The expansion of personalized medicine is encouraging the development of platforms capable of supporting individualized imaging and therapeutic strategies. The combination of antibodies, with their intrinsic selectivity, and a modular molecular probe provides a strong foundation for such approaches. In this context, a versatile platform enabling positron emission tomography (PET) imaging followed by copper-free click-based functionalization is developed. A DFO-Lysine-DBCO probe is synthesized and site-specifically coupled to trastuzumab, allowing the introduction of diverse payloads, including β- or α-emitter chelators, a fluorophore, and a cytotoxic agent. Within this toolbox, the DFO/DOTAGA bischelate is selected for detailed evaluation. Radiolabeling confirms the selectivity of DFO and DOTAGA for 89Zr and 177Lu, respectively. PET imaging in mice bearing HCC1954 xenografts (HER2-overexpressing, trastuzumab-resistant) using [89Zr]Zr-ss-Tzb-DFO-DOTAGA and [89Zr]Zr-ss-Tzb-DFO-Lu(III)DOTAGA, in which DOTAGA is pre-loaded with cold lutetium, enables clear tumor visualization and indicates that second-chelator occupancy does not alter biodistribution. Despite unexpectedly lower internalization and tumor uptake, [177Lu]Lu-ss-Tzb-DFO-DOTAGA demonstrates significant antitumor activity with good tolerability in a preliminary therapeutic study. This modular platform, enabling site-specific conjugation, provides a broadly adaptable route to generate multifunctional antibody constructs, offering a versatile foundation for integrating imaging, therapy, and payload customization within a single molecular scaffold.

PURPOSE:Colorectal cancer (CRC) remains one of the most prevalent and lethal malignancies worldwide. Although external beam radiotherapy (RT) plays a growing role in primary and metastatic CRC, dose escalation may remain limited due to the high dose received by neighboring organs which may cause toxicity. Targeted Radionuclide Therapy (TRT) selectively delivers cytotoxic radiation to tumor cells through a molecular vector that targets a specific protein overexpressed by cancer cells, and is linked to a therapeutic radionuclide. The present study aims to provide proof-of-concept for combining in vivo RT with anti-PDL1-targeted TRT delivered via an anti-PDL1 antibody. METHODS AND MATERIALS:An anti-PDL1 monocolonal antibody (mAb) was bioconjugated with a DOTAGA chelating agent and radiolabeled with either indium-111 (111In) for imaging purposes (SPECT imaging) or lutetium-177 (177Lu) for therapeutic purposes (TRT). 111In-mAb-PDL1 biodistribution and TRT evaluation were performed in CT26 tumor-bearing mice six days after RT (8Gy) by i.v. injection of 111In-mAb-PDL1 or 177Lu-mAb-PDL1. Epitope saturation assay was performed by co-administrating an excess of unconjugated mAb-PDL1. RESULTS:RT induced a significant increase in PDL1 expression in colon tumors in vivo enhancing the intratumoral uptake of radiolabeled anti-PDL1 mAb with 111In or 177Lu. A high uptake of radiolabeled anti-PDL1 mAb was found in the spleen that hampered the efficacy of the combination of RT with anti-PDL1 TRT by inducing a significant decrease in CD8+ T lymphocytes infiltration in tumors. Epitope-saturation with a 15-fold excess of unlabeled anti-PDL1 mAb significantly reduced the spleen uptake of 111In-mAb-PDL1 while preserving tumor uptake. This restored the efficacy of the combination of RT with 177Lu-mAb-PDL1, compared to both treatments alone. CONCLUSIONS:The combination of RT and anti-PDL1 TRT shows promising synergistic effects but it requires the blockade of anti-PDL1 mAb uptake in the spleen.

Purpose Colorectal cancer remains one of the most prevalent and lethal malignancies worldwide. Although external beam radiation therapy (RT) plays a growing role in primary and metastatic colorectal cancer, dose escalation may remain limited due to the high dose received by neighboring organs, which may cause toxicity. Targeted radionuclide therapy (TRT) selectively delivers cytotoxic radiation to tumor cells through a molecular vector that targets a specific protein overexpressed by cancer cells and that is linked to a therapeutic radionuclide. The present study aims to provide proof-of-concept for combining in vivo RT with anti-Programmed Death-Ligand 1 (PDL1)–targeted TRT delivered via an anti-PDL1 antibody. Methods and Materials An anti-PDL1 monoclonal antibody (mAb) was bioconjugated with a DOTAGA (2,2′,2”-(10-(2,6-dioxotetrahydro-2H-pyran-3-yl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl) triacetic acid) chelating agent and radiolabeled with either indium-111 (111In) for imaging purposes (single-photon emission computed tomography [SPECT] imaging) or lutetium-177 (177Lu) for therapeutic purposes (TRT). 111In-mAb-PDL1 biodistribution and TRT evaluation were performed in CT26 tumor-bearing mice 6 days after RT (8 Gy) by i.v. injection of 111In-mAb-PDL1 or 177Lu-mAb-PDL1. An epitope-saturation assay was performed by co-administering an excess of unconjugated mAb-PDL1. Results RT induced a significant increase in PDL1 expression in colon tumors in vivo, enhancing the intratumoral uptake of radiolabeled anti-PDL1 mAb with 111In or 177Lu. A high uptake of radiolabeled anti-PDL1 mAb was found in the spleen, which hampered the efficacy of the combination of RT with anti-PDL1 TRT by inducing a significant decrease in CD8+ T lymphocytes infiltration in tumors. Epitope-saturation with a 15-fold excess of unlabeled anti-PDL1 mAb significantly reduced the spleen uptake of 111In-mAb-PDL1 while preserving tumor uptake. This restored the efficacy of the combination of RT with 177Lu-mAb-PDL1, compared with both treatments alone. Conclusions The combination of RT and anti-PDL1 TRT shows promising synergistic effects, but it requires the blockade of anti-PDL1 mAb uptake in the spleen.

Complexation of radiometals by chelators allows for convenient radiolabeling of molecules of interest for the preparation of radiopharmaceuticals. In the chelator family, triazacyclononane (TACN)-based macrocycles have been used ubiquitously over the last 40 years, and many bifunctional derivatives have been developed. Despite this diversity, researchers commonly make their chelator selection based on practical factors like (commercial) availability and compatibility with the desired radionuclide, acknowledging that these considerations often outweigh achieving ideal in vivo pharmacokinetics. In this study, we generated and preclinically evaluated four gallium-68-labeled anti-CEA Nanobody-based tracers carrying different TACN-derivatives: p-NCS-Bn-NOTA, p-NCS-Bn-NODAGA, NODAGA-Sq, and NODAGA-NHS. Since the macrocyclic chelator is highly similar in these derivativesthey all present a NOTA ((1,4,7-triazacyclononane-1,4,7-triacetic acid) scaffoldthe effect of the bioconjugation handle on the pharmacokinetic properties could be examined in a side-by-side comparison. The four PET tracers were prepared and could easily be labeled with gallium-68. Then, their stability, target affinity, and hydrophilic character were determined in vitro. Next, their in vivo biodistribution was evaluated using PET/CT imaging in a subcutaneous tumor mouse model. Despite their high structural similarity, notable differences in pharmacokinetics were observed in vivo, more specifically in the tumor and liver signal. Tracer [68Ga]-Ga-NODAGA-Sq-NbCEA was found to be the best performer in our study, with a tumor signal 1.6-fold higher than [68Ga]-Ga-NODAGA-NbCEA and a tumor-to-liver ratio 1.5-fold and 1.7-fold higher than that of [68Ga]-Ga-NOTA-Bn-NCS-NbCEA and [68Ga]-Ga-NODAGA-Bn-NCS-NbCEA, respectively. By comparing this tracer to the negative control [68Ga]-Ga-NODAGA-Sq-R3b23, specific tumor targeting was demonstrated.

Protein bioconjugates are at the forefront of precision medicine, enabling the design of highly selective drugs for diagnostic and therapeutic applications. While increasing the number of payloads attached to a protein is a proven strategy to enhance the potency of a bioconjugate, the introduction of additional conjugation sites often risks compromising the protein's targeting properties. In this study, we investigate the potential of 1,3,4-thiadiazole-N-oxides (TNO), a heterocyclic scaffold exhibiting excellent stability in biological media. We demonstrate that this reactive partner undergoes an unprecedented double addition reaction with bicyclo[6.1.0]non-4-yne derivatives. This unique reactivity is harnessed to achieve the site-specific attachment of two probes per conjugation site on a monoclonal antibody. Importantly, this strategy preserves antibody targeting properties, as confirmed by in vivo imaging studies. These findings establish TNO and the Strain-Promoted Alkyne-1,3,4-Thiadiazole-N-Oxide coupling (SPATOC) reaction as valuable new tools in the bioconjugation arsenal, expanding the possibilities for precise and efficient protein modification.

Bioconjugation is a critical step in the development of Antibody Drug Conjugates with two main strategies dominating the field. One approach employs covalent chemistry to randomly bind a drug to the accessible Lysines or Cysteines on an antibody. The other strategy is site-specific, using covalent chemistry to bind a drug ligand at defined amino acid positions within the antibody. AbYlinkTM is a novel regio-selective labeling method for antibodies, enabling a single-step covalent conjugation of payloads such as radionuclide chelators to the Fc domain of an antibody. Given the selectivity of this reaction for the Fc region of the immunoglobulin, the affinity of the antibody to the antigen isn’t compromised, unlike randomly labelled antibodies. The chelators that are covalently attached to the antibody enable radiolabeling with radioisotopes such as Gallium-68, Lutetium-177 and Indium-111 for molecular radiotherapy or molecular imaging purposes. The commercially available trastuzumab was labeled via regio-selective conjugation with a DOTA-GA chelating agent using the AbYlinkTM technology, then radiolabeled with Indium-111. The in vivo biodistribution of the HER2 radiolabeled bioconjugate was evaluated in mice bearing NCI-N87 gastric cancer tumors. Trastuzumab conjugation resulted in a homogeneous labeling of antibodies with a Degree of Conjugation (DoC) close to 2, conducted in a regio-selective manner. The biodistribution and imaging experiments demonstrated successful accumulation of the antibody within the NCI-N87 tumour implanted in mice. The radiolabeled conjugate remained stable in vitro and in vivo, demonstrating the AbYlink™ as a valuable tool for biologics conjugation. We have successfully validated in vivo the use of AbYlink™ technology in the context of Antibody Radio Conjugates. This regio-selective bioconjugation strategy holds potential for wider application across molecular radiotherapies or pharmacodynamic assessment of antibodies. Céline Mothes, Peggy Provent, Marie Ruch, Mathieu Moreau, Michael Claron, Alex Helbling, Viktoriia Postupalenko, Léo Marx, Patrick Garrouste, Eftychia Koumarianou. Pharmacological evaluation of bioconjugated trastuzumab using the AbYlinkTM regio-selective conjugation technology in gastric cancer expressing HER2+ [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1825.

Abstract At Oncodesign-Services we aim to provide cutting-edge technologies and products to support the development of radiopharmaceuticals for theranostics. Starting from the optimization of lead compounds, the site-specific bioconjugation chemistry of a bifunctional chelator to large biological compounds, such as antibodies, can preserve the biological profile and the reliable batch production. Thanks to new technologies we can conjugate a variety of payloads (cytotoxins, radioactive chelates, fluorescent dyes) on antibodies at targeted lysine residues of the Fc region, independent of Fc glycosylation. Moreover, we aim to use relevant models for valuable translational results. In line with this, we established tumor spheroids to finely monitor the diffusion and subcellular distribution of novel fluorescent and radioactive probes in a 3D environment. Furthermore, we are currently generating two animal tumor models for optimal target expression levels and recapitulation of the human tumor microenvironment. Our first model is a PSMA+ expressing tumour model, in a non radiosensitive rodent strain allowing improved assessment of novel radiopharmaceuticals. Our second tumor model is under development to assess novel FAPI tracers. Finally, we present in partnership with ImaginAb 89Zr Crefmirlimab Berdoxam​, a minibody (human and murine analog) with high affinity to the CD8α glycoprotein, a valuable PET imaging tool for preclinical tracking and assessment of CD8 cells. This PET imaging can be used to evaluate immunoresponse following treatment, autoimmune, inflammatory and/or infectious diseases models. To conclude, our continuous efforts aim at expanding our service portfolio to fulfil the needs of our various projects, as presented herein. Our experience and expertise allow us to suggest alternatives based on the latest technological progresses to facilitate and expedite the drug discovery progress from bench to bedside. Citation Format: Sarah Belderbos, Celine Mothes, Claire Bernhard, Franck Denat, Pierre Adumeau, Merari Tumin Chevalier, Jordi Llop, Agnieszka Kownacka, Calmen Tihansky, Marie Ruch, Michael Claron, Mathieu Moreau, Cyril Berthet, Eftychia Koumarianou. New technologies and capabilities supporting the development of novel molecular radiotherapy agents [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2592.

Purpose: Radiation therapy (RT) exerts its anti-tumour efficacy by inducing direct damage to cancer cells but also through modification of the tumour microenvironment (TME) by inducing immunogenic antitumor response. Conversely, RT also promotes an immunosuppressive TME notably through the recruitment of regulatory T cells (Tregs). Glycoprotein A repetitions predominant (GARP), a transmembrane protein highly expressed by activated Tregs, plays a key role in the activation of TGF-β and thus promotes the immunosuppressive action of Tregs. The development of a theranostic approach targeting GARP combining imaging and targeted radionuclide therapy (TRT) was carried out. Methods: A preclinical model of 4T1 triple negative breast tumour-bearing BALB/c mice was used to show that GARP expression is increased after external beam radiation in the TME of our cancer model. We generated a theranostic probe through the bioconjugation of the chelating agent DOTAGA onto an anti-GARP monoclonal antibody. The bioconjugation with DOTAGA allows the radiolabelling of the DOTAGA-GARP conjugate with both Indium-111 for SPECT imaging and Lutetium-177 for TRT purposes. Results: We demonstrate that GARP expression is increased following RT in vivo and can be specifically detected and quantified using in vivo SPECT imaging with [111In]In-DOTAGA-GARP. In addition, 177Lu-DOTAGA-GARP limits tumour growth in our cancer model. Conclusion: This theranostic strategy may allow for the personalization of cancer treatments by early detection of activated Tregs infiltration following RT and identification of patients likely to respond to Tregs-targeted therapy via TRT.

Noninvasive imaging of idiopathic pulmonary fibrosis (IPF) remains a challenge. The aim of this study was to develop an antibody-based radiotracer targeting Lysyl Oxidase-like 2 (LOXL2), an enzyme involved in the fibrogenesis process, for SPECT/CT imaging of pulmonary fibrosis. The bifunctional chelator DOTAGA-PEG4-NH2 was chemoenzymatically conjugated to the murine antibody AB0023 using microbial transglutaminase, resulting in a degree of labeling (number of chelators per antibody) of 2.3. Biolayer interferometry confirmed that the binding affinity of DOTAGA-AB0023 to LOXL2 was preserved with a dissociation constant of 2.45 ± 0.04 nM. DOTAGA-AB0023 was then labeled with 111In and in vivo experiments were carried out in a mice model of progressive pulmonary fibrosis induced by intratracheal administration of bleomycin. [111In]In-DOTAGA-AB0023 was injected in three groups of mice (control, fibrotic, and treated with nintedanib). SPECT/CT images were recorded over 4 days p.i. and an ex vivo biodistribution study was performed by gamma counting. A significant accumulation of the tracer in the lungs of the fibrotic mice was observed at D18 post-bleomycin. Interestingly, the tracer uptake was found selectively upregulated in fibrotic lesions observed on CT scans. Images of mice that received the antifibrotic drug nintedanib from D8 up to D18 showed a decrease in [111In]In-DOTAGA-AB0023 lung uptake associated with a decrease in pulmonary fibrosis measured by CT scan. In conclusion, we report the first radioimmunotracer targeting the protein LOXL2 for nuclear imaging of IPF. The tracer showed promising results in a preclinical model of bleomycin-induced pulmonary fibrosis, with high lung uptake in fibrotic areas, and accounted for the antifibrotic activity of nintedanib.

Imidazole thiones appear as interesting building blocks for Cu(I) chelation and protection against Cu-mediated oxidative stress. Therefore, a series of tripodal molecules derived from nitrilotriacetic acid appended with three imidazole thiones belonging either to histamine-like or histidine-like moieties were synthesized. These tripods demonstrate intermediate affinity between that previously measured for tripodal analogues bearing three thiol moieties such as cysteine and those grafted with three thioethers, like methionines, consistently with the thione group in the imidazole thione moiety existing as a tautomer between a thiol and a thione. The two non-alkylated tripods derived from thioimidazole, TH and TH* demonstrated three orders of magnitude larger affinity for Cu(I) (logKpH 7.4 = 14.3) than their analogues derived from N,N'-dialkylated thioimidazole TMe and TEt (logKpH 7.4 = 11-11.6). Their efficiency to inhibit Cu-mediated oxidative stress is demonstrated by several assays involving ascorbate consumption or biomolecule damages and correlates with their ability to chelate Cu(I), related to their conditional complexation constants at pH 7.4. The two non-alkylated tripods derived from thioimidazole, TH and TH* are significantly more powerful in reducing Cu-mediated oxidative stress than their analogues derived from N,N'-dialkylated thioimidazole TMe and TEt.

Melanoma is a highly metastatic and deadly form of cancer. Invasive melanoma cells overexpress integrin alpha(v)beta(3), which is a well-known target for Arg-Gly-Asp-based (RGD) peptides. We developed a sophisticated method to synthetize milligram amounts of a targeted vector that allows the RGD-mediated targeting, internalization, and release of a mitochondria-disruptive peptide derived from the pro-apoptotic Bax protein. We found that 2.5 mu M Bax[109-127] was sufficient to destabilize the mitochondria in ten different tumor cell lines, even in the presence of the anti-apoptotic Bcl2 protein, which is often involved in tumor resistance. This pore-forming peptide displayed antitumor activity when it was covalently linked by a disulfide bridge to the tetrameric RAFT-c[RGD] (4)-platform and after intravenous injection in a human melanoma tumor model established in humanized immuno-competent mice. In addition to its direct toxic effect, treatment with this combination induced the release of the immuno-stimulating factor monocyte chimoattractant protein 1 (MCP1) in the blood and a decrease in the level of the pro-angiogenic factor FGF2. Our novel multifunctional, apoptosis-inducing agent could be further customized and assayed for potential use in tumortargeted therapy.

The access to multifunctional biomolecular compounds involves multistep reactions usually with a complicated protection scheme and lengthy separation processes. The development of a strategy combining several orthogonal ligations is highly desirable. Herein, we introduce a new method that involves two orthogonal copper-mediated ligations of azide with alkyne, and amine with thioacid. We established compatible conditions to carry out molecular assemblies of three different chemical components in a single one-pot reaction. The effectiveness of the method was demonstrated in the synthesis of biomolecular compounds that are known to target tumor tissue. The simple reaction conditions suggest that this strategy of combining several orthogonal ligations could have wide potential for the chemical synthesis of complex macromolecules.

The access to multifunctional biomolecular compounds involves multistep reactions usually with a complicated protection scheme and lengthy separation processes. The development of a strategy combining several orthogonal ligations is highly desirable. Herein, we introduce a new method that involves two orthogonal copper-mediated ligations of azide with alkyne, and amine with thioacid. We established compatible conditions to carry out molecular assemblies of three different chemical components in a single one-pot reaction. The effectiveness of the method was demonstrated in the synthesis of biomolecular compounds that are known to target tumor tissue. The simple reaction conditions suggest that this strategy of combining several orthogonal ligations could have wide potential for the chemical synthesis of complex macromolecules.

A quartz crystal microbalance technique with dissipation monitoring and a complementary optical microscopy technique were used for monitoring the capture and release of specific cells on a surface displaying a bifunctional molecular device, composed of a molecular scaffold endowed with the cell recognition property of an RGD ligand and a β‐CD/Fc redox‐switchable system.

64Cu-cyclam-RAFT-c(-RGDfK-)4, an αVβ3 integrin-targeting tetrameric cyclic RGD peptide probe, is a potential theranostic compound for positron emission tomography (PET) of tumor angiogenesis and for internal radiotherapy owing to the multiple decay modes of 64Cu. Since kidneys are dose-limiting organs in internal radiotherapy, we aimed to reduce the renal accumulation of 64Cu-cyclam-RAFT-c(-RGDfK-)4 by co-injection with Gelofusine (GF), a succinylated gelatin solution, and/or l-lysine (Lys), and to explore, for the first time, the related mechanisms using the noninvasive and quantitative PET imaging technology. Biodistribution assays, dynamic and static PET scans, and metabolism studies with radio-thin-layer chromatography (radio-TLC) were performed in healthy or αVβ3-positive tumor-bearing mice. In the results, co-injection with GF markedly reduced the renal uptake and slightly increased the tumor uptake of 64Cu-cyclam-RAFT-c(-RGDfK-)4. l-Lysine alone had no effect on the probe biodistribution, but the combined use of Lys and GF tended to enhance the effect of GF. Dynamic PET and metabolite analysis by radio-TLC highly revealed that GF blocks the renal reabsorption of 64Cu-cyclam-RAFT-c(-RGDfK-)4, but does not interfere with its metabolism and excretion. In conclusion, administration of GF and Lys is a useful strategy for kidney protection in 64Cu-cyclam-RAFT-c(-RGDfK-)4-based internal radiotherapy.

The purpose of this study was to develop a clinically relevant orthotopic xenotransplantation model of pancreatic cancer and to perform a preclinical evaluation of a new positron emission tomography (PET) imaging probe, 64 Cu-labeled cyclam-RAFT-c(-RGDfK-) 4 peptide ( 64 Cu-RAFT-RGD), using this model. Varying degrees of α v β 3 integrin expression in several human pancreatic cancer cell lines were examined by flow cytometry and Western blotting. The cell line BxPC-3, which is stably transfected with a red fluorescence protein (RFP), was used for surgical orthotopic implantation. Orthotopic xenograft was established in the pancreas of recipient nude mice. An in vivo probe biodistribution and receptor blocking study, preclinical PET imaging coregistered with contrast-enhanced computed tomography (CECT) comparing 64 Cu-RAFT-RGD and 18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) accumulation in tumor, postimaging autoradiography, and histologic and immunohistochemical examinations were done. Biodistribution evaluation with a blocking study confirmed that efficient binding of probe to tumor is highly α v β 3 integrin specific. 64 Cu-RAFT-RGD PET combined with CECT provided for precise and easy detection of cancer lesions. Autoradiography, histologic, and immunohistochemical examinations confirmed the accumulation of 64 Cu-RAFT-RGD in tumor versus nontumor tissues. In comparative PET studies, 64 Cu-RAFT-RGD accumulation provided better tumor contrast to background than 18 F-FDG. Our results suggest that 64 Cu-RAFT-RGD PET imaging is potentially applicable for the diagnosis of α v β 3 integrin–expressing pancreatic tumors.

The purpose of this study was to develop a clinically relevant orthotopic xenotransplantation model of pancreatic cancer and to perform a preclinical evaluation of a new positron emission tomography (PET) imaging probe, 64 Cu-labeled cyclam-RAFT-c(-RGDfK-) 4 peptide ( 64 Cu-RAFT-RGD), using this model. Varying degrees of α v β 3 integrin expression in several human pancreatic cancer cell lines were examined by flow cytometry and Western blotting. The cell line BxPC-3, which is stably transfected with a red fluorescence protein (RFP), was used for surgical orthotopic implantation. Orthotopic xenograft was established in the pancreas of recipient nude mice. An in vivo probe biodistribution and receptor blocking study, preclinical PET imaging coregistered with contrast-enhanced computed tomography (CECT) comparing 64 Cu-RAFT-RGD and 18 F-fluoro-2-deoxy-D-glucose ( 18 F-FDG) accumulation in tumor, postimaging autoradiography, and histologic and immunohistochemical examinations were done. Biodistribution evaluation with a blocking study confirmed that efficient binding of probe to tumor is highly α v β 3 integrin specific. 64 Cu-RAFT-RGD PET combined with CECT provided for precise and easy detection of cancer lesions. Autoradiography, histologic, and immunohistochemical examinations confirmed the accumulation of 64 Cu-RAFT-RGD in tumor versus nontumor tissues. In comparative PET studies, 64 Cu-RAFT-RGD accumulation provided better tumor contrast to background than 18 F-FDG. Our results suggest that 64 Cu-RAFT-RGD PET imaging is potentially applicable for the diagnosis of α v β 3 integrin–expressing pancreatic tumors.

64 Cu-cyclam-RAFT-c(-RGDfK-) 4 is a novel multimeric positron emission tomography (PET) probe for α V β 3 integrin imaging. Its uptake and α V β 3 expression in tumors showed a linear correlation. Since α V β 3 integrin is strongly expressed on activated endothelial cells during angiogenesis, we aimed to determine whether 64 Cu-cyclam-RAFT-c(-RGDfK-) 4 PET can be used to image tumor angiogenesis and monitor the antiangiogenic effect of a novel multi-targeted tyrosine kinase inhibitor, TSU-68. Athymic nude mice bearing human hepatocellular carcinoma HuH-7 xenografts, which expressed negligible α V β 3 levels on the tumor cells, received intraperitoneal injections of TSU-68 or the vehicle for 14 days. Antiangiogenic effects were determined at the end of therapy in terms of 64 Cu-cyclam-RAFT-c(-RGDfK-) 4 uptake evaluated using PET, biodistribution assay, and autoradiography, and they were compared with microvessel density (MVD) determined by CD31 immunostaining. 64 Cu-cyclam-RAFT-c(-RGDfK-) 4 PET enabled clear tumor visualization by targeting the vasculature, and the biodistribution assay indicated high tumor-to-blood and tumor-to-muscle ratios of 31.6 ± 6.3 and 6.7 ± 1.1, respectively, 3 h after probe injection. TSU-68 significantly slowed tumor growth and reduced MVD; these findings were consistent with a significant reduction in the tumor 64 Cu-cyclam-RAFT-c(-RGDfK-) 4 uptake. Moreover, a linear correlation was observed between tumor MVD and the corresponding standardized uptake value (SUV) (r = 0.829, P = 0.011 for SUV mean ; r = 0.776, P = 0.024 for SUV max ) determined by quantitative PET. Autoradiography and immunostaining showed that the distribution of intratumoral radioactivity and tumor vasculature corresponded. We concluded that 64 Cu-cyclam-RAFT-c(-RGDfK-) 4 PET can be used for in vivo angiogenesis imaging and monitoring of tumor response to antiangiogenic therapy.

Fluorescent molecules for surgeryThe chemical assembly of functions such cellular recognition and detection on molecular frame allows to obtain selective and flexible tumour guidance systems which open new applications in the field of the detection and therapy. In particular, the validation in animal of fluorescent guidance systems for tumour with the development of near infrared cameras is able to be valued for the development of technologies such as the assistance to the surgical gesture by real-time fluorescence imaging.