator, glycine-serine-serine-cysteine (GSSC), and a similar variant labeled with In-111 using a maleimido derivative of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator. Both (99)mTc-DEAVDANS-ADAPT6-GSSC and In-111-DEAVDANS-ADAPT6-GSSC-DOTA accumulated specifically in HER2-expressing SKOV3 xenografts. The tumor uptake of both variants did not differ significantly and average values were in the range of 19-21% ID/g. However, there was an appreciable variation in uptake of conjugates in normal tissues that resulted in a notable difference in the tumor-to-organ ratios. The In-111-DOTA label provided 2-6 fold higher tumor-to-organ ratios than (99)mTc-GSSC and is therefore the preferable label for ADAPTs.
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| 18. |
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| 19. |
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| 20. |
- Garousi, Javad, et al.
(författare)
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Influence of the N -Terminal Composition on Targeting Properties of Radiometal-Labeled Anti-HER2 Scaffold Protein ADAPT6
- 2016
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Ingår i: Bioconjugate chemistry. - : American Chemical Society (ACS). - 1043-1802 .- 1520-4812. ; 27:11, s. 2678-2688
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Tidskriftsartikel (refereegranskat)abstract
- 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: GCH(6)DANS (2), GC(HE)(3)DANS (3), GCDEAVDANS (4), and GCVD.ANS(5). These were compared with the parental variant: GCSS(HE)(3)DEAVDANS (1). All variants were site-specifically conjugated with a maleimido-derivative of a DOTA chelator and labeled with In-III. 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 In-III-labeled parental ADAPT variant 1 (In-III-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 (InD)-In-III-OTA-2 was associated with elevated hepatic uptake compared to the (HE)(3)-containing counterpart, In-III-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, In-III-DOTA-3 and In-III-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 In-III-DOTA-3 was significantly higher than the uptake of the parental In-III-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 In-III-DOTA-5 and (IIII)n-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.
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| 21. |
- Garousi, Javad, et al.
(författare)
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PET imaging of epidermal growth factor receptor expression in tumours using Zr-89-labelled ZEGFR:2377 affibody molecules
- 2016
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Ingår i: International Journal of Oncology. - : Spandidos. - 1019-6439 .- 1791-2423. ; 48:4, s. 1325-1332
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Tidskriftsartikel (refereegranskat)abstract
- Epidermal growth factor receptor (EGFR) is a transmembrane tyrosine kinase receptor, which is overexpressed in many types of cancer. The use of EGFR-targeting monoclonal antibodies and tyrosine-kinase inhibitors improves significantly survival of patients with colorectal, non-small cell lung cancer and head and neck squamous cell carcinoma. Detection of EGFR overexpression provides important prognostic and predictive information influencing management of the patients. The use of radionuclide molecular imaging would enable non-invasive repeatable determination of EGFR expression in disseminated cancer. Moreover, positron emission tomography (PET) would provide superior sensitivity and quantitation accuracy in EGFR expression imaging. Affibody molecules are a new type of imaging probes, providing high contrast in molecular imaging. In the present study, an EGFR-binding affibody molecule (ZEGFR:2377) was site-specifically conjugated with a deferoxamine (DFO) chelator and labelled under mild conditions (room temperature and neutral pH) with a radionuclide Zr-89. The Zr-89-DFO-ZEGFR:2377 tracer demonstrated specific high affinity (160 +/- 60 pM) binding to EGFR-expressing A431 epidermoid carcinoma cell line. In mice bearing A431 xenografts, Zr-89-DFO-ZEGFR: 2377 demonstrated specific uptake in tumours and EGFR-expressing tissues. The tracer provided tumour uptake of 2.6 +/- 0.5% ID/g and tumour-to-blood ratio of 3.7 +/- 0.6 at 24 h after injection. Zr-89-DFO-ZEGFR: 2377 provides higher tumour-to-organ ratios than anti-EGFR antibody Zr-89-DFO-cetuximab at 48 h after injection. EGFR-expressing tumours were clearly visualized by microPET using Zr-89-DFO-ZEGFR: 2377 at both 3 and 24 h after injection. In conclusion, Zr-89-DFO-ZEGFR: 2377 is a potential probe for PET imaging of EGFR-expression in vivo.
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| 22. |
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| 23. |
- Garousi, Javad, et al.
(författare)
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The use of radiocobalt as a label improves imaging of EGFR using DOTA-conjugated Affibody molecule
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Several anti-cancer therapies target the epidermal growth factor receptor (EGFR). Radionuclide imaging of EGFR expression in tumours may aid in selection of optimal cancer therapy. The In-111-labelled DOTA-conjugated Z(EGFR:2377) Affibody molecule was successfully used for imaging of EGFR-expressing xenografts in mice. An optimal combination of radionuclide, chelator and targeting protein may further improve the contrast of radionuclide imaging. The aim of this study was to evaluate the targeting properties of radiocobalt-labelled DOTA-Z(EGFR:2377). DOTA-Z(EGFR:2377) was labelled with Co-57 (T-1/2 = 271.8 d), Co-55 (T-1/2 = 17.5 h), and, for comparison, with the positron-emitting radionuclide Ga-68 (T-1/2 = 67.6 min) with preserved specificity of binding to EGFR-expressing A431 cells. The long-lived cobalt radioisotope Co-57 was used in animal studies. Both Co-57-DOTA-Z(EGFR:2377) and Ga-68-DOTA-Z(EGFR:2377) demonstrated EGFR-specific accumulation in A431 xenografts and EGFR-expressing tissues in mice. Tumour-to-organ ratios for the radiocobalt-labelled DOTA-Z(EGFR:2377) were significantly higher than for the gallium-labelled counterpart already at 3 h after injection. Importantly, Co-57-DOTA-Z(EGFR:2377) demonstrated a tumour-to-liver ratio of 3, which is 7-fold higher than the tumour-to-liver ratio for (68)GaDOTA-Z(EGFR:2377). The results of this study suggest that the positron-emitting cobalt isotope 55Co would be an optimal label for DOTA-Z(EGFR:2377) and further development should concentrate on this radionuclide as a label.
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| 24. |
- Lindbo, Sarah, et al.
(författare)
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Optimized Molecular Design of ADAPT-Based HER2-Imaging Probes Labeled with 111In and 68Ga
- 2018
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Ingår i: Molecular Pharmaceutics. - : American Chemical Society (ACS). - 1543-8384 .- 1543-8392. ; 15:7, s. 2674-2683
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Tidskriftsartikel (refereegranskat)abstract
- Radionuclide molecular imaging is a promising tool for visualization of cancer associated molecular abnormalities in vivo and stratification of patients for specific therapies. ADAPT is a new type of small engineered proteins based on the scaffold of an albumin binding domain of protein G. ADAPTs have been utilized to select and develop high affinity binders to different proteinaceous targets. ADAPT6 binds to human epidermal growth factor 2 (HER2) with low nanomolar affinity and can be used for its in vivo visualization. Molecular design of 111In-labeled anti-HER2 ADAPT has been optimized in several earlier studies. In this study, we made a direct comparison of two of the most promising variants, having either a DEAVDANS or a (HE)3DANS sequence at the N-terminus, conjugated with a maleimido derivative of DOTA to a GSSC amino acids sequence at the C-terminus. The variants (designated DOTA-C59-DEAVDANS-ADAPT6-GSSC and DOTA-C61-(HE)3DANS-ADAPT6-GSSC) were stably labeled with 111In for SPECT and 68Ga for PET. Biodistribution of labeled ADAPT variants was evaluated in nude mice bearing human tumor xenografts with different levels of HER2 expression. Both variants enabled clear discrimination between tumors with high and low levels of HER2 expression. 111In-labeled ADAPT6 derivatives provided higher tumor-to-organ ratios compared to 68Ga-labeled counterparts. The best performing variant was DOTA-C61-(HE)3DANS-ADAPT6-GSSC, which provided tumor-to-blood ratios of 208 ± 36 and 109 ± 17 at 3 h for 111In and 68Ga labels, respectively.
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| 25. |
- Lindbo, Sarah, et al.
(författare)
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Radionuclide Tumor Targeting Using ADAPT Scaffold Proteins : Aspects of Label Positioning and Residualizing Properties of the Label
- 2018
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 59:1, s. 93-99
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Tidskriftsartikel (refereegranskat)abstract
- Visualization of cancer-associated alterations of molecular phenotype using radionuclide imaging is a noninvasive approach to stratifying patients for targeted therapies. The engineered albumin-binding domain-derived affinity protein (ADAPT) is a promising tracer for radionuclide molecular imaging because of its small size (6.5 kDa), which satisfies the precondition for efficient tumor penetration and rapid clearance. Previous studies demonstrated that the human epidermal growth factor receptor type 2 (HER2)-targeting ADAPT6 labeled with radiometals at the N terminus is able to image HER2 expression in xenografts a few hours after injection. The aim of this study was to evaluate whether the use of a non-residualizing label or placement of the labels at the C terminus would further improve the targeting properties of ADAPT6. Methods: Two constructs, Cys(2)-ADAPT6 and Cys(59)-ADAPT6, having the (HE)(3)DANS sequence at the N terminus were produced and site-specifically labeled using In-111-DOTA or I-125-iodo-((4-hydroxyphenyl) ethyl) maleimide (HPEM). The conjugates were compared in vitro and in vivo. HER2-targeting properties and biodistribution were evaluated in BALB/C nu/nu mice bearing ovarian carcinoma cell (SKOV-3) xenografts. Results: Specific HER2 binding and high affinity were preserved after labeling. Both Cys(2)-ADAPT6 and Cys59-ADAPT6 were internalized slowly by HER2-expressing cancer cells. Depending on the label position, uptake at 4 h after injection varied from 10% to 22% of the injected dose per gram of tumor tissue. Regardless of terminus position, the I-125-HPEM label provided more than 140-fold lower renal uptake than the In-111-DOTA label at 4 after injection. The tumor-to-organ ratios were, in contrast, higher for both of the (111)InDOTA- labeled ADAPT variants in other organs. Tumor-to-blood ratios for In-111-labeled Cys(2)-ADAPT6 and Cys(59)-ADAPT6 did not differ significantly (250-280), but In-111-DOTA-Cys(59)-ADAPT6 provided significantly higher tumor-to-lung, tumor-to-liver, tumor-to-spleen, and tumor-to-muscle ratios. Radioiodinated variants had similar tumor-to-organ ratios, but I-125-HPEM-Cys(59)-ADAPT6 had significantly higher tumor uptake and a higher tumor-to-kidney ratio. Conclusion: Residualizing properties of the label strongly influence the targeting properties of ADAPT6. The position of the radiolabel influences targeting as well, although to a lesser extent. Placement of a label at the C terminus yields the best biodistribution features for both radiometal and radiohalogen labels. Low renal retention of the radioiodine label creates a precondition for radionuclide therapy using I-131-labeled HPEM-Cys(59)-ADAPT6.
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