SUPRAMOLECULAR AGENTS AS RADIOTHERANOSTIC DRUGS

Project Information

SMARTdrugs

Grant agreement ID: 101129886

DOI

10.3030/101129886

EC signature date 2 October 2023

Start date 1 January 2024

End date 31 December 2027

Funded under

• The European Innovation Council (EIC)

Total cost

€ 2 713 190,75

EU contribution

€ 2 713 190,75

Coordinated by

TECHNISCHE UNIVERSITAET MUENCHEN
Germany

Periodic Reporting for period 1 - SMARTdrugs (SUPRAMOLECULAR AGENTS AS RADIOTHERANOSTIC DRUGS)

Reporting period: 2024-01-01 to 2024-12-31

Summary of the context and overall objectives of the project

Radiopharmaceuticals are at the forefront of modern personalized medicine, from diagnostic applications that quantify and characterize biomarker expression in cancer patients to molecularly targeted radionuclide therapy that has improved patient outcomes. The radical long-term vision of SMARTdrugs is to harness the untapped potential of supramolecular chemistry to create a new class of therapies - radiotheranostics - which combine both diagnostic and therapeutic radionuclides in one compound. Using self-assembly of host-guest supramolecular complexes and interlocked molecules as scaffolds to develop supramolecular radiotheranostic drugs, this approach introduces novel synthesis methods that move beyond traditional medicinal chemistry approaches, addressing challenges like tumor targeting, in vivo stability, and efficacy. SMARTdrugs will demonstrate the utility of non-covalent systems as multifunctional radiotheranostic agents with tailored pharmacokinetics and test their application in challenging drug-delivery scenarios, including targeted delivery to cancers of the lung and brain.

Our 3 main objectives are:
Objective 1 – Develop new chemical landscapes using non-covalent bonding to create functionalized supramolecular compounds for cancer-specific theranostics
Objective 2 – Elucidate the key relationships between supramolecular radiotheranostics and the complex tumour microenvironment that determine drug efficacy in vivo
Objective 3 – Perform head-to-head studies to establish a proof-of-principle that supramolecular chemistry is a viable alternative to classical radiopharmaceutical design

The long-term goal is to establish a new chemical landscape for radiotheranostic design, and to facilitate clinical translation of this new technology. Successful experiments will lay the foundations for exploiting supramolecular chemistry in the wider context of drug delivery and theranostics, and to study biological interactions at the cellular to whole-organism level.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

During this first year, the project focused on building a library of supramolecules and related building blocks for further structural characterization. In particular, different types of metallacages of the type M2L4 (M = Pd2+, Pt2+, L = ditopic N-donor ligand) were synthesized and fully characterized. We devoted significant time to design cage scaffolds exo-functionalized with different moieties for tethering to bioactive ligands, including synthons for radiolabeling, fluorophores and peptides. The conditions for the radiolabeling were optimized for the free ligands and ongoing studies are focused on the obtainment of the respective cage structures. Preliminary studies were conducted to study the host-guest chemistry of the new metallacages.
For rotaxane-based molecules, we focused on synthesizing monomeric building blocks to create a flexible and modular rotaxane platform. Preliminary test reactions were conducted to demonstrate the concept of rotaxane self-assembly. However, further synthetic refinement is required to optimize rotaxane synthesis and expand the library of monomeric compounds with diverse functional units in the coming months. Finally, we developed N-heterocyclic carbene (NHC) ligands as stabilizers of gold nanoparticles. In particular, water soluble NHCs were synthesized based on the imidazole and benzimidazole scaffolds. Further, the synthesis of the NHC@AuNPs was attempted using two different bottom-up approaches. Significant time was devoted to developing a methodology yielding stable, non-aggregated and small-sized uniform particles.
To prepare for the biological evaluation of our agents, a high-throughput screening platform was developed to conduct saturation binding assays with radioligands in vitro. Access to resected medulloblastoma tissue was further granted through the UMCU/PMC biobank. Here, target expression was determined through gold-standard immunohistochemistry and independently scored by pathology. In addition, the chicken chorioallantoic membrane (CAM) model was optimized to grow multiple NSCLC xenograft tumors. We will use this model as the primary in vivo screen for our novel agents. Importantly, we have performed technology transfer of these techniques from KCL to UMCU to use the CAM model for growth and in ovo analysis of medulloblastoma. To date, the model has been successfully implemented, and the growth of three patient-derived organoids has been achieved. Moreover, we have developed and optimised the growth of orthotopic, PDX, and GEMM in vivo models of NSCLC.
It is important to compare our novel supramolecular radiotheranostics with gold-standard agents using conventional covalent chemistry. We have made progress towards developing antibody-based ‘conventional’ radiotheranostics that target both EGFR and xCT.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Substantial effort has been spent towards dissemination and communication. Thus, two perspective review papers were published, which outline a new conceptual framework to achieve next-generation radiotheranostic agents, illustrating the benefits and challenges of supramolecular approaches at the low nanoscale level. The two papers showcase how supramolecular platforms provide concomitant synthetic flexibility, rapid generation through self-assembly, facile labeling, unique topologies, tunable reversibility of the enabling noncovalent interactions (NCIs) and opportunities for host-guest chemistry and mechanical bonding. Recent advances in the design and radiopharmaceutical application of discrete self-assembled coordination complexes and mechanically interlocked molecules - namely metallacages and rotaxanes, respectively - are critically presented. These concepts were further disseminated via presentations in scientific conferences and workshops.
Significant efforts have been directed toward the development of a high-throughput screening platform designed for the in vitro evaluation of novel radiolabeled compounds through saturation-binding assays. This cutting-edge platform, currently operating under semi-automated conditions, facilitates the precise determination of critical receptor-ligand interaction parameters, including the dissociation constant (KD) and the maximum receptor concentration (Bmax). The platform integrates a robust combination of well-established equipment and standardized procedures, ensuring reliability and reproducibility of results. While the reliance on existing methodologies precludes intellectual property (IP) protection, this approach allows for seamless adoption and scalability. Importantly, it paves the way for future exploitation within the project and beyond. For instance, the platform can serve as the basis for providing specialized research services under contract agreements with companies or academic and industrial research institutions, fostering collaboration and enabling impactful applications in drug discovery and development.