| 1. |
- Deyev, Sergey M., et al.
(author)
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Effect of a radiolabel biochemical nature on tumor-targeting properties of EpCAM-binding engineered scaffold protein DARPin Ec1
- 2020
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In: International Journal of Biological Macromolecules. - : ELSEVIER. - 0141-8130 .- 1879-0003. ; 145, s. 216-225
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Journal article (peer-reviewed)abstract
- Radionuclide-based imaging of molecular therapeutic targets might facilitate stratifying patients for specific biotherapeutics. New type of imaging probes, based on designed ankyrin repeat proteins (DARPins), have demonstrated excellent contrast of imaging of human epidermal growth factor type 2 (HER2) expression in preclinical models. We hypothesized that labeling approaches, which result in lipophilic radiometabolites (non-residualizing labels), would provide the best imaging contrast for DARPins that internalize slowly after binding to cancer cells. The hypothesis was tested using DARPin Ec1 that binds to epithelial cell adhesion molecule (EpCAM). EpCAM is a promising therapeutic target. Ec1 was labeled with I-125 using two methods to obtain the non-residualizing labels, while residualizing labels were obtained by labeling it with Tc-99m. All labeled Ec1 variants preserved target specificity and picomolar binding affinity to EpCAM-expressing pancreatic adenocarcinoma BxPC-3 cells. In murine models, all the variants provided similar tumor uptake. However, I-125-PIB-H-6-Ec1 had noticeably lower retention in normal tissues, which provided appreciably higher tumor-to-organ ratios. Furthermore, I-125-PIB-H-6-Ec1 demonstrated the highest imaging contrast in preclinical models than any other EpCAM-imaging agent tested so far. In conclusion, DARPin Ec1 in combination with a non-residualizing label is a promising probe for imaging EpCAM expression a few hours after injection.
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| 2. |
- Deyev, Sergey M., et al.
(author)
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Influence of the Position and Composition of Radiometals and Radioiodine Labels on Imaging of Epcam Expression in Prostate Cancer Model Using the DARPin Ec1
- 2021
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In: Cancers. - : MDPI AG. - 2072-6694. ; 13:14
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Journal article (peer-reviewed)abstract
- Simple Summary Metastasis-targeting therapy might improve outcomes in oligometastatic prostate cancer. Epithelial cell adhesion molecule (EpCAM) is overexpressed in 40-60% of prostate cancer cases and might be used as a target for specific delivery of toxins and drugs. Radionuclide molecular imaging could enable non-invasive detection of EpCAM and stratification of patients for targeted therapy. Designed ankyrin repeat proteins (DARPins) are scaffold proteins, which can be selected for specific binding to different targets. The DARPin Ec1 binds strongly to EpCAM. To determine an optimal design of Ec1-based probes, we labeled Ec1 at two different positions with four different nuclides (Ga-68, In-111, Co-57 and I-125) and investigated the impact on Ec1 biodistribution. We found that the C-terminus is the best position for labeling and that In-111 and I-125 provide the best imaging contrast. This study might be helpful for scientists developing imaging probes based on scaffold proteins. The epithelial cell adhesion molecule (EpCAM) is intensively overexpressed in 40-60% of prostate cancer (PCa) cases and can be used as a target for the delivery of drugs and toxins. The designed ankyrin repeat protein (DARPin) Ec1 has a high affinity to EpCAM (68 pM) and a small size (18 kDa). Radiolabeled Ec1 might be used as a companion diagnostic for the selection of PCa patients for therapy. The study aimed to investigate the influence of radiolabel position (N- or C-terminal) and composition on the targeting and imaging properties of Ec1. Two variants, having an N- or C-terminal cysteine, were produced, site-specifically conjugated to a DOTA chelator and labeled with cobalt-57, gallium-68 or indium-111. Site-specific radioiodination was performed using ((4-hydroxyphenyl)-ethyl)maleimide (HPEM). Biodistribution of eight radiolabeled Ec1-probes was measured in nude mice bearing PCa DU145 xenografts. In all cases, positioning of a label at the C-terminus provided the best tumor-to-organ ratios. The non-residualizing [I-125]I-HPEM label provided the highest tumor-to-muscle and tumor-to-bone ratios and is more suitable for EpCAM imaging in early-stage PCa. Among the radiometals, indium-111 provided the highest tumor-to-blood, tumor-to-lung and tumor-to-liver ratios and could be used at late-stage PCa. In conclusion, label position and composition are important for the DARPin Ec1.
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| 3. |
- Deyev, Sergey M., et al.
(author)
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Preclinical Evaluation of HER2-Targeting DARPin G3: Impact of Albumin-Binding Domain (ABD) Fusion
- 2024
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In: International Journal of Molecular Sciences. - : Multidisciplinary Digital Publishing Institute (MDPI). - 1661-6596 .- 1422-0067. ; 25:8
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Journal article (peer-reviewed)abstract
- Designed ankyrin repeat protein (DARPin) G3 is an engineered scaffold protein. This small (14.5 kDa) targeting protein binds with high affinity to human epidermal growth factor receptor 2 (HER2). HER2 is overexpressed in several cancers. The use of the DARPin G3 for radionuclide therapy is complicated by its high renal reabsorption after clearance via the glomeruli. We tested the hypothesis that a fusion of the DARPin G3 with an albumin-binding domain (ABD) would prevent rapid renal excretion and high renal reabsorption resulting in better tumour targeting. Two fusion proteins were produced, one with the ABD at the C-terminus (G3-ABD) and another at the N-terminus (ABD-G3). Both variants were labelled with 177Lu. The binding properties of the novel constructs were evaluated in vitro and their biodistribution was compared in mice with implanted human HER2-expressing tumours. Fusion with the ABD increased the retention time of both constructs in blood compared with the non-ABD-fused control. The effect of fusion with the ABD depended strongly on the order of the domains in the constructs, resulting in appreciably better targeting properties of [177Lu]Lu-G3-ABD. Our data suggest that the order of domains is critical for the design of targeting constructs based on scaffold proteins.
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| 4. |
- Tolmachev, Vladimir, et al.
(author)
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Targeted nuclear medicine. Seek and destroy
- 2022
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In: Russian Chemical Reviews. - : IOP Publishing. - 0036-021X .- 1468-4837. ; 91:3
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Research review (peer-reviewed)abstract
- The targeted delivery of radionuclides to tumours holds great promise for diagnosis and treatment of malignant neoplasms. The development of scaffold proteins has significantly simplified the design of targeting agents with desirable properties. This review comprehensively describes the key aspects of the design of radionuclide compounds, including classification of radionuclides, methodology for their attachment to targeting agents and characteristics of these agents that affect their behaviour in the body. Various targeting molecules are compared in terms of their ability to specifically find malignant foci in the body. The most recent achievements of cancer theranostics that aim at increasing the selectivity of antitumour effect are described, such as the fusion of targeting scaffold proteins with the albumin-binding domain and pretargeting. Special attention is paid to the creation of targeted radionanomaterials. Advantages and disadvantages of different strategies are analyzed and approaches for improving the delivery to tumours and for minimizing the undesirable impact on healthy organs and tissues are proposed. Particular emphasis is placed on the results of studies published in 2020 ?? 2021 that have not yet been covered by reviews.
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| 5. |
- Tolmachev, Vladimir, et al.
(author)
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Visualization of epithelial cell adhesion molecule-expressing renal cell carcinoma xenografts using designed ankyrin repeat protein Ec1 labelled with Tc-99m and I-125
- 2023
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In: Oncology Letters. - : SPANDIDOS PUBL LTD. - 1792-1074 .- 1792-1082. ; 25:1
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Journal article (peer-reviewed)abstract
- The upregulation of epithelial cell adhesion molecule (EpCAM) expression, found in a substantial fraction of renal cell carcinomas (RCCs), renders it a potential molecular target for the treatment of disseminated RCC. However, the heterogeneous expression of EpCAM necessitates first identifying the patients with sufficiently high expression of EpCAM in tumors. Using the specific radionuclide-based visualization of EpCAM might enable such identification. The designed ankyrin repeat protein, Ec1, is a small (molecular weight, 18 kDa) targeting protein with a subnanomolar affinity to EpCAM. Using a modified Ec1, a tracer was developed for the radionuclide-based visualization of EpCAM in vivo, i.e., an EpCAM-visualizing designed ankyrin repeat protein (EVD). EVD was labelled with either technetium-99m using technetium tricarbonyl or with iodine-125 (as a surrogate for iodine-123) by coupling it to para-[I-125]iodobenzoyl ([I-125]PIB) groups. Both the I-125-labelled EVD (I-125-EVD) and Tc-99m-labelled EVD (Tc-99m-EVD) bound specifically to EpCAM-expressing SK-RC-52 renal carcinoma cells. The binding affinity (K-D value) of Tc-99m-EVD to SK-RC-52 cells was 400 +/- 28 pM. The tracers' uptake in SK-RC-52 xenografts at 3 h after injection was 5.2 +/- 1.4%ID/g for I-125-EVD and 6.0 +/- 1.4%ID/g for Tc-99m-EVD (no significant difference). These uptake values in SK-RC-52 xenografts were significantly higher (P<0.001) than those in Ramos lymphoma xenografts (used as EpCAM-negative control). The tumor-to-blood uptake ratio was significantly higher for Tc-99m-EVD (25 +/- 6) compared with that of I-125-EVD (14 +/- 3). However, I-125-EVD was associated with higher tumor-to-liver, tumor-to-salivary gland, tumor-to-spleen and tumor-to-intestinal wall ratios. This makes it the preferable tracer for visualizing EpCAM expression levels in the frequently occurring abdominal metastases of RCC.
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| 6. |
- Vorobyeva, Anzhelika, et al.
(author)
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Optimal composition and position of histidine-containing tags improves biodistribution of Tc-99m-labeled DARP in G3
- 2019
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In: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 9
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Journal article (peer-reviewed)abstract
- Radionuclide molecular imaging of HER2 expression in disseminated cancer enables stratification of patients for HER2-targeted therapies. DARP in G3, a small (14 kDa) engineered scaffold protein, is a promising probe for imaging of HER2. We hypothesized that position (C- or N-terminus) and composition (hexahistidine or (HE)(3)) of histidine-containing tags would influence the biodistribution of [Tc-99m]Tc(CO)(3)-labeled DARP in G3. To test the hypothesis, G3 variants containing tags at N-terminus (H-6-G3 and (HE)(3)-G3) or at C-terminus (G3-H-6 and G3-(HE)(3)) were labeled with [Tc-99m]Tc(CO)(3). Labeling yield, label stability, specificity and affinity of the binding to HER2, biodistribution and tumor targeting properties of these variants were compared side-by-side. There was no substantial influence of position and composition of the tags on binding of [Tc-99m]Tc(CO)(3)-labeled variants to HER2. The specificity of HER2 targeting in vivo was confirmed. The tumor uptake in BALB/c nu/nu mice bearing SKOV3 xenografts was similar for all variants. On the opposite, there was a strong influence of the tags on uptake in normal tissues. The tumor-to-liver ratio for [Tc-99m]Tc(CO)(3)-(HE)(3)-G3 was three-fold higher compared to the hexahistidine-tag containing variants. Overall, [Tc-99m]Tc(CO)(3)-(HE)(3)-G3 variant provided the highest tumor-to-lung, tumor-to-liver, tumor-to-bone and tumor-to-muscle ratios, which should improve sensitivity of HER2 imaging in these common metastatic sites.
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| 7. |
- Xu, Tianqi, et al.
(author)
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Epithelial cell adhesion molecule-targeting designed ankyrin repeat protein-toxin fusion Ec1-LoPE exhibits potent cytotoxic action in prostate cancer cells
- 2022
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In: Oncology Reports. - : Spandidos Publications. - 1021-335X .- 1791-2431. ; 47:5
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Journal article (peer-reviewed)abstract
- Targeted anticancer therapeutics offer the advantage of reducing cytotoxic side effects to normal cells by directing the cytotoxic payload selectively to cancer cells. Designed ankyrin repeat proteins (DARPins) are promising non-immunoglobulin-based scaffold proteins for payload delivery to cancer-associated molecular targets. Epithelial cell adhesion molecule (EpCAM) is overexpressed in 40-60% of prostate cancers (PCs) and is associated with metastasis, increased risk of PC recurrence and resistance to treatment. Here, we investigated the use of DARPin Ec1 for targeted delivery of Pseudomonas exotoxin A variant (LoPE) with low immunogenicity and low non-specific toxicity to EpCAM-expressing prostate cancer cells. Ec1-LoPE fusion protein was radiolabeled with tricarbonyl technetium-99m and its binding specificity, binding kinetics, cellular processing, internalization and cytotoxicity were evaluated in PC-3 and DU145 cell lines. Ec1-LoPE showed EpCAM-specific binding to EpCAM-expressing prostate cancer cells. Rapid internalization mediated potent cytotoxic effect with picomolar IC50 values in both studied cell lines. Taken together, these data support further evaluation of Ec1-LoPE in a therapeutic setting in a prostate cancer model in vivo.
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| 8. |
- Xu, Tianqi, et al.
(author)
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Feasibility of Co-Targeting HER3 and EpCAM Using Seribantumab and DARPin-Toxin Fusion in a Pancreatic Cancer Xenograft Model
- 2023
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In: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:3
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Journal article (peer-reviewed)abstract
- Pancreatic cancer (PC) is one of the most aggressive malignancies. A combination of targeted therapies could increase the therapeutic efficacy in tumors with heterogeneous target expression. Overexpression of the human epidermal growth factor receptor type 3 (HER3) and the epithelial cell adhesion molecule (EpCAM) in up to 40% and 30% of PCs, respectively, is associated with poor prognosis and highlights the relevance of these targets. Designed ankyrin repeat protein (DARPin) Ec1 fused with the low immunogenic bacterial toxin LoPE provides specific and potent cytotoxicity against EpCAM-expressing cancer cells. Here, we investigated whether the co-targeting of HER3 using the monoclonal antibody seribantumab (MM-121) and of EpCAM using Ec1-LoPE would improve the therapeutic efficacy in comparison to the individual agents. Radiolabeled Tc-99m(CO)(3)-Ec1-LoPE showed specific binding with rapid internalization in EpCAM-expressing PC cells. MM-121 did not interfere with the binding of Ec1-LoPE to EpCAM. Evaluation of cytotoxicity indicated synergism between Ec1-LoPE and MM-121 in vitro. An experimental therapy study using Ec1-LoPE and MM-121 in mice bearing EpCAM- and HER3-expressing BxPC3 xenografts demonstrated the feasibility of the therapy. Further development of the co-targeting approach using HER3 and EpCAM could therefore be justified.
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| 9. |
- Xu, Tianqi, et al.
(author)
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Imaging-Guided Therapy Simultaneously Targeting HER2 and EpCAM with Trastuzumab and EpCAM-Directed Toxin Provides Additive Effect in Ovarian Cancer Model
- 2021
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In: Cancers. - : MDPI AG. - 2072-6694. ; 13:16
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Journal article (peer-reviewed)abstract
- Simple Summary Targeted therapeutics provide cytostatic or cytotoxic action selectively to tumor cells while reducing the toxicity to normal cells. Targeting two molecular receptors overexpressed on tumor cells is a way to overcome heterogeneity of expression and improve therapeutic efficacy. Combining drugs with different modes of action might also increase the cytotoxic effect and decrease the chance for the cancer cells to develop resistance to treatment. In this work, we investigated a combination of the clinically used monoclonal antibody trastuzumab with a potent targeting protein-toxin fusion, directed at two different targets present in a large fraction of ovarian cancers. Co-targeted treatment provided a significant reduction in tumor growth and extended the survival of mice compared with the control and monotherapy groups. Our findings support further development of targeted combination therapies for treatment of aggressive and resistant cancer types. Efficient treatment of disseminated ovarian cancer (OC) is challenging due to its heterogeneity and chemoresistance. Overexpression of human epidermal growth factor receptor 2 (HER2) and epithelial cell adhesion molecule (EpCAM) in approx. 30% and 70% of ovarian cancers, respectively, allows for co-targeted treatment. The clinical efficacy of the monoclonal antibody trastuzumab in patients with HER2-positive breast, gastric and gastroesophageal cancers makes it readily available as the HER2-targeting component. As the EpCAM-targeting component, we investigated the designed ankyrin repeat protein (DARPin) Ec1 fused to a truncated variant of Pseudomonas exotoxin A with reduced immunogenicity and low general toxicity (LoPE). Ec1-LoPE was radiolabeled, evaluated in ovarian cancer cells in vitro and its biodistribution and tumor-targeting properties were studied in vivo. The therapeutic efficacy of Ec1-LoPE alone and in combination with trastuzumab was studied in mice bearing EpCAM- and HER2-expressing SKOV3 xenografts. SPECT/CT imaging enabled visualization of EpCAM and HER2 expression in the tumors. Co-treatment using Ec1-LoPE and trastuzumab was more effective at reducing tumor growth and prolonged the median survival of mice compared with mice in the control and monotherapy groups. Repeated administration of Ec1-LoPE was well tolerated without signs of hepatic or kidney toxicity. Co-treatment with trastuzumab and Ec1-LoPE might be a potential therapeutic strategy for HER2- and EpCAM-positive OC.
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| 10. |
- Zelepukin, Ivan V., et al.
(author)
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Rediscovery of mononuclear phagocyte system blockade for nanoparticle drug delivery
- 2024
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In: Perspectives. - : Springer Nature. - 1360-3108 .- 1460-7018. ; 15:1
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Research review (peer-reviewed)abstract
- Rapid uptake of nanoparticles by mononuclear phagocyte system (MPS) significantly hampers their therapeutic efficacy. Temporal MPS blockade is one of the few ways to overcome this barrier - the approach rediscovered many times under different names but never extensively used in clinic. Using meta-analysis of the published data we prove the efficacy of this technique for enhancing particle circulation in blood and their delivery to tumours, describe a century of its evolution and potential combined mechanism behind it. Finally, we discuss future directions of the research focusing on the features essential for successful clinical translation of the method. Temporal blockade of the mononuclear phagocyte system is an approach to enhance the therapeutic efficiency of nanocarrier drug-delivery systems but the broad applicability is hindered by the complexity of optimisation and management of potential side effects. Here, the authors review the development of this technique and show its efficiency using meta-analysis of the published data and discuss essential features for its successful translation to clinic.
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