Three-Dimensional Cell Culture Systems in Radiopharmaceutical Cancer Research

Dynamic 3D in vitro lung models: applications of inorganic nanoparticles for model development and characterization

Being a vital organ exposed to the external environment, the lung is susceptible to a plethora of pathogens and pollutants. This is reflected in high incidences of chronic respiratory diseases, which remain a leading cause of mortality world-wide and pose a persistent global burden. It is thus of paramount importance to improve our understanding of these pathologies and provide better therapeutic options. This necessitates the development of representative and physiologically relevant in vitro models. Advances in bioengineering have enabled the development of sophisticated models that not only capture the three-dimensional architecture of the cellular environment but also incorporate the dynamics of local biophysical stimuli. However, such complex models also require novel approaches that provide reliable characterization. Within this review we explore how 3D bioprinting and nanoparticles can serve as multifaceted tools to develop such dynamic 4D printed in vitro lung models and facilitate their characterization in the context of pulmonary fibrosis and breast cancer lung metastasis.

Anaplastic thyroid cancer spheroids as preclinical models to test therapeutics

Anaplastic thyroid cancer (ATC) is the most aggressive thyroid cancer. Despite advances in tissue culture techniques, a robust model for ATC spheroid culture is yet to be developed. In this study, we created an efficient and cost-effective 3D tumor spheroids culture system from human ATC cells and existing cell lines that better mimic patient tumors and that can enhance our understanding of in vivo treatment response. We found that patient-derived ATC cells and cell lines can readily form spheroids in culture with a unique morphology, size, and cytoskeletal organization. We observed both cohesive (dense and solid structures) and discohesive (irregularly shaped structures) spheroids within the same culture condition across different cell lines. BRAFWT ATC spheroids grew in a cohesive pattern, while BRAFV600E-mutant ATC spheroids had a discohesive organization. In the patient-derived BRAFV600E-mutant ATC spheroids, we observed both growth patterns, but mostly the discohesive type. Histologically, ATC spheroids had a similar morphology to the patient's tumor through H&E staining and proliferation marker staining. Moreover, RNA sequencing analysis revealed that the gene expression profile of tumor cells derived from the spheroids closely matched parental patient tumor-derived cells in comparison to monolayer cultures. In addition, treatment response to combined BRAF and MEK inhibition in BRAFV600E-mutant ATC spheroids exhibited a similar sensitivity to the patient clinical response. Our study provides a robust and novel ex vivo spheroid model system that can be used in both established ATC cell lines and patient-derived tumor samples to better understand the biology of ATC and to test therapeutics.

Impact of Viscosity on Human Hepatoma Spheroids in Soft Core-Shell Microcapsules

The extracellular environment regulates the structures and functions of cells, from the molecular to the tissue level. However, the underlying mechanisms influencing the organization and adaptation of cancer in three-dimensional (3D) environments are not yet fully understood. In this study, the influence of the viscosity of the environment is investigated on the mechanical adaptability of human hepatoma cell (HepG2) spheroids in vitro, using 3D microcapsule reactors formed with droplet-based microfluidics. To mimic the environment with different mechanical properties, HepG2 cells are encapsulated in alginate core-shell reservoirs (i.e., microcapsules) with different core viscosities tuned by incorporating carboxymethylcellulose. The significant changes in cell and spheroid distribution, proliferation, and cytoskeleton are observed and quantified. Importantly, changes in the expression and distribution of F-actin and keratin 8 indicate the relation between spheroid stiffness and viscosity of the surrounding medium. The increase of F-actin levels in the viscous medium can indicate an enhanced ability of tumor cells to traverse dense tissue. These results demonstrate the ability of cancer cells to dynamically adapt to the changes in extracellular viscosity, which is an important physical cue regulating tumor development, and thus of relevance in cancer biology.

Radiopharmaceuticals: navigating the frontier of precision medicine and therapeutic innovation

This review article explores the dynamic field of radiopharmaceuticals, where innovative developments arise from combining radioisotopes and pharmaceuticals, opening up exciting therapeutic possibilities. The in-depth exploration covers targeted drug delivery, delving into passive targeting through enhanced permeability and retention, as well as active targeting using ligand-receptor strategies. The article also discusses stimulus-responsive release systems, which orchestrate controlled release, enhancing precision and therapeutic effectiveness. A significant focus is placed on the crucial role of radiopharmaceuticals in medical imaging and theranostics, highlighting their contribution to diagnostic accuracy and image-guided curative interventions. The review emphasizes safety considerations and strategies for mitigating side effects, providing valuable insights into addressing challenges and achieving precise drug delivery. Looking ahead, the article discusses nanoparticle formulations as cutting-edge innovations in next-generation radiopharmaceuticals, showcasing their potential applications. Real-world examples are presented through case studies, including the use of radiolabelled antibodies for solid tumors, peptide receptor radionuclide therapy for neuroendocrine tumors, and the intricate management of bone metastases. The concluding perspective envisions the future trajectory of radiopharmaceuticals, anticipating a harmonious integration of precision medicine and artificial intelligence. This vision foresees an era where therapeutic precision aligns seamlessly with scientific advancements, ushering in a new epoch marked by the fusion of therapeutic resonance and visionary progress.

Tumor Organoids: The Era of Personalized Medicine

The strategies of future medicine are aimed to modernize and integrate quality approaches including early molecular-genetic profiling, identification of new therapeutic targets and adapting design for clinical trials, personalized drug screening (PDS) to help predict and individualize patient treatment regimens. In the past decade, organoid models have emerged as an innovative in vitro platform with the potential to realize the concept of patient-centered medicine. Organoids are spatially restricted three-dimensional clusters of cells ex vivo that self-organize into complex functional structures through genetically programmed determination, which is crucial for reconstructing the architecture of the primary tissue and organs. Currently, there are several strategies to create three-dimensional (3D) tumor systems using (i) surgically resected patient tissue (PDTOs, patient-derived tumor organoids) or (ii) single tumor cells circulating in the patient's blood. Successful application of 3D tumor models obtained by co-culturing autologous tumor organoids (PDTOs) and peripheral blood lymphocytes have been demonstrated in a number of studies. Such models simulate a 3D tumor architecture in vivo and contain all cell types characteristic of this tissue, including immune system cells and stem cells. Components of the tumor microenvironment, such as fibroblasts and immune system cells, affect tumor growth and its drug resistance. In this review, we analyzed the evolution of tumor models from two-dimensional (2D) cell cultures and laboratory animals to 3D tissue-specific tumor organoids, their significance in identifying mechanisms of antitumor response and drug resistance, and use of these models in drug screening and development of precision methods in cancer treatment.

GRPR-targeting radiotheranostics for breast cancer management

Breast Cancer (BC) is the most common cancer worldwide and, despite the advancements made toward early diagnosis and novel treatments, there is an urgent need to reduce its mortality. The Gastrin-Releasing Peptide Receptor (GRPR) is a promising target for the development of theranostic radioligands for luminal BC with positive estrogen receptor (ER) expression, because GRPR is expressed not only in primary lesions but also in lymph nodes and distant metastasis. In the last decades, several GRPR-targeting molecules have been evaluated both at preclinical and clinical level, however, most of the studies have been focused on prostate cancer (PC). Nonetheless, given the relevance of non-invasive diagnosis and potential treatment of BC through Peptide Receptor Radioligand Therapy (PRRT), this review aims at collecting the available preclinical and clinical data on GRPR-targeting radiopeptides for the imaging and therapy of BC, to better understand the current state-of-the-art and identify future perspectives and possible limitations to their clinical translation. In fact, since luminal-like tumors account for approximately 80% of all BC, many BC patients are likely to benefit from the development of GRPR-radiotheranostics.

Cell Line-Based Human Bladder Organoids with Bladder-like Self-Organization-A New Standardized Approach in Bladder Cancer Research

Three-dimensional tumor models have gained significant importance in bladder cancer (BCa) research. Organoids consisting of different cell types better mimic solid tumors in terms of 3D architecture, proliferation, cell-cell interaction and drug responses. We developed four organoids from human BCa cell lines with fibroblasts and smooth muscle cells of the bladder, aiming to find models for BCa research. The organoids were characterized in terms of cytokeratins, vimentin, α-actin and KI67 by immunoreactivity. Further, we studied ligand-dependent activation of the Wnt/β-catenin pathway and investigated the responses to anti-tumor therapies. The organoids mimicked the structure of an inverse bladder wall, with outside urothelial cells and a core of supportive cells. The cytokeratin staining patterns and proliferation rate were in conjunction with the origins of the BCa cells. RT-112 even showed stratification of the epithelium. Treatment with Wnt10B led to increased β-catenin (active) levels in high-grade organoids, but not in low-grade BCa cells. Doxorubicin treatment resulted in clearly reduced viability (10-30% vs. untreated). In contrast, the effectivity of radiotherapy depended on the proliferation status of BCa cells. In conclusion, cell-line-based organoids can form bladder-like structures and reproduce in vivo features such as urothelial differentiation and stratification. Thus, they can be useful tools for functional studies in BCa and anti-cancer drug development.

Evaluation of novel anti-CEACAM6 antibody-based conjugates for radioimmunotheranostics of pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant solid tumor that lacks early diagnostic methods. Recently, targeted immunotherapy and radiotherapy have been integrated with radionuclide-antibody conjugate drugs, which can be used for targeted diagnosis and dynamic imaging of tumors. CEACAM6 is overexpressed in pancreatic tumors and is a potential theranostic target for PDAC. We aimed to develop a novel targeted carrier for theranostics of PDAC and other solid tumors.

METHODS

Based on camelid heavy-chain-only antibodies, we developed a CEACAM6-targeting recombinant antibody NY004, and evaluated it as a novel antibody-carrier for imaging and therapy of cancer in tumor models. We labeled NY004 with theranostic nuclides and applied this self-developed antibody platform in diagnostic imaging and antitumor assessment in PDAC models.

RESULTS

Through microPET, IHC, and biodistribution assays, targeting and biodistribution of [89Zr]-NY004 in solid tumors including PDAC was examined, and the investigated tumors were all CEACAM6-positive malignancies. We found that NY004 was suitable for use as a drug carrier for radioimmunotheranostics. Our study showed that NY004 was characterized by high targeted uptake and a long retention time in PANC-1 tumors (up to 6 days post-injection), with good specificity and high imaging efficiency. Therapeutic evaluation of the radionuclide-labeled antibody drug [177Lu]-NY004 in PDAC tumor-bearing model revealed that NY004 had high and prolonged uptake in tumors, relatively low non-target organ uptake, and good anti-tumor efficacy.

CONCLUSION

As a drug platform for radiotheranostics, CEACAM6-specific antibody NY004 met the requirements of easy-labeling, targeting specificity, and effective persistence in pancreatic adenocarcinoma tissues.

KEY POINTS

• [89Zr]-NY004 has good specificity and high imaging efficiency, and is characterized by high tumor-targeting uptake and a long tumor retention time as a PET molecular imaging tracer. • Therapeutic radionuclide-conjugated antibody drug [177Lu]-NY004 has high uptake and prolonged uptake duration in tumors, low non-target organ uptake, and significant tumor-inhibiting efficacy in PDAC model. • The self-developed antibody structure NY004 is a promising drug platform for radioimmunotheranostics of CEACAM6-positive tumors including pancreatic ductal adenocarcinoma.

Nuclear Medicine Preclinical Research: The Role of Cell Cultures

Cell lines are essential in biomedical research due to their adaptability and precise simulation of physiological and pathophysiological conditions. Cell culture techniques have greatly advanced our understanding of biology in various fields and are widely regarded as a reliable and durable tool. Their diverse applications make them indispensable in scientific research. Radiation-emitting compounds are commonly used in cell culture research to investigate biological processes. Radiolabeled compounds are utilized to study cell function, metabolism, molecular markers, receptor density, drug binding and kinetics, as well as to analyze the direct interaction of radiotracers with target organ cells. This allows for the examination of normal physiology and disease states. The In Vitro system simplifies the study and filters out nonspecific signals from the In Vivo environment, leading to more specific results. Moreover, cell cultures offer ethical advantages when evaluating new tracers and drugs in preclinical studies. While cell experiments cannot entirely replace animal experiments, they reduce the need for live animals in experimentation.

Estrogens and endocrine-disrupting chemicals differentially impact the bioenergetic fluxes of mammary epithelial cells in two- and three-dimensional models

Due to its sensitivity to hormonal signaling, the mammary gland is often referred to as a sentinel organ for the study of endocrine-disrupting chemicals (EDCs), environmental pollutants that can interfere with the estrogen signaling pathway and induce mammary developmental defects. If and how EDCs impact mammary epithelial cell metabolism has not yet been documented. Herein, to study how estrogens and EDCs modulate mammary gland metabolism, we performed bioenergetic flux analyses using mouse mammary epithelial organoids compared to cells grown in monolayer culture. Several EDCs were tested, including bisphenol A (BPA), its close derivative BPS, a new BPA replacement copolyester called TritanTM, and the herbicide glyphosate. We report that estrogens reprogrammed mammary epithelial cell metabolism differently when grown in two- and three-dimensional models. Specific EDCs were also demonstrated to alter bioenergetic fluxes, thus identifying a new potential adverse effect of these molecules. Notably, organoids were more sensitive to low EDC concentrations, highlighting them as a key model for screening the impact of various environmental pollutants. Mechanistically, transcriptomic analyses revealed that EDCs interfered with the regulation of estrogen target genes and the expression of metabolic genes in organoids. Furthermore, co-treatment with the anti-estrogen fulvestrant blocked these metabolic impacts of EDCs, suggesting that, at least partially, they act through modulation of the estrogen receptor activity. Finally, we demonstrate that mammary organoids can be used for long-term studies on EDC exposure to study alterations in organogenesis/morphogenesis and that past pregnancies can modulate the sensitivity of mammary epithelial organoids to specific EDCs. Overall, this study demonstrates that estrogens and EDCs modulate mammary epithelial cell metabolism in monolayer and organoid cultures. A better understanding of the metabolic impacts of EDCs will allow a better appreciation of their adverse effects on mammary gland development and function.

Gell: A GPU-powered 3D hybrid simulator for large-scale multicellular system

As a powerful but computationally intensive method, hybrid computational models study the dynamics of multicellular systems by evolving discrete cells in reacting and diffusing extracellular microenvironments. As the scale and complexity of studied biological systems continuously increase, the exploding computational cost starts to limit large-scale cell-based simulations. To facilitate the large-scale hybrid computational simulation and make it feasible on easily accessible computational devices, we develop Gell (GPU Cell), a fast and memory-efficient open-source GPU-based hybrid computational modeling platform for large-scale system modeling. We fully parallelize the simulations on GPU for high computational efficiency and propose a novel voxel sorting method to further accelerate the modeling of massive cell-cell mechanical interaction with negligible additional memory footprint. As a result, Gell efficiently handles simulations involving tens of millions of cells on a personal computer. We compare the performance of Gell with a state-of-the-art paralleled CPU-based simulator on a hanging droplet spheroid growth task and further demonstrate Gell with a ductal carcinoma in situ (DCIS) simulation. Gell affords ~150X acceleration over the paralleled CPU method with one-tenth of the memory requirement.

Chemoresistance in pancreatic ductal adenocarcinoma: Overcoming resistance to therapy

Pancreatic ductal adenocarcinoma (PDAC), a prominent cause of cancer deaths worldwide, is a highly aggressive cancer most frequently detected at an advanced stage that limits treatment options to systemic chemotherapy, which has provided only marginal positive clinical outcomes. More than 90% of patients with PDAC die within a year of being diagnosed. PDAC is increasing at a rate of 0.5-1.0% per year, and it is expected to be the second leading cause of cancer-related mortality by 2030. The resistance of tumor cells to chemotherapeutic drugs, which can be innate or acquired, is the primary factor contributing to the ineffectiveness of cancer treatments. Although many PDAC patients initially responds to standard of care (SOC) drugs they soon develop resistance caused partly by the substantial cellular heterogeneity seen in PDAC tissue and the tumor microenvironment (TME), which are considered key factors contributing to resistance to therapy. A deeper understanding of molecular mechanisms involved in PDAC progression and metastasis development, and the interplay of the TME in all these processes is essential to better comprehend the etiology and pathobiology of chemoresistance observed in PDAC. Recent research has recognized new therapeutic targets ushering in the development of innovative combinatorial therapies as well as enhancing our comprehension of several different cell death pathways. These approaches facilitate the lowering of the therapeutic threshold; however, the possibility of subsequent resistance development still remains a key issue and concern. Discoveries, that can target PDAC resistance, either alone or in combination, have the potential to serve as the foundation for future treatments that are effective without posing undue health risks. In this chapter, we discuss potential causes of PDAC chemoresistance and approaches for combating chemoresistance by targeting different pathways and different cellular functions associated with and mediating resistance.

Towards using 3D cellular cultures to model the activation and diverse functions of macrophages

The advent of 3D cell culture technology promises to enhance understanding of cell biology within tissue microenvironments. Whilst traditional cell culturing methods have been a reliable tool for decades, they inadequately portray the complex environments in which cells inhabit in vivo. The need for better disease models has pushed the development of effective 3D cell models, providing more accurate drug screening assays. There has been great progress in developing 3D tissue models in fields such as cancer research and regenerative medicine, driven by desires to recreate the tumour microenvironment for the discovery of new chemotherapies, or development of artificial tissues or scaffolds for transplantation. Immunology is one field that lacks optimised 3D models and the biology of tissue resident immune cells such as macrophages has yet to be fully explored. This review aims to highlight the benefits of 3D cell culturing for greater understanding of macrophage biology. We review current knowledge of macrophage interactions with their tissue microenvironment and highlight the potential of 3D macrophage models in the development of more effective treatments for disease.

Characterisation of collagen type I matrices for pathophysiologically relevant spatial cancer cell cultures

Specific cues provided to cells by the extracellular matrix (ECM) are determined by its composition. Except of collagens other naturally occurring ECM components should be considered in designing 3D models of diseases. We used spectrophotometric and rheological measurements and confocal imaging to characterise collagen matrices of human origin that can be modified by clinically relevant ECM components. pH of the neutralising solution, but not incubation of solidified collagen matrices in serum-free culture medium with pH 5.0-9.0 affected distribution of collagen fibres. Admixture of fibronectin or tenascin-C influenced assembly kinetics and resulted in slight increase in the Young's moduli of the matrices, indicating their incorporation into the collagen matrices. Co-localization of fibronectin with collagen fibres was confirmed by fluorescence imaging. Various cell types relevant for tumour tissue were able to proliferate within the matrices suggesting that they can be used to study role of ECM components in cancer in spatial models.

Therapeutic Response of Multifunctional Lipid and Micelle Formulation in Hepatocellular Carcinoma

Hepatic stellate cells (HSCs), as an important part of the tumor microenvironment (TME), could be activated by tumor cells as cancer-associated fibroblasts (CAFs), thereby promoting the production of extracellular matrix (ECM) and favoring the development of tumors. Therefore, blocking the "CAFs-ECM" axis is a promising pathway to improve antitumor efficacy. Based on this, we developed a multifunctional nanosized delivery system composed of hyaluronic acid-modified pH-sensitive liposomes (CTHLs) and glycyrrheic acid-modified nanomicelles (DGNs), which combines the advantages of targeted delivery, pH-sensitivity, and deep drug penetration. To mimic actual TME, a novel HSCs+BEL-7402 cocultured cell model and a m-HSCs+H22 coimplanted mice model were established. As expected, CTHLs and DGNs could target CAFs and tumor cells, respectively, and promote the drug penetration and retention in tumor regions. Notably, CTHLs+DGNs not only exhibited a superior antitumor effect in three-level tumor-bearing mice but also presented excellent antimetastasis efficiency in lung-metastatic mice. The antitumor mechanism revealed that the lipid&micelle mixed formulations effectively inhibited the activation of CAFs, reduced the deposition of ECM, and reversed the epithelial-mesenchymal transition (EMT) of tumor cells. In brief, the nanosized delivery system composed of CTHLs and DGNs could effectively improve the therapeutic effect of liver cancer by blocking the "CAFs-ECM" axis, which has a good clinical application prospect.

Surface-Fabrication of Fluorescent Hydroxyapatite for Cancer Cell Imaging and Bio-Printing Applications

Hydroxyapatite (HAP) materials are widely applied as biomedical materials due to their stable performance, low cost, good biocompatibility and biodegradability. Here, a green, fast and efficient strategy was designed to construct a fluorescent nanosystem for cell imaging and drug delivery based on polyethyleneimine (PEI) and functionalized HAP via simple physical adsorption. First, HAP nanorods were functionalized with riboflavin sodium phosphate (HE) to provide them with fluorescence properties based on ligand-exchange process. Next, PEI was attached on the surface of HE-functionalized HAP (HAP-HE@PEI) via electrostatic attraction. The fluorescent HAP-HE@PEI nanosystem could be rapidly taken up by NIH-3T3 fibroblast cells and successfully applied to for cell imaging. Additionally, doxorubicin hydrochloride (DOX) containing HAP-HE@PEI with high loading capacity was prepared, and in-vitro release results show that the maximum release of DOX at pH 5.4 (31.83%) was significantly higher than that at pH 7.2 (9.90%), which can be used as a drug delivery tool for cancer therapy. Finally, HAP-HE@PEI as the 3D inkjet printing ink were printed with GelMA hydrogel, showing a great biocompatible property for 3D cell culture of RAW 264.7 macrophage cells. Altogether, because of the enhanced affinity with the cell membrane of HAP-HE@PEI, this green, fast and efficient strategy may provide a prospective candidate for bio-imaging, drug delivery and bio-printing.

Concept development of an on-chip PET system

Background

Organs-on-Chips (OOCs), microdevices mimicking in vivo organs, find growing applications in disease modeling and drug discovery. With the increasing number of uses comes a strong demand for imaging capabilities of OOCs as monitoring physiologic processes within OOCs is vital for the continuous improvement of this technology. Positron Emission Tomography (PET) would be ideal for OOC imaging, however, current PET systems are insufficient for this task due to their inadequate spatial resolution. In this work, we propose the concept of an On-Chip PET system capable of imaging OOCs and optimize its design using a Monte Carlo Simulation (MCS).

Material and methods

The proposed system consists of four detectors arranged around the OOC device. Each detector is made of two monolithic LYSO crystals and covered with Silicon photomultipliers (SiPMs) on multiple surfaces. We use a Convolutional Neural Network (CNN) trained with data from a MCS to predict the first gamma-ray interaction position inside the detector from the light patterns that are recorded by the SiPMs on the detector’s surfaces.

Results

The CNN achieves a mean average prediction error of 0.80 mm in the best configuration. The proposed system achieves a sensitivity of 34.81% for 13 mm thick crystals and does not show a prediction degradation near the boundaries of the detector. We use the trained network to reconstruct an image of a grid of 21 point sources spread across the field-of-view and obtain a mean spatial resolution of 0.55 mm. We show that 25,000 Line of Responses (LORs) are needed to reconstruct a realistic OOC phantom with adequate image quality.

Conclusions

We demonstrate that it is possible to achieve a spatial resolution of almost 0.5 mm in a PET system made of multiple monolithic LYSO crystals by directly predicting the scintillation position from light patterns created with SiPMs. We observe that a thinner crystal performs better than a thicker one, that increasing the SiPM size from 3 mm to 6 mm only slightly decreases the prediction performance, and that certain surfaces encode significantly more information for the scintillation-point prediction than others.

CRISPR/Cas9 Mediated Knockout of Cyclooxygenase-2 Gene Inhibits Invasiveness in A2058 Melanoma Cells

The inducible isoenzyme cyclooxygenase-2 (COX-2) is an important hub in cellular signaling, which contributes to tumor progression by modulating and enhancing a pro-inflammatory tumor microenvironment, tumor growth, apoptosis resistance, angiogenesis and metastasis. In order to understand the role of COX-2 expression in melanoma, we investigated the functional knockout effect of COX-2 in A2058 human melanoma cells. COX-2 knockout was validated by Western blot and flow cytometry analysis. When comparing COX-2 knockout cells to controls, we observed significantly reduced invasion, colony and spheroid formation potential in cell monolayers and three-dimensional models in vitro, and significantly reduced tumor development in xenograft mouse models in vivo. Moreover, COX-2 knockout alters the metabolic activity of cells under normoxia and experimental hypoxia as demonstrated by using the radiotracers [¹⁸F]FDG and [¹⁸F]FMISO. Finally, a pilot protein array analysis in COX-2 knockout cells verified significantly altered downstream signaling pathways that can be linked to cellular and molecular mechanisms of cancer metastasis closely related to the enzyme. Given the complexity of the signaling pathways and the multifaceted role of COX-2, targeted suppression of COX-2 in melanoma cells, in combination with modulation of related signaling pathways, appears to be a promising therapeutic approach.

Butyrate and Metformin Affect Energy Metabolism Independently of the Metabolic Phenotype in the Tumor Therapy Model

The BALB/c cell transformation assay (BALB-CTA) considers inter- and intra-tumor heterogeneities and affords the possibility of a direct comparison between untransformed and malignant cells. In the present study, we established monoclonal cell lines that originate from the BALB-CTA and mimic heterogeneous tumor cell populations, in order to investigate phenotype-specific effects of the anti-diabetic drug metformin and the short-chain fatty acid butyrate. Growth inhibitory effects were measured with a ViCell XR cell counter. The BALB/c tumor therapy model (BALB-TTM) was performed, and the extracellular glucose level was measured in the medium supernatant. Using a Seahorse Analyzer, the metabolic phenotypes of four selected clones were characterized, and effects on energy metabolism were investigated. Anti-carcinogenic effects and reduced glucose uptake after butyrate application were observed in the BALB-TTM. Metabolic characterization of the cell clones revealed three different phenotypes. Surprisingly, treatment with metformin or butyrate induced opposite metabolic shifts with similar patterns in all cell clones tested. In conclusion, the BALB-TTM is a relevant model for mechanistic cancer research, and the generation of monoclonal cell lines offers a novel possibility to investigate specific drug effects in a heterogeneous tumor cell population. The results indicate that induced alterations in energy metabolism seem to be independent of the original metabolic phenotype.

Three-Dimensional Culture Systems for Dissecting Notch Signalling in Health and Disease

Three-dimensional (3D) culture systems opened up new horizons in studying the biology of tissues and organs, modelling various diseases, and screening drugs. Producing accurate in vitro models increases the possibilities for studying molecular control of cell–cell and cell–microenvironment interactions in detail. The Notch signalling is linked to cell fate determination, tissue definition, and maintenance in both physiological and pathological conditions. Hence, 3D cultures provide new accessible platforms for studying activation and modulation of the Notch pathway. In this review, we provide an overview of the recent advances in different 3D culture systems, including spheroids, organoids, and “organ-on-a-chip” models, and their use in analysing the crucial role of Notch signalling in the maintenance of tissue homeostasis, pathology, and regeneration.

Three-dimensional bioprinted cancer models: A powerful platform for investigating tunneling nanotube-like cell structures in complex microenvironments

Bioprinting technology offers layer-by-layer positioning of cells within 3D space with complexity and a defined architecture. Cancer models based in this biofabrication technique are important tools to achieve representative and realistic in vivo conditions of the tumor microenvironment. Here, we show the development of a proof-of-concept three-dimensional bioprinted cancer model that successfully recapitulates the intercellular communication via the assembly of functional tunneling nanotube (TNT)-like cell projections. Different combinations of collagen-containing culture medium, sodium alginate and gelatin were initially prepared and rheologically evaluated. The optimized mixture was used to print two preliminary 3D models for cancer cell seeding. Favourable results in cell viability and proliferation led to the inclusion of 786-O renal cancer cells into the biomaterial mixture to directly bioprint the most suitable 3D model with embedded cells. Bioprinted cells remained viable for at least 15 days of culture and proliferated. More importantly, these cancer cells were able to build TNT-like cellular projections inside the hydrogel that established direct contacts between distant cells. We show that these structures were used as channels for the scrolling and intercellular transfer of mitochondria thus reproducing TNT's function in 2D culture systems. This 3D bioprinted renal cancer model provides a novel alternative tool for studying the functional relevance of TNT-like structures in tumorigenesis and anticancer drug susceptibility in a highly controlled and reproducible tumor microenvironment.

Models for Translational Proton Radiobiology-From Bench to Bedside and Back

The number of proton therapy centers worldwide are increasing steadily, with more than two million cancer patients treated so far. Despite this development, pending questions on proton radiobiology still call for basic and translational preclinical research. Open issues are the on-going discussion on an energy-dependent varying proton RBE (relative biological effectiveness), a better characterization of normal tissue side effects and combination treatments with drugs originally developed for photon therapy. At the same time, novel possibilities arise, such as radioimmunotherapy, and new proton therapy schemata, such as FLASH irradiation and proton mini-beams. The study of those aspects demands for radiobiological models at different stages along the translational chain, allowing the investigation of mechanisms from the molecular level to whole organisms. Focusing on the challenges and specifics of proton research, this review summarizes the different available models, ranging from in vitro systems to animal studies of increasing complexity as well as complementing in silico approaches.

Transcending toward Advanced 3D-Cell Culture Modalities: A Review about an Emerging Paradigm in Translational Oncology

Cancer is a disorder characterized by an uncontrollable overgrowth and a fast-moving spread of cells from a localized tissue to multiple organs of the body, reaching a metastatic state. Throughout years, complexity of cancer progression and invasion, high prevalence and incidence, as well as the high rise in treatment failure cases leading to a poor patient prognosis accounted for continuous experimental investigations on animals and cellular models, mainly with 2D- and 3D-cell culture. Nowadays, these research models are considered a main asset to reflect the physiological events in many cancer types in terms of cellular characteristics and features, replication and metastatic mechanisms, metabolic pathways, biomarkers expression, and chemotherapeutic agent resistance. In practice, based on research perspective and hypothesis, scientists aim to choose the best model to approach their understanding and to prove their hypothesis. Recently, 3D-cell models are seen to be highly incorporated as a crucial tool for reflecting the true cancer cell microenvironment in pharmacokinetic and pharmacodynamics studies, in addition to the intensity of anticancer drug response in pharmacogenomics trials. Hence, in this review, we shed light on the unique characteristics of 3D cells favoring its promising usage through a comparative approach with other research models, specifically 2D-cell culture. Plus, we will discuss the importance of 3D models as a direct reflector of the intrinsic cancer cell environment with the newest multiple methods and types available for 3D-cells implementation.

Molecular alterations in pancreatic tumors

Genetic alterations in pancreatic tumors can usually be classified in: (1) Mutational activation of oncogenes; (2) Inactivation of tumor suppressor genes; and (3) Inactivation of genome maintenance genes controlling the repair of DNA damage. Endoscopic ultrasound-guided fine-needle aspiration has improved pre-operative diagnosis, but the management of patients with a pancreatic lesion is still challenging. Molecular testing could help mainly in solving these “inconclusive” specimens. The introduction of multi-gene analysis approaches, such as next-generation sequencing, has provided a lot of useful information on the molecular characterization of pancreatic tumors. Different types of pancreatic tumors (e.g., pancreatic ductal adenocarcinomas, intraductal papillary mucinous neoplasms, solid pseudopapillary tumors) are characterized by specific molecular alterations. The aim of this review is to summarize the main molecular alterations found in pancreatic tumors.

Patient-Derived Organoids as a Model for Cancer Drug Discovery

In the search for the ideal model of tumours, the use of three-dimensional in vitro models is advancing rapidly. These are intended to mimic the in vivo properties of the tumours which affect cancer development, progression and drug sensitivity, and take into account cell–cell interactions, adhesion and invasiveness. Importantly, it is hoped that successful recapitulation of the structure and function of the tissue will predict patient response, permitting the development of personalized therapy in a timely manner applicable to the clinic. Furthermore, the use of co-culture systems will allow the role of the tumour microenvironment and tissue–tissue interactions to be taken into account and should lead to more accurate predictions of tumour development and responses to drugs. In this review, the relative merits and limitations of patient-derived organoids will be discussed compared to other in vitro and ex vivo cancer models. We will focus on their use as models for drug testing and personalized therapy and how these may be improved. Developments in technology will also be considered, including the use of microfluidics, 3D bioprinting, cryopreservation and circulating tumour cell-derived organoids. These have the potential to enhance the consistency, accessibility and availability of these models.

Rapid Evaluation of Novel Therapeutic Strategies Using a 3D Collagen-Based Tissue-Like Model

2D cell cultures are commonly used to rapidly evaluate the therapeutic potential of various treatments on living cells. However, the effects of the extracellular matrix (ECM) including the 3D arrangement of cells and the complex physiology of native environment are missing, which makes these models far from in vivo conditions. 3D cell models have emerged in preclinical studies to simulate the impact of the ECM and partially bridge the gap between monolayer cultures and in vivo tissues. To date, the difficulty to handle the existing 3D models, the cost of their production and their poor reproducibility have hindered their use. Here, we present a reproducible and commercially available "3D cell collagen-based model" (3D-CCM) that allows to study the influence of the matrix on nanoagent uptake and radiation effects. The cell density in these samples is homogeneous. The oxygen concentration in the 3D-CCM is tunable, which opens the opportunity to investigate hypoxic effects. In addition, thanks to the intrinsic properties of the collagen, the second harmonic imaging microscopy may be used to probe the whole volume and visualize living cells in real-time. Thus, the architecture and composition of 3D-CCMs as well as the impact of various therapeutic strategies on cells embedded in the ECM is observed directly. Moreover, the disaggregation of the collagen matrix allows recovering of cells without damaging them. It is a major advantage that makes possible single cell analysis and quantification of treatment effects using clonogenic assay. In this work, 3D-CCMs were used to evaluate the correlative efficacies of nanodrug exposure and medical radiation on cells contained in a tumor like sample. A comparison with monolayer cell cultures was performed showing the advantageous outcome and the higher potential of 3D-CCMs. This cheap and easy to handle approach is more ethical than in vivo experiments, thus, giving a fast evaluation of cellular responses to various treatments.

Understanding cell-cell communication and signaling in the colorectal cancer microenvironment

Carcinomas are complex heterocellular systems containing epithelial cancer cells, stromal fibroblasts, and multiple immune cell-types. Cell-cell communication between these tumor microenvironments (TME) and cells drives cancer progression and influences response to existing therapies. In order to provide better treatments for patients, we must understand how various cell-types collaborate within the TME to drive cancer and consider the multiple signals present between and within different cancer types. To investigate how tissues function, we need a model to measure both how signals are transferred between cells and how that information is processed within cells. The interplay of collaboration between different cell-types requires cell-cell communication. This article aims to review the current in vitro and in vivo mono-cellular and multi-cellular cultures models of colorectal cancer (CRC), and to explore how they can be used for single-cell multi-omics approaches for isolating multiple types of molecules from a single-cell required for cell-cell communication to distinguish cancer cells from normal cells. Integrating the existing single-cell signaling measurements and models, and through understanding the cell identity and how different cell types communicate, will help predict drug sensitivities in tumor cells and between- and within-patients responses.

HIF2alpha-Associated Pseudohypoxia Promotes Radioresistance in Pheochromocytoma: Insights from 3D Models

Pheochromocytomas and paragangliomas (PCCs/PGLs) are rare neuroendocrine tumors arising from chromaffin tissue located in the adrenal or ganglia of the sympathetic or parasympathetic nervous system. The treatment of non-resectable or metastatic PCCs/PGLs is still limited to palliative measures, including somatostatin type 2 receptor radionuclide therapy with [¹⁷⁷Lu]Lu-DOTA-TATE as one of the most effective approaches to date. Nevertheless, the metabolic and molecular determinants of radiation response in PCCs/PGLs have not yet been characterized. This study investigates the effects of hypoxia-inducible factor 2 alpha (HIF2α) on the susceptibility of PCCs/PGLs to radiation treatments using spheroids grown from genetically engineered mouse pheochromocytoma (MPC) cells. The expression of Hif2α was associated with the significantly increased resistance of MPC spheroids to external X-ray irradiation and exposure to beta particle-emitting [¹⁷⁷Lu]LuCl₃ compared to Hif2α-deficient controls. Exposure to [¹⁷⁷Lu]LuCl₃ provided an increased long-term control of MPC spheroids compared to single-dose external X-ray irradiation. This study provides the first experimental evidence that HIF2α-associated pseudohypoxia contributes to a radioresistant phenotype of PCCs/PGLs. Furthermore, the external irradiation and [¹⁷⁷Lu]LuCl₃ exposure of MPC spheroids provide surrogate models for radiation treatments to further investigate the metabolic and molecular determinants of radiation responses in PCCs/PGLs and evaluate the effects of neo-adjuvant-in particular, radiosensitizing-treatments in combination with targeted radionuclide therapies.