Tubuloids derived from human adult kidney and urine for personalized disease modeling

Progress of personalized medicine of cystic fibrosis in the times of efficient CFTR modulators

BACKGROUND

Cystic fibrosis (CF) is a systemic disorder of exocrine glands that is caused by mutations in the CFTR gene.

MAIN BODY

The basic defect in people with CF (pwCF) leads to impaired epithelial transport of chloride and bicarbonate that can be assessed by CFTR biomarkers, i.e. the β-adrenergic sweat rate and sweat chloride concentration (SCC), chloride conductance of the nasal respiratory epithelium (NPD), urine secretion of bicarbonate, intestinal current measurements (ICM) of chloride secretory responses in rectal biopsies and in bioassays of chloride transport in organoids or cell cultures. CFTR modulators are a novel class of drugs that improve defective posttranslational processing, trafficking and function of mutant CFTR. By April 2025, triple combination therapy with the CFTR potentiator ivacaftor (IVA) and the CFTR correctors elexacaftor (ELX) and tezacaftor (TEZ) has been approved in Europe for the treatment of all pwCF who do not carry two minimal function CFTR mutations. Previous phase 3 and post-approval phase 4 studies in pwCF who harbour one or two alleles of the major mutation F508del consistently reported significant improvements of lung function and anthropometry upon initiation of ELX/TEZ/IVA compared to baseline. Normalization of SCC, NPD and ICM correlated with clinical outcomes on the population level, but the restoration of CFTR function was diverse and not predictive for clinical outcome in the individual patient. Theratyping of non-F508del CF genotypes in patient-derived organoids and cell cultures revealed for most cases clinically meaningful increases of CFTR activity upon exposure to ELX/TEZ/IVA. Likewise, every second CF patient with non-F508del genotypes improved in SCC and clinical outcome upon exposure to ELX/TEZ/IVA indicating that triple CFTR modulator therapy is potentially beneficial for all pwCF who do not carry two minimal function CFTR mutations. This group who is not eligible for CFTR modulators may opt for gene addition therapy in the future, as the first-in-human trial with a recombinant lentiviral vector is underway.

FUTURE DIRECTIONS

The upcoming generation of pwCF will probably experience a rather normal life in childhood and adolescence. To classify the upcoming personal signatures of CF disease in the times of efficient modulators, we need more sensitive CFTR biomarkers that address the long-term course of airway and gut microbiome, host defense, epithelial homeostasis and multiorgan metabolism.

A perfused iPSC-derived proximal tubule model for predicting drug-induced kidney injury

The kidney is frequently exposed to high levels of drugs and their metabolites, which can injure the kidney and the proximal tubule (PT) in particular. In order to detect nephrotoxicity early during drug development, relevant in vitro models are essential. Here, we introduce a robust and versatile cell culture insert-based iPSC-derived PT model, which can be maintained in a microphysiological system for at least ten days. We demonstrate the model's ability to predict drug-induced PT injury using polymyxin B, cyclosporin A, and cisplatin, and observe that perfusion distinctly impacts our model's response to xenobiotics. We observe that the upregulation of metallothioneins that is described in vivo after treatment with these drugs is reliably detected in dynamic, but not static in vitro PT models. Finally, we use our model to alleviate polymyxin-induced nephrotoxicity by supplementing the antioxidant curcumin. Together, these findings illustrate that our perfused iPSC-derived PT model is versatile and well-suited for in vitro studies investigating nephrotoxicity and its prevention. Reliable and user-friendly in vitro models like this enable the early detection of nephrotoxic potential, thereby minimizing adverse effects and reducing drug attrition.

From organoids to organoids-on-a-chip: Current applications and challenges in biomedical research

ABSTRACT

The high failure rates in clinical drug development based on animal models highlight the urgent need for more representative human models in biomedical research. In response to this demand, organoids and organ chips were integrated for greater physiological relevance and dynamic, controlled experimental conditions. This innovative platform-the organoids-on-a-chip technology-shows great promise in disease modeling, drug discovery, and personalized medicine, attracting interest from researchers, clinicians, regulatory authorities, and industry stakeholders. This review traces the evolution from organoids to organoids-on-a-chip, driven by the necessity for advanced biological models. We summarize the applications of organoids-on-a-chip in simulating physiological and pathological phenotypes and therapeutic evaluation of this technology. This section highlights how integrating technologies from organ chips, such as microfluidic systems, mechanical stimulation, and sensor integration, optimizes organoid cell types, spatial structure, and physiological functions, thereby expanding their biomedical applications. We conclude by addressing the current challenges in the development of organoids-on-a-chip and offering insights into the prospects. The advancement of organoids-on-a-chip is poised to enhance fidelity, standardization, and scalability. Furthermore, the integration of cutting-edge technologies and interdisciplinary collaborations will be crucial for the progression of organoids-on-a-chip technology.

Kidney Fibrosis In Vitro and In Vivo Models: Path Toward Physiologically Relevant Humanized Models

Chronic kidney disease (CKD) affects over 10% of the global population and is a leading cause of mortality. Kidney fibrosis, a key endpoint of CKD, disrupts nephron tubule anatomy and filtration function, and disease pathomechanisms are not fully understood. Kidney fibrosis is currently investigated with in vivo models, that gradually support the identification of possible mechanisms of fibrosis, but with limited translational research, as they do not fully recapitulate human kidney physiology, metabolism, and molecular pathways. In vitro 2D cell culture models are currently used, as a starting point in disease modeling and pharmacology, however, they lack the 3D kidney architecture complexity and functions. The failure of several therapies and drugs in clinical trials highlights the urgent need for advanced 3D in vitro models. This review discusses the urinary system's anatomy, associated diseases, and diagnostic methods, including biomarker analysis and tissue biopsy. It evaluates 2D and in vivo models, highlighting their limitations. The review explores the state-of-the-art 3D-humanized in vitro models, such as 3D cell aggregates, on-chip models, biofabrication techniques, and hybrid models, which aim to mimic kidney morphogenesis and functions. These advanced models hold promise for translating new therapies and drugs for kidney fibrosis into clinics.

Unveiling spontaneous renal tubule-like structures from human adult renal progenitor cell spheroids derived from urine

The rapidly developing field of renal spheroids and organoids has emerged as a valuable tool for modeling nephrotoxicity, kidney disorders, and kidney development. However, existing studies have relied on intricate and sophisticated differentiation protocols to generate organoids and tubuloids, necessitating the external administration of multiple growth factors within precise timeframes. In our study, we demonstrated that human adult renal progenitor cells (ARPCs) isolated from the urine of both healthy subjects and patients can form spheroids that naturally generated very long tubule-like structures. Importantly, the generation of these tubule-like structures is driven solely by ARPCs, without the need for the external use of chemokines or growth factors to artificially induce this process. These tubule-like structures exhibit the expression of structural and functional renal tubule markers and bear, in some cases, striking structural similarities to various nephron regions, including the distal convoluted tubule, the loop of Henle, and proximal convoluted tubules. Furthermore, ARPC spheroids express markers typical of pluripotent cells, such as stage-specific embryonic antigen 4 (SSEA4), secrete elevated levels of renin, and exhibit angiogenic properties. Notably, ARPCs isolated from the urine of patients with IgA nephropathy form spheroids capable of recapitulating the characteristic IgA1 deposition observed in this disease. These findings represent significant advancements in the field, opening up new avenues for regenerative medicine in the study of kidney development, mechanisms underlying renal disorders, and the development of regenerative therapies for kidney-related ailments.

Human and rat renal proximal tubule in vitro models for ADME applications

The kidney is a major organ dictating excretion rates of chemicals and their metabolites from the body and thus renal clearance is frequently a major component of pharmaco-(toxico)-kinetic profiles. Within the nephron, the proximal tubule is the major site for xenobiotic reabsorption from glomerular filtrate and xenobiotic secretion from the blood into the lumen via the expression of multiple inward (lumen to interstitium) and outward transport systems (interstitium to lumen). While there exist several human proximal tubular cell culture options that could be utilized for modelling the proximal tubule component of renal clearance, they do not necessarily represent the full complement of xenobiotic transport processes of their in vivo counterparts. Here, we review available human and rat renal proximal tubule in vitro models, including subcellular fractions, immortalized cell lines, primary cell cultures, induced pluripotent stem cell (iPSC)-derived models and also consider more organotypic cell culture environments such as microporous growth supports, organoids and microfluidic systems. This review focuses on expression levels and function of human and rat renal transporters and phase I and II metabolizing enzymes in these models in order to critically assess their usefulness and to identify potential solutions to overcome identified limitations.

The biological macromolecules constructed Matrigel for cultured organoids in biomedical and tissue engineering

Matrigel is the most commonly used matrix for 3D organoid cultures. Research on the biomaterial basis of Matrigel for organoid cultures is a highly challenging field. Currently, many studies focus on Matrigel-based biological macromolecules or combinations to construct natural Matrigel and synthetic hydrogel scaffolds based on collagen, peptides, polysaccharides, microbial transglutaminase, DNA supramolecules, and polymers for organoid culture. In this review, we discuss the limitations of both natural and synthetic Matrigel, and describe alternative scaffolds that have been employed for organoid cultures. The patient-derived organoids were constructed in different cancer types and limitations of animal-derived organoids based on the hydrogel or Matrigel. The constructed techniques utilizing 3D bioprinting platforms, air-liquid interface (ALI) culture, microfluidic culture, and organ-on-a-chip platform are summarized. Given the potential of organoids for a wide range of therapeutic, tissue engineering and pharmaceutical applications, it is indeed imperative to develop defined and customized hydrogels in addition to Matrigel.

Organoids from pluripotent stem cells and human tissues: When two cultures meet each other

Human organoids are a widely used tool in cell biology to study homeostatic processes, disease, and development. The term organoids covers a plethora of model systems from different cellular origins that each have unique features and applications but bring their own challenges. This review discusses the basic principles underlying organoids generated from pluripotent stem cells (PSCs) as well as those derived from tissue stem cells (TSCs). We consider how well PSC- and TSC-organoids mimic the different intended organs in terms of cellular complexity, maturity, functionality, and the ongoing efforts to constitute predictive complex models of in vivo situations. We discuss the advantages and limitations associated with each system to answer different biological questions including in the field of cancer and developmental biology, and with respect to implementing emerging advanced technologies, such as (spatial) -omics analyses, CRISPR screens, and high-content imaging screens. We postulate how the two fields may move forward together, integrating advantages of one to the other.

Human kidney organoids for modeling the development of different diseases

The increasing incidence of kidney diseases has highlighted the need for in vitro experimental models to mimic disease development and to test new therapeutic approaches. Traditional two-dimensional in vitro experimental models are not fully able to recapitulate renal diseases. Instead, kidney organoids represent three-dimensional models that better mimic the human organ from both structural and functional points of view. Human pluripotent stem cells (PSCs), both embryonic and induced, are ideal sources for generating renal organoids. These organoids contain all renal cell types and the protocols to differentiate PSCs into renal organoids consist of three different stages that recapitulate embryonic development: mesodermal induction, nephron progenitor formation, and nephron differentiation. Recently it has been establish a renal organoid model where collecting ducts are also present. In this case, the presence of ureteric bud progenitor cells is essential. Renal organoids are particularly useful for studying genetic diseases, by introducing the specific mutations in PSCs by genome editing or generating organoids from patient-derived PSCs. Moreover, renal organoids represent promising models in toxicology studies and testing new therapeutic approaches. Renal organoids can be established also from adult stem cells. This type of organoid, named tubuloid, is composed only of epithelial cells and recapitulates the tissue repair process. The tubuloids can be generated from adult stem or progenitor cells, obtained from renal biopsies or urine, and are promising in vitro models for studying tubular functions, diseases, and regeneration. Tubuloids can be derived from patients and permit the study of genetic diseases, performing personalized drug screening and modeling renal pathologies.

Wilms tumor primary cultures capture phenotypic heterogeneity and facilitate preclinical screening

Wilms tumors (WT) are characterized by variable contributions of blastemal, epithelial and stromal elements, reflecting their diverse cellular origins and genetic drivers. In vitro models remain rare, despite a growing need to better characterize tumor biology and evaluate new treatments. Using three approaches, we have now established a large collection of long-term cultures that represent this diversity. Adherent WT cultures are predominated by stromal cells, 3D spheroids model blastema, and patient-derived organoid cultures of both tumor and healthy kidney tissue result in the preferential growth of epithelial cells. Adherent, spheroid and organoid cultures are also clearly distinguishable by their transcriptome. Preclinical drug screening experiments revealed sensitivity to a range of inhibitors, that are highly effective in other childhood solid tumors. Sensitivity was related to MYCN status, a marker associated with adverse outcome across human cancers including WT. The combination of the three culture techniques represents a promising tool to both explore tumor heterogeneity in vitro and to facilitate characterization of candidate driver genes, in order to improve treatment regimens in the future.

A systematic review on the culture methods and applications of 3D tumoroids for cancer research and personalized medicine

Cancer is a highly heterogeneous disease, and thus treatment responses vary greatly between patients. To improve therapy efficacy and outcome for cancer patients, more representative and patient-specific preclinical models are needed. Organoids and tumoroids are 3D cell culture models that typically retain the genetic and epigenetic characteristics, as well as the morphology, of their tissue of origin. Thus, they can be used to understand the underlying mechanisms of cancer initiation, progression, and metastasis in a more physiological setting. Additionally, co-culture methods of tumoroids and cancer-associated cells can help to understand the interplay between a tumor and its tumor microenvironment. In recent years, tumoroids have already helped to refine treatments and to identify new targets for cancer therapy. Advanced culturing systems such as chip-based fluidic devices and bioprinting methods in combination with tumoroids have been used for high-throughput applications for personalized medicine. Even though organoid and tumoroid models are complex in vitro systems, validation of results in vivo is still the common practice. Here, we describe how both animal- and human-derived tumoroids have helped to identify novel vulnerabilities for cancer treatment in recent years, and how they are currently used for precision medicine.

Metabolic profiling of patient-derived organoids reveals nucleotide synthesis as a metabolic vulnerability in malignant rhabdoid tumors

Malignant rhabdoid tumor (MRT) is one of the most aggressive childhood cancers for which no effective treatment options are available. Reprogramming of cellular metabolism is an important hallmark of cancer, with various metabolism-based drugs being approved as a cancer treatment. In this study, we use patient-derived tumor organoids (tumoroids) to map the metabolic landscape of several pediatric cancers. Combining gene expression analyses and metabolite profiling using mass spectrometry, we find nucleotide biosynthesis to be a particular vulnerability of MRT. Treatment of MRT tumoroids with de novo nucleotide synthesis inhibitors methotrexate (MTX) and BAY-2402234 lowers nucleotide levels in MRT tumoroids and induces apoptosis. Lastly, we demonstrate in vivo efficacy of MTX in MRT patient-derived xenograft (PDX) mouse models. Our study reveals nucleotide biosynthesis as an MRT-specific metabolic vulnerability, which can ultimately lead to better treatment options for children suffering from this lethal pediatric malignancy.

Establishment of nasal and olfactory epithelium organoids for unveiling mechanism of tissue regeneration and pathogenesis of nasal diseases

Organoid is an ideal in vitro model with cellular heterogeneity and genetic stability when passaging. Currently, organoids are exploited as new tools in a variety of preclinical researches and applications for disease modeling, drug screening, host-microbial interactions, and regenerative therapy. Advances have been made in the establishment of nasal and olfactory epithelium organoids that are used to investigate the pathogenesis of smell-related diseases and cellular/molecular mechanism underlying the regeneration of olfactory epithelium. A set of critical genes are identified to function in cell proliferation and neuronal differentiation in olfactory epithelium organoids. Besides, nasal epithelium organoids derived from chronic rhinosinusitis patients have been established to reveal the pathogenesis of this disease, potentially applied in drug responses in individual patient. The present article reviews recent research progresses of nasal and olfactory epithelium organoids in fundamental and preclinical researches, and proposes current advances and potential future direction in the field of organoid research and application.

A semi-permeable insert culture model for the distal part of the nephron with human and mouse tubuloid epithelial cells

Tubuloids are advanced in vitro models obtained from adult human or mouse kidney cells with great potential for modelling kidney function in health and disease. Here, we developed a polarized human and mouse tubuloid epithelium on cell culture inserts, namely Transwell™ filters, as a model of the distal nephron with an accessible apical and basolateral side that allow for characterization of epithelial properties such as leak-tightness and epithelial resistance. Tubuloids formed a leak-tight and confluent epithelium on Transwells™ and the human tubuloids were differentiated towards the distal part of the nephron. Differentiation induced a significant upregulation of mRNA and protein expression of crucial segment transporters/channels NKCC2 (thick ascending limb of the loop of Henle), NCC (distal convoluted tubule), AQP2 (connecting tubule and collecting duct) and Na+/K+-ATPase (all segments) in a polarized fashion. In conclusion, this study illustrates the potential of human and mouse tubuloid epithelium on Transwells™ for studies of tubuloid epithelium formation and tubuloid differentiation towards the distal nephron. This approach holds great promise for assisting future research towards kidney (patho)physiology and transport function.

Patient-derived tumor organoids: A preclinical platform for personalized cancer therapy

Patient-derived tumor organoids (PDTOs) represent a significant advancement in cancer research and personalized medicine. These organoids, derived from various cancer types, have shown the ability to retain the genetic and molecular characteristics of the original tumors, allowing for the detailed study of tumor biology and drug responses on an individual basis. The success rates of establishing PDTOs vary widely and are influenced by factors such as cancer type, tissue quality, and media composition. Furthermore, the dynamic nature of organoid cultures may also lead to unique molecular characteristics that deviate from the original tumors, affecting their interpretation in clinical settings without the implementation of rigorous validation and establishment of standardized protocols. Recent studies have supported the correlation between PDTOs and the corresponding patient response. Although these studies involved a small number of patients, they promoted the integration of PDTOs in observational and interventional clinical trials to advance translational cancer therapies.

Embracing sex-specific differences in engineered kidney models for enhanced biological understanding of kidney function

In vitro models serve as indispensable tools for advancing our understanding of biological processes, elucidating disease mechanisms, and establishing screening platforms for drug discovery. Kidneys play an instrumental role in the transport and elimination of drugs and toxins. Nevertheless, despite the well-documented inter-individual variability in kidney function and the multifaceted nature of renal diseases-spanning from their origin, trigger and which segment of the kidney is affected-to presentation, progression and prognosis, few studies take into consideration the variable of sex. Notably, the inherent disparities between female and male biology warrants a more comprehensive representation within in vitro models of the kidney. The omission of sex as a fundamental biological variable carries the substantial risk of overlooking sex-specific mechanisms implicated in health and disease, along with potential differences in drug responsiveness and toxicity profiles between sexes. This review emphasizes the importance of incorporating cellular, biological and functional sex-specific features of renal activity in health and disease in in vitro models. For that, we thoroughly document renal sex-specific features and propose a strategic experimental framework to integrate sex-based differences into human kidney in vitro models by outlining critical design criteria to elucidate sex-based features at cellular and tissue levels. The goal is to enhance the accuracy of models to unravel renal mechanisms, and improve our understanding of their impact on drug efficacy and safety profiles, paving the way for a more comprehensive understanding of patient-specific treatment modalities.

Ciliopathy organoid models: a comprehensive review

Cilia are membrane-bound organelles found on the surface of most mammalian cell types and play numerous roles in human physiology and development, including osmo- and mechanosensation, as well as signal transduction. Ciliopathies are a large group of, usually rare, genetic disorders resulting from abnormal ciliary structure or ciliary dysfunction that have a high collective prevalence. Autosomal dominant or recessive polycystic kidney disease (ADPKD/ARPKD), Bardet-Biedl-Syndrome, and primary ciliary dyskinesia (PCD) are the most frequent etiologies. Rodent and zebrafish models have improved the understanding of ciliopathy pathophysiology. Yet, the limitations of these genetically modified animal strains include the inability to fully replicate the phenotypic heterogeneity found in humans, including variable multiorgan involvement. Organoids, self-assembled three-dimensional cell-based models derived from human induced pluripotent stem cells (iPSCs) or primary tissues, can recapitulate certain aspects of the development, architecture, and function of the target organ "in the dish." The potential of organoids to model patient-specific genotype-phenotype correlations has increased their popularity in ciliopathy research and led to the first preclinical organoid-based ciliopathy drug screens. This review comprehensively summarizes and evaluates current ciliopathy organoid models, focusing on kidney, airway, liver, and retinal organoids, as well as the specific methodologies used for their cultivation and for interrogating ciliary dysfunction.

Trends and challenges in organoid modeling and expansion with pluripotent stem cells and somatic tissue

The increasing demand for disease modeling, preclinical drug testing, and long waiting lists for alternative organ substitutes has posed significant challenges to current limitations in organoid technology. Consequently, organoid technology has emerged as a cutting-edge tool capable of accurately recapitulating the complexity of actual organs in physiology and functionality. To bridge the gaps between basic research and pharmaceutical as well as clinical applications, efforts have been made to develop organoids from tissue-derived stem cells or pluripotent stem cells. These developments include optimizing starting cells, refining culture systems, and introducing genetic modifications. With the rapid development of organoid technology, organoid composition has evolved from single-cell to multi-cell types, enhancing their level of biomimicry. Tissue structure has become more refined, and core challenges like vascularization are being addressed actively. These improvements are expected to pave the way for the construction of organoid atlases, automated large-scale cultivation, and universally compatible organoid biobanks. However, major obstacles remain to be overcome before urgently proof-of-concept organoids can be readily converted to practical applications. These obstacles include achieving structural and functional summarily to native tissue, remodeling the microenvironment, and scaling up production. This review aims to summarize the status of organoid development and applications, highlight recent progress, acknowledge existing limitations and challenges, and provide insights into future advancements. It is expected that this will contribute to the establishment of a reliable, scalable, and practical platform for organoid production and translation, further promoting their use in the pharmaceutical industry and regenerative medicine.

Patient-derived organoids in precision cancer medicine

Organoids are three-dimensional (3D) cultures, normally derived from stem cells, that replicate the complex structure and function of human tissues. They offer a physiologically relevant model to address important questions in cancer research. The generation of patient-derived organoids (PDOs) from various human cancers allows for deeper insights into tumor heterogeneity and spatial organization. Additionally, interrogating non-tumor stromal cells increases the relevance in studying the tumor microenvironment, thereby enhancing the relevance of PDOs in personalized medicine. PDOs mark a significant advancement in cancer research and patient care, signifying a shift toward more innovative and patient-centric approaches. This review covers aspects of PDO cultures to address the modeling of the tumor microenvironment, including extracellular matrices, air-liquid interface and microfluidic cultures, and organ-on-chip. Specifically, the role of PDOs as preclinical models in gene editing, molecular profiling, drug testing, and biomarker discovery and their potential for guiding personalized treatment in clinical practice are discussed.

Recent advances in extracellular matrix manipulation for kidney organoid research

The kidney plays a crucial role in maintaining the body's microenvironment homeostasis. However, current treatment options and therapeutic agents for chronic kidney disease (CKD) are limited. Fortunately, the advent of kidney organoids has introduced a novel in vitro model for studying kidney diseases and drug screening. Despite significant efforts has been leveraged to mimic the spatial-temporal dynamics of fetal renal development in various types of kidney organoids, there is still a discrepancy in cell types and maturity compared to native kidney tissue. The extracellular matrix (ECM) plays a crucial role in regulating cellular signaling, which ultimately affects cell fate decision. As a result, ECM can refine the microenvironment of organoids, promoting their efficient differentiation and maturation. This review examines the existing techniques for culturing kidney organoids, evaluates the strengths and weaknesses of various types of kidney organoids, and assesses the advancements and limitations associated with the utilization of the ECM in kidney organoid culture. Additionally, it presents a discussion on constructing specific physiological and pathological microenvironments using decellularized extracellular matrix during certain developmental stages or disease occurrences, aiding the development of kidney organoids and disease models.

Glucocorticoids induce a maladaptive epithelial stress response to aggravate acute kidney injury

Acute kidney injury (AKI) is a frequent and challenging clinical condition associated with high morbidity and mortality and represents a common complication in critically ill patients with COVID-19. In AKI, renal tubular epithelial cells (TECs) are a primary site of damage, and recovery from AKI depends on TEC plasticity. However, the molecular mechanisms underlying adaptation and maladaptation of TECs in AKI remain largely unclear. Here, our study of an autopsy cohort of patients with COVID-19 provided evidence that injury of TECs by myoglobin, released as a consequence of rhabdomyolysis, is a major pathophysiological mechanism for AKI in severe COVID-19. Analyses of human kidney biopsies, mouse models of myoglobinuric and gentamicin-induced AKI, and mouse kidney tubuloids showed that TEC injury resulted in activation of the glucocorticoid receptor by endogenous glucocorticoids, which aggravated tubular damage. The detrimental effect of endogenous glucocorticoids on injured TECs was exacerbated by the administration of a widely clinically used synthetic glucocorticoid, dexamethasone, as indicated by experiments in mouse models of myoglobinuric- and folic acid-induced AKI, human and mouse kidney tubuloids, and human kidney slice cultures. Mechanistically, studies in mouse models of AKI, mouse tubuloids, and human kidney slice cultures demonstrated that glucocorticoid receptor signaling in injured TECs orchestrated a maladaptive transcriptional program to hinder DNA repair, amplify injury-induced DNA double-strand break formation, and dampen mTOR activity and mitochondrial bioenergetics. This study identifies glucocorticoid receptor activation as a mechanism of epithelial maladaptation, which is functionally important for AKI.

Mimicking the extracellular world: from natural to fully synthetic matrices utilizing supramolecular biomaterials

The extracellular matrix (ECM) has evolved around complex covalent and non-covalent interactions to create impressive function-from cellular signaling to constant remodeling. A major challenge in the biomedical field is the de novo design and control of synthetic ECMs for applications ranging from tissue engineering to neuromodulation to bioelectronics. As we move towards recreating the ECM's complexity in hydrogels, the field has taken several approaches to recapitulate the main important features of the native ECM (i.e. mechanical, bioactive and dynamic properties). In this review, we first describe the wide variety of hydrogel systems that are currently used, ranging from fully natural to completely synthetic to hybrid versions, highlighting the advantages and limitations of each class. Then, we shift towards supramolecular hydrogels that show great potential for their use as ECM mimics due to their biomimetic hierarchical structure, inherent (controllable) dynamic properties and their modular design, allowing for precise control over their mechanical and biochemical properties. In order to make the next step in the complexity of synthetic ECM-mimetic hydrogels, we must leverage the supramolecular self-assembly seen in the native ECM; we therefore propose to use supramolecular monomers to create larger, hierarchical, co-assembled hydrogels with complex and synergistic mechanical, bioactive and dynamic features.

Knocking Out CD70 Rescues CD70-Specific NanoCAR T Cells from Antigen-Induced Exhaustion

CD70 is an attractive target for chimeric antigen receptor (CAR) T-cell therapy for the treatment of both solid and liquid malignancies. However, the functionality of CD70-specific CAR T cells is modest. We optimized a CD70-specific VHH-based CAR (nanoCAR). We evaluated the nanoCARs in clinically relevant models in vitro, using co-cultures of CD70-specific nanoCAR T cells with malignant rhabdoid tumor organoids, and in vivo, using a diffuse large B-cell lymphoma patient-derived xenograft (PDX) model. Although the nanoCAR T cells were highly efficient in organoid co-cultures, they showed only modest efficacy in the PDX model. We determined that fratricide was not causing this loss in efficacy but rather CD70 interaction in cis with the nanoCAR-induced exhaustion. Knocking out CD70 in nanoCAR T cells using CRISPR/Cas9 resulted in dramatically enhanced functionality in the diffuse large B-cell lymphoma PDX model. Through single-cell transcriptomics, we obtained evidence that CD70 knockout CD70-specific nanoCAR T cells were protected from antigen-induced exhaustion. In addition, we demonstrated that wild-type CD70-specific nanoCAR T cells already exhibited signs of exhaustion shortly after production. Their gene signature strongly overlapped with gene signatures of exhausted CAR T cells. Conversely, the gene signature of knockout CD70-specific nanoCAR T cells overlapped with the gene signature of CAR T-cell infusion products leading to complete responses in chronic lymphatic leukemia patients. Our data show that CARs targeting endogenous T-cell antigens negatively affect CAR T-cell functionality by inducing an exhausted state, which can be overcome by knocking out the specific target.

Progress and breakthroughs in human kidney organoid research

The three-dimensional (3D) kidney organoid is a breakthrough model for recapitulating renal morphology and function in vitro, which is grown from stem cells and resembles mammalian kidney organogenesis. Currently, protocols for cultivating this model from induced pluripotent stem cells (iPSCs) and patient-derived adult stem cells (ASCs) have been widely reported. In recent years, scientists have focused on combining cutting-edge bioengineering and bioinformatics technologies to improve the developmental accuracy of kidney organoids and achieve high-throughput experimentation. As a remarkable tool for mechanistic research of the renal system, kidney organoid has both potential and challenges. In this review, we have described the evolution of kidney organoid establishment methods and highlighted the latest progress leading to a more sophisticated kidney transformation research model. Finally, we have summarized the main applications of renal organoids in exploring kidney disease.

Complexin vitromodels positioned for impact to drug testing in pharma: a review

Recent years have seen the creation and popularization of various complexin vitromodels (CIVMs), such as organoids and organs-on-chip, as a technology with the potential to reduce animal usage in pharma while also enhancing our ability to create safe and efficacious drugs for patients. Public awareness of CIVMs has increased, in part, due to the recent passage of the FDA Modernization Act 2.0. This visibility is expected to spur deeper investment in and adoption of such models. Thus, end-users and model developers alike require a framework to both understand the readiness of current models to enter the drug development process, and to assess upcoming models for the same. This review presents such a framework for model selection based on comparative -omics data (which we term model-omics), and metrics for qualification of specific test assays that a model may support that we term context-of-use (COU) assays. We surveyed existing healthy tissue models and assays for ten drug development-critical organs of the body, and provide evaluations of readiness and suggestions for improving model-omics and COU assays for each. In whole, this review comes from a pharma perspective, and seeks to provide an evaluation of where CIVMs are poised for maximum impact in the drug development process, and a roadmap for realizing that potential.

Liver organoids: updates on generation strategies and biomedical applications

The liver is the most important metabolic organ in the body. While mouse models and cell lines have further deepened our understanding of liver biology and related diseases, they are flawed in replicating key aspects of human liver tissue, particularly its complex structure and metabolic functions. The organoid model represents a major breakthrough in cell biology that revolutionized biomedical research. Organoids are in vitro three-dimensional (3D) physiological structures that recapitulate the morphological and functional characteristics of tissues in vivo, and have significant advantages over traditional cell culture methods. In this review, we discuss the generation strategies and current advances in the field focusing on their application in regenerative medicine, drug discovery and modeling diseases.

A Decade of Organoid Research: Progress and Challenges in the Field of Organoid Technology

Organoid technology, revolutionizing biomedical research, offers a transformative approach to studying human developmental biology, disease pathology, and drug discovery. Originating from the pioneering work of Henry Van Peters Wilson in 1907 and evolving through subsequent breakthroughs, organoids are three-dimensional structures derived from stem cells or tissue explants that mimic the architecture and function of organs in vitro. With the ability to model various organs such as intestine, liver, brain, kidney, and more, organoids provide unprecedented insights into organ development, disease mechanisms, and drug responses. This review highlights the historical context, generation methods, applications, and challenges of organoid technology. Furthermore, it discusses recent advancements, including strategies to address hypoxia-induced cell death and enhance vascularization within organoids, aiming to refine their physiological relevance and unlock their full potential in personalized medicine and organ transplantation.

Reconstitution of human tissue barrier function for precision and personalized medicine

Tissue barriers in a body, well known as tissue-to-tissue interfaces represented by endothelium of the blood vessels or epithelium of organs, are essential for maintaining physiological homeostasis by regulating molecular and cellular transports. It is crucial for predicting drug response to understand physiology of tissue barriers through which drugs are absorbed, distributed, metabolized and excreted. Since the FDA Modernization Act 2.0, which prompts the inception of alternative technologies for animal models, tissue barrier chips, one of the applications of organ-on-a-chip or microphysiological system (MPS), have only recently been utilized in the context of drug development. Recent advancements in stem cell technology have brightened the prospects for the application of tissue barrier chips in personalized medicine. In past decade, designing and engineering these microfluidic devices, and demonstrating the ability to reconstitute tissue functions were main focus of this field. However, the field is now advancing to the next level of challenges: validating their utility in drug evaluation and creating personalized models using patient-derived cells. In this review, we briefly introduce key design parameters to develop functional tissue barrier chip, explore the remarkable recent progress in the field of tissue barrier chips and discuss future perspectives on realizing personalized medicine through the utilization of tissue barrier chips.

Kidney Disease Modeling with Organoids and Organs-on-Chips

Kidney disease is a global health crisis affecting more than 850 million people worldwide. In the United States, annual Medicare expenditures for kidney disease and organ failure exceed $81 billion. Efforts to develop targeted therapeutics are limited by a poor understanding of the molecular mechanisms underlying human kidney disease onset and progression. Additionally, 90% of drug candidates fail in human clinical trials, often due to toxicity and efficacy not accurately predicted in animal models. The advent of ex vivo kidney models, such as those engineered from induced pluripotent stem (iPS) cells and organ-on-a-chip (organ-chip) systems, has garnered considerable interest owing to their ability to more accurately model tissue development and patient-specific responses and drug toxicity. This review describes recent advances in developing kidney organoids and organ-chips by harnessing iPS cell biology to model human-specific kidney functions and disease states. We also discuss challenges that must be overcome to realize the potential of organoids and organ-chips as dynamic and functional conduits of the human kidney. Achieving these technological advances could revolutionize personalized medicine applications and therapeutic discovery for kidney disease.

A multispectral 3D live organoid imaging platform to screen probes for fluorescence guided surgery

Achieving complete tumor resection is challenging and can be improved by real-time fluorescence-guided surgery with molecular-targeted probes. However, pre-clinical identification and validation of probes presents a lengthy process that is traditionally performed in animal models and further hampered by inter- and intra-tumoral heterogeneity in target expression. To screen multiple probes at patient scale, we developed a multispectral real-time 3D imaging platform that implements organoid technology to effectively model patient tumor heterogeneity and, importantly, healthy human tissue binding.

Advances and challenges in organ-on-chip technology: toward mimicking human physiology and disease in vitro

Organs-on-chips have been tissues or three-dimensional (3D) mini-organs that comprise numerous cell types and have been produced on microfluidic chips to imitate the complicated structures and interactions of diverse cell types and organs under controlled circumstances. Several morphological and physiological distinctions exist between traditional 2D cultures, animal models, and the growing popular 3D cultures. On the other hand, animal models might not accurately simulate human toxicity because of physiological variations and interspecies metabolic capability. The on-chip technique allows for observing and understanding the process and alterations occurring in metastases. The present study aimed to briefly overview single and multi-organ-on-chip techniques. The current study addresses each platform's essential benefits and characteristics and highlights recent developments in developing and utilizing technologies for single and multi-organs-on-chips. The study also discusses the drawbacks and constraints associated with these models, which include the requirement for standardized procedures and the difficulties of adding immune cells and other intricate biological elements. Finally, a comprehensive review demonstrated that the organs-on-chips approach has a potential way of investigating organ function and disease. The advancements in single and multi-organ-on-chip structures can potentially increase drug discovery and minimize dependency on animal models, resulting in improved therapies for human diseases.

Enhancing maturity in 3D kidney micro-tissues through clonogenic cell combinations and endothelial integration

As an advance laboratory model, three-dimensional (3D) organoid culture has recently been recruited to study development, physiology and abnormality of kidney tissue. Micro-tissues derived from primary renal cells are composed of 3D epithelial structures representing the main characteristics of original tissue. In this research, we presented a simple method to isolate mouse renal clonogenic mesenchymal (MLCs) and epithelial-like cells (ELCs). Then we have done a full characterization of MLCs using flow cytometry for surface markers which showed that more than 93% of cells expressed these markers (Cd44, Cd73 and Cd105). Epithelial and stem/progenitor cell markers characterization also performed for ELC cells and upregulating of these markers observed while mesenchymal markers expression levels were not significantly increased in ELCs. Each of these cells were cultured either alone (ME) or in combination with human umbilical vein endothelial cells (HUVECs) (MEH; with an approximate ratio of 10:5:2) to generate more mature kidney structures. Analysis of 3D MEH renal micro-tissues (MEHRMs) indicated a significant increase in renal-specific gene expression including Aqp1 (proximal tubule), Cdh1 (distal tubule), Umod (loop of Henle), Wt1, Podxl and Nphs1 (podocyte markers), compared to those groups without endothelial cells, suggesting greater maturity of the former tissue. Furthermore, ex ovo transplantation showed greater maturation in the constructed 3D kidney.

Exploring tumor organoids for cancer treatment

As a life-threatening chronic disease, cancer is characterized by tumor heterogeneity. This heterogeneity is associated with factors that lead to treatment failure and poor prognosis, including drug resistance, relapse, and metastasis. Therefore, precision medicine urgently needs personalized tumor models that accurately reflect the tumor heterogeneity. Currently, tumor organoid technologies are used to generate in vitro 3D tissues, which have been shown to precisely recapitulate structure, tumor microenvironment, expression profiles, functions, molecular signatures, and genomic alterations in primary tumors. Tumor organoid models are important for identifying potential therapeutic targets, characterizing the effects of anticancer drugs, and exploring novel diagnostic and therapeutic options. In this review, we describe how tumor organoids can be cultured and summarize how researchers can use them as an excellent tool for exploring cancer therapies. In addition, we discuss tumor organoids that have been applied in cancer therapy research and highlight the potential of tumor organoids to guide preclinical research.

Organoids as a new approach for improving pediatric cancer research

A key challenge in cancer research is the meticulous development of models that faithfully emulates the intricacies of the patient scenario, with emphasis on preserving intra-tumoral heterogeneity and the dynamic milieu of the tumor microenvironment (TME). Organoids emerge as promising tool in new drug development, drug screening and precision medicine. Despite advances in the diagnoses and treatment of pediatric cancers, certain tumor subtypes persist in yielding unfavorable prognoses. Moreover, the prognosis for a significant portion of children experiencing disease relapse is dismal. To improve pediatric outcome many groups are focusing on the development of precision medicine approach. In this review, we summarize the current knowledge about using organoid system as model in preclinical and clinical solid-pediatric cancer. Since organoids retain the pivotal characteristics of primary parent tumors, they exert great potential in discovering novel tumor biomarkers, exploring drug-resistance mechanism and predicting tumor responses to chemotherapy, targeted therapy and immunotherapies. We also examine both the potential opportunities and existing challenges inherent organoids, hoping to point out the direction for future organoid development.

Advanced 3D imaging and organoid bioprinting for biomedical research and therapeutic applications

Organoid cultures offer a valuable platform for studying organ-level biology, allowing for a closer mimicry of human physiology compared to traditional two-dimensional cell culture systems or non-primate animal models. While many organoid cultures use cell aggregates or decellularized extracellular matrices as scaffolds, they often lack precise biochemical and biophysical microenvironments. In contrast, three-dimensional (3D) bioprinting allows precise placement of organoids or spheroids, providing enhanced spatial control and facilitating the direct fusion for the formation of large-scale functional tissues in vitro. In addition, 3D bioprinting enables fine tuning of biochemical and biophysical cues to support organoid development and maturation. With advances in the organoid technology and its potential applications across diverse research fields such as cell biology, developmental biology, disease pathology, precision medicine, drug toxicology, and tissue engineering, organoid imaging has become a crucial aspect of physiological and pathological studies. This review highlights the recent advancements in imaging technologies that have significantly contributed to organoid research. Additionally, we discuss various bioprinting techniques, emphasizing their applications in organoid bioprinting. Integrating 3D imaging tools into a bioprinting platform allows real-time visualization while facilitating quality control, optimization, and comprehensive bioprinting assessment. Similarly, combining imaging technologies with organoid bioprinting can provide valuable insights into tissue formation, maturation, functions, and therapeutic responses. This approach not only improves the reproducibility of physiologically relevant tissues but also enhances understanding of complex biological processes. Thus, careful selection of bioprinting modalities, coupled with appropriate imaging techniques, holds the potential to create a versatile platform capable of addressing existing challenges and harnessing opportunities in these rapidly evolving fields.

Bioengineering toolkits for potentiating organoid therapeutics

Organoids are three-dimensional, multicellular constructs that recapitulate the structural and functional features of specific organs. Because of these characteristics, organoids have been widely applied in biomedical research in recent decades. Remarkable advancements in organoid technology have positioned them as promising candidates for regenerative medicine. However, current organoids still have limitations, such as the absence of internal vasculature, limited functionality, and a small size that is not commensurate with that of actual organs. These limitations hinder their survival and regenerative effects after transplantation. Another significant concern is the reliance on mouse tumor-derived matrix in organoid culture, which is unsuitable for clinical translation due to its tumor origin and safety issues. Therefore, our aim is to describe engineering strategies and alternative biocompatible materials that can facilitate the practical applications of organoids in regenerative medicine. Furthermore, we highlight meaningful progress in organoid transplantation, with a particular emphasis on the functional restoration of various organs.

Modern In Vitro Techniques for Modeling Hearing Loss

Sensorineural hearing loss (SNHL) is a prevalent and growing global health concern, especially within operational medicine, with limited therapeutic options available. This review article explores the emerging field of in vitro otic organoids as a promising platform for modeling hearing loss and developing novel therapeutic strategies. SNHL primarily results from the irreversible loss or dysfunction of cochlear mechanosensory hair cells (HCs) and spiral ganglion neurons (SGNs), emphasizing the need for innovative solutions. Current interventions offer symptomatic relief but do not address the root causes. Otic organoids, three-dimensional multicellular constructs that mimic the inner ear's architecture, have shown immense potential in several critical areas. They enable the testing of gene therapies, drug discovery for sensory cell regeneration, and the study of inner ear development and pathology. Unlike traditional animal models, otic organoids closely replicate human inner ear pathophysiology, making them invaluable for translational research. This review discusses methodological advances in otic organoid generation, emphasizing the use of human pluripotent stem cells (hPSCs) to replicate inner ear development. Cellular and molecular characterization efforts have identified key markers and pathways essential for otic organoid development, shedding light on their potential in modeling inner ear disorders. Technological innovations, such as 3D bioprinting and microfluidics, have further enhanced the fidelity of these models. Despite challenges and limitations, including the need for standardized protocols and ethical considerations, otic organoids offer a transformative approach to understanding and treating auditory dysfunctions. As this field matures, it holds the potential to revolutionize the treatment landscape for hearing and balance disorders, moving us closer to personalized medicine for inner ear conditions.

Precise Targeting of Autoantigen-Specific B Cells in Lupus Nephritis with Chimeric Autoantibody Receptor T Cells

Despite conventional therapy, lupus nephritis (LN) remains a significant contributor to short- and long-term morbidity and mortality. B cell abnormalities and the production of autoantibodies against nuclear complexes like anti-dsDNA are recognised as key players in the pathogenesis of LN. To address the challenges of chronic immunosuppression associated with current therapies, we have engineered T cells to express chimeric autoantibody receptors (DNA-CAART) for the precise targeting of B cells expressing anti-dsDNA autoantibodies. T cells from LN patients were transduced using six different CAAR vectors based on their antigen specificity, including alpha-actinin, histone-1, heparan sulphate, or C1q. The cytotoxicity, cytokine production, and cell-cell contact of DNA-CAART were thoroughly investigated in co-culture experiments with B cells isolated from patients, both with and without anti-dsDNA positivity. The therapeutic effects were further evaluated using an in vitro immune kidney LN organoid. Among the six proposed DNA-CAART, DNA4 and DNA6 demonstrated superior selectively cytotoxic activity against anti-dsDNA+ B cells. Notably, DNA4-CAART exhibited improvements in organoid morphology, apoptosis, and the inflammatory process in the presence of IFNα-stimulated anti-dsDNA+ B cells. Based on these findings, DNA4-CAART emerge as promising candidates for modulating autoimmunity and represent a novel approach for the treatment of LN.

Advancements in kidney organoids and tubuloids to study (dys)function

The rising prevalence of kidney diseases urges the need for novel therapies. Kidney organoids and tubuloids are advanced in vitro models and have recently been described as promising tools to study kidney (patho)physiology. Recent developments have shown their application in disease modeling, drug screening, and nephrotoxicity. These applications rely on their ability to mimic (dys)function in vitro including endocrine activity and drug, electrolyte, and water transport. This review provides an overview of these emerging kidney models and focuses on the most recent developments that utilize their functional capabilities. In addition, we cover current limitations and provide future perspectives for this rapidly evolving field, including what these functional properties mean for translational and personalized medicine now and in the future.

Application of organoids in otolaryngology: head and neck surgery

PURPOSE

The purpose of this review is to systematically summarize the application of organoids in the field of otolaryngology and head and neck surgery. It aims to shed light on the current advancements and future potential of organoid technology in these areas, particularly in addressing challenges like hearing loss, cancer research, and organ regeneration.

METHODS

Review of current literature regrading organoids in the field of otolaryngology and head and neck surgery.

RESULTS

The review highlights several advancements in the field. In otology, the development of organoid replacement therapies offers new avenues for treating hearing loss. In nasal science, the creation of specific organoid models aids in studying nasopharyngeal carcinoma and respiratory viruses. In head and neck surgery, innovative approaches for squamous cell carcinoma prediction and thyroid regeneration using organoids have been developed.

CONCLUSION

Organoid research in otolaryngology-head and neck surgery is still at an early stage. This review underscores the potential of this technology in advancing our understanding and treatment of various conditions, predicting a transformative impact on future medical practices in these fields.

Mice with renal-specific alterations of stem cell-associated signaling develop symptoms of chronic kidney disease but surprisingly no tumors

Previously, we found that Wnt and Notch signaling govern stem cells of clear cell kidney cancer (ccRCC) in patients. To mimic stem cell responses in the normal kidney in vitro in a marker-unbiased fashion, we have established tubular organoids (tubuloids) from total single adult mouse kidney epithelial cells in Matrigel and serum-free conditions. Deep proteomic and phosphoproteomic analyses revealed that tubuloids resembled renewal of adult kidney tubular epithelia, since tubuloid cells displayed activity of Wnt and Notch signaling, long-term proliferation and expression of markers of proximal and distal nephron lineages. In our wish to model stem cell-derived human ccRCC, we have generated two types of genetic double kidney mutants in mice: Wnt-β-catenin-GOF together with Notch-GOF and Wnt-β-catenin-GOF together with a most common alteration in ccRCC, Vhl-LOF. An inducible Pax8-rtTA-LC1-Cre was used to drive recombination specifically in adult kidney epithelial cells. We confirmed mutagenesis of β-catenin, Notch and Vhl alleles on DNA, protein and mRNA target gene levels. Surprisingly, we observed symptoms of chronic kidney disease (CKD) in mutant mice, but no increased proliferation and tumorigenesis. Thus, the responses of kidney stem cells in the tubuloid and genetic systems produced different phenotypes, i.e. enhanced renewal versus CKD.

Application status and optimization suggestions of tumor organoids and CAR-T cell co-culture models

Tumor organoids, especially patient-derived organoids (PDOs) exhibit marked similarities in histopathological morphology, genomic alterations, and specific marker expression profiles to those of primary tumour tissues. They are applied in various fields including drug screening, gene editing, and identification of oncogenes. However, CAR-T therapy in the treatment of solid tumours is still at an exploratory stage. Tumour organoids offer unique advantages over other preclinical models commonly used for CAR-T therapy research, which the preservation of the biological characteristics of primary tumour tissue is critical for the study of early-stage solid tumour CAR-T therapies. Although some investigators have used this co-culture model to validate newly targeted CAR-T cells, optimise existing CAR-T cells and explore combination therapy strategies, there is still untapped potential in the co-culture models used today. This review introduces the current status of the application of tumour organoid and CAR-T cell co-culture models in recent years and commented on the limitations of the current co-cultivation model. Meanwhile, we compared the tumour organoid model with two pre-clinical models commonly used in CAR-T therapy research. Eventually, combined with the new progress of organoid technologies, optimization suggestions were proposed for the co-culture model from five perspectives: preserving or reconstructing the tumor microenvironment, systematization, vascularization, standardized culture procedures, and expanding the tumor organoids resource library, aimed at assisting related researchers to better utilize co-culture models.

Single-cell guided prenatal derivation of primary fetal epithelial organoids from human amniotic and tracheal fluids

Isolation of tissue-specific fetal stem cells and derivation of primary organoids is limited to samples obtained from termination of pregnancies, hampering prenatal investigation of fetal development and congenital diseases. Therefore, new patient-specific in vitro models are needed. To this aim, isolation and expansion of fetal stem cells during pregnancy, without the need for tissue samples or reprogramming, would be advantageous. Amniotic fluid (AF) is a source of cells from multiple developing organs. Using single-cell analysis, we characterized the cellular identities present in human AF. We identified and isolated viable epithelial stem/progenitor cells of fetal gastrointestinal, renal and pulmonary origin. Upon culture, these cells formed clonal epithelial organoids, manifesting small intestine, kidney tubule and lung identity. AF organoids exhibit transcriptomic, protein expression and functional features of their tissue of origin. With relevance for prenatal disease modeling, we derived lung organoids from AF and tracheal fluid cells of congenital diaphragmatic hernia fetuses, recapitulating some features of the disease. AF organoids are derived in a timeline compatible with prenatal intervention, potentially allowing investigation of therapeutic tools and regenerative medicine strategies personalized to the fetus at clinically relevant developmental stages.

Cancer organoids: A platform in basic and translational research

An accumulation of previous work has established organoids as good preclinical models of human tumors, facilitating translation from basic research to clinical practice. They are changing the paradigm of preclinical cancer research because they can recapitulate the heterogeneity and pathophysiology of human cancers and more closely approximate the complex tissue environment and structure found in clinical tumors than in vitro cell lines and animal models. However, the potential applications of cancer organoids remain to be comprehensively summarized. In the review, we firstly describe what is currently known about cancer organoid culture and then discuss in depth the basic mechanisms, including tumorigenesis and tumor metastasis, and describe recent advances in patient-derived tumor organoids (PDOs) for drug screening and immunological studies. Finally, the present challenges faced by organoid technology in clinical practice and its prospects are discussed. This review highlights that organoids may offer a novel therapeutic strategy for cancer research.

Bioengineered Tubular Biliary Organoids

Liver organoids have emerged as promising in vitro models for toxicology, drug discovery, and disease modeling. However, conventional 3D epithelial organoid culture systems suffer from significant drawbacks, including limited culture duration, a nonphysiological 3D cystic anatomy with an inaccessible apical surface, and lack of in vivo-like cellular organization. To address these limitations, herein a hydrogel-based organoid-on-a-chip model for the development functional tubular biliary organoids is reported. The resulting constructs demonstrate long-term stability for a minimum duration of 45 d, while retaining their biliary organoid identity and exhibiting key cholangiocyte characteristics including transport activities, formation of primary cilia, and protective glycocalyx. Additionally, tubular organoids are susceptible to physical and chemical injury, which cannot be applied in such resolution to classical organoids. To enhance tissue-level complexity, in vitro formation of a perfusable branching network is induced using a predetermined geometry that faithfully mimics the intricate structure of the intrahepatic biliary tree. Finally, cellular complexity is augmented through co-culturing with vascular endothelial cells and fibroblasts. The models described in this study offer valuable opportunities for investigating biliary morphogenesis and elucidating associated pathophysiological mechanisms.

Hallmark discoveries in the biology of Wilms tumour

The modern study of Wilms tumour was prompted nearly 50 years ago, when Alfred Knudson proposed the 'two-hit' model of tumour development. Since then, the efforts of researchers worldwide have substantially expanded our knowledge of Wilms tumour biology, including major advances in genetics - from cloning the first Wilms tumour gene to high-throughput studies that have revealed the genetic landscape of this tumour. These discoveries improve understanding of the embryonal origin of Wilms tumour, familial occurrences and associated syndromic conditions. Many efforts have been made to find and clinically apply prognostic biomarkers to Wilms tumour, for which outcomes are generally favourable, but treatment of some affected individuals remains challenging. Challenges are also posed by the intratumoural heterogeneity of biomarkers. Furthermore, preclinical models of Wilms tumour, from cell lines to organoid cultures, have evolved. Despite these many achievements, much still remains to be discovered: further molecular understanding of relapse in Wilms tumour and of the multiple origins of bilateral Wilms tumour are two examples of areas under active investigation. International collaboration, especially when large tumour series are required to obtain robust data, will help to answer some of the remaining unresolved questions.

Tissue Organoid Cultures Metabolize Dietary Carcinogens Proficiently and Are Effective Models for DNA Adduct Formation

Human tissue three-dimensional (3D) organoid cultures have the potential to reproduce in vitro the physiological properties and cellular architecture of the organs from which they are derived. The ability of organoid cultures derived from human stomach, liver, kidney, and colon to metabolically activate three dietary carcinogens, aflatoxin B1 (AFB1), aristolochic acid I (AAI), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), was investigated. In each case, the response of a target tissue (liver for AFB1; kidney for AAI; colon for PhIP) was compared with that of a nontarget tissue (gastric). After treatment cell viabilities were measured, DNA damage response (DDR) was determined by Western blotting for p-p53, p21, p-CHK2, and γ-H2AX, and DNA adduct formation was quantified by mass spectrometry. Induction of the key xenobiotic-metabolizing enzymes (XMEs) CYP1A1, CYP1A2, CYP3A4, and NQO1 was assessed by qRT-PCR. We found that organoids from different tissues can activate AAI, AFB1, and PhIP. In some cases, this metabolic potential varied between tissues and between different cultures of the same tissue. Similarly, variations in the levels of expression of XMEs were observed. At comparable levels of cytotoxicity, organoids derived from tissues that are considered targets for these carcinogens had higher levels of adduct formation than a nontarget tissue.