Platform For Translational Research Research Articles

CanSAR 2024-an update to the public drug discovery knowledgebase.

canSAR (https://cansar.ai) continues to serve as the largest publicly available platform for cancer-focused drug discovery and translational research. It integrates multidisciplinary data from disparate and otherwise siloed public data sources as well as data curated uniquely for canSAR. In addition, canSAR deploys a suite of curation and standardization tools together with AI algorithms to generate new knowledge from these integrated data to inform hypothesis generation. Here we report the latest updates to canSAR. As well as increasing available data, we provide enhancements to our algorithms to improve the offering to the user. Notably, our enhancements include a revised ligandability classifier leveraging Positive Unlabeled Learning that finds twice as many ligandable opportunities across the pocketome, and our revised chemical standardization pipeline and hierarchy better enables the aggregation of structurally related molecular records.

SAPPHIRE —establishment of small animal proton and photon image-guided radiation experiments

The in vivo evolution of radiotherapy necessitates innovative platforms for preclinical investigation, bridging the gap between bench research and clinical applications. Understanding the nuances of radiation response, specifically tailored to proton and photon therapies, is critical for optimizing treatment outcomes. Within this context, preclinical in vivo experimental setups incorporating image guidance for both photon and proton therapies are pivotal, enabling the translation of findings from small animal models to clinical settings. The SAPPHIRE project represents a milestone in this pursuit, presenting the installation of the small animal radiation therapy integrated beamline (SmART+ IB, Precision X-Ray Inc., Madison, Connecticut, USA) designed for preclinical image-guided proton and photon therapy experiments at University Proton Therapy Dresden. Through Monte Carlo simulations, low-dose on-site cone beam computed tomography imaging and quality assurance alignment protocols, the project ensures the safe and precise application of radiation, crucial for replicating clinical scenarios in small animal models. The creation of Hounsfield lookup tables and comprehensive proton and photon beam characterizations within this system enable accurate dose calculations, allowing for targeted and controlled comparison experiments. By integrating these capabilities, SAPPHIRE bridges preclinical investigations and potential clinical applications, offering a platform for translational radiobiology research and cancer therapy advancements.

Abstract 6913: A preclinical platform of prostate cancer PDX and derived cellular models as a tool for pharmacological screening and functional studies

Abstract Prostate Cancer (PCa) is the most frequently diagnosed cancer in men and remains one of the leading causes of cancer death worldwide. Despite undeniable progress in understanding the biology and genetics of this highly heterogenous and complex disease, the development of effective therapies is hampered by the lack of relevant experimental models recapitulating its diversity. To tackle this issue, over the last years, we have generated and characterized at the molecular and pharmacology level a collection of prostate cancer patient-derived xenografts (PDX) that accurately reproduce PCa histological and molecular heterogeneity. Although the development of these PCa PDX has been challenging, we are now able to offer a preclinical platform of 11 fully characterized PCa PDX models and in vitro cellular counterparts for preclinical evaluation of novel treatment modalities. Our platform consists of a collection of 4 androgen receptor high (ARPC), 2 androgen receptor low (ARLPC), 1 amphicrine prostate carcinoma (AMPC) and 4 castration-resistant neuroendocrine prostate cancer (CRPC-NE) PDX models and 6 cellular models derived from these PDX (PDXDC). Most of these PDX models were obtained by transplantation of post-surgery tumor specimens either by grafting of tumor fragments in the interscapular region of nude mice or in the subrenal capsule of NOD scid gamma mice. One model is a CTC-derived eXplant established using circulating tumor cells (CTCs) obtained by diagnostic leukapheresis injected into the fat pad of NOD scid gamma mice. PDXDC were obtained from dissociated PDX tumors cultured under various media and matrix conditions. They were characterized by comparison with the parental PDX by Short Tandem Repeat (STR) profiling before performing a master bank. All models (PDX and PDXDC) were characterized at molecular level by whole exome and RNA sequencing. PDX were characterized pharmacologically for response to standards of care, physical castration and response to the androgen receptor inhibitor enzalutamide. In vitro drug sensitivity of PDXDC was compared with their parental PDX in vivo drug response. This unique PDX panel reflects the molecular heterogeneity of prostate cancer and reproduces the molecular and drug response profile of human tumors. Associated to in vitro cell derivatives, our collection provides a powerful preclinical platform for translational research to identify mechanisms underlying acquired resistance to current therapies and develop novel treatment strategies against PCa and CRPC. Citation Format: Emilie Indersie, Léa Sinayen, Ludovic Bigot, Katell Mevel, Aurore Gorse, Marie Tavernier, Enora Le Ven, Luc Friboulet, Françoise Farace, Ester Morgado, Laurent Pouyet, Yohann Loriot, François Romagné, Olivier Déas. A preclinical platform of prostate cancer PDX and derived cellular models as a tool for pharmacological screening and functional studies [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 6913.

Zebrafish as a Model for Cardiovascular and Metabolic Disease: The Future of Precision Medicine.

The zebrafish (Danio rerio) has emerged as an appreciated and versatile model organism for studying cardiovascular and metabolic diseases, offering unique advantages for both basic research and drug discovery. The genetic conservation between zebrafish and humans and their high fecundity and transparent embryos allow for efficient large-scale genetic and drug-oriented screening studies. Zebrafish possess a simplified cardiovascular system that shares similarities with mammals, making them particularly suitable for modeling various aspects of heart development, function, and disease. The transparency of zebrafish embryos enables the real-time visualization of cardiovascular dynamics, offering insights into early embryonic events and facilitating the study of heart-related anomalies. In metabolic research, zebrafish provide a cost-effective platform for modeling obesity, type 2 diabetes, hyperlipidemia, and other metabolic disorders. Their high reproductive rate allows for the generation of large cohorts for robust statistical analyses, while advanced genetic tools, such as CRISPR/Cas9, enable precise gene editing with which to model specific genetic mutations associated with human diseases. Zebrafish metabolic models have been instrumental in elucidating the molecular mechanisms underlying metabolic diseases, studying the effects of environmental factors, and identifying potential therapeutic targets. Additionally, the permeability of zebrafish embryos to small molecules facilitates drug discovery and screening, offering a rapid and economical approach to identifying compounds with therapeutic potential. In conclusion, zebrafish cardiovascular and metabolic disease models continue to contribute significantly to our perception of disease pathogenesis, providing a platform for translational research and developing novel therapeutic interventions. The versatility, scalability, and genetic manipulability of zebrafish position them as an invaluable asset in unraveling the complexities of cardiovascular and metabolic diseases. This review presents an overview of the zebrafish model's key features and contributions to investigating cardiovascular and metabolic disorders. We discuss the benefits and drawbacks of using zebrafish models to study human disease and the critical findings revealed by the progress in this endeavor to date.

Development of a Strategic Initiative at MD Anderson Cancer Center to Improve Outcomes in Immune-Related Adverse Events.

Immune checkpoint inhibitors (ICIs) have transformed the treatment paradigm for many cancer types. The clinical use of ICIs is increasing rapidly, including in combinations associated with increased risk of toxicities, termed "immune-related adverse events" (irAEs). Therefore, MD Anderson Cancer Center (MDACC) in Houston, Texas has proactively responded by developing a priority endeavor known as the Immuno-Oncology Toxicity (IOTOX) initiative. This strategic initiative aims to facilitate the seamless integration of key domains: (1) standardized clinical practice and innovative decision toolsets; (2) patient and provider education; and (3) a comprehensive clinical and translational research platform. The ultimate goal of this initiative is to develop and disseminate clinical best practices and biologic insights into irAEs to improve outcomes of patients with irAEs at MDACC and in the wider oncology community.

Patient-Derived Xenograft Models for Translational Prostate Cancer Research and Drug Development.

Patient-derived xenografts (PDXs) are a valuable preclinical research platform generated through transplantation of a patient's resected tumor into an immunodeficient or humanized mouse. PDXs serve as a high-fidelity avatar for both precision medicine and therapeutic testing against the cancer patient's disease state. While PDXs show mixed response to initial establishment, those that successfully engraft and can be sustained with serial passaging form a useful tool for basic and translational prostate cancer (PCa) research. While genetically engineered mouse (GEM) models and human cancer cell lines, and their xenografts, each play beneficial roles in discovery science and initial drug screening, PDX tumors are emerging as the gold standard approach for therapeutic proof-of-concept prior to entering clinical trial. PDXs are a powerful platform, with PCa PDXs shown to represent the original patient tumor cell population and architecture, histopathology, genomic and transcriptomic landscape, and heterogeneity. Furthermore, PDX response to anticancer drugs in mice has been closely correlated to the original patient's susceptibility to these treatments in the clinic. Several PDXs have been established and have undergone critical in-depth characterization at the cellular and molecular level across multiple PCa tumor subtypes representing both primary and metastatic patient tumors and their inherent levels of androgen responsiveness and/or treatment resistance, including androgen-sensitive, castration resistant, and neuroendocrine PCa. Multiple PDX networks and repositories have been generated for the collaborative and shared use of these vital translational cancer tools. Here we describe the creation of a PDX maintenance colony from an established well-characterized PDX, best practice for PDX maintenance in mice, and their subsequent application in preclinical drug testing. This chapter aims to serve as a go to resource for the preparation and adoption of PCa PDX models in the research laboratory and for their use as a valuable preclinical platform for translational research and therapeutic agent development.

Current advancement in the preclinical models used for the assessment of diabetic neuropathy.

Diabetic neuropathy is one of the prevalent and debilitating microvascular complications of diabetes mellitus, affecting a significant portion of the global population. Relational preclinical animal models are essential to understand its pathophysiology and develop effective treatments. This abstract provides an overview of current knowledge and advancements in such models. Various animal models have been developed to mimic the multifaceted aspects of human diabetic neuropathy, including both type 1 and type 2 diabetes. These models involve rodents (rats and mice) and larger animals like rabbits and dogs. Induction of diabetic neuropathy in these models is achieved through chemical, genetic, or dietary interventions, such as diabetogenic agents, genetic modifications, or high-fat diets. Preclinical animal models have greatly contributed to studying the intricate molecular and cellular mechanisms underlying diabetic neuropathy. They have shed light on hyperglycemia-induced oxidative stress, neuroinflammation, mitochondrial dysfunction, and altered neurotrophic factor signaling. Additionally, these models have allowed for the investigation of morphological changes, functional alterations, and behavioral manifestations associated with diabetic neuropathy. These models have also been crucial for evaluating the efficacy and safety of potential therapeutic interventions. Novel pharmacological agents, gene therapies, stem cell-based approaches, exercise, dietary modifications, and neurostimulation techniques have been tested using these models. However, limitations and challenges remain, including physiological differences between humans and animals, complex neuropathy phenotypes, and the need for translational validation. In conclusion, preclinical animal models have played a vital role in advancing our understanding and management of diabetic neuropathy. They have enhanced our knowledge of disease mechanisms, facilitated the development of novel treatments, and provided a platform for translational research. Ongoing efforts to refine and validate these models are crucial for future treatment developments for this debilitating condition.

Radiobiological Characterization of Pancreatic Cancer Patient-Derived Organoids

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most aggressive and lethal tumors with a 5-year survival rate of less than 10%. Neoadjuvant radio(chemo)therapy aiming tumor downsizing fails in about 70% due to high heterogeneity, strong desmoplastic stroma and intrinsic radioresistance. In this project, pancreatic cancer patient-derived organoids (PDOs) are characterized regarding radioresponse, DNA-damage, proliferation and hypoxia, and clinical patients' outcome is correlated with the preclinical radiobiological data. In contrast to 2D monolayer cultures, PDOs maintain similar appearance, organization and functionality as the original tissue and therefore might have the potential as advanced preclinical model in radiation oncology. The radiation response of nine different pancreatic cancer PDO lines was determined by 3D cell viability assay. PDOs were irradiated with 0, 2, 4, 6, and 8 Gy (CellRad, Precision, USA) 24h after seeding and the ATP-dependent viability assay was performed 72h and 7d after irradiation (RT). Changes in morphology, number, and size were investigated by microscopy at different time points after RT. PDOs were characterized immunohistochemically by y-H2AX (DNA damage), and Ki-67 (proliferation) staining. RNA sequencing data of treatment-naive PDOs were analyzed by gene set enrichment analyses (GSEA) regarding radioresistance. Preclinical results were correlated with corresponding clinical data of PDAC patients. After optimization of the experimental set-up, PDOs showed a dose-dependent decrease in viability 7d after RT and heterogeneity in radioresponse. PDO lines were classified into radiosensitive, -intermediate, and -resistant subclasses. Immunohisto-chemical staining showed a significant increase in DNA double-strand breaks after RT. A correlation between radiosensitivity and enhanced proliferation index Ki67 was observed. Based on RNA sequencing data, OXPHOS- and hypoxia-dependent genes, amongst others, were identified as pathways significantly differentially regulated between the subclasses by GSEA. Preclinical radioresistance was associated with worse survival and poor clinical outcome. The results of the preclinical experiments demonstrate the heterogeneity among PDOs in response to RT reflecting the clinical situation of patients with PDAC. The findings from the GSEA show promising aspects for further experiments to understand the role of hypoxia in PDAC and its effect on radioresistance. PDOs have the potential as a novel translational research platform in radiation oncology. Prospectively, we aim to implement the screening of the radiosensitivity of PDOs in clinical practice for the realization of truly personalized radiotherapy in PDAC patients.

State-of-the-art methodologies used in preclinical studies to assess left ventricular diastolic and systolic function in mice, pitfalls and troubleshooting.

Cardiovascular diseases (CVD) are still the leading cause of death worldwide. The improved survival of patients with comorbidities such as type 2 diabetes, hypertension, obesity together with the extension of life expectancy contributes to raise the prevalence of CVD in the increasingly aged society. Therefore, a translational research platform that enables precise evaluation of cardiovascular function in healthy and disease condition and assess the efficacy of novel pharmacological treatments, could implement basic science and contribute to reduce CVD burden. Heart failure is a deadly syndrome characterized by the inability of the heart to meet the oxygen demands of the body (unless there is a compensatory increased of filling pressure) and can manifest either with reduced ejection fraction (HFrEF) or preserved ejection fraction (HFpEF). The development and progression of HFrEF is mostly attributable to impaired contractile performance (systole), while in HFpEF the main problem resides in decreased ability of left ventricle to relax and allow the blood filling (diastole). Murine preclinical models have been broadly used in research to understand pathophysiologic mechanisms of heart failure and test the efficacy of novel therapies. Several methods have been employed to characterise cardiac systolic and diastolic function including Pressure Volume (PV) loop hemodynamic analysis, echocardiography and Magnetic Resonance Imaging (MRI). The choice of one methodology or another depends on many aspects including budget available, skills of the operator and design of the study. The aim of this review is to discuss the importance of several methodologies that are commonly used to characterise the cardiovascular phenotype of preclinical models of heart failure highlighting advantages and limitation of each procedure. Although it requires highly skilled operators for execution, PV loop analysis represents the "gold standard" methodology that enables the assessment of left ventricular performance also independently of vascular loading conditions and heart rate, which conferee a really high physiologic importance to this procedure.

The Edge Effect in High-Throughput Proteomics: A Cautionary Tale.

In order for mass spectrometry to continue to grow as a platform for high-throughput clinical and translational research, careful consideration must be given to quality control by ensuring that the assay performs reproducibly and accurately and precisely. In particular, the throughput required for large cohort clinical validation in biomarker discovery and diagnostic screening has driven the growth of multiplexed targeted liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) assays paired with sample preparation and analysis in multiwell plates. However, large scale MS-based proteomics studies are often plagued by batch effects: sources of technical variation in the data, which can arise from a diverse array of sources such as sample preparation batches, different reagent lots, or indeed MS signal drift. These batch effects can confound the detection of true signal differences, resulting in incorrect conclusions being drawn about significant biological effects or lack thereof. Here, we present an intraplate batch effect termed the edge effect arising from temperature gradients in multiwell plates, commonly reported in preclinical cell culture studies but not yet reported in a clinical proteomics setting. We present methods herein to ameliorate the phenomenon including proper assessment of heating techniques for multiwell plates and incorporation of surrogate standards, which can normalize for intraplate variation.

250 A Living Library for Uveal Melanoma

OBJECTIVES/GOALS: Overall response rates for metastatic uveal melanoma (UM), regardless of treatment modality, are less than 20%, highlighting an urgent need for novel therapies. Herein, we present a UM patient-derived organoid (PDO) biobank as a novel platform for translational research. METHODS/STUDY POPULATION: Patients with primary choroidal or ciliochoroidal UM undergoing enucleation from 7/1/2019-9/30/2022 were invited to enroll. Tumor tissue was harvested within 30 minutes of globe removal. Cells were isolated using the human tumor isolation kit and gentleMACS dissociation protocol (Miltenyi Biotech). PDOs were placed on Cultrex-coated multiwell plates and cultured in supplemented RPMI media. DNA and RNA were isolated using kits from Zymo Research. Exon-enriched libraries and RNA were sequenced using an Illumina HiSeq 4000. Immunohistochemistry (IHC) assessed the following histone post-translational modifications: H3K4me1/3, H3K27Ac, and H3K27me. RESULTS/ANTICIPATED RESULTS: PDOs were established in 19 of 20 (95%) attempted cases. BAP1 protein expression was retained (n=7) or lost (n=12) in the primary tumors, with matching phenotype confirmed in PDOs. In 9 sequenced cases, a driving mutation was present in GNAQ (n=4), GNA11 (n=4), or CYSLTR2 (n=1). Morphology ranged from spindle-like to epithelioid clusters, mimicking primary tumor histopathology. Pigmentation increased with time in culture. Growth in culture was slow, and 1-2 months were allotted prior to passaging in most cases. Whole exome and RNA-sequencing confirmed distinct molecular profiles, with differential staining of active chromatin marks by IHC. DISCUSSION/SIGNIFICANCE: A biobank of primary UM PDOs with unique morphological and molecular characteristics has been established. These will serve as a model of human disease to facilitate translational research and investigate personalized treatments for patients with UM.

The RAPID Consortium: A Platform for Clinical and Translational Pituitary Tumor Research.

Objectives Pituitary tumor treatment is hampered by the relative rarity of the disease, absence of a multicenter collaborative platform, and limited translational-clinical research partnerships. Prior studies offer limited insight into the formation of a multicenter consortium. Design The authors describe the establishment of a multicenter research initiative, Registry of Adenomas of the Pituitary and Related Disorders (RAPID), to encourage quality improvement and research, promote scholarship, and apply innovative solutions in outcomes research. Methods The challenges encountered during the formation of other research registries were reviewed with those lessons applied to the development of RAPID. Setting/Participants RAPID was formed by 11 academic U.S. pituitary centers. Results A Steering Committee, bylaws, data coordination center, and leadership team have been established. Clinical modules with standardized data fields for nonfunctioning adenoma, prolactinoma, acromegaly, Cushing's disease, craniopharyngioma, and Rathke's cleft cyst were created using a Health Insurance Portability and Accountability Act-compliant cloud-based platform. Currently, RAPID has received institutional review board approval at all centers, compiled retrospective data and agreements from most centers, and begun prospective data collection at one site. Existing institutional databases are being mapped to one central repository. Conclusion The RAPID consortium has laid the foundation for a multicenter collaboration to facilitate pituitary tumor and surgical research. We sought to share our experiences so that other groups also contemplating this approach may benefit. Future studies may include outcomes benchmarking, clinically annotated biobank tissue, multicenter outcomes studies, prospective intervention studies, translational research, and health economics studies focused on value-based care questions.

Generation and maturation of human iPSC-derived 3D organotypic cardiac microtissues in long-term culture

Cardiovascular diseases remain the leading cause of death worldwide; hence there is an increasing focus on developing physiologically relevant in vitro cardiovascular tissue models suitable for studying personalized medicine and pre-clinical tests. Despite recent advances, models that reproduce both tissue complexity and maturation are still limited. We have established a scaffold-free protocol to generate multicellular, beating human cardiac microtissues in vitro from hiPSCs—namely human organotypic cardiac microtissues (hOCMTs)—that show some degree of self-organization and can be cultured for long term. This is achieved by the differentiation of hiPSC in 2D monolayer culture towards cardiovascular lineage, followed by further aggregation on low-attachment culture dishes in 3D. The generated hOCMTs contain multiple cell types that physiologically compose the heart and beat without external stimuli for more than 100 days. We have shown that 3D hOCMTs display improved cardiac specification, survival and metabolic maturation as compared to standard monolayer cardiac differentiation. We also confirmed the functionality of hOCMTs by their response to cardioactive drugs in long-term culture. Furthermore, we demonstrated that they could be used to study chemotherapy-induced cardiotoxicity. Due to showing a tendency for self-organization, cellular heterogeneity, and functionality in our 3D microtissues over extended culture time, we could also confirm these constructs as human cardiac organoids (hCOs). This study could help to develop more physiologically-relevant cardiac tissue models, and represent a powerful platform for future translational research in cardiovascular biology.

A Genomically and Clinically Annotated Patient-Derived Xenograft Resource for Preclinical Research in Non-Small Cell Lung Cancer.

Patient-derived xenografts of lung cancer retain key features observed in the originating patient tumors and show expected responses to treatment with standard-of-care agents, providing experimentally tractable and reproducible models for preclinical investigations.

Quantifying dynamic facial expressions under naturalistic conditions.

Facial affect is expressed dynamically - a giggle, grimace, or an agitated frown. However, the characterisation of human affect has relied almost exclusively on static images. This approach cannot capture the nuances of human communication or support the naturalistic assessment of affective disorders. Using the latest in machine vision and systems modelling, we studied dynamic facial expressions of people viewing emotionally salient film clips. We found that the apparent complexity of dynamic facial expressions can be captured by a small number of simple spatiotemporal states - composites of distinct facial actions, each expressed with a unique spectral fingerprint. Sequential expression of these states is common across individuals viewing the same film stimuli but varies in those with the melancholic subtype of major depressive disorder. This approach provides a platform for translational research, capturing dynamic facial expressions under naturalistic conditions and enabling new quantitative tools for the study of affective disorders and related mental illnesses.

Physiological calcium combined with electrical pacing accelerates maturation of human engineered heart tissue.

SummaryHuman-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have wide potential application in basic research, drug discovery, and regenerative medicine, but functional maturation remains challenging. Here, we present a method whereby maturation of hiPSC-CMs can be accelerated by simultaneous application of physiological Ca2+ and frequency-ramped electrical pacing in culture. This combination produces positive force-frequency behavior, physiological twitch kinetics, robust β-adrenergic response, improved Ca2+ handling, and cardiac troponin I expression within 25 days. This study provides insights into the role of Ca2+ in hiPSC-CM maturation and offers a scalable platform for translational and clinical research.

Porcine Organotypic Epicardial Slice Protocol: A Tool for the Study of Epicardium in Cardiovascular Research.

The epicardium has recently gained interest in the cardiovascular field due to its capacity to support heart regeneration after ischemic injury. Models to study the epicardium of large animals in vitro are limited and mainly based on epicardial cell isolation/differentiation from stem cells, followed by 2D cells culture. In this method paper, we describe the procedure to obtain and culture 3D organotypic heart slices presenting an intact epicardium, as a novel model to study the epicardial physiology and activation. Epicardial slices are obtained from porcine hearts using a high-precision vibratome and retain a healthy epicardial layer embedded in its native extracellular environment and connected with other cardiac cells (cardiomyocytes, fibroblasts, vascular cells etc.). Epicardial slices can be cultured for 72 h, providing an ideal model for studying the epicardium physiology or perform pharmacological interventions/gene therapy approaches. We also report on methods to assesses the viability and composition of the epicardial slices, and evaluate their architecture in 3D through tissue decoloration. Finally, we present a potential application for a nanomaterial-based gene transfer method for tracking of epicardial cells within the slice. Crucially, given the similarity in morphology and physiology of porcine heart with its human counterpart, our system provides a platform for translational research while providing a clinically relevant and ethical alternative to the use of small animals in this type of research.

Generation of human tonsil epithelial organoids as an ex vivo model for SARS-CoV-2 infection

The palatine tonsils (hereinafter referred to as “tonsils”) serve as a reservoir for viral infections and play roles in the immune system's first line of defense. The aims of this study were to establish tonsil epithelial cell–derived organoids and examine their feasibility as an ex vivo model for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The tonsil organoids successfully recapitulated the key characteristics of the tonsil epithelium, including cellular composition, histologic properties, and biomarker distribution. Notably, the basal layer cells of the organoids express molecules essential for SARS-CoV-2 entry, such as angiotensin-converting enzyme 2 (ACE2), transmembrane serine protease 2 (TMPRSS2) and furin, being susceptible to the viral infection. Changes in the gene expression profile in tonsil organoids revealed that 395 genes associated with oncostatin M signaling and lipid metabolism were highly upregulated within 72 h after SARS-CoV-2 infection. Notably, remdesivir suppressed the viral RNA copy number in organoid culture supernatants and intracellular viral protein levels in a dose-dependent manner. Here, we suggest that tonsil epithelial organoids could provide a preclinical and translational research platform for investigating SARS-CoV-2 infectivity and transmissibility or for evaluating antiviral candidates.

EXTH-62. COMBINATORIAL THERAPY TARGETING TRANSCIPTION AND IMMUNO-METABOLISM IN RECURRENT GLIOBLASTOMA

Abstract Recurrent glioblastomas (GBM) are notoriously difficult to treat, and in spite of aggressive chemo- and radiation therapy they inevitably recur in almost all GBM patients within 14 months following initial diagnosis. To interrogate pathways driving therapeutic resistance, we compared matched primary and recurrent IDH wild type glioblastoma samples from a cohort of patients, using RNA-Seq. Our analyses showed that pathways involved with tumor immune and metabolic reprogramming were up-regulated in recurrent GBMs compared to untreated, primary samples. Based on these findings, we tested the anti-tumor efficacy of over 20 rationally selected targeted therapeutic agents alone and in combination in a high-throughput drug screen assay designed to measure long term cell viability of primary tumorspheres from patients who underwent surgery for recurrent GBM. Top performing drug combinations from these screens were validated in vivo using patient-derived intracranial mouse models of glioma. Our data demonstrated that the combination of the transcriptional/metabolic inhibitor TG02 and the dual PI3K/mTOR inhibitor GDC-0084 significantly prolonged in vivo survival of tumor bearing mice, performing better than either drug alone. Notably, both inhibitors are undergoing human clinical trials as single agents with positive initial safety profiles and superior blood brain barrier penetrance. RNA Seq and functional assays of tumor samples from treated mice showed that only the combination treatment (TG02 + GDC-0084) significantly inhibited expression of immunomodulatory cytokines driving tumor progression, including those identified by us to be overexpressed in recurrent human GBM samples. Overall, these data suggest that combining TG02 and GDC-0084 is an effective treatment for recurrent GBMs. Furthermore, our results support the use of a translational research platform consisting of a personalized pharmaco-genomics testing, using patient-derived tumor samples towards designing more effective treatment for recurrent GBM patients.

D-Peptide-Based Probe for CXCR4-Targeted Molecular Imaging and Radionuclide Therapy

Positron emission tomography (PET) imaging of the C-X-C chemokine receptor 4 (CXCR4) with [68Ga]PentixaFor has intrinsic diagnostic value and is used to select patients for personalized CXCR4-targeted radionuclide therapy with its therapeutic radiopharmaceutical companion [177Lu]PentixaTher. However, a CXCR4-targeting radiopharmaceutical labeled with fluorine-18 is still of high value due to its favorable characteristics over gallium-68. Furthermore, clinical results with [177Lu]PentixaTher are promising, but there is still room for improvement regarding pharmacokinetics and dosimetry profile. Therefore, this study aimed to develop innovative CXCR4-targeting radiopharmaceuticals, both for diagnostic and therapeutic purposes, starting from a D-amino acid-based peptide probe (DV1-k-(DV3)) that conserves high CXCR4 binding affinity after radiolabeling. AlF-NOTA-DV1-k-(DV3) showed similar in vitro binding affinity to human CXCR4 (hCXCR4) compared to [natGa]PentixaFor (half-maximal inhibitory concentration (IC50): 5.3 ± 0.9 nM and 8.6 ± 1.1 nM, respectively) and also binds to murine CXCR4 (mCXCR4) (IC50: 33.4 ± 13.5 nM) while [natGa]PentixaFor is selective for hCXCR4 (IC50 > 1000 nM for mCXCR4). Both the diagnostic radiotracers based on the DV1-k-(DV3) vector platform, [18F]AlF-NOTA-DV1-k-(DV3) and [68Ga]Ga-DOTA-DV1-k-(DV3), and their therapeutic companion [177Lu]Lu-DOTA-DV1-k-(DV3) were successfully produced in high yield, demonstrated high in vitro and in vivo stability, and have the same favorable pharmacokinetic profile. Furthermore, in wild-type mice and a hCXCR4-expressing tumor model, [18F]AlF-NOTA-DV1-k-(DV3) shows CXCR4-specific targeting in mCXCR4-expressing organs such as liver (mean standardized uptake value (SUVmean) 8.2 ± 1.0 at 75 min post-injection (p.i.)), spleen (SUVmean 2.5 ± 1.0 at 75 min p.i.), and bone (SUVmean 0.4 ± 0.1 at 75 min p.i., femur harboring bone marrow) that can be blocked with the CXCR4 antagonist AMD3100. However, in a hCXCR4-expressing tumor model, tumor uptake of [18F]AlF-NOTA-DV1-k-(DV3) was significantly lower (SUVmean 0.6 ± 0.2) compared to [68Ga]PentixaFor (SUVmean 2.9). This might be explained by the high affinity of [18F]AlF-NOTA-DV1-k-(DV3) toward both mCXCR4 and hCXCR4. High mCXCR4 expression in mouse liver results in a large fraction of [18F]AlF-NOTA-DV1-k-(DV3) that is sequestered to the liver, resulting despite its similar in vitro affinity for hCXCR4, in lower tumor accumulation compared to [68Ga]PentixaFor. As CXCR4 is not expressed in healthy human liver, the findings in mice are not predictive for the potential clinical performance of this novel class of CXCR4-targeting radiotracers. In conclusion, the DV1-k-(DV3) scaffold is a promising vector platform for translational CXCR4-directed research.