The use of 3-D cultures for high-throughput screening: the multicellular spheroid model

Anticancer activity of new water-soluble sulfonated thiosemicarbazone copper(II) complexes targeting disulfide isomerase

Copper complexes have shown promising anticancer properties, but they are often poorly soluble in aqueous solutions, thus limiting their possible medical developments and applications. We have recently isolated some copper(II) complexes with salicylaldehyde thiosemicarbazone ligands exhibiting remarkable nanomolar cytotoxic activity, but in vivo tests evidenced several difficulties related to their poor solubility. To overcome these limitations and increase solubility in aqueous solution, herein we report the synthetic strategy that led to the introduction of the sulfonic group on the ligands, then separated as salts (NaH2L1 - NaH2L5), as well as the synthesis and characterization of the related copper(II) complexes. The characterization of the complexes is completed by the analysis of the structures obtained by X-rays diffraction on single crystals on the species [Cu(HL5)(H2O)]2.2H2O, [Cu(HL2)(H2O)2].2H2O, and [Cu(HL1)(H2O]2.2H2O. While the uncoordinated ligands do not affect cancer cell viability, copper(II) complexes exhibit low to sub-micromolar cytotoxic activity, which is maintained in 3D (HCT-15 and 2008) spheroidal models of cancer cell. Notably, copper(II) complexes were selective towards cancer cells, showing high selectivity indexes. Investigations focused on elucidating the mechanism of action evidenced the protein disulfide-isomerase as an innovative molecular target for this class of water-soluble copper(II) complexes. Finally, preliminary in vivo experiments performed with the most representative derivative in the murine Lewis Lung Carcinoma, highlight its significant antitumor efficacy and better tolerability profile with respect to the reference metallodrug, suggesting for this sulfonated Cu(II) complex a potential clinical relevance.

Development of a Bladder Cancer-on-a-Chip Model to Assess Bladder Cancer Cell Invasiveness

We have developed a bladder cancer-on-a-chip model which supports the 3D growth of cells and can be used to assess and quantify bladder cancer cell invasiveness in a physiologically appropriate environment. Three bladder cancer cell lines (T24, J82, and RT4) were resuspended in 50% Matrigel® and grown within a multi-channel organ-on-a-chip system. The ability of live cells to invade across into an adjacent 50% Matrigel®-only channel was assessed over a 2-day period. Cell lines isolated from patients with high-grade bladder cancer (T24 and J82) invaded across into the Matrigel®-only channel at a much higher frequency compared to cells isolated from a patient with low-grade cancer (RT4) (p < 0.001). The T24 and J82 cells also invaded further distances into the Matrigel®-only channel compared to the RT4 cells (p < 0.001). The cell phenotype within the model was maintained as assessed by cell morphology and immunohistochemical analysis of E-cadherin. Treatment with ATN-161, an α5β1 integrin inhibitor and well-known migrastatic drug, caused a dose-dependent decrease in the invasiveness of the J82 cells (p < 0.01). The combined data demonstrate that our bladder cancer-on-a-chip model supports the retention of the bladder cancer cell phenotype and can be used to reproducibly assess and quantify the invasiveness of live bladder cancer cells.

Designer cellular spheroids with DNA origami for drug screening

Current in vitro models struggle to balance the complexity of human diseases with suitability for large-scale drug tests. While 3D cultures simulate human tissues, they lack cellular intricacy, and integrating these models with high-throughput drug screening remains a challenge. Here, we introduce a method that uses self-assembling nucleic acid nanostructures decorated living cells, termed NACs, to create spheroids with a customizable 3D layout. To demonstrate its uniqueness, our method effectively creates designer 3D spheroids by combining parenchymal cells, stromal cells, and immune cells, leading to heightened physiological relevance and detailed modeling of complex chronic diseases and immune-stromal interactions. Our approach achieves a high level of biological fidelity while being standardized and straightforward to construct with the potential for large-scale drug discovery applications. By merging the precision of DNA nanotechnology with advanced cell culture techniques, we are streamlining human-centric models, striking a balance between complexity and standardization, to boost drug screening efficiency.

Spheroid Model of Mammary Tumor Cells: Epithelial-Mesenchymal Transition and Doxorubicin Response

Breast cancer is the most prevalent cancer among women worldwide. Therapeutic strategies to control tumors and metastasis are still challenging. Three-dimensional (3D) spheroid-type systems more accurately replicate the features of tumors in vivo, working as a better platform for performing therapeutic response analysis. This work aimed to characterize the epithelial-mesenchymal transition and doxorubicin (dox) response in a mammary tumor spheroid (MTS) model. We evaluated the doxorubicin treatment effect on MCF-7 spheroid diameter, cell viability, death, migration and proteins involved in the epithelial-mesenchymal transition (EMT) process. Spheroids were also produced from tumors formed from 4T1 and 67NR cell lines. MTSs mimicked avascular tumor characteristics, exhibited adherens junction proteins and independently produced their own extracellular matrix. Our spheroid model supports the 3D culturing of cells isolated from mice mammary tumors. Through the migration assay, we verified a reduction in E-cadherin expression and an increase in vimentin expression as the cells became more distant from spheroids. Dox promoted cytotoxicity in MTSs and inhibited cell migration and the EMT process. These results suggest, for the first time, that this model reproduces aspects of the EMT process and describes the potential of dox in inhibiting the metastatic process, which can be further explored.

Label-free fluorescence lifetime imaging for the assessment of cell viability in living tumor fragments

Significance

To enable non-destructive longitudinal assessment of drug agents in intact tumor tissue without the use of disruptive probes, we have designed a label-free method to quantify the health of individual tumor cells in excised tumor tissue using multiphoton fluorescence lifetime imaging microscopy (MP-FLIM).

Aim

Using murine tumor fragments which preserve the native tumor microenvironment, we seek to demonstrate signals generated by the intrinsically fluorescent metabolic co-factors nicotinamide adenine dinucleotide phosphate [NAD(P)H] and flavin adenine dinucleotide (FAD) correlate with irreversible cascades leading to cell death.

Approach

We use MP-FLIM of NAD(P)H and FAD on tissues and confirm viability using standard apoptosis and live/dead (Caspase 3/7 and propidium iodide, respectively) assays.

Results

Through a statistical approach, reproducible shifts in FLIM data, determined through phasor analysis, are shown to correlate with loss of cell viability. With this, we demonstrate that cell death achieved through either apoptosis/necrosis or necroptosis can be discriminated. In addition, specific responses to common chemotherapeutic treatment inducing cell death were detected.

Conclusions

These data demonstrate that MP-FLIM can detect and quantify cell viability without the use of potentially toxic dyes, thus enabling longitudinal multi-day studies assessing the effects of therapeutic agents on tumor fragments.

Quantifying Imaging Agent Binding and Dissociation in 3-D Cancer Spheroid Tissue Culture Using Paired-Agent Principles

Binding kinetics play an important role in cancer diagnosis and therapeutics. However, current methods of quantifying binding kinetics fail to consider the three-dimensional environment that drugs and imaging agents experience in biological tissue. In response, a methodology to assay agent binding and dissociation in 3-D tissue culture was developed using paired-agent molecular imaging principles. To test the methodology, the uptakes of ABY-029 (an IRDye 800CW-labeled epidermal growth factor receptor (EGFR)-targeted antibody mimetic) and IRDye-700DX carboxylate in 3-D spheroids were measured in four different human cancer cell lines throughout staining and rinsing. A compartment model (optimized for the application) was then fit to the kinetic curves of both imaging agents to estimate binding and dissociation rate constants of the EGFR-targeted ABY-029 agent. A statistically significant correlation was observed between apparent association rate constant (k3) and the receptor concentration experimentally and in simulations (r = 0.99, p < 0.05). A statistically significant difference was found between effective k3 (apparent rate constant of ABY-029 binding to EGFR) values for cell lines with varying levels of EGFR expression (p < 0.05), with no significant difference found between cell lines and controls for other fit parameters. Additionally, a similar binding affinity profile compared to a gold standard method was determined by this model. This low-cost methodology to quantify imaging agent or drug binding affinity in clinically relevant 3-D tumor spheroid models can be used to guide timing of imaging in molecular guided surgery and could have implications in drug development.

Sustainable Nanoparticles from Stephania glabra and Analysis of Their Anticancer Potential on 2D and 3D Models of Prostate Cancer

In pursuit of a novel effective treatment for prostate cancer, methanolic extract of Stephania glabra tubers (Sg-ME) was utilized to fabricate silver (Sg-AgNP), copper oxide (Sg-CuONP), and silver-copper bimetallic nanoparticles (Sg-BNP). The characterization of the nanoparticles confirmed spherical shape with average diameters of 30.72, 32.19, and 25.59 nm of Sg-AgNP, Sg-CuONP, and Sg-BNP, respectively. Interestingly, these nanoparticles exhibited significant cytotoxicity toward the prostate cancer (PC3) cell line while being non-toxic toward normal cells. The nanoparticles were capable of inducing apoptosis in PC3 cells by enhancing reactive oxygen species (ROS) generation and mitochondrial depolarization. Furthermore, the shrinkage of 3D prostate tumor spheroids was observed after 4 days of treatment with these green nanoparticles. The 3D model system was less susceptible to nanoparticles as compared to the 2D model system. Sg-BNP showed the highest anticancer potential on 2D and 3D prostate cancer models.

Advantages of Using 3D Spheroid Culture Systems in Toxicological and Pharmacological Assessment for Osteogenesis Research

Bone differentiation is crucial for skeletal development and maintenance. Its dysfunction can cause various pathological conditions such as rickets, osteoporosis, osteogenesis imperfecta, or Paget's disease. Although traditional two-dimensional cell culture systems have contributed significantly to our understanding of bone biology, they fail to replicate the intricate biotic environment of bone tissue. Three-dimensional (3D) spheroid cell cultures have gained widespread popularity for addressing bone defects. This review highlights the advantages of employing 3D culture systems to investigate bone differentiation. It highlights their capacity to mimic the complex in vivo environment and crucial cellular interactions pivotal to bone homeostasis. The exploration of 3D culture models in bone research offers enhanced physiological relevance, improved predictive capabilities, and reduced reliance on animal models, which have contributed to the advancement of safer and more effective strategies for drug development. Studies have highlighted the transformative potential of 3D culture systems for expanding our understanding of bone biology and developing targeted therapeutic interventions for bone-related disorders. This review explores how 3D culture systems have demonstrated promise in unraveling the intricate mechanisms governing bone homeostasis and responses to pharmacological agents.

Triiron Complex with N-Ferrocenyl Aminocarbyne Ligand Bridging a Diiron Core: DFT, Electrochemical, and Biological Insights

The first N-ferrocenyl aminocarbyne complex, [Fe2Cp2(CO)2(μ-CO){μ-CN(Me)(Fc)}]CF3SO3 ([2]CF3SO3), was synthesized with an 88% yield from [Fe2Cp2(CO)4], isocyanoferrocene (CNFc), and methyl triflate. The synthesis proceeded through the intermediate formation of [Fe2Cp2(CO)3(CNFc)], 1. Multinuclear NMR experiments revealed the presence of cis and trans isomers for [2]CF3SO3 in organic solvents, in agreement with DFT outcomes. Electrochemical and spectroelectrochemical studies demonstrated one reduction process occurring prevalently at the diiron core and one oxidation involving the ferrocenyl substituent. The oxidation process is expected to favor the redox activation of [2]+ in a biological environment. Both [2]CF3SO3 and its phenyl analogue [Fe2Cp2(CO)2(μ-CO){μ-CN(Me)(Ph)}]CF3SO3 ([3]CF3SO3), prepared for comparison, exerted moderate antiproliferative activity against the human cancer cell lines A431, HCT-15, PSN-1, 2008, and U1285. However, [2]CF3SO3 exhibited a higher cytotoxicity than [3]CF3SO3, showed a substantial ability to induce intracellular ROS production, and outperformed cisplatin in a three-dimensional SCLC cell model.

Modelling the disease: H2S-sensitivity and drug-resistance of triple negative breast cancer cells can be modulated by embedding in isotropic micro-environment

Three-dimensional (3D) cell culture systems provide more physiologically relevant information, representing more accurately the actual microenvironment where cells reside in tissues. However, the differences between the tissue culture plate (TCP) and 3D culture systems in terms of tumour cell growth, proliferation, migration, differentiation and response to the treatment have not been fully elucidated. Tumoroid microspheres containing the MDA-MB 231 breast cancer cell line were prepared using either tunable PEG-fibrinogen (PFs) or tunable PEG-silk fibroin (PSFs) hydrogels, respectively named MDAPFs and MDAPSFs. The cancer cells in the tumoroids showed changes both in globular morphology and at the protein expression level. A decrease of both Histone H3 acetylation and cyclin D1 expression in all 3D systems, compared to the 2D cell culture, was detected in parallel to changes of the matrix stiffness. The effects of a glutathionylated garlic extract (GSGa), a slow H2S-releasing donor, were investigated on both tumoroid systems. A pro-apoptotic effect of GSGa on tumour cell growth in 2D culture was observed as opposed to a pro-proliferative effect apparent in both MDAPFs and MDAPSFs. A dedicated ad hoc 3D cell migration chip was designed and optimized for studying tumour cell invasion in a gel-in-gel configuration. An anti-cell-invasion effect of the GSGa was observed in the 2D cell culture, whereas a pro-migratory effect in both MDAPFs and MDAPSFs was observed in the 3D cell migration chip assay. An increase of cyclin D1 expression after GSGa treatment was observed in agreement with an increase of the cell invasion index. Our results suggest that the "dimensionality" and the stiffness of the 3D cell culture milieu can change the response to both the gasotransmitter H2S and doxorubicin due to differences in both H2S diffusion and changes in protein expression. Moreover, we uncovered a direct relation between the cyclin D1 expression and the stiffness of the 3D cell culture milieu, suggesting the potential causal involvement of the cyclin D1 as a bio-marker for sensitivity of the tumour cells to their matrix stiffness. Therefore, our hydrogel-based tumoroids represent a valid tunable model for studying the physically induced transdifferentiation (PiT) of cancer cells and as a more reliable and predictive in vitro screening platform to investigate the effects of anti-tumour drugs.

Effect of HepG2 cell 3D cultivation on the metabolism of the anabolic androgenic steroid metandienone

The elucidation of the metabolic fate of prohibited substances is crucial for the abuse detection. The human hepatocyte cell line HepG2 can be used to study biotransformation. In order to improve this in vitro model system, we compared the HepG2 spheroid generation using three different techniques: a forced floating, a scaffold-free and a scaffold-based method. We characterized the spheroids with regard to the expression levels of the proliferation marker Mki67, the liver-specific marker albumin and biotransformation enzymes. Moreover, the metandienone metabolite pattern was comparatively analysed by high-performance liquid chromatography mass spectrometry. With all three techniques, HepG2 spheroids were generated showing a degree of differentiation. The forced floating method resulted in very large spheroids (1 mm in diameter) showing signs of necrosis in the centre and a very low metandienone conversion rate. The spheroids formed by the two other techniques were comparable in size with 0.5 mm in diameter on average. Among the three different 3D cultivation methods, the HepG2 spheroids formed on Matrigel® as extracellular matrix were the most promising regarding biotransformation studies on anabolic androgenic steroids. Prospectively, HepG2 spheroids are a promising in vitro model system to study multidrug setups, drug-drug interactions and the biotransformation of other substance classes.

Patient-derived lymphoma spheroids integrating immune tumor microenvironment as preclinical follicular lymphoma models for personalized medicine

BACKGROUND

Follicular lymphoma (FL), the most common indolent non-Hodgkin's Lymphoma, is a heterogeneous disease and a paradigm of the contribution of immune tumor microenvironment to disease onset, progression, and therapy resistance. Patient-derived models are scarce and fail to reproduce immune phenotypes and therapeutic responses.

METHODS

To capture disease heterogeneity and microenvironment cues, we developed a patient-derived lymphoma spheroid (FL-PDLS) model culturing FL cells from lymph nodes (LN) with an optimized cytokine cocktail that mimics LN stimuli and maintains tumor cell viability.

RESULTS

FL-PDLS, mainly composed of tumor B cells (60% on average) and autologous T cells (13% CD4 and 3% CD8 on average, respectively), rapidly organizes into patient-specific three-dimensional (3D) structures of three different morphotypes according to 3D imaging analysis. RNAseq analysis indicates that FL-PDLS reproduces FL hallmarks with the overexpression of cell cycle, BCR, or mTOR signaling related gene sets. FL-PDLS also recapitulates the exhausted immune phenotype typical of FL-LN, including expression of BTLA, TIGIT, PD-1, TIM-3, CD39 and CD73 on CD3+ T cells. These features render FL-PDLS an amenable system for immunotherapy testing. With this aim, we demonstrate that the combination of obinutuzumab (anti-CD20) and nivolumab (anti-PD1) reduces tumor load in a significant proportion of FL-PDLS. Interestingly, B cell depletion inversely correlates with the percentage of CD8+ cells positive for PD-1 and TIM-3.

CONCLUSIONS

In summary, FL-PDLS is a robust patient-derived 3D system that can be used as a tool to mimic FL pathology and to test novel immunotherapeutic approaches in a context of personalized medicine.

Macrophage Profiling in Head and Neck Cancer to Improve Patient Prognosis and Assessment of Cancer Cell-Macrophage Interactions Using Three-Dimensional Coculture Models

Tumor-associated macrophages are key components of the tumor microenvironment and play important roles in the progression of head and neck cancer, leading to the development of effective strategies targeting immune cells in tumors. Our study demonstrated the prognostic potential of a new scoring system (Macroscore) based on the combination of the ratio and the sum of the high and low densities of M1 (CD80+) and M2 (CD163+) macrophages in a series of head and neck cancer patients, including a training population (n = 54) and a validation population (n = 19). Interestingly, the Macroscore outperformed TNM criteria and p16 status, showing a significant association with poor patient prognosis, and demonstrated significant predictive value for overall survival. Additionally, 3D coculture spheroids were established to analyze the crosstalk between cancer cells and monocytes/macrophages. Our data revealed that cancer cells can induce monocyte differentiation into protumoral M2 macrophages, creating an immunosuppressive microenvironment. This coculture also induced the production of immunosuppressive cytokines, such as IL10 and IL8, known to promote M2 polarization. Finally, we validated the ability of the macrophage subpopulations to induce apoptosis (M1) or support proliferation (M2) of cancer cells. Overall, our research highlights the potential of the Macroscore as a valuable prognostic biomarker to enhance the clinical management of patients and underscores the relevance of a spheroid model in gaining a better understanding of the mechanisms underlying cancer cell-macrophage interactions.

3D Porous Scaffold-Based High-Throughput Platform for Cancer Drug Screening

Natural polymer-based porous scaffolds have been investigated to serve as three-dimensional (3D) tumor models for drug screening owing to their structural properties with better resemblance to human tumor microenvironments than two-dimensional (2D) cell cultures. In this study, a 3D chitosan-hyaluronic acid (CHA) composite porous scaffold with tunable pore size (60, 120 and 180 µm) was produced by freeze-drying and fabricated into a 96-array platform for high-throughput screening (HTS) of cancer therapeutics. We adopted a self-designed rapid dispensing system to handle the highly viscous CHA polymer mixture and achieved a fast and cost-effective large-batch production of the 3D HTS platform. In addition, the adjustable pore size of the scaffold can accommodate cancer cells from different sources to better mimic the in vivo malignancy. Three human glioblastoma multiforme (GBM) cell lines were tested on the scaffolds to reveal the influence of pore size on cell growth kinetics, tumor spheroid morphology, gene expression and dose-dependent drug response. Our results showed that the three GBM cell lines showed different trends of drug resistance on CHA scaffolds of varying pore size, which reflects the intertumoral heterogeneity across patients in clinical practice. Our results also demonstrated the necessity to have a tunable 3D porous scaffold for adapting the heterogeneous tumor to generate the optimal HTS outcomes. It was also found that CHA scaffolds can produce a uniform cellular response (CV < 0.15) and a wide drug screening window (Z' > 0.5) on par with commercialized tissue culture plates, and therefore, can serve as a qualified HTS platform. This CHA scaffold-based HTS platform may provide an improved alternative to traditional 2D-cell-based HTS for future cancer study and novel drug discovery.

Applications and Advances of Multicellular Tumor Spheroids: Challenges in Their Development and Analysis

Biomedical research requires both in vitro and in vivo studies in order to explore disease processes or drug interactions. Foundational investigations have been performed at the cellular level using two-dimensional cultures as the gold-standard method since the early 20th century. However, three-dimensional (3D) cultures have emerged as a new tool for tissue modeling over the last few years, bridging the gap between in vitro and animal model studies. Cancer has been a worldwide challenge for the biomedical community due to its high morbidity and mortality rates. Various methods have been developed to produce multicellular tumor spheroids (MCTSs), including scaffold-free and scaffold-based structures, which usually depend on the demands of the cells used and the related biological question. MCTSs are increasingly utilized in studies involving cancer cell metabolism and cell cycle defects. These studies produce massive amounts of data, which demand elaborate and complex tools for thorough analysis. In this review, we discuss the advantages and disadvantages of several up-to-date methods used to construct MCTSs. In addition, we also present advanced methods for analyzing MCTS features. As MCTSs more closely mimic the in vivo tumor environment, compared to 2D monolayers, they can evolve to be an appealing model for in vitro tumor biology studies.

Mitoxantrone and Mitoxantrone-Loaded Iron Oxide Nanoparticles Induce Cell Death in Human Pancreatic Ductal Adenocarcinoma Cell Spheroids

Pancreatic ductal adenocarcinoma is a hard-to-treat, deadly malignancy. Traditional treatments, such as surgery, radiation and chemotherapy, unfortunately are still not able to significantly improve long-term survival. Three-dimensional (3D) cell cultures might be a platform to study new drug types in a highly reproducible, resource-saving model within a relevant pathophysiological cellular microenvironment. We used a 3D culture of human pancreatic ductal adenocarcinoma cell lines to investigate a potential new treatment approach using superparamagnetic iron oxide nanoparticles (SPIONs) as a drug delivery system for mitoxantrone (MTO), a chemotherapeutic agent. We established a PaCa DD183 cell line and generated PANC-1^{SMAD4 (-/-)} cells by using the CRISPR-Cas9 system, differing in a prognostically relevant mutation in the TGF-β pathway. Afterwards, we formed spheroids using PaCa DD183, PANC-1 and PANC-1^{SMAD4 (-/-)} cells, and analyzed the uptake and cytotoxic effect of free MTO and MTO-loaded SPIONs by microscopy and flow cytometry. MTO and SPION-MTO-induced cell death in all tumor spheroids in a dose-dependent manner. Interestingly, spheroids with a SMAD4 mutation showed an increased uptake of MTO and SPION-MTO, while at the same time being more resistant to the cytotoxic effects of the chemotherapeutic agents. MTO-loaded SPIONs, with their ability for magnetic drug targeting, could be a future approach for treating pancreatic ductal adenocarcinomas.

Blockade of ß-Adrenergic Receptors by Nebivolol Enables Tumor Control Potential for Uveal Melanoma in 3D Tumor Spheroids and 2D Cultures

Uveal melanoma (UM) is the most common primary cancer of the eye in adults. A new systemic therapy is needed to reduce the high metastasis and mortality rate. As β-blockers are known to have anti-tumor effects on various cancer entities, this study focuses on investigating the effect of β1-selective blockers atenolol, celiprolol, bisoprolol, metoprolol, esmolol, betaxolol, and in particular, nebivolol on UM. The study was performed on 3D tumor spheroids as well as 2D cell cultures, testing tumor viability, morphological changes, long-term survival, and apoptosis. Flow cytometry revealed the presence of all three β-adrenoceptors with a dominance of β2-receptors on cell surfaces. Among the blockers tested, solely nebivolol concentration-dependently decreased viability and altered 3D tumor spheroid structure. Nebivolol blocked the repopulation of cells spreading from 3D tumor spheroids, indicating a tumor control potential at a concentration of ≥20 µM. Mechanistically, nebivolol induced ATP depletion and caspase-3/7 activity, indicating that mitochondria-dependent signaling is involved. D-nebivolol or nebivolol combined with the β2-antagonist ICI 118.551 displayed the highest anti-tumor effects, suggesting a contribution of both β1- and β2-receptors. Thus, the present study reveals the tumor control potential of nebivolol in UM, which may offer a perspective for co-adjuvant therapy to reduce recurrence or metastasis.

From cells to organoids: The evolution of blood-brain barrier technology for modelling drug delivery in brain cancer

Brain cancer remains the deadliest cancer. The blood-brain barrier (BBB) is impenetrable to most drugs and is a complex 3D network of multiple cell types including endothelial cells, astrocytes, and pericytes. In brain cancers, the BBB becomes disrupted during tumor progression and forms the blood-brain tumor barrier (BBTB). To advance therapeutic development, there is a critical need for physiologically relevant BBB in vitro models. 3D cell systems are emerging as valuable preclinical models to accelerate discoveries for diseases. Given the versatility and capability of 3D cell models, their potential for modelling the BBB and BBTB is reviewed. Technological advances of BBB models and challenges of in vitro modelling the BBTB, and application of these models as tools for assessing therapeutics and nano drug delivery, are discussed. Quantitative, in vitro BBB models that are predictive of effective brain cancer therapies will be invaluable for accelerating advancing new treatments to the clinic.

Development of Spheroid-FPOP: An In-Cell Protein Footprinting Method for 3D Tumor Spheroids

Many cancer drugs fail at treating solid epithelial tumors with hypoxia and insufficient drug penetration thought to be contributing factors to the observed chemoresistance. Owing to this, it is imperative to evaluate potential cancer drugs in conditions as close to in vivo as possible, which is not always done. To address this, we developed a mass spectrometry-based protein footprinting method for exploring the impact of hypoxia on protein in 3D colorectal cancer cells. Our group has previously extended the protein footprinting method fast photochemical oxidation of proteins (FPOP) for live cell analysis (IC-FPOP); however, this is the first application of IC-FPOP in a 3D cancer model. In this study, we perform IC-FPOP on intact spheroids (Spheroid-FPOP) using a modified version of the static platform incubator with an XY movable stage (PIXY) FPOP platform. We detected modification in each of three spheroid layers, even the hypoxic core. Pathway analysis revealed protein modifications in over 10 distinct protein pathways, including some involved in protein ubiquitination; a process modulated in cancer pathologies. These results demonstrate the feasibility of Spheroid-FPOP to be utilized as a tool to interrogate protein interactions within a native tumor microenvironment.

Novel Silver Complexes Based on Phosphanes and Ester Derivatives of Bis(pyrazol-1-yl)acetate Ligands Targeting TrxR: New Promising Chemotherapeutic Tools Relevant to SCLC Management

Bis(pyrazol-1-yl)acetic acid (HC(pz)₂COOH) and bis(3,5-dimethyl-pyrazol-1-yl)acetic acid (HC(pz^Me2)₂COOH) were converted into the methyl ester derivatives 1 (L^OMe) and 2 (L^2OMe), respectively, and were used for the preparation of silver(I) complexes 3-5. The Ag(I) complexes were prepared by the reaction of AgNO₃ and 1,3,5-triaza-7-phosphaadamantane (PTA) or triphenylphosphine (PPh₃) with L^OMe and L^2OMe in methanol solution. All Ag(I) complexes showed a significant in vitro antitumor activity, proving to be more effective than the reference drug cisplatin in the in-house human cancer cell line panel containing examples of different solid tumors. Compounds were particularly effective against the highly aggressive and intrinsically resistant human small-cell lung carcinoma (SCLC) cells, either in 2D and 3D cancer cell models. Mechanistic studies revealed their ability to accumulate into cancer cells and to selectively target Thioredoxin (TrxR), thus leading to redox homeostasis unbalance and ultimately inducing cancer cell death through apoptosis.

Pixelated Microfluidics for Drug Screening on Tumour Spheroids and Ex Vivo Microdissected Tumour Explants

Anticancer drugs have the lowest success rate of approval in drug development programs. Thus, preclinical assays that closely predict the clinical responses to drugs are of utmost importance in both clinical oncology and pharmaceutical research. 3D tumour models preserve the tumoral architecture and are cost- and time-efficient. However, the short-term longevity, limited throughput, and limitations of live imaging of these models have so far driven researchers towards less realistic tumour models such as monolayer cell cultures. Here, we present an open-space microfluidic drug screening platform that enables the formation, culture, and multiplexed delivery of several reagents to various 3D tumour models, namely cancer cell line spheroids and ex vivo primary tumour fragments. Our platform utilizes a microfluidic pixelated chemical display that creates isolated adjacent flow sub-units of reagents, which we refer to as fluidic 'pixels', over tumour models in a contact-free fashion. Up to nine different treatment conditions can be tested over 144 samples in a single experiment. We provide a proof-of-concept application by staining fixed and live tumour models with multiple cellular dyes. Furthermore, we demonstrate that the response of the tumour models to biological stimuli can be assessed using the platform. Upscaling the microfluidic platform to larger areas can lead to higher throughputs, and thus will have a significant impact on developing treatments for cancer.

High-Throughput Screening for the Potential Inhibitors of SARS-CoV-2 with Essential Dynamic Behavior

Global health security has been challenged by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) pandemic. Due to the lengthy process of generating vaccinations, it is vital to reposition currently available drugs in order to relieve anti-epidemic tensions and accelerate the development of therapies for Coronavirus Disease 2019 (COVID-19), the public threat caused by SARS-CoV-2. High throughput screening techniques have established their roles in the evaluation of already available medications and the search for novel potential agents with desirable chemical space and more cost-effectiveness. Here, we present the architectural aspects of highthroughput screening for SARS-CoV-2 inhibitors, especially three generations of virtual screening methodologies with structural dynamics: ligand-based screening, receptor-based screening, and machine learning (ML)-based scoring functions (SFs). By outlining the benefits and drawbacks, we hope that researchers will be motivated to adopt these methods in the development of novel anti- SARS-CoV-2 agents.

Non-uniformity in in vitro drug-induced cytotoxicity as evidenced by differences in IC50 values - implications and way forward

Cell lines have proven indispensable for in vitro experiments and their utility as experimental models range from understanding the fundamental cell functioning to drug discovery. One of the most common utility of cell lines is for in vitro drug testing. Drug testing involves determining the cytotoxic effects of the drugs and such a measurement is expressed as the IC₅₀ values of drugs. Although determination of IC₅₀ values of drugs on cell lines is one of the most common in vitro experimental approaches, a significant amount of variations can be observed in the results obtained from such studies. Although the variations in the IC₅₀ values of a drug on different cells lines can and should vary, the non-uniformity of such results reported from different studies using a particular drug on a specific cell line is a matter of concern. We present the IC₅₀ values of 5 most commonly used drugs 5-fluorouracil, bleomycin, cisplatin, doxorubicin and methotrexate obtained from several in vitro cell line-based studies. Some of the factors which contribute to the non-uniformity of the IC₅₀ values for a particular drug from different studies are discussed as three types of factors, the biological, non-biological and human factors. Also, ways in which such variations can be reduced to obtain universally common, reliable results are presented.

Automated Quantitative Analysis of Shape Features in Human Epithelial Monolayers and Spheroids Generated from Colorectal Cancer Cells

Advancements in microscopy techniques permit us to acquire endless datasets of images. A major bottleneck in cell imaging is how to analyze petabytes of data in an effective, reliable, objective, and effortless way. Quantitative imaging is becoming crucial to disentangle the complexity of many biological and pathological processes. For instance, cell shape is a summary readout of a myriad of cellular processes. Changes in cell shape use to reflect changes in growth, migration mode (including speed and persistence), differentiation stage, apoptosis, or gene expression, serving to predict health or disease. However, in certain contexts, e.g., tissues or tumors, cells are tightly packed together, and measurement of individual cellular shapes can be challenging and laborious. Bioinformatics solutions like automated computational image methods provide a blind and efficient analysis of large image datasets. Here we describe a detailed and friendly step-by-step protocol to extract various cellular shape parameters quickly and accurately from colorectal cancer cells forming either monolayers or spheroids. We envision those similar settings could be extended to other cell lines, colorectal and beyond, either label/unlabeled or in 2D/3D environments.

Cell Viability Assays for 3D Cellular Constructs

In vitro models fall short of replicating the complex in vivo processes including cell growth and differentiation. For many years, molecular biology research and drug development have relied on the use of cells grown within tissue culture dishes. These traditional in vitro two-dimensional (2D) cultures fail to recapitulate the 3D microenvironment of in vivo tissues. Due to inadequate surface topography, surface stiffness, cell-to-cell, and cell-to-ECM matrices, 2D cell culture systems are incapable of mimicking cell physiology seen in living healthy tissues. These factors can also place selective pressure on cells that substantially alter their molecular and phenotypic properties. With these disadvantages in mind, new and adaptive cell culture systems are necessary to recapitulate the cellular microenvironment in a more accurate manner for drug development, toxicity studies, drug delivery, and much more. Newly developed biofabrication technologies capable of creating 3D tissue constructs can open new opportunities for cell growth and developmental modeling. These constructs show great promise in representing an environment that allows cells to interact with other cells and their microenvironment in a much more physiologically accurate manner. When transitioning from 2D to 3D systems, there is the need to translate common cell viability analysis techniques from that of 2D cell culture to these 3D tissue constructs. Cell viability assays are critical in evaluating the health of cells in response to drug treatment or other stimuli to better understand how these factors effect the tissue constructs. As 3D cellular systems become the new standard in biomedical engineering, this chapter provides different assays used to assess cell viability qualitatively and quantitatively in 3D environments.

A Biomimetic Hyaluronic Acid Hydrogel Models Mass Dormancy in Brain Metastatic Breast Cancer Spheroids

Approximately 90% of breast cancer related mortalities are due to metastasis to distant organs. At the metastatic sites, cancer cells are capable of evading death by exhibiting cellular or mass dormancy. However, the mechanisms involved in attaining dormancy at the metastatic site are not well understood. This is partly due to the lack of experimental models to study metastatic site-specific interactions, particularly in the context of brain metastatic breast cancer (BMBC). Herein, an in vitro hyaluronic acid (HA) hydrogel-based model is developed to study mass dormancy in BMBC. HA hydrogels with a stiffness of ≈0.4 kPa are utilized to mimic the brain extracellular matrix. MDA-MB-231Br or BT474Br3 BMBC spheroids are prepared and cultured on top of HA hydrogels or in suspension for 7 days. HA hydrogel induced a near mass dormant state in spheroids by achieving a balance between proliferating and dead cells. In contrast, these spheroids displayed growth in suspension cultures. The ratio of %p-ERK to %p-p38 positive cells is significantly lower in HA hydrogels compared to suspension cultures. Further, it is demonstrated that hydrogel induced mass dormant state is reversible. Overall, such models provide useful tools to study dormancy in BMBC and could be employed for drug screening.

Role of Patient-Derived Models of Cancer in Translational Oncology

Cancer is a heterogeneous disease. Each individual tumor is unique and characterized by structural, cellular, genetic and molecular features. Therefore, patient-derived cancer models are indispensable tools in cancer research and have been actively introduced into the healthcare system. For instance, patient-derived models provide a good reproducibility of susceptibility and resistance of cancer cells against drugs, allowing personalized therapy for patients. In this article, we review the advantages and disadvantages of the following patient-derived models of cancer: (1) PDC-patient-derived cell culture, (2) PDS-patient-derived spheroids and PDO-patient-derived organoids, (3) PDTSC-patient-derived tissue slice cultures, (4) PDX-patient-derived xenografts, humanized PDX, as well as PDXC-PDX-derived cell cultures and PDXO-PDX-derived organoids. We also provide an overview of current clinical investigations and new developments in the area of patient-derived cancer models. Moreover, attention is paid to databases of patient-derived cancer models, which are collected in specialized repositories. We believe that the widespread use of patient-derived cancer models will improve our knowledge in cancer cell biology and contribute to the development of more effective personalized cancer treatment strategies.

Biofabrication of Modular Spheroids as Tumor-Scale Microenvironments for Drug Screening

To streamline the drug discovery pipeline, there is a pressing need for preclinical models which replicate the complexity and scale of native tumors. While there have been advancements in the formation of microscale tumor units, these models are cell-line dependent, time-consuming and have not improved clinical trial success rates. In this study, two methods for generating 3D tumor microenvironments are compared, rapidly fabricated hydrogel microspheres and traditional cell-dense spheroids. These modules are then bioassembled into 3D printed thermoplastic scaffolds, using an automated biofabrication process, to form tumor-scale models. Modules are formed with SKOV3 and HFF cells as monocultures and cocultures, and the fabrication efficiency, cell architecture, and drug response profiles are characterized, both as single modules and as multimodular constructs. Cell-encapsulated Gel-MA microspheres are fabricated with high-reproducibility and dimensions necessary for automated tumor-scale bioassembly regardless of cell type, however, only cocultured spheroids form compact modules suitable for bioassembly. Chemosensitivity assays demonstrate the reduced potency of doxorubicin in coculture bioassembled constructs and a ≈five-fold increase in drug resistance of cocultured cells in 3D modules compared with 2D monolayers. This bioassembly system is efficient and tailorable so that a variety of relevant-sized tumor constructs could be developed to study tumorigenesis and modernize drug discovery.

In Vitro Setup for Determination of Nanoparticle-Mediated Magnetic Cell and Drug Accumulation in Tumor Spheroids under Flow Conditions

Superparamagnetic iron oxide nanoparticles (SPIONs) are used in nanomedicine as transporter systems for therapeutic cargos, or to magnetize cells to make them magnetically guidable. In cancer treatment, the site-directed delivery of chemotherapeutics or immune effector cells to the tumor can increase the therapeutic efficacy in the target region, and simultaneously reduce toxic side-effects in the rest of the body. To enable the transfer of new methods, such as the nanoparticle-mediated transport from bench to bedside, suitable experimental setups must be developed. In vivo, the SPIONs or SPION-loaded cells must be applied into the blood stream, to finally reach the tumor: consequently, targeting and treatment efficacy should be analyzed under conditions which are as close to in vivo as possible. Here, we established an in vitro method, including tumor spheroids placed in a chamber system under the influence of a magnetic field, and adapted to a peristaltic pump, to mimic the blood flow. This enabled us to analyze the magnetic capture and antitumor effects of magnetically targeted mitoxantrone and immune cells under dynamic conditions. We showed that the magnetic nanoparticle-mediated accumulation increased the anti-tumor effects, and reduced the unspecific distribution of both mitoxantrone and cells. Especially for nanomedical research, investigation of the site-specific targeting of particles, cells or drugs under circulation is important. We conclude that our in vitro setup improves the screening process of nanomedical candidates for cancer treatment.

HMGN5 Escorts Oncogenic STAT3 Signaling by Regulating the Chromatin Landscape in Breast Cancer Tumorigenesis

Cancer progression is highly dependent on the ability of cancer cell tumor formation, in which epigenetic modulation plays an essential role. However, the epigenetic factors promoting breast tumor formation are less known. Screened from three-dimensional (3D)-sphere tumor formation model, HMGN5 that regulates chromatin structures became the candidate therapeutic target in breast cancer, though its role is obscure. HMGN5 is highly expressed in 3D-spheres of breast cancer cells and clinical tumors, also an unfavorable prognostic marker in patients. Furthermore, HMGN5 controls tumor formation and metastasis of breast cancer cells in vitro and in vivo. Mechanistically, HMGN5 is governed by active STAT3 transcriptionally and further escorts STAT3 to shape the oncogenic chromatin landscape and transcriptional program. More importantly, interference of HMGN5 by nanovehicle-packaged siRNA effectively inhibits tumor growth in breast cancer cell-derived xenograft mice model.

IMPLICATIONS

Our findings reveal a novel feed-forward circuit between HMGN5 and STAT3 in promoting breast cancer tumorigenesis and suggest HMGN5 as a novel epigenetic therapeutic target in STAT3-hyperactive breast cancer.

From simplicity to complexity in current melanoma models

Despite the recent impressive clinical success of immunotherapy against melanoma, development of primary and adaptive resistance against immune checkpoint inhibitors remains a major issue in a large number of treated patients. This highlights the need for melanoma models that replicate the tumor's intricate dynamics in the tumor microenvironment (TME) and associated immune suppression to study possible resistance mechanisms in order to improve current and test novel therapeutics. While two-dimensional melanoma cell cultures have been widely used to perform functional genomics screens in a high-throughput fashion, they are not suitable to answer more complex scientific questions. Melanoma models have also been established in a variety of experimental (humanized) animals. However, due to differences in physiology, such models do not fully represent human melanoma development. Therefore, fully human three-dimensional in vitro models mimicking melanoma cell interactions with the TME are being developed to address this need for more physiologically relevant models. Such models include melanoma organoids, spheroids, and reconstructed human melanoma-in-skin cultures. Still, while major advances have been made to complement and replace animals, these in vitro systems have yet to fully recapitulate human tumor complexity. Lastly, technical advancements have been made in the organ-on-chip field to replicate functions and microstructures of in vivo human tissues and organs. This review summarizes advancements made in understanding and treating melanoma and specifically aims to discuss the progress made towards developing melanoma models, their applications, limitations, and the advances still needed to further facilitate the development of therapeutics.

17-β Estradiol up-regulates energy metabolic pathways, cellular proliferation and tumor invasiveness in ER+ breast cancer spheroids

Several biological processes related to cancer malignancy are regulated by 17-β estradiol (E2) in ER+-breast cancer. To establish the role of E2 on the atypical cancer energy metabolism, a systematic study analyzing transcription factors, proteins, and fluxes associated with energy metabolism was undertaken in multicellular tumor spheroids (MCTS) from human ER+ MCF-7 breast cancer cells. At E2 physiological concentrations (10 and 100 nM for 24 h), both ERα and ERβ receptors, and their protein target pS2, increased by 0.6-3.5 times vs. non-treated MCTS, revealing an activated E2/ER axis. E2 also increased by 30-470% the content of several transcription factors associated to mitochondrial biogenesis and oxidative phosphorylation (OxPhos) (p53, PGC1-α) and glycolytic pathways (HIF1-α, c-MYC). Several OxPhos and glycolytic proteins (36-257%) as well as pathway fluxes (48-156%) significantly increased being OxPhos the principal ATP cellular supplier (&gt;75%). As result of energy metabolism stimulation by E2, cancer cell migration and invasion processes and related proteins (SNAIL, FN, MM-9) contents augmented by 24-189% vs. non-treated MCTS. Celecoxib at 10 nM blocked OxPhos (60%) as well as MCTS growth, cell migration and invasiveness (&gt;40%); whereas the glycolytic inhibitor iodoacetate (0.5 µM) and doxorubicin (70 nM) were innocuous. Our results show for the first time using a more physiological tridimensional cancer model, resembling the initial stages of solid tumors, that anti-mitochondrial therapy may be useful to deter hormone-dependent breast carcinomas.

PRP-1, a toll-like receptor ligand, upregulates the unfolded protein response in human chondrosarcoma cells

BACKGROUND

Previous studies showed that proline-rich polypeptide (PRP-1) is a ligand for innate immunity toll-like receptors (TLR), and an inhibitor of the mammalian target of rapamycin complex 1 (mTORC1) which induces the death of chondrosarcoma cancer stem cells (CSC). The aim of this study was to investigate the effect of PRP-1 on the regulation of unfolded protein response (UPR) in human chondrosarcoma cells.

MATERIALS AND METHODS

Lysates were prepared from a monolayer (bulk or ALDH^high population), or spheroids chondrosarcoma cell cultures and treated with PRP-1 or control, followed by protein levels quantification by western blotting and mRNA expression by RT-qPCR of protein-RNA-like endoplasmic reticulum kinase (PERK), eukaryotic translation initiation factor 2α (eIF2α), activating transcription factor 4 (ATF4), CCAAT-enhancer-binding protein homologous protein (CHOP), activating transcription factor 6 (ATF6), inositol-requiring enzyme 1 (IRE1α), and X-box binding protein (XBP1).

RESULTS

The PRP-1 has been shown to increase the expression of PERK, eIF2α, ATF4, CHOP, ATF6, IRE1α, and XBP1, on both protein and mRNA levels.

CONCLUSION

PRP-1 activated UPR branches in monolayer, spheroid, and stem cell populations of human chondrosarcoma.

3-Dimensional mesothelioma spheroids provide closer to natural pathophysiological tumor microenvironment for drug response studies

Traditional studies using cancer cell lines are often performed on a two-dimensional (2D) cell culture model with a low success rate of translating to Phase I or Phase II clinical studies. In comparison, with the advent of developments three-dimensional (3D) cell culture has been championed as the latest cellular model system that better mimics in vivo conditions and pathological conditions such as cancer. In comparison to biospecimens taken from in vivo tissue, the details of gene expression of 3D culture models are largely undefined, especially in mesothelioma – an aggressive cancer with very limited effective treatment options. In this study, we examined the veracity of the 3D mesothelioma cell culture model to study cell-to-cell interaction, gene expression and drug response from 3D cell culture, and compared them to 2D cell and tumor samples. We confirmed via SEM analysis that 3D cells grown using the spheroid methods expressed highly interconnected cell-to-cell junctions. The 3D spheroids were revealed to be an improved mini-tumor model as indicated by the TEM visualization of cell junctions and microvilli, features not seen in the 2D models. Growing 3D cell models using decellularized lung scaffold provided a platform for cell growth and infiltration for all cell types including primary cell lines. The most time-effective method was growing cells in spheroids using low-adhesive U-bottom plates. However, not every cell type grew into a 3D model using the the other methods of hanging drop or poly-HEMA. Cells grown in 3D showed more resistance to chemotherapeutic drugs, exhibiting reduced apoptosis. 3D cells stained with H&E showed cell-to-cell interactions and internal architecture that better represent that of in vivo patient tumors when compared to 2D cells. IHC staining revealed increased protein expression in 3D spheroids compared to 2D culture. Lastly, cells grown in 3D showed very different microRNA expression when compared to that of 2D counterparts. In conclusion, 3D cell models, regardless of which method is used. Showed a more realistic tumor microenvironment for architecture, gene expression and drug response, when compared to 2D cell models, and thus are superior preclinical cancer models.

Investigation of anti-cancer effects of new pyrazino[1,2-a]benzimidazole derivatives on human glioblastoma cells through 2D in vitro model and 3D-printed microfluidic device

AIMS

Recent studies show targeted therapy of new pyrazino[1,2-a]benzimidazole derivatives with COX-II inhibitory effects on different cancer cells. This study aimed to investigate 2D cell culture and 3D spheroid formation of glioblastoma multiforme (GBM) cells using a microfluidic device after exposure to these compounds.

MAIN METHODS

After isolating astrocytes from human GBM samples, IC50 of 2,6-dimethyl pyrazino[1,2-a]benzimidazole (L1) and 3,4,5-trimethoxy pyrazino[1,2-a]benzimidazole (L2) were determined as 13 μM and 85 μM, respectively. Then, in all experiments, cells were exposed to subtoxic concentrations of L1 (6.5 μM) and L2 (42.5 μM), which were ½IC50. In the following, in two phases, cell cycle, migration, and gene expression through 2D cell culture and tumor spheroid formation ability using a 3D-printed microfluidic chip were assessed.

KEY FINDINGS

The obtained results showed that both compounds have positive effects in reducing G2/M cell population and GBM cell migration. Furthermore, real-time gene expression data showed that L1 and L2 significantly impact the upregulation of P21 and P53 and down-regulation of cyclin D1, MMP2, and MMP9. On the other hand, GBM spheroids exposed to L1 and L2 become smaller with fewer live cells.

SIGNIFICANCE

Our data on human isolated astrocyte cells in 2D and 3D cell culture conditions showed that L1 and L2 compounds could reduce GBM cells' invasion by controlling gene expressions associated with migration and proliferation. Moreover, designing microfluidic platform and related cell culture protocols facilitates the broad screening of 3D multicellular tumor spheroids derived from GBM tumor biopsies and provides effective drug development for brain gliomas.

Imaging Techniques: Essential Tools for the Study of SARS-CoV-2 Infection

The world has seen the emergence of a new virus in 2019, SARS-CoV-2, causing the COVID-19 pandemic and millions of deaths worldwide. Microscopy can be much more informative than conventional detection methods such as RT-PCR. This review aims to present the up-to-date microscopy observations in patients, the in vitro studies of the virus and viral proteins and their interaction with their host, discuss the microscopy techniques for detection and study of SARS-CoV-2, and summarize the reagents used for SARS-CoV-2 detection. From basic fluorescence microscopy to high resolution techniques and combined technologies, this article shows the power and the potential of microscopy techniques, especially in the field of virology.

VEGF‑mediated tumour growth and EMT in 2D and 3D cell culture models of hepatocellular carcinoma

The purpose of the present study was to evaluate the effects of vascular endothelial growth factor (VEGF) on tumorigenic properties in two-dimensional (2D) and three-dimensional (3D) cultures of hepatoma cells. The proliferation and invasion of hepatoma cells was assessed using wound healing, chemotaxis Transwell, invasion, tube-forming and hanging drop assays in both 2D and 3D cultures. The expression levels of epithelial-mesenchymal transition (EMT) and stemness markers were analysed using reverse transcription-quantitative PCR (RT-qPCR) for mRNA expression and immunofluorescence assay for protein expression. To validate the role of VEGF in tumour growth, a VEGF receptor (VEGFR) inhibitor (sorafenib) was used. The results demonstrated that the hepatoma cells formed 3D spheroids that differed in size and density in the absence and presence of the growth factor, VEGF. In all spheroids, invasion and angiogenesis were more aggressive in 3D cultures in comparison to 2D conditions following treatment with VEGF. Mechanistically, the VEGF-mediated increase in the levels of EMT markers, including Vimentin, N-cadherin 2 (Cadherin 2) and Thy-1 Cell Surface Antigen was observed in the 2D and 3D cultures. Sorafenib treatment for 24 h culminated in a marked reduction in cell migration, cell-cell adhesion, spheroid compaction and EMT gene expression in 3D models as compared to the 2D models. On the whole, the findings of the present study suggested that as compared to the 2D cell cultures, 3D cell cultures model may be used as a more realistic model for the study of tumour growth and invasion in the presence of angiogenic factors, as well as for tumour inhibitor screening.

Assessment of Cell-Material Interactions in Three Dimensions through Dispersed Coaggregation of Microsized Biomaterials into Tissue Spheroids

In biomaterials R&D, conventional monolayer cell culture on flat/planar material samples, such as films, is still commonly employed at early stages of the assessment of interactions of cells with candidate materials considered for a biomedical application. In this feasibility study, an approach for the assessment of 3D cell-material interactions through dispersed coaggregation of microparticles from biomaterials into tissue spheroids is presented. Biomaterial microparticles can be created comparatively quickly and easily, allow the miniaturization of the assessment platform, and enable an unhindered remodeling of the dynamic cell-biomaterial system at any time. The aggregation of the microsized biomaterials and the cells is supported by low-attachment round-bottom microwells from thin polymer films arranged in densely packed arrays. The study is conducted by the example of MG63 osteoblast-like and human mesenchymal stem/stromal cells, and a small library of model microbiomaterials related to bone repair and regeneration. For the proof of concept, example interactions including cell adhesion to the material, the hybrid spheroids' morphology, size, and shape, material-associated cell death, cell metabolic activity, cell proliferation, and (osteogenic) differentiation are investigated. The cells in the spheroids are shown to respond to differences in the microbiomaterials' properties, their amounts, and the duration of interaction with them.

Investigating Cutaneous Squamous Cell Carcinoma in vitro and in vivo: Novel 3D Tools and Animal Models

Cutaneous Squamous Cell Carcinoma (cSCC) represents the second most common type of skin cancer, which incidence is continuously increasing worldwide. Given its high frequency, cSCC represents a major public health problem. Therefore, to provide the best patients’ care, it is necessary having a detailed understanding of the molecular processes underlying cSCC development, progression, and invasion. Extensive efforts have been made in developing new models allowing to study the molecular pathogenesis of solid tumors, including cSCC tumors. Traditionally, in vitro studies were performed with cells grown in a two-dimensional context, which, however, does not represent the complexity of tumor in vivo. In the recent years, new in vitro models have been developed aiming to mimic the three-dimensionality (3D) of the tumor, allowing the evaluation of tumor cell-cell and tumor-microenvironment interaction in an in vivo-like setting. These models include spheroids, organotypic cultures, skin reconstructs and organoids. Although 3D models demonstrate high potential to enhance the overall knowledge in cancer research, they lack systemic components which may be solved only by using animal models. Zebrafish is emerging as an alternative xenotransplant model in cancer research, offering a high-throughput approach for drug screening and real-time in vivo imaging to study cell invasion. Moreover, several categories of mouse models were developed for pre-clinical purpose, including xeno- and syngeneic transplantation models, autochthonous models of chemically or UV-induced skin squamous carcinogenesis, and genetically engineered mouse models (GEMMs) of cSCC. These models have been instrumental in examining the molecular mechanisms of cSCC and drug response in an in vivo setting. The present review proposes an overview of in vitro, particularly 3D, and in vivo models and their application in cutaneous SCC research.

Preclinical platforms to study therapeutic efficacy of human γδ T cells

BACKGROUND

Gamma delta (γδ) T lymphocytes are promising candidate for adoptive T cell therapy, however, their treatment efficacy is not satisfactory. Vδ2 T cells are unique to primates and few suitable models are available to assay their anti-tumour function.

METHODS

We tested human γδ T cell activation, tumour infiltration, and tumour-killing in four three-dimensional (3D) models, including unicellular, bicellular and multicellular melanoma spheroids, and patient-derived melanoma organoids. We studied the effects of checkpoint inhibitors on γδ T cells and performed a small molecule screen using these platforms.

RESULTS

γδ T cells rapidly responded to melanoma cells and infiltrated melanoma spheroids better than αβ T cells in PBMCs. Cancer-associated fibroblasts (CAFs) in bicellular spheroids, stroma cells in multicellular melanoma spheroids and inhibitory immune cells in organoids significantly inhibited immune cell infiltrates including γδ T cells and lessened their cytotoxicity to tumour cells. Tumour-infiltrating γδ T cells showed exhausted immunophenotypes with high checkpoints expression (CTLA-4, PD-1 and PD-L1). Immune checkpoint inhibitors increased γδ T cell infiltration of 3D models and killing of melanoma cells in all four 3D models. Our small molecule screen assay and subsequent mechanistic studies demonstrated that epigenetic modifiers enhanced the chemotaxis and cytotoxicity of γδ T cells through upregulating MICA/B, inhibiting HDAC6/7 pathway and downregulating the levels of PD-L1 and PD-L2 in CAFs and tumour cells. These compounds increased CXCR4 and CD107a expression, IFN-γ production and decreased PD-1 expression of γδ T cells.

CONCLUSIONS

Tumour-infiltrating γδ T cells show exhausted immunophenotypes and limited anti-tumour capacity in melanoma 3D models. Checkpoint inhibitors and epigenetic modifiers enhance anti-tumour functions of γδ T cells. These four 3D models provided valuable preclinical platforms to test γδ T cell functions for immunotherapy.

The impact of microfluidics in high-throughput drug-screening applications

Drug discovery is an expensive and lengthy process. Among the different phases, drug discovery and preclinical trials play an important role as only 5-10 of all drugs that begin preclinical tests proceed to clinical trials. Indeed, current high-throughput screening technologies are very expensive, as they are unable to dispense small liquid volumes in an accurate and quick way. Moreover, despite being simple and fast, drug screening assays are usually performed under static conditions, thus failing to recapitulate tissue-specific architecture and biomechanical cues present in vivo even in the case of 3D models. On the contrary, microfluidics might offer a more rapid and cost-effective alternative. Although considered incompatible with high-throughput systems for years, technological advancements have demonstrated how this gap is rapidly reducing. In this Review, we want to further outline the role of microfluidics in high-throughput drug screening applications by looking at the multiple strategies for cell seeding, compartmentalization, continuous flow, stimuli administration (e.g., drug gradients or shear stresses), and single-cell analyses.

Mechanical Cues, E-Cadherin Expression and Cell "Sociality" Are Crucial Crossroads in Determining Pancreatic Ductal Adenocarcinoma Cells Behavior

E-cadherin, an epithelial-to-mesenchymal transition (EMT) marker, is coupled to actin cytoskeleton and distributes cell forces acting on cells. Since YAP transduces mechanical signals involving actin cytoskeleton, we aimed to investigate the relationship between YAP and mechanical cues in pancreatic ductal adenocarcinoma (PDAC) cell lines, characterized by different EMT-related phenotypes, cultured in 2D monolayers and 3D spheroids. We observed that the YAP/p-YAP ratio was reduced in HPAC and MIA PaCa-2 cell lines and remained unchanged in BxPC-3 cells when cultured in a 3D setting. CTGF and CYR61 gene expression were down-regulated in all PDAC 3D compared to 2D cultures, without any significant effect following actin cytoskeleton inhibition by Cytochalasin B (CyB) treatment. Moreover, LATS1 mRNA, indicating the activation of the Hippo pathway, was not influenced by CyB and differed in all PDAC cell lines having different EMT-related phenotype but a similar pattern of CTGF and CYR61 expression. Although the role of YAP modulation in response to mechanical cues in cancer cells remains to be completely elucidated, our results suggest that cell arrangement and phenotype can determine variable outcomes to mechanical stimuli in PDAC cells. Moreover, it is possible to speculate that YAP and Hippo pathways may act as parallel and not exclusive inputs that, converging at some points, may impact cell behavior.

Upregulation of p75NTR by Histone Deacetylase Inhibitors Sensitizes Human Neuroblastoma Cells to Targeted Immunotoxin-Induced Apoptosis

Histone deacetylase (HDAC) inhibitors are novel chemotherapy agents with potential utility in the treatment of neuroblastoma, the most frequent solid tumor of childhood. Previous studies have shown that the exposure of human neuroblastoma cells to some HDAC inhibitors enhanced the expression of the common neurotrophin receptor p75NTR. In the present study we investigated whether the upregulation of p75NTR could be exploited to render neuroblastoma cells susceptible to the cytotoxic action of an anti-p75NTR antibody conjugated to the toxin saporin-S6 (p75IgG-Sap). We found that two well-characterized HDAC inhibitors, valproic acid (VPA) and entinostat, were able to induce a strong expression of p75NTR in different human neuroblastoma cell lines but not in other cells, with entinostat, displaying a greater efficacy than VPA. Cell pretreatment with entinostat enhanced p75NTR internalization and intracellular saporin-S6 delivery following p75IgG-Sap exposure. The addition of p75IgG-Sap had no effect on vehicle-pretreated cells but potentiated the apoptotic cell death that was induced by entinostat. In three-dimensional neuroblastoma cell cultures, the subsequent treatment with p75IgG-Sap enhanced the inhibition of spheroid growth and the impairment of cell viability that was produced by entinostat. In athymic mice bearing neuroblastoma xenografts, chronic treatment with entinostat increased the expression of p75NTR in tumors but not in liver, kidney, heart, and cerebellum. The administration of p75IgG-Sap induced apoptosis only in tumors of mice that were pretreated with entinostat. These findings define a novel experimental strategy to selectively eliminate neuroblastoma cells based on the sequential treatment with entinostat and a toxin-conjugated anti-p75NTR antibody.

Validation of CD98hc as a Therapeutic Target for a Combination of Radiation and Immunotherapies in Head and Neck Squamous Cell Carcinoma

Most patients with head and neck squamous cell carcinomas (HNSCC) are diagnosed at a locally advanced stage and show heterogeneous treatment responses. Low SLC3A2 (solute carrier family 3 member 2) mRNA and protein (CD98hc) expression levels are associated with higher locoregional control in HNSCC patients treated with primary radiochemotherapy or postoperative radiochemotherapy, suggesting that CD98hc could be a target for HNSCC radiosensitization. One of the targeted strategies for tumor radiosensitization is precision immunotherapy, e.g., the use of chimeric antigen receptor (CAR) T cells. This study aimed to define the potential clinical value of new treatment approaches combining conventional radiotherapy with CD98hc-targeted immunotherapy. To address this question, we analyzed the antitumor activity of the combination of fractionated irradiation and switchable universal CAR (UniCAR) system against radioresistant HNSCC cells in 3D culture. CD98hc-redirected UniCAR T cells showed the ability to destroy radioresistant HNSCC spheroids. Also, the infiltration rate of the UniCAR T cells was enhanced in the presence of the CD98hc target module. Furthermore, sequential treatment with fractionated irradiation followed by CD98hc-redirected UniCAR T treatment showed a synergistic effect. Taken together, our obtained data underline the improved antitumor effect of the combination of radiotherapy with CD98hc-targeted immunotherapy. Such a combination presents an attractive approach for the treatment of high-risk HNSCC patients.

In Vitro Models of Bone Marrow Remodelling and Immune Dysfunction in Space: Present State and Future Directions

Spaceflight affects the body on every level. Reports on astronaut health identify bone marrow remodelling and dysfunction of the innate immune system as significant health risks of long-term habitation in space. Microgravity-induced alterations of the bone marrow induce physical changes to the bone marrow stem cell niche. Downstream effects on innate immunity are expected due to impaired hematopoiesis and myelopoiesis. To date, few studies have investigated these effects in real microgravity and the sparsely available literature often reports contrasting results. This emphasizes a need for the development of physiologically relevant in vitro models of the bone marrow stem cell niche, capable of delivering appropriate sample sizes for robust statistics. Here, we review recent findings on the impact of spaceflight conditions on innate immunity in in vitro and animal models and discusses the latest in vitro models of the bone marrow stem cell niche and their potential translatability to gravitational biology research.

A novel cell line from human eccrine sweat gland duct cells for investigating sweating physiology

OBJECTIVE

Human eccrine sweat glands represent vital components of the skin involved in regulating body temperature. Especially the eccrine duct, which opens directly into the skin surface and releases the aqueous sweat, constitutes the first contact point with topically applied substances. For scientific investigations and to understand the underlying sweating mechanism on a cellular level defined cellular material is beneficial. We, therefore, strived to generate a cell line derived from human eccrine sweat gland duct cells for identifying new mechanisms in sweating control, as such a standardize cell line is currently lacking.

MATERIAL AND METHODS

Isolated primary human eccrine sweat gland duct cells were transduced with simian virus 40 large T antigen (SV40T) by lentiviral transduction. Successfully SV40T-transduced clones were selected by single cell cloning with one clone, named 1D10, being particularly described in this work.

RESULTS

In performed cellular investigations, SV40T-transduced duct-derived cells exhibited an extended lifespan with stable population doubling times suggesting its immortality. Besides, 1D10 clonal cell culture demonstrated similarities with parental, primary duct cells regarding gene expression of selected sweat gland-related markers. When combined with primary coil cells in a hanging drop co-culture, those transduced duct-derived cells showed some duct cell-like features. Further, a certain degree of cellular communication and a specific reaction towards substance application was observed.

CONCLUSION

Generated and herein described cell line derived from isolated human eccrine sweat gland duct cells is, based on the presented scientific findings, considered as immortal. Besides, this cell line shows some similarity with primary duct cells, although alterations from native glands were detected, among which is loss of expression of CFTR. Provided some further investigations, presented SV40T-transduced duct-cell derived cell line seems a suited surrogate of primary eccrine duct cells.

Three-Dimensional Modelling of Ovarian Cancer: From Cell Lines to Organoids for Discovery and Personalized Medicine

Ovarian cancer has the highest mortality of all of the gynecological malignancies. There are several distinct histotypes of this malignancy characterized by specific molecular events and clinical behavior. These histotypes have differing responses to platinum-based drugs that have been the mainstay of therapy for ovarian cancer for decades. For histotypes that initially respond to a chemotherapeutic regime of carboplatin and paclitaxel such as high-grade serous ovarian cancer, the development of chemoresistance is common and underpins incurable disease. Recent discoveries have led to the clinical use of PARP (poly ADP ribose polymerase) inhibitors for ovarian cancers defective in homologous recombination repair, as well as the anti-angiogenic bevacizumab. While predictive molecular testing involving identification of a genomic scar and/or the presence of germline or somatic BRCA1 or BRCA2 mutation are in clinical use to inform the likely success of a PARP inhibitor, no similar tests are available to identify women likely to respond to bevacizumab. Functional tests to predict patient response to any drug are, in fact, essentially absent from clinical care. New drugs are needed to treat ovarian cancer. In this review, we discuss applications to address the currently unmet need of developing physiologically relevant in vitro and ex vivo models of ovarian cancer for fundamental discovery science, and personalized medicine approaches. Traditional two-dimensional (2D) in vitro cell culture of ovarian cancer lacks critical cell-to-cell interactions afforded by culture in three-dimensions. Additionally, modelling interactions with the tumor microenvironment, including the surface of organs in the peritoneal cavity that support metastatic growth of ovarian cancer, will improve the power of these models. Being able to reliably grow primary tumoroid cultures of ovarian cancer will improve the ability to recapitulate tumor heterogeneity. Three-dimensional (3D) modelling systems, from cell lines to organoid or tumoroid cultures, represent enhanced starting points from which improved translational outcomes for women with ovarian cancer will emerge.

Cell encapsulation in alginate-based microgels using droplet microfluidics; a review on gelation methods and applications

Cell encapsulation within the microspheres using a semi-permeable polymer allows the two-way transfer of molecules such as oxygen, nutrients, and growth factors. The main advantages of cell encapsulation technology include controlling the problems involved in transplanting rejection in tissue engineering applications and reducing the long-term need for immunosuppressive drugs following organ transplantation to eliminate the side effects. Cell-laden microgels can also be used in 3D cell cultures, wound healing, and cancerous clusters for drug testing. Since cell encapsulation is used for different purposes, several techniques have been developed to encapsulate cells. Droplet-based microfluidics is one of the most valuable techniques in cell encapsulating. This study aimed to review the geometries and the mechanisms proposed in microfluidic systems to precisely control cell-laden microgels production with different biopolymers. We also focused on alginate gelation techniques due to their essential role in cell encapsulation applications. Finally, some applications of these microgels and researches will be explored.