| 1. |
- 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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| 2. |
- Bezverkhniaia, Ekaterina, et al.
(författare)
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Preclinical Evaluation of a Novel High-Affinity Radioligand [99mTc]Tc-BQ0413 Targeting Prostate-Specific Membrane Antigen (PSMA)
- 2023
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:24
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Tidskriftsartikel (refereegranskat)abstract
- Radionuclide imaging using radiolabeled inhibitors of prostate-specific membrane antigen (PSMA) can be used for the staging of prostate cancer. Previously, we optimized the Glu-urea-Lys binding moiety using a linker structure containing 2-napththyl-L-alanine and L-tyrosine. We have now designed a molecule that contains mercaptoacetyl-triglutamate chelator for labeling with Tc-99m (designated as BQ0413). The purpose of this study was to evaluate the imaging properties of [Tc-99m]Tc-BQ0413. PSMA-transfected PC3-pip cells were used to evaluate the specificity and affinity of [Tc-99m]Tc-BQ0413 binding in vitro. PC3-pip tumor-bearing BALB/C nu/nu mice were used as an in vivo model. [Tc-99m]Tc-BQ0413 bound specifically to PC3-pip cells with an affinity of 33 +/- 15 pM. In tumor-bearing mice, the tumor uptake of [Tc-99m]Tc-BQ0413 (38 +/- 6 %IA/g in PC3-pip 3 h after the injection of 40 pmol) was dependent on PSMA expression (3 +/- 2 %IA/g and 0.9 +/- 0.3 %IA/g in PSMA-negative PC-3 and SKOV-3 tumors, respectively). We show that both unlabeled BQ0413 and the commonly used binder PSMA-11 enable the blocking of [Tc-99m]Tc-BQ0413 uptake in normal PSMA-expressing tissues without blocking the uptake in tumors. This resulted in an appreciable increase in tumor-to-organ ratios. At the same injected mass (5 nmol), the use of BQ0413 was more efficient in suppressing renal uptake than the use of PSMA-11. In conclusion, [Tc-99m]Tc-BQ0413 is a promising probe for the visualization of PSMA-positive lesions using single-photon emission computed tomography (SPECT).
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| 3. |
- Leitao, Charles Dahlsson, 1992-, et al.
(författare)
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Conditionally activated affibody-based prodrug targeting EGFR demonstrates improved tumour selectivity
- 2023
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Ingår i: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 357, s. 185-195
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Tidskriftsartikel (refereegranskat)abstract
- Safety and efficacy of cancer-targeting treatments can be improved by conditional activation enabled by the distinct milieu of the tumour microenvironment. Proteases are intricately involved in tumourigenesis and commonly dysregulated with elevated expression and activity. Design of prodrug molecules with protease -dependent activation has the potential to increase tumour-selective targeting while decreasing exposure to healthy tissues, thus improving the safety profile for patients. Higher selectivity could also allow for adminis-tration of higher doses or use of more aggressive treatment options, leading to higher therapeutic efficacy. We have previously developed an affibody-based prodrug with conditional targeting of EGFR conferred by an anti-idiotypic affibody masking domain (ZB05). We could show that binding to endogenous EGFR on cancer cells in vitro was restored following proteolytic removal of ZB05. In this study we evaluate a novel affibody-based pro -drug design, which incorporates a protease substrate sequence recognized by cancer-associated proteases and demonstrate the potential of this approach for selective tumour-targeting and shielded uptake in healthy tissues in vivo using tumour-bearing mice. This may widen the therapeutic index of cytotoxic EGFR-targeted thera-peutics by decreasing side effects, improving selectivity of drug delivery, and enabling the use of more potent cytotoxic drugs.
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| 4. |
- Liu, Yongsheng, et al.
(författare)
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Radionuclide Therapy of HER2-Expressing Xenografts Using [Lu-177]Lu-ABY-027 Affibody Molecule Alone and in Combination with Trastuzumab
- 2023
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Ingår i: Cancers. - : MDPI. - 2072-6694. ; 15:9
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Tidskriftsartikel (refereegranskat)abstract
- Affibody molecules are artificial proteins that can recognize cancer-related molecular abnormalities in the living body. Clinical studies demonstrated that Affibody molecules can be successfully used for radionuclide diagnostics. Targeted radionuclide therapy selectively delivers cytotoxic radionuclides to malignant tumors, thus sparing normal tissues. For radionuclide therapy, Affibody molecules were re-engineered to decrease accumulation in the kidneys. This study has demonstrated that radionuclide therapy using re-engineered Affibody molecules increases the survival of immunodeficient mice bearing human tumors. The therapy was more efficient than the treatment with a monoclonal antibody, which is currently used in clinical practice. The best results were obtained when both the antibody and radiolabeled Affibody molecules were used simultaneously. This work provides a preclinical rationale for a potentially more efficient treatment in HER2-positive cancers.ABY-027 is a scaffold-protein-based cancer-targeting agent. ABY-027 includes the second-generation Affibody molecule Z(HER2:2891), which binds to human epidermal growth factor receptor type 2 (HER2). An engineered albumin-binding domain is fused to Z(HER2:2891) to reduce renal uptake and increase bioavailability. The agent can be site-specifically labeled with a beta-emitting radionuclide Lu-177 using a DOTA chelator. The goals of this study were to test the hypotheses that a targeted radionuclide therapy using [Lu-177]Lu-ABY-027 could extend the survival of mice with HER2-expressing human xenografts and that co-treatment with [Lu-177]Lu-ABY-027 and the HER2-targeting antibody trastuzumab could enhance this effect. Balb/C nu/nu mice bearing HER2-expressing SKOV-3 xenografts were used as in vivo models. A pre-injection of trastuzumab did not reduce the uptake of [Lu-177]Lu-ABY-027 in tumors. Mice were treated with [Lu-177]Lu-ABY-027 or trastuzumab as monotherapies and a combination of these therapies. Mice treated with vehicle or unlabeled ABY-027 were used as controls. Targeted monotherapy using [Lu-177]Lu-ABY-027 improved the survival of mice and was more efficient than trastuzumab monotherapy. A combination of therapies utilizing [Lu-177]Lu-ABY-027 and trastuzumab improved the treatment outcome in comparison with monotherapies using these agents. In conclusion, [Lu-177]Lu-ABY-027 alone or in combination with trastuzumab could be a new potential agent for the treatment of HER2-expressing tumors.
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| 5. |
- Tolmachev, Vladimir, et al.
(författare)
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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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Ingår i: Oncology Letters. - : SPANDIDOS PUBL LTD. - 1792-1074 .- 1792-1082. ; 25:1
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Tidskriftsartikel (refereegranskat)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. |
- Xu, Tianqi, et al.
(författare)
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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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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 24:3
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Yin, Wen, 1993-, et al.
(författare)
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Comparison of HER2-targeted affibody conjugates loaded with auristatin-and maytansine-derived drugs
- 2023
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Ingår i: Journal of Controlled Release. - : Elsevier. - 0168-3659 .- 1873-4995. ; 355, s. 515-527
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Tidskriftsartikel (refereegranskat)abstract
- Treatment with antibody drug conjugates targeting receptors over-expressed on cancer cells is well established for clinical use in several types of cancer, however, resistance often occurs motivating the development of novel drugs. We have recently investigated a drug conjugate consisting of an affibody molecule targeting the human epidermal growth factor receptor 2 (HER2), fused to an albumin-binding domain (ABD) for half-life extension, loaded with the cytotoxic maytansine derivative DM1. In this study, we investigated the impact of the cytotoxic payload on binding properties, cytotoxicity and biodistribution by comparing DM1 with the auristatins MMAE and MMAF, as part of the drug conjugate. All constructs had specific and high affinity binding to HER2, human and mouse albumins with values in the low- to sub-nM range. ZHER2-ABD-mcMMAF demonstrated the most potent cytotoxic effect on several HER2-over-expressing cell lines. In an experimental therapy study, the MMAFbased conjugate provided complete tumor regression in 50% of BALB/c nu/nu mice bearing HER2-overexpressing SKOV3 tumors at a 2.9 mg/kg dose, while the same dose of ZHER2-ABD-mcDM1 provided only a moderate anti-tumor effect. A comparison with the non-targeting ZTaq-ABD-mcMMAF control demonstrated HER2-targeting specificity. In conclusion, a combination of potent cytotoxicity in vitro, with minimal uptake in normal organs in vivo, and efficient delivery to tumors provided a superior anti-tumor effect of ZHER2-ABDmcMMAF, while maintaining a favorable toxicity profile with no observed adverse effects.
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