Gene expression perturbation in vitro--a growing case for three-dimensional (3D) culture systems

Three-Dimensional Evaluation of the Cytotoxicity and Antibacterial Properties of Alpha Lipoic Acid-Capped Silver Nanoparticle Constructs for Oral Applications

There is a need to develop bifunctional scaffolds that provide antibacterial protection while encouraging host cell attachment/proliferation. This study evaluates HyStem®-C, and photo-cross-linked GelMA hydrogels for encapsulation and stabilisation of silver nanoparticles (AgNPs). We studied the behaviour of AgNPs and matrix interactions within both hydrogel systems. The cell viability of encapsulated human gingival fibroblasts (HGFs) was determined by Prestoblue® assay and live/dead staining. The release of AgNPs was monitored by inductively coupled plasma-mass spectroscopy. The antibacterial properties of the GelMA-AgNP constructs were determined using disc diffusion. Even distribution of AgNPs in GelMA induced a significant decrease in cell viability (p < 0.0001), whereas AgNP aggregates did not induce cytotoxicity in HyStem®-C. AgNPs doses ≥ 0.5 µg/mL in GelMA were significantly toxic to the HGFs (p < 0.0001). The release of AgNPs from GelMA after 48 h was 20% w/w for 0.1 µg/mL and 51% for 100 µg/mL of AgNPs. At ≥5 µg/mL, a significant intra-construct bactericidal effect was observed. The disc diffusion assay shows that GelMA-incorporated AgNPs were found to be effective against both Escherichia coli and Staphylococcus aureus at 50 and 100 µg/mL, respectively. Visible photo-cross-linked GelMA stably incorporated AgNPs to provide an antimicrobial regenerative construct for oral applications.

Reconstruction of the alveolar-capillary barrier in vitro based on a photo-responsive stretchable Janus membrane

The lung is the respiratory organ of the human body, and the alveoli are the most basic functional units of the lung. Herein, a photo-responsive stretchable Janus membrane was proposed for the reconstruction of the alveolar-capillary barrier in vitro. This Janus membrane was fabricated by photocrosslinking methylacrylamide gelatin (Gelma) hydrogel and N-isoacrylamide (NIPAM) hydrogel mixed with graphene oxide (GO). The Gelma hydrogel containing large amounts of collagen provides a natural extracellular matrix environment for cell growth, while the temperature-sensitive NIPAM hydrogel combined with GO gives the membrane a light-controlled stretching property. Based on this Janus membrane, an open polydimethylsiloxane chip was established to coculture alveolar epithelial cells and vascular endothelial cells at the air-liquid interface. It was demonstrated that the alveolar epithelial cells cultured on the upper side of the Janus membrane could express epithelial cell marker protein E-cadherin and secrete alveolar surfactant. In addition, VE-cadherin, an endothelium-specific protein located at the junction between endothelial cells, was also detected in vascular endothelial cells cultured on the underside of Janus membrane. The constructed lung tissue model with the dynamically stretchable Janus membrane is well-suited for COVID-19 infection studies and drug testing.

Lung-on-chip microdevices to foster pulmonary drug discovery

Respiratory diseases account for unprecedented mortality owing to a lack of personalized or insufficient therapeutic interventions. Fostering pulmonary research into managing pulmonary threat requires a potential alternative approach that can mimick the in vivo complexities of the human body. The in vitro miniaturized bionic simulation of the lung holds great potential in the quest for a successful therapeutic intervention. This review discusses the emerging roles of lung-on-chip microfluidic simulator devices in fostering translational pulmonary drug discovery and personalized medicine. This review also explicates how the lung-on-chip model emulates the breathing patterns, elasticity, and vascularization of lungs in creating a 3D pulmonary microenvironment.

Organoid factory: The recent role of the human induced pluripotent stem cells (hiPSCs) in precision medicine

During the last decades, hiPSC-derived organoids have been extensively studied and used as in vitro models for several applications among which research studies. They can be considered as organ and tissue prototypes, especially for those difficult to obtain. Moreover, several diseases can be accurately modeled and studied. Hence, patient-derived organoids (PDOs) can be used to predict individual drug responses, thus paving the way toward personalized medicine. Lastly, by applying tissue engineering and 3D printing techniques, organoids could be used in the future to replace or regenerate damaged tissue. In this review, we will focus on hiPSC-derived 3D cultures and their ability to model human diseases with an in-depth analysis of gene editing applications, as well as tumor models. Furthermore, we will highlight the state-of-the-art of organoid facilities that around the world offer know-how and services. This is an increasing trend that shed the light on the need of bridging the publicand the private sector. Hence, in the context of drug discovery, Organoid Factories can offer biobanks of validated 3D organoid models that can be used in collaboration with pharmaceutical companies to speed up the drug screening process. Finally, we will discuss the limitations and the future development that will lead hiPSC-derived technology from bench to bedside, toward personalized medicine, such as maturity, organoid interconnections, costs, reproducibility and standardization, and ethics. hiPSC-derived organoid technology is now passing from a proof-of-principle to real applications in the clinic, also thanks to the applicability of techniques, such as CRISPR/Cas9 genome editing system, material engineering for the scaffolds, or microfluidic systems. The benefits will have a crucial role in the advance of both basic biological and translational research, particularly in the pharmacological field and drug development. In fact, in the near future, 3D organoids will guide the clinical decision-making process, having validated patient-specific drug screening platforms. This is particularly important in the context of rare genetic diseases or when testing cancer treatments that could in principle have severe side effects. Therefore, this technology has enabled the advancement of personalized medicine in a way never seen before.

Customizable 3D printed perfusion bioreactor for the engineering of stem cell microenvironments

Faithful modeling of tissues and organs requires the development of systems reflecting their dynamic 3D cellular architecture and organization. Current technologies suffer from a lack of design flexibility and complex prototyping, preventing their broad adoption by the scientific community. To make 3D cell culture more available and adaptable we here describe the use of the fused deposition modeling (FDM) technology to rapid-prototype 3D printed perfusion bioreactors. Our 3D printed bioreactors are made of polylactic acid resulting in reusable systems customizable in size and shape. Following design confirmation, our bioreactors were biologically validated for the culture of human mesenchymal stromal cells under perfusion for up to 2 weeks on collagen scaffolds. Microenvironments of various size/volume (6-12 mm in diameter) could be engineered, by modulating the 3D printed bioreactor design. Metabolic assay and confocal microscopy confirmed the homogenous mesenchymal cell distribution throughout the material pores. The resulting human microenvironments were further exploited for the maintenance of human hematopoietic stem cells. Following 1 week of stromal coculture, we report the recapitulation of 3D interactions between the mesenchymal and hematopoietic fractions, associated with a phenotypic expansion of the blood stem cell populations.Our data confirm that perfusion bioreactors fit for cell culture can be generated using a 3D printing technology and exploited for the 3D modeling of complex stem cell systems. Our approach opens the gates for a more faithful investigation of cellular processes in relation to a dynamic 3D microenvironment.

Spheroids as a 3D Model of the Hypoxic Tumor Microenvironment

Spheroids enable the study of tumors and tumor hypoxia using a more representative model of the physiological environment compared to 2D cell culture. Spheroids can be grown in a cell suspension or when adhered to a solid scaffold. The spheroid formation method used is dependent on cell type. Here we describe the most common spheroid formation methods, including hanging drop, low adhesion plates, hydrogel, micropatterned plates, and microfluidics. After spheroids are formed, they can be used for drug treatment trials and analyzed using Western Blots, qPCR, and microscopy. Microscopy can then be used to measure the invasiveness of cells when a basement membrane is added to spheroids and for monitoring changes in the proliferation, quiescent, and necrotic zones of spheroids.

Transcriptomics indicate nuclear division and cell adhesion not recapitulated in MCF7 and MCF10A compared to luminal A breast tumours

Breast cancer (BC) cell lines are useful experimental models to understand cancer biology. Yet, their relevance to modelling cancer remains unclear. To better understand the tumour-modelling efficacy of cell lines, we performed RNA-seq analyses on a combined dataset of 2D and 3D cultures of tumourigenic MCF7 and non-tumourigenic MCF10A. To our knowledge, this was the first RNA-seq dataset comprising of 2D and 3D cultures of MCF7 and MCF10A within the same experiment, which facilitates the elucidation of differences between MCF7 and MCF10A across culture types. We compared the genes and gene sets distinguishing MCF7 from MCF10A against separate RNA-seq analyses of clinical luminal A (LumA) and normal samples from the TCGA-BRCA dataset. Among the 1031 cancer-related genes distinguishing LumA from normal samples, only 5.1% and 15.7% of these genes also distinguished MCF7 from MCF10A in 2D and 3D cultures respectively, suggesting that different genes drive cancer-related differences in cell lines compared to clinical BC. Unlike LumA tumours which showed increased nuclear division-related gene expression compared to normal tissue, nuclear division-related gene expression in MCF7 was similar to MCF10A. Moreover, although LumA tumours had similar cell adhesion-related gene expression compared to normal tissues, MCF7 showed reduced cell adhesion-related gene expression compared to MCF10A. These findings suggest that MCF7 and MCF10A cell lines were limited in their ability to model cancer-related processes in clinical LumA tumours.

Towards an artificial human lung: modelling organ-like complexity to aid mechanistic understanding

Respiratory diseases account for over 5 million deaths yearly and are a huge burden to healthcare systems worldwide. Murine models have been of paramount importance to decode human lung biology in vivo, but their genetic, anatomical, physiological and immunological differences with humans significantly hamper successful translation of research into clinical practice. Thus, to clearly understand human lung physiology, development, homeostasis and mechanistic dysregulation that may lead to disease, it is essential to develop models that accurately recreate the extraordinary complexity of the human pulmonary architecture and biology. Recent advances in micro-engineering technology and tissue engineering have allowed the development of more sophisticated models intending to bridge the gap between the native lung and its replicates in vitro Alongside advanced culture techniques, remarkable technological growth in downstream analyses has significantly increased the predictive power of human biology-based in vitro models by allowing capture and quantification of complex signals. Refined integrated multi-omics readouts could lead to an acceleration of the translational pipeline from in vitro experimental settings to drug development and clinical testing in the future. This review highlights the range and complexity of state-of-the-art lung models for different areas of the respiratory system, from nasal to large airways, small airways and alveoli, with consideration of various aspects of disease states and their potential applications, including pre-clinical drug testing. We explore how development of optimised physiologically relevant in vitro human lung models could accelerate the identification of novel therapeutics with increased potential to translate successfully from the bench to the patient's bedside.

The Development of a Three-Dimensional Platform for Patient-Derived Ovarian Cancer Tissue Models: A Systematic Literature Review

There is an unmet biomedical need for ex vivo tumour models that would predict drug responses and in turn help determine treatment regimens and potentially predict resistance before clinical studies. Research has shown that three dimensional models of ovarian cancer (OvCa) are more realistic than two dimensional in vitro systems as they are able to capture patient in vivo conditions in more accurate manner. The vast majority of studies aiming to recapitulate the ovarian tumour morphology, behaviors, and study chemotherapy responses have been using ovarian cancer cell lines. However, despite the advantages of utilising cancer cell lines to set up a platform, they are not as informative as systems applying patient derived cells, as cell lines are not able to recapitulate differences between each individual patient characteristics. In this review we discussed the most recent advances in the creation of 3D ovarian cancer models that have used patient derived material, the challenges to overcome and future applications.

Different Expression of Thyroid-Specific Proteins in Thyroid Cancer Cells between 2-Dimensional (2D) and 3-Dimensional (3D) Culture Environment

The two-dimensional (2D) monolayer culture as a conventional method has been widely applied in molecular biology fields, but it has limited capability to recapitulate real cell environments, being prone to misinterpretation with poor prediction of in vivo behavior. Recently, the three-dimensional (3D) spheroid culture has been studied extensively. Spheroids are self-assembled cell aggregates that have biomimicry capabilities. The behavior of thyroid cancer under the 3D spheroid culture environment has been studied; however, there are no reports regarding differences in the degree of thyroid cancer cell differentiation under 2D and 3D culture conditions. This study investigated the expression of thyroid differentiation proteins related to iodide-metabolizing mechanisms in thyroid cancer cells under different culture conditions. Four thyroid cancer cell lines and one thyroid follicular epithelial cell line were grown in adherent 2D cell culture and 3D spheroid culture with agarose-coated plates. We observed changes in proliferation, hypoxia, extracellular matrix (ECM), cytoskeleton, thyroid-specific proteins, and thyroid transcription factors. All cell lines were successfully established in the spheroid following cell aggregation. Proliferation considerably decreased, while hypoxia-inducible factor 1-α(HIF1-α) was promoted in 3D spheroids; moreover, 3D spheroids with thyroid cancers showed diminished thyroid differentiation markers, but thyroid follicular epithelial cells revealed either a maintenance or weak decline of protein expression. We verified that the 3D spheroid culture environment can be similar to in vivo conditions because of its alterations in numerous cellular and functional activities, including morphology, cellular proliferation, viability, hypoxia, ECM, cytoskeleton, and thyroid differentiation, compared to the conventional 2D monolayer culture environment. An in vitro experimental study using 3D spheroid culture is ideal for the faster discovery of new drugs.

Endogenous Synthesis of Tetrahydroisoquinoline Derivatives from Dietary Factors: Neurotoxicity Assessment on a 3D Neurosphere Culture

Tetrahydroisoquinoline (THIQ) alkaloids and their derivatives have a structural similarity to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a well-known neurotoxin. THIQs seem to present a broad range of actions in the brain, critically dependent on their catechol moieties and metabolism. These properties make it reasonable to assume that an acute or chronic exposure to some THIQs might lead to neurodegenerative diseases including essential tremor (ET). We developed a method to search for precursor carbonyl compounds produced during the Maillard reaction in overcooked meats to study their reactivity with endogenous amines and identify the reaction products. Then, we predicted in silico their pharmacokinetic and toxicological properties toward the central nervous system. Finally, their possible neurological effects on a novel in vitro 3D neurosphere model were assessed. The obtained data indicate that meat is an alkaloid precursor, and we identified the alkaloid 1-benzyl-1,2,3,4-tetrahydroisoquinoline-6,7-diol (1-benz-6,7-diol THIQ) as the condensation product of phenylacetaldehyde with dopamine; in silico study of 1-benz-6,7-diol-THIQ reveals modulation of dopamine receptor D1 and D2; and in vitro study of 1-benz-6,7-diol-THIQ for cytotoxicity and oxidative stress induction does not show any difference after 24 h contact for all tested concentrations. To conclude, our in vitro data do not support an eventual neurotoxic effect for 1-benz-6,7-diol-THIQ.

Application of "Click" Chemistry in Biomedical Hydrogels

Since "click" chemistry was first reported in 2001, it has remained a popular research topic in the field of chemistry due to its high yield without byproducts, fast reaction rate, simple reaction, and biocompatibility. It has achieved good applications in various fields, especially for the preparation of hydrogels. The development of biomedicine presents new challenges and opportunities for hydrogels, and "click" chemistry provides a library of chemical tools for the preparation of various innovative hydrogels, including cell culture, 3D bioprinting, and drug release. This article summarizes several common "click" reactions, including copper-catalyzed azide-alkyne cycloaddition reactions, strain-promoted azide-alkyne cycloaddition (SPAAC) reaction, thiol-ene reaction, the Diels-Alder reaction, and the inverse electron demand Diels-Alder (IEDDA) reaction. We introduce the "click" reaction in the nucleic acid field to expand the concept of "click" chemistry. This article focuses on the application of "click" chemistry for preparing various types of biomedical hydrogels and highlights the advantages of "click" reactions for cross-linking to obtain hydrogels. This review also discusses applications of "click" chemistry outside the field of hydrogels, such as drug synthesis, targeted delivery, and surface modification, hydrogels have great application potential in these fields in the future and hopefully inspire other applications of hydrogels.

Establishment and large-scale validation of a three-dimensional tumor model on an array chip for anticancer drug evaluation

Two-dimensional (2D) tumor model has always poorly predicted drug response of animal model due to the lack of recapitulation of tumor microenvironment. Establishing a biomimetic, controllable, and cost-effective three-dimensional (3D) model and large-scale validation of its in vivo predictivity has shown promise in bridging the gap between the 2D tumor model and animal model. Here, we established a matrigel-based 3D micro-tumor model on an array chip for large-scale anticancer drug evaluation. Compared with the 2D tumor model, the 3D tumor model on the chip showed spheroid morphology, slower proliferation kinetics, and comparable reproducibility. Next, the results of the chemotherapeutic evaluation from 18 drugs against 27 cancer cell lines showed 17.6% of drug resistance on the 3D tumor model. Moreover, the evaluation results of targeted drugs showed expected sensitivity and higher specificity on the 3D tumor model compared with the 2D model. Finally, the evaluation results on the 3D tumor model were more consistent with the in vivo cell-derived xenograft model, and excluded 95% false-positive results from the 2D model. Overall, the matrigel-based 3D micro-tumor model on the array chip provides a promising tool to accelerate anticancer drug discovery.

Decellularization of xenografted tumors provides cell-specific in vitro 3D environment

In vitro cell culture studies are common in the cancer research field, and reliable biomimetic 3D models are needed to ensure physiological relevance. In this manuscript, we hypothesized that decellularized xenograft tumors can serve as an optimal 3D substrate to generate a top-down approach for in vitro tumor modeling. Multiple tumor cell lines were xenografted and the formed solid tumors were recovered for their decellularization by several techniques and further characterization by histology and proteomics techniques. Selected decellularized tumor xenograft samples were seeded with the HCC1806 human triple-negative breast cancer (TNBC) basal-like subtype cell line, and cell behavior was compared among them and with other control 2D and 3D cell culture methods. A soft treatment using Freeze-EDTA-DNAse allows proper decellularization of xenografted tumor samples. Interestingly, proteomic data show that samples decellularized from TNBC basal-like subtype xenograft models had different extracellular matrix (ECM) compositions compared to the rest of the xenograft tumors tested. The in vitro recellularization of decellularized ECM (dECM) yields tumor-type–specific cell behavior in the TNBC context. Data show that dECM derived from xenograft tumors is a feasible substrate for reseeding purposes, thereby promoting tumor-type–specific cell behavior. These data serve as a proof-of-concept for further potential generation of patient-specific in vitro research models.

Herpesvirus-induced spermidine synthesis and eIF5A hypusination for viral episomal maintenance

Spermidine is essential for cellular growth and acts as a prerequisite of hypusination, a post-translational modification of eukaryotic initiation factor 5A (eIF5A), allowing the translation of polyproline-containing proteins. Here, we show that oncogenic Kaposi's sarcoma-associated herpesvirus (KSHV) increases spermidine synthesis and eIF5A hypusination to enhance expression of polyproline-containing latency-associated nuclear antigen (LANA) for viral episomal maintenance. KSHV upregulates intracellular spermidine levels by dysregulating polyamine metabolic pathways in three-dimensional (3D) culture and 2D de novo infection conditions. Increased intracellular spermidine leads to increased eIF5A hypusination, ultimately enhancing LANA expression. In contrast, inhibition of spermidine synthesis or eIF5A hypusination alleviates LANA expression, decreasing viral episomal maintenance and KSHV-infected cell proliferation in vitro and in vivo, which is reversed by spermidine supplement. This demonstrates that KSHV hijacks spermidine synthesis and eIF5A hypusination pathways to enhance LANA expression for viral episomal maintenance, suggesting polyamine metabolism and eIF5A hypusination as therapeutic targets for KSHV-induced tumorigenesis.

Spheroid culture for chondrocytes triggers early stage of endochondral ossification

Endochondral ossification is the process of bone formation derived from growing cartilage during the development of the skeletal system. In previous studies, we have attempted to evoke the osteocyte differentiation of osteoblast precursor cells under a three-dimensional (3D) culture model. In order to recapitulate the endochondral ossification, the present study utilized the self-organized scaffold-free spheroid model reconstructed by pre-chondrocyte cells. Within 2-day cultivation in the absence of the chemically induced chondrogenesis supplements, the chondrocyte marker was greatly expressed in the inner region of the spheroid, whereas the hypertrophic chondrocyte marker was strongly detected in the surface region of the spheroid. Notably, we found out that the gene expression levels of osteocyte markers were also greatly up-regulated compared to the conventional 2D monolayer. Moreover, there was a hypertrophied morphologic change in the pre-chondrocyte spheroid from 4-day to 28-day cultivation. In this study, we highlighted the potentials of the 3D culture method to acquire the hypertrophic chondrocyte differentiation of the pre-chondrocyte cells to recapitulate the early stage of the endochondral ossification. This article is protected by copyright. All rights reserved.

Three-dimensional (3D) cell culture: a valuable step in advancing treatments for human hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most common malignant cancer and the third most frequent cause of tumour-related mortality worldwide. Currently, several surgical and medical therapeutic strategies are available for HCCs; however, the interaction between neoplastic cells and non-neoplastic stromal cells within the tumour microenvironment (TME) results in strong therapeutic resistance of HCCs to conventional treatment. Therefore, the development of novel treatments is urgently needed to improve the survival of patients with HCC. The first step in developing efficient chemotherapeutic drugs is the establishment of an appropriate system for studying complex tumour culture and microenvironment interactions. Three-dimensional (3D) culture model might be a crucial bridge between in vivo and in vitro due to its ability to mimic the naturally complicated in vivo TME compared to conventional two-dimensional (2D) cultures. In this review, we shed light on various established 3D culture models of HCC and their role in the investigation of tumour-TME interactions and HCC-related therapeutic resistance.

3D Cell Cultures: Evolution of an Ancient Tool for New Applications

Recently, research is undergoing a drastic change in the application of the animal model as a unique investigation strategy, considering an alternative approach for the development of science for the future. Although conventional monolayer cell cultures represent an established and widely used in vitro method, the lack of tissue architecture and the complexity of such a model fails to inform true biological processes in vivo. Recent advances in cell culture techniques have revolutionized in vitro culture tools for biomedical research by creating powerful three-dimensional (3D) models to recapitulate cell heterogeneity, structure and functions of primary tissues. These models also bridge the gap between traditional two-dimensional (2D) single-layer cultures and animal models. 3D culture systems allow researchers to recreate human organs and diseases in one dish and thus holds great promise for many applications such as regenerative medicine, drug discovery, precision medicine, and cancer research, and gene expression studies. Bioengineering has made an important contribution in the context of 3D systems using scaffolds that help mimic the microenvironments in which cells naturally reside, supporting the mechanical, physical and biochemical requirements for cellular growth and function. We therefore speak of models based on organoids, bioreactors, organ-on-a-chip up to bioprinting and each of these systems provides its own advantages and applications. All of these techniques prove to be excellent candidates for the development of alternative methods for animal testing, as well as revolutionizing cell culture technology. 3D systems will therefore be able to provide new ideas for the study of cellular interactions both in basic and more specialized research, in compliance with the 3R principle. In this review, we provide a comparison of 2D cell culture with 3D cell culture, provide details of some of the different 3D culture techniques currently available by discussing their strengths as well as their potential applications.

Nucleoside-Derived Low-Molecular-Weight Gelators as a Synthetic Microenvironment for 3D Cell Culture

For the last few decades, many efforts have been made in developing cell culture methods in order to overcome the biological limitations of the conventional two-dimensional culture. This paradigm shift is driven by a large amount of new hydrogel-based systems for three-dimensional culture, among other systems, since they are known to mimic some living tissue properties. One class of hydrogel precursors has received interest in the field of biomaterials, low-molecular-weight gelators (LMWGs). In comparison to polymer gels, LMWG gels are formed by weak interactions upon an external trigger between the molecular subunits, giving them the ability to reverse the gelation, thus showing potential for many applications of practical interest. This study presents the use of the nucleoside derivative subclass of LMWGs, which are glyco-nucleo-bola-amphiphiles, as a proof of concept of a 3D cell culture scaffold. Physicochemical characterization was performed in order to reach the optimal features to fulfill the requirements of the cell culture microenvironment, in terms of the mechanical properties, architecture, molecular diffusion, porosity, and experimental practicality. The retained conditions were tested by culturing glioblastoma cells for over a month. The cell viability, proliferation, and spatial organization showed during the experiments demonstrate the proof of concept of nucleoside-derived LMWGs as a soft 3D cell culture scaffold. One of the hydrogels tested permits cell proliferation and spheroidal organization over the entire culture time. These systems offer many advantages as they consume very few matters within the optimal range of viscoelasticity for cell culture, and the thermoreversibility of these hydrogels permits their use with few instruments. The LMWG-based scaffold for the 3D cell culture presented in this study unlocked the ability to grow spheroids from patient cells to reach personalized therapies by dramatically reducing the variability of the lattice used.

An Engineered Protein-Based Building Block (Albumin Methacryloyl) for Fabrication of a 3D In Vitro Cryogel Model

Drug-induced liver injury (DILI) is a leading cause of attrition in drug development or withdrawal; current animal experiments and traditional 2D cell culture systems fail to precisely predict the liver toxicity of drug candidates. Hence, there is an urgent need for an alternative in vitro model that can mimic the liver microenvironments and accurately detect human-specific drug hepatotoxicity. Here, for the first time we propose the fabrication of an albumin methacryloyl cryogel platform inspired by the liver’s microarchitecture via emulating the mechanical properties and extracellular matrix (ECM) cues of liver. Engineered crosslinkable albumin methacryloyl is used as a protein-based building block for fabrication of albumin cryogel in vitro models that can have potential applications in 3D cell culture and drug screening. In this work, protein modification, cryogelation, and liver ECM coating were employed to engineer highly porous three-dimensional cryogels with high interconnectivity, liver-like stiffness, and liver ECM as artificial liver constructs. The resulting albumin-based cryogel in vitro model provided improved cell–cell and cell–material interactions and consequently displayed excellent liver functional gene expression, being conducive to detection of fialuridine (FIAU) hepatotoxicity.

Liver Acinus Dynamic Chip for Assessment of Drug-Induced Zonal Hepatotoxicity

Zonation along the liver acinus is considered a key feature of liver physiology. Here, we developed a liver acinus dynamic (LADY) chip that recapitulates a key functional structure of the liver acinus and hepatic zonation. Corresponding to the blood flow from portal triads to the central vein in vivo, gradual flow of oxygen and glucose–carrying culture medium into the HepG2 cell chamber of the LADY chip generated zonal protein expression patterns in periportal (PP) zone 1 and perivenous (PV) zone 3. Higher levels of albumin secretion and urea production were obtained in a HepG2/HUVECs co-culture LADY chip than in HepG2 mono-culture one. Zonal expression of PEPCK as a PP marker and CYP2E1 as a PV marker was successfully generated. Cell death rate of the PV cells was higher than that of the PP cells since zonal factors responsible for metabolic activation of acetaminophen (APAP) were highly expressed in the PV region. We also found the co-culture enhanced metabolic capacity to process APAP, thus improving resistance to APAP toxicity, in comparison with HepG2 mono-culture. These results indicate that our LADY chip successfully represents liver zonation and could be useful in drug development studies as a drug-induced zonal hepatotoxicity testing platform.

The urothelium: a multi-faceted barrier against a harsh environment

All mucosal surfaces must deal with the challenge of exposure to the outside world. The urothelium is a highly specialized layer of stratified epithelial cells lining the inner surface of the urinary bladder, a gruelling environment involving significant stretch forces, osmotic and hydrostatic pressures, toxic substances, and microbial invasion. The urinary bladder plays an important barrier role and allows the accommodation and expulsion of large volumes of urine without permitting urine components to diffuse across. The urothelium is made up of three cell types, basal, intermediate, and umbrella cells, whose specialized functions aid in the bladder's mission. In this review, we summarize the recent insights into urothelial structure, function, development, regeneration, and in particular the role of umbrella cells in barrier formation and maintenance. We briefly review diseases which involve the bladder and discuss current human urothelial in vitro models as a complement to traditional animal studies.

Nanocelluloses - Nanotoxicology, Safety Aspects and 3D Bioprinting

Nanocelluloses have good rheological properties that facilitate the extrusion of nanocellulose gels in micro-extrusion systems. It is considered a highly relevant characteristic that makes it possible to use nanocellulose as an ink component for 3D bioprinting purposes. The nanocelluloses assessed in this book chapter include wood nanocellulose (WNC), bacterial nanocellulose (BNC), and tunicate nanocellulose (TNC), which are often assumed to be non-toxic. Depending on various chemical and mechanical processes, both cellulose nanofibrils (CNF) and cellulose nanocrystals (CNC) can be obtained from the three mentioned nanocelluloses (WNC, BNC, and TNC). Pre/post-treatment processes (chemical and mechanical) cause modifications regarding surface chemistry and nano-morphology. Hence, it is essential to understand whether physicochemical properties may affect the toxicological profile of nanocelluloses. In this book chapter, we provide an overview of nanotoxicology and safety aspects associated with nanocelluloses. Relevant regulatory requirements are considered. We also discuss hazard assessment strategies based on tiered approaches for safety testing, which can be applied in the early stages of the innovation process. Ensuring the safe development of nanocellulose-based 3D bioprinting products will enable full market use of these sustainable resources throughout their life cycle.

Changes in Elastic Moduli of Fibrin Hydrogels Within the Myogenic Range Alter Behavior of Murine C2C12 and Human C25 Myoblasts Differently

Fibrin hydrogels have proven highly suitable scaffold materials for skeletal muscle tissue engineering in the past. Certain parameters of those types of scaffolds, however, greatly affect cellular mechanobiology and therefore the myogenic outcome. The aim of this study was to identify the influence of apparent elastic properties of fibrin scaffolds in 2D and 3D on myoblasts and evaluate if those effects differ between murine and human cells. Therefore, myoblasts were cultured on fibrin-coated multiwell plates ("2D") or embedded in fibrin hydrogels ("3D") with different elastic moduli. Firstly, we established an almost linear correlation between hydrogels' fibrinogen concentrations and apparent elastic moduli in the range of 7.5 mg/ml to 30 mg/ml fibrinogen (corresponds to a range of 7.7-30.9 kPa). The effects of fibrin hydrogel elastic modulus on myoblast proliferation changed depending on culture type (2D vs 3D) with an inhibitory effect at higher fibrinogen concentrations in 3D gels and vice versa in 2D. The opposite effect was evident in differentiating myoblasts as shown by gene expression analysis of myogenesis marker genes and altered myotube morphology. Furthermore, culture in a 3D environment slowed down proliferation compared to 2D, with a significantly more pronounced effect on human myoblasts. Differentiation potential was also substantially impaired upon incorporation into 3D gels in human, but not in murine, myoblasts. With this study, we gained further insight in the influence of apparent elastic modulus and culture type on cellular behavior and myogenic outcome of skeletal muscle tissue engineering approaches. Furthermore, the results highlight the need to adapt parameters of 3D culture setups established for murine cells when applied to human cells.

Cytotoxicity evaluation of sodium lauryl sulfate in a paper-based 3D cell culture system

Because three-dimensional (3D) cell culture is more similar to in vivo cell microenvironments than two-dimensional (2D) cell culture, various 3D cell culture systems have been developed. Recently, paper has been used as a promising material for 3D cell culture and tissue models due to its flexibility, ease of manufacture, low cost, and widespread accessibility. In this study, we fabricated a paper-based 3D cell culture platform consisting of a hydrophilic region for cell attachment and a hydrophobic region printed with wax. Using this paper platform for 3D culture of L929 cells, we evaluated the cytotoxicity of a model substance, sodium lauryl sulfate (SLS), using water-soluble tetrazolium salt, Live/Dead, and luminescence assays. Then we compared those cytotoxicity results with results from a conventional 3D cell culture kit and 2D cell culture. We found that 3D cultured cells on paper responded more sensitively to SLS than 2D cultured cells, and the cytotoxicity of SLS to cells grown on the paper-based 3D cell culture platform was similar to that of cells grown using a commercially available 3D cell culture kit. Therefore, we expect that our paper-based 3D cell culture platform can be applied as a simple and facile tool for cell viability evaluation.

3D Neuronal Cell Culture Modeling Based on Highly Porous Ultra-High Molecular Weight Polyethylene

Cell culturing methods in its classical 2D approach have limitations associated with altered cell morphology, gene expression patterns, migration, cell cycle and proliferation. Moreover, high throughput drug screening is mainly performed on 2D cell cultures which are physiologically far from proper cell functions resulting in inadequate hit-compounds which subsequently fail. A shift to 3D culturing protocols could solve issues with altered cell biochemistry and signaling which would lead to a proper recapitulation of physiological conditions in test systems. Here, we examined porous ultra-high molecular weight polyethylene (UHMWPE) as an inexpensive and robust material with varying pore sizes for cell culturing. We tested and developed culturing protocols for immortalized human neuroblastoma and primary mice hippocampal cells which resulted in high rate of cell penetration within one week of cultivation. UHMWPE was additionally functionalized with gelatin, poly-L-lysine, BSA and chitosan, resulting in increased cell penetrations of the material. We have also successfully traced GFP-tagged cells which were grown on a UHMWPE sample after one week from implantation into mice brain. Our findings highlight the importance of UHMWPE use as a 3D matrix and show new possibilities arising from the use of cheap and chemically homogeneous material for studying various types of cell-surface interactions further improving cell adhesion, viability and biocompatibility.

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.

Real-time monitoring of immediate drug response and adaptation upon repeated treatment in a microfluidic chip system

Microfluidic tissue culture and organ-on-a-chip models provide efficient tools for drug testing in vivo and are considered to become the basis of in vitro test systems to analyze drug response, drug interactions and toxicity to complement and reduce animal testing. A major limitation is the efficient recording of drug action. Here we present an efficient experimental setup that allows long-term cultivation of cells in a microfluidic system in combination with continuous recording of luciferase reporter gene expression. The system combines a sensitive cooled luminescence camera system in combination with a custom build miniaturized incubation chamber. The setup allows to monitor time-dependent activation, but also the end of drug response. Repeated activation and recovery as well as varying durations of drug treatment periods can be monitored, and different modes of drug activity can be visualized.

Biomimetic Alveolus-on-a-Chip for SARS-CoV-2 Infection Recapitulation

SARS-CoV-2 has caused a severe pneumonia pandemic worldwide with high morbidity and mortality. How to develop a preclinical model for recapitulating SARS-CoV-2 pathogenesis is still urgent and essential for the control of the pandemic. Here, we have established a 3D biomimetic alveolus-on-a-chip with mechanical strain and extracellular matrix taken into consideration. We have validated that the alveolus-on-a-chip is capable of recapitulating key physiological characteristics of human alveolar units, which lays a fundamental basis for viral infection studies at the organ level. Using virus-analogous chemicals and pseudovirus, we have explored virus pathogenesis and blocking ability of antibodies during viral infection. This work provides a favorable platform for SARS-CoV-2-related researches and has a great potential for physiology and pathophysiology studies of the human lung at the organ level in vitro.

Transcriptional Factor Repertoire of Breast Cancer in 3D Cell Culture Models

Simple Summary

Knowledge of the transcriptional regulation of breast cancer tumorigenesis is largely based on studies performed in two-dimensional (2D) monolayer culture models, which lack tissue architecture and therefore fail to represent tumor heterogeneity. However, three-dimensional (3D) cell culture models are better at mimicking in vivo tumor microenvironment, which is critical in regulating cellular behavior. Hence, 3D cell culture models hold great promise for translational breast cancer research.

Abstract

Intratumor heterogeneity of breast cancer is driven by extrinsic factors from the tumor microenvironment (TME) as well as tumor cell–intrinsic parameters including genetic, epigenetic, and transcriptomic traits. The extracellular matrix (ECM), a major structural component of the TME, impacts every stage of tumorigenesis by providing necessary biochemical and biomechanical cues that are major regulators of cell shape/architecture, stiffness, cell proliferation, survival, invasion, and migration. Moreover, ECM and tissue architecture have a profound impact on chromatin structure, thereby altering gene expression. Considering the significant contribution of ECM to cellular behavior, a large body of work underlined that traditional two-dimensional (2D) cultures depriving cell–cell and cell–ECM interactions as well as spatial cellular distribution and organization of solid tumors fail to recapitulate in vivo properties of tumor cells residing in the complex TME. Thus, three-dimensional (3D) culture models are increasingly employed in cancer research, as these culture systems better mimic the physiological microenvironment and shape the cellular responses according to the microenvironmental cues that will regulate critical cell functions such as cell shape/architecture, survival, proliferation, differentiation, and drug response as well as gene expression. Therefore, 3D cell culture models that better resemble the patient transcriptome are critical in defining physiologically relevant transcriptional changes. This review will present the transcriptional factor (TF) repertoire of breast cancer in 3D culture models in the context of mammary tissue architecture, epithelial-to-mesenchymal transition and metastasis, cell death mechanisms, cancer therapy resistance and differential drug response, and stemness and will discuss the impact of culture dimensionality on breast cancer research.

Bioengineered models of Parkinson's disease using patient-derived dopaminergic neurons exhibit distinct biological profiles in a 3D microenvironment

Three-dimensional (3D) in vitro culture systems using human induced pluripotent stem cells (hiPSCs) are useful tools to model neurodegenerative disease biology in physiologically relevant microenvironments. Though many successful biomaterials-based 3D model systems have been established for other neurogenerative diseases, such as Alzheimer's disease, relatively few exist for Parkinson's disease (PD) research. We employed tissue engineering approaches to construct a 3D silk scaffold-based platform for the culture of hiPSC-dopaminergic (DA) neurons derived from healthy individuals and PD patients harboring LRRK2 G2019S or GBA N370S mutations. We then compared results from protein, gene expression, and metabolic analyses obtained from two-dimensional (2D) and 3D culture systems. The 3D platform enabled the formation of dense dopamine neuronal network architectures and developed biological profiles both similar and distinct from 2D culture systems in healthy and PD disease lines. PD cultures developed in 3D platforms showed elevated levels of α-synuclein and alterations in purine metabolite profiles. Furthermore, computational network analysis of transcriptomic networks nominated several novel molecular interactions occurring in neurons from patients with mutations in LRRK2 and GBA. We conclude that the brain-like 3D system presented here is a realistic platform to interrogate molecular mechanisms underlying PD biology.

Photoactive 3D-Printed Hypertensile Metamaterials for Improving Dynamic Modeling of Stem Cells

Current three-dimensional (3D) cell culture systems mainly rely on static cell culture and lack the ability to thoroughly manage cell intrinsic behaviors and biological characteristics, leading to unsatisfied cell activity. Herein, we have developed photoactive 3D-printed hypertensile metamaterials based dynamic cell culture system (MetaFold) for guiding cell fate. MetaFold exhibited high elasticity and photothermal conversion efficiency due to its metapattern architecture and micro/nanoscale polydopamine coating, allowing for responding to mechanical and light stimulation to construct dynamic culture conditions. In addition, MetaFold possessed excellent cell adhesion capability and could promote cell viability and function under dynamic stimulation, thereby maximizing cell activity. Importantly, MetaFold could improve the differentiation efficacy of stem cells into cardiomyocytes and even their maturation, offering high-quality precious candidates for cell therapy. Therefore, we present a dual stimuli-responsive dynamic culture system, which provides a physiologically realistic environment for cell culture and biological study.

Three-dimensional cell culture (3DCC) improves secretion of signaling molecules of mesenchymal stem cells (MSCs)

OBJECTIVES

The secretome of mesenchymal stem cells (MSCs), also called MSC-conditioned media (MSC-CM), represents one of the promising strategies for cellular therapy and tissue repair and regeneration. MSC-CM contains growth factors and cytokines that control many cellular responses during development and regeneration. Traditional 2D cell culture (2DCC) has previously been used to generate MSC-CM while evidence has proved that the physiological and biological behaviors of cells in 2DCC are significantly different from those in 3D cell culture (3DCC). Therefore, the objective is to compare the content of MSC-CM generated from traditional 2DCC and 3DCC using a 3D scaffold.

METHODS

Adipose tissue-derived MSCs (AT-MSCs) were isolated from four donors (N = 4) and characterized according to the criteria stipulated by the International Society for Cell Therapy (ISCT). MSCs at passage 3 were grown in traditional 2DCC until 70% confluence and MSC-CM were collected at 24, 48, and 94 h. On the other hand, MSCs at passage 3 were grown on a polystyrene scaffold for 10 days to generate a 3D model of MSCs, and then MSC-CM was collected at 24, 48, and 94 h. MSC-CM from both 2DCC and 3DCC were analyzed for protein content using ELISA. Haematoxylin eosin (HE) staining and immunofluorescence (IF) were used to characterize the 3DCC of MSCs.

RESULTS

MSCs from 2DCC were fibroblast like cells, and flow cytometry showed they were positive for CD73 and CD105 while being negative for CD14, CD19, and HLA-DR. They were also able to differentiate into adipocytes, osteoblasts, and chondrocytes. HE and IF showed that MSCs formed 3D model structures on the polystyrene scaffold. MSC-CM collected from both 2DCC and 3DCC contained growth factors, e.g., platelet derived growth factor (PDGF-AB), transforming growth factor-1 (TGF-1), hepatocyte growth factor (HGF), stromal derived factor-1 (SDF-1), interleukin 1 (IL-1), and interleukin 6 (IL-6). Concentrations of biomolecules secreted by MSCs in 3DCC were significantly higher than in 2DCC.

CONCLUSION

It could be concluded that 3DCC of MSCs using a polystyrene scaffold is a novel approach to generate MSC secretome for therapeutic applications.

Transitioning pre-clinical glioblastoma models to clinical settings with biomarkers identified in 3D cell-based models: A systematic scoping review

Glioblastoma (GBM) remains incurable despite the overwhelming discovery of 2-dimensional (2D) cell-based potential therapeutics since the majority of them have met unsatisfactory results in animal and clinical settings. Incremental empirical evidence has laid the widespread need of transitioning 2D to 3-dimensional (3D) cultures that better mimic GBM's complex and heterogenic nature to allow better translation of pre-clinical results. This systematic scoping review analyses the transcriptomic data involving 3D models of GBM against 2D models from 22 studies identified from four databases (PubMed, ScienceDirect, Medline, and Embase). From a total of 499 genes reported in these studies, 313 (63%) genes were upregulated across 3D models cultured using different scaffolds. Our analysis showed that 4 of the replicable upregulated genes are associated with GBM stemness, epithelial to mesenchymal transition (EMT), hypoxia, and migration-related genes regardless of the type of scaffolds, displaying close resemblances to primitive undifferentiated tumour phenotypes that are associated with decreased overall survival and increased hazard ratio in GBM patients. The upregulation of drug response and drug efflux genes (e.g. cytochrome P450s and ABC transporters) mirrors the GBM genetic landscape that contributes to in vivo and clinical treatment resistance. These upregulated genes displayed strong protein-protein interactions when analysed using an online bioinformatics software (STRING). These findings reinforce the need for widespread transition to 3D GBM models as a relatively inexpensive humanised pre-clinical tool with suitable genetic biomarkers to bridge clinical gaps in potential therapeutic evaluations.

Patient-Derived Organoids in Precision Medicine: Drug Screening, Organoid-on-a-Chip and Living Organoid Biobank

Organoids are in vitro self-assembling, organ-like, three-dimensional cellular structures that stably retain key characteristics of the respective organs. Organoids can be generated from healthy or pathological tissues derived from patients. Cancer organoid culture platforms have several advantages, including conservation of the cellular composition that captures the heterogeneity and pharmacotypic signatures of the parental tumor. This platform has provided new opportunities to fill the gap between cancer research and clinical outcomes. Clinical trials have been performed using patient-derived organoids (PDO) as a tool for personalized medical decisions to predict patients' responses to therapeutic regimens and potentially improve treatment outcomes. Living organoid biobanks encompassing several cancer types have been established, providing a representative collection of well-characterized models that will facilitate drug development. In this review, we highlight recent developments in the generation of organoid cultures and PDO biobanks, in preclinical drug discovery, and methods to design a functional organoid-on-a-chip combined with microfluidic. In addition, we discuss the advantages as well as limitations of human organoids in patient-specific therapy and highlight possible future directions.

Advancements in 3D Cell Culture Systems for Personalizing Anti-Cancer Therapies

Over 90% of potential anti-cancer drug candidates results in translational failures in clinical trials. The main reason for this failure can be attributed to the non-accurate pre-clinical models that are being currently used for drug development and in personalised therapies. To ensure that the assessment of drug efficacy and their mechanism of action have clinical translatability, the complexity of the tumor microenvironment needs to be properly modelled. 3D culture models are emerging as a powerful research tool that recapitulates in vivo characteristics. Technological advancements in this field show promising application in improving drug discovery, pre-clinical validation, and precision medicine. In this review, we discuss the significance of the tumor microenvironment and its impact on therapy success, the current developments of 3D culture, and the opportunities that advancements that in vitro technologies can provide to improve cancer therapeutics.

Thermosensitive chitosan-based hydrogels supporting motor neuron-like NSC-34 cell differentiation

Motor neuron diseases are neurodegenerative diseases that predominantly affect the neuromuscular system. To date, there are no valid therapeutic treatments for such diseases, and the classical experimental models fail in faithfully reproducing the pathological mechanisms behind them. In this regard, the use of three-dimensional (3D) culture systems, which more closely reproduce the native in vivo environment, can be a promising approach. Hydrogel-based systems are among the most used materials to reproduce the extracellular matrix, featuring an intrinsic similarity with its physiological characteristics. In this study, we developed a thermosensitive chitosan-based hydrogel combined with β-glycerophosphate (βGP) and sodium hydrogen carbonate (SHC), which give the system optimal mechanical properties and injectability, inducing the hydrogel sol-gel transition at 37 °C. An ad hoc protocol for the preparation of the hydrogel was established in order to obtain a highly homogeneous system, leading to reproducible physicochemical characteristics and easy cell encapsulation. All formulations supported the viability of a neuroblastoma/spinal cord hybrid cell line (NSC-34) beyond two weeks of culture and enabled cell differentiation towards a motor neuron-like morphology, characterized by the presence of extended neurites. Based on our results, these hydrogels represent excellent candidates for establishing 3D in vitro models of motor neuron diseases.

Development of a Simple Spheroid Production Method Using Fluoropolymers with Reduced Chemical and Physical Damage

Establishing an in vitro–based cell culture system that can realistically simulate in vivo cell dynamics is desirable. It is thus necessary to develop a method for producing a large amount of cell aggregates (i.e., spheroids) that are uniform in size and quality. Various methods have been proposed for the preparation of spheroids; however, none of them satisfy all requirements, such as cost, size uniformity, and throughput. Herein, we successfully developed a new cell culture method by combining fluoropolymers and dot patterned extracellular matrix substrates to achieve size-controlled spheroids. First, the spheroids were spontaneously formed by culturing them two-dimensionally, after which the cells were detached with a weak liquid flow and cultured in suspension without enzyme treatment. Stable quality spheroids were easily produced, and it is expected that the introduction and running costs of the technique will be low; therefore, this method shows potential for application in the field of regenerative medicine.

Development of Breast Cancer Spheroids to Evaluate Cytotoxic Response to an Anticancer Peptide

Breast cancer (BC) is the most commonly diagnosed cancer in women and one of the most common causes of cancer-related deaths. Despite intense research efforts, BC treatment still remains challenging. Improved drug development strategies are needed for impactful benefit to patients. Current preclinical studies rely mostly on cell-based screenings, using two-dimensional (2D) cell monolayers that do not mimic in vivo tumors properly. Herein, we explored the development and characterization of three-dimensional (3D) models, named spheroids, of the most aggressive BC subtypes (triple-negative breast cancer-TNBC; and human-epidermal growth receptor-2-HER2+), using the liquid overlay technique with several selected cell lines. In these cell line-derived spheroids, we studied cell density, proliferation, ultrastructure, apoptosis, reactive oxygen species (ROS) production, and cell permeabilization (live/dead). The results showed a formation of compact and homogeneous spheroids on day 7 after seeding 2000 cells/well for MDA-MB-231 and 5000 cells/well for BT-20 and BT-474. Next, we compared the efficacy of a model anticancer peptide (ACP) in cell monolayers and spheroids. Overall, the results demonstrated spheroids to be less sensitive to treatment than cell monolayers, revealing the need for more robust models in drug development.

A multidimensional biosensor system to guide LUAD individualized treatment

Lung cancer, mainly non-small cell lung cancer (NSCLC), has been a global health problem, leading to maximum cancer death. Across adenocarcinoma patients, significant genetic and phenotypic heterogeneity was identified as responsible for individual cancer drug resistance, driving an urgent need for individualized treatment. High expectation has been set on individualized treatment for better responses and extended survival. There are pressing needs for and significant advantages of testing dosages and drugs directly on patient-specific cancer cells for preclinical drug testing and personalized drug selection. Monitoring the drug response based on patient-derived cells (PDCs) is a step toward effective drug development and individualized treatment. Despite the dependence on optical labels, optical equipment, and other complex manual operation, we here report a multidimensional biosensor system to guide adenocarcinoma individualized treatment by integrating 2D and 3D PDC models and cellular impedance biosensors. The cellular impedance biosensors were applied to quantitate drug response in 2D and 3D environments. Compared with 2D plate culture, 3D cultured cells were found to show higher resistance to anti-cancer drugs. Cell-cell, cell-ECM, and mechanical interactions in the 3D environment led to stronger drug resistance. The in vivo results demonstrated the reliability of the multidimensional biosensor system. Cellular impedance biosensors allow a fast, non-invasive, and quantitative manner for preselected drug screening in individualized treatment. Considering the potential for good distinguishment of different anti-cancer drugs, our newly developed strategy may contribute to drug response prediction in individualized treatment and new drug development.

Biologia Futura: the importance of 3D organoids-a new approach for research on neurological and rare diseases

3D cell cultures and organoid approach are increasingly being used for basic research and drug discovery of several diseases. Recent advances in these technologies, enabling research on tissue-like structures created in vitro is very important for the value of the data produced. Application of 3D cultures will not only contribute to advancing basic research, but also help to reduce animal usage in biomedical science. The 3D organoid approach is important for research on diseases where patient tissue is difficult to obtain. Therefore, this review aims to show recent advances in the 3D organoid technology in disease modeling and potential usage in translational and personalized medicine of diseases with limited patient material such as neurological diseases and rare diseases.

Characterization of in vitro 3D cultures

Over the past decade, 3D culture models of human and animal cells have found their way into tissue differentiation, drug development, personalized medicine and tumour behaviour studies. Embryoid bodies (EBs) are in vitro 3D cultures established from murine pluripotential stem cells, whereas tumoroids are patient-derived in vitro 3D cultures. This thesis aims to describe a new implication of an embryoid body model and to characterize the patient-specific microenvironment of the parental tumour in relation to tumoroid growth rate. In this thesis, we described a high-throughput monitoring method, where EBs are used as a dynamic angiogenesis model. In this model, digital image analysis (DIA) is implemented on immunohistochemistry (IHC) stained sections of the cultures over time. Furthermore, we have investigated the correlation between the genetic profile and inflammatory microenvironment of parental tumours on the in vitro growth rate of tumoroids. The EBs were cultured in spinner flasks. The samples were collected at days 4, 6, 9, 14, 18 and 21, dehydrated and embedded in paraffin. The histological sections were IHC stained for the endothelial marker CD31 and digitally scanned. The virtual whole-image slides were digitally analysed by Visiopharm® software. Histological evaluation showed vascular-like structures over time. The quantitative DIA was plausible to monitor significant increase in the total area of the EBs and an increase in endothelial differentiation. The tumoroids were established from 32 colorectal adenocarcinomas. The in vitro growth rate of the tumoroids was followed by automated microscopy over an 11-day period. The parental tumours were analysed by next-generation sequencing for KRAS, TP53, PIK3CA, SMAD4, MAP2K1, BRAF, FGFR3 and FBXW7 status. The tumoroids established from KRAS-mutated parental tumours showed a significantly higher growth rate compared to their wild-type counterparts. The density of CD3+ T lymphocytes and CD68+ macrophages was calculated in the centre of the tumours and at the invasive margin of the tumours. The high density of CD3+ cells and the low density of CD68+ cells showed a significant correlation with a higher growth rate of the tumoroids. In conclusion, a novel approach for histological monitoring of endothelial differentiation is presented in the stem cell-derived EBs. Furthermore, the KRAS status and density of CD3+ T cells and macrophages in the parental tumour influence the growth rate of the tumoroids. Our results indicate that these parameters should be included when tumoroids are to be implemented in personalized medicine.

Three-Dimensional Aggregated Spheroid Model of Hepatocellular Carcinoma Using a 96-Pillar/Well Plate

A common method of three-dimensional (3D) cell cultures is embedding single cells in Matrigel. Separated cells in Matrigel migrate or grow to form spheroids but lack cell-to-cell interaction, which causes difficulty or delay in forming mature spheroids. To address this issue, we proposed a 3D aggregated spheroid model (ASM) to create large single spheroids by aggregating cells in Matrigel attached to the surface of 96-pillar plates. Before gelling the Matrigel, we placed the pillar inserts into blank wells where gravity allowed the cells to gather at the curved end. In a drug screening assay, the ASM with Hepatocellular carcinoma (HCC) cell lines showed higher drug resistance compared to both a conventional spheroid model (CSM) and a two-dimensional (2D) cell culture model. With protein expression, cytokine activation, and penetration analysis, the ASM showed higher expression of cancer markers associated with proliferation (p-AKT, p-Erk), tight junction formation (Fibronectin, ZO-1, Occludin), and epithelial cell identity (E-cadherin) in HCC cells. Furthermore, cytokine factors were increased, which were associated with immune cell recruitment/activation (MIF-3α), extracellular matrix regulation (TIMP-2), cancer interaction (IL-8, TGF-β2), and angiogenesis regulation (VEGF-A). Compared to CSM, the ASM also showed limited drug penetration in doxorubicin, which appears in tissues in vivo. Thus, the proposed ASM better recapitulated the tumor microenvironment and can provide for more instructive data during in vitro drug screening assays of tumor cells and improved prediction of efficacious drugs in HCC patients.

Advances in culture methods for acute myeloid leukemia research

Conventional suspension cultures have been used in Acute Myeloid Leukemia (AML) research to study its biology as well as to screen any drug molecules, since its inception. Co-culture models of AML cells and other stromal cells as well as 3 dimensional (3D) culture models have gained much attention recently. These culture models try to recapitulate the tumour microenvironment and are found to be more suitable than suspension cultures. Though animal models are being used, they require more time, effort and facilities and hence, it is essential to develop cell culture models for high-throughput screening of drugs. Here, we discuss a new co-culture model developed by our research group involving acute myeloid leukemia (AML) cells and stimulated macrophages. Other studies on co-culture systems and relevance of 3D culture in leukemic research in understanding the pathology and treatment of leukemia are also reviewed.

Generation of Hepatobiliary Cell Lineages from Human Induced Pluripotent Stem Cells: Applications in Disease Modeling and Drug Screening

The possibility to reproduce key tissue functions in vitro from induced pluripotent stem cells (iPSCs) is offering an incredible opportunity to gain better insight into biological mechanisms underlying development and disease, and a tool for the rapid screening of drug candidates. This review attempts to summarize recent strategies for specification of iPSCs towards hepatobiliary lineages -hepatocytes and cholangiocytes-and their use as platforms for disease modeling and drug testing. The application of different tissue-engineering methods to promote accurate and reliable readouts is discussed. Space is given to open questions, including to what extent these novel systems can be informative. Potential pathways for improvement are finally suggested.

Microarray profiling emphasizes transcriptomic differences between hippocampal in vivo tissue and in vitro cultures

Primary hippocampal cell cultures are routinely used as an experimentally accessible model platform for the hippocampus and brain tissue in general. Containing multiple cell types including neurons, astrocytes and microglia in a state that can be readily analysed optically, biochemically and electrophysiologically, such cultures have been used in many in vitro studies. To what extent the in vivo environment is recapitulated in primary cultures is an on-going question. Here, we compare the transcriptomic profiles of primary hippocampal cell cultures and intact hippocampal tissue. In addition, by comparing profiles from wild type and the PrP 101LL transgenic model of prion disease, we also demonstrate that gene conservation is predominantly conserved across genetically altered lines.

Cancer Cell Direct Bioprinting: A Focused Review

Three-dimensional printing technologies allow for the fabrication of complex parts with accurate geometry and less production time. When applied to biomedical applications, two different approaches, known as direct or indirect bioprinting, may be performed. The classical way is to print a support structure, the scaffold, and then culture the cells. Due to the low efficiency of this method, direct bioprinting has been proposed, with or without the use of scaffolds. Scaffolds are the most common technology to culture cells, but bioassembly of cells may be an interesting methodology to mimic the native microenvironment, the extracellular matrix, where the cells interact between themselves. The purpose of this review is to give an updated report about the materials, the bioprinting technologies, and the cells used in cancer research for breast, brain, lung, liver, reproductive, gastric, skin, and bladder associated cancers, to help the development of possible treatments to lower the mortality rates, increasing the effectiveness of guided therapies. This work introduces direct bioprinting to be considered as a key factor above the main tissue engineering technologies.

Thermosensitive and Conductive Hybrid Polymer for Real-Time Monitoring of Spheroid Growth and Drug Responses

Three-dimensional (3D) cell culture based on polymer scaffold provides a promising tool to mimic a physiological microenvironment for drug testing; however, the next-generation cell activity monitoring technology for 3D cell culture is still challenging. Conventionally, drug efficacy evaluation and cell growth heavily rely on cell staining assays, using optical devices or flow cytometry. Here, we report a dual-function polymer scaffold (DFPS) composed of thermosensitive, silver flake- and gold nanoparticle-decorated polymers, enabling conductance change upon cell proliferation or death for in situ cell activity monitoring and drug screening. The cell activity can be quantitatively monitored via measuring the conductance change induced by polymeric network swelling or shrinkage. This novel dual-function system (1) provides a 3D microenvironment to enable the formation and growth of tumor spheroid in vitro and streamlines the harvesting of tumor spheroids through the thermosensitive scaffold and (2) offers a simple and direct quantitative method to monitor 3D cell culture in situ for drug responses. As a proof of concept, we demonstrated that a breast cancer stem cell line MDA-MB-436 was able to form cell spheroids in the scaffold, and the conductance change of the sensor exhibited a linear relationship with cell concentration. To examine its potential in drug screening, cancer spheroids in the cell sensor were treated with paclitaxel (PTX) and docetaxel (DTX), and predicted quantitative evaluation of the cytotoxic effect of drugs was established. Our results indicated that this cell sensing system may hold promising potential in expanding into an array device for high-throughput drug screening.