Making In Vitro Tumor Models Whole Again

Hydrogel-Mediated Preservation of Live Tumor Explants for Drug Development in Peritoneal Metastases

Clinically effective treatments for peritoneal metastases (PM) remain a significant unmet need. To expedite drug development in PM, hyaluronan (HA) hydrogel-supported PM patient-derived tumor explants (PDTE) that better preserve histological features, composition, and biological pathways of the original tumor, as compared to conventional PDTE culture methods are developed. Hydrogel modulation shows that stiffness, degradation, three-dimensional embedding, and HA itself are key parameters that enhance PDTE maintenance ex vivo. Further, HA hydrogels effectively preserve PDTE viability by disrupting myosin II-mediated tissue contraction, a phenomenon that occurs in the absence of hydrogel embedding. Lastly, the addition of ascites into PM PDTE not only recapitulates changes to the tumor microenvironment as observed in patients but also ascites-dependent drug efficacy, highlighting the importance of incorporating ascites into ex vivo PM models for accurate therapeutic evaluation. The bioengineered PM PDTE models in this study serve as a valuable platform for drug development and treatment personalization.

Three-dimensional in vitro models in head and neck cancer: current trends and applications

Head and neck cancer (HNC) is the sixth most prevalent malignancy worldwide and includes a variety of upper gastrointestinal abnormalities. HNC includes oral, throat, voice box, nasal cavity, paranasal sinuses, and salivary gland cancers. Squamous cells in the mouth, nose, and throat cause HNC. Drugs, alcohol, poor diets, smoking, and genetics all contribute to this condition. Cancer research has focused on three-dimensional (3D) models in HNC biology in recent decades. An adequate microenvironmental system and cancer cell culture are the initial steps to understanding cancer cells' complicated interactions with their surroundings. New 3D models claim to bridge in vivo and in vitro investigations and erase the gap. Interdisciplinary cell biology and tissue engineering researchers are creating 3D cancer tissue models to better understand the illness and develop more accurate cancer medicines. Tissue engineering researchers, who are always exploring novel approaches to treat cancer, have been able to include the third dimension into laboratory settings and mimic cell-to-cell and cell-to-matrix interactions by recreating the tumor microenvironment using 3D models and so make research on cancer easier. This review addresses recent developments in tissue engineering with an emphasis on 3D models in HNC.

Exploring Mechanical Features of 3D Head and Neck Cancer Models

Head and neck squamous cell carcinoma (HNSCC) presents significant challenges in oncology due to its complex biology and poor prognosis. Traditional two-dimensional (2D) cell culture models cannot replicate the intricate tumor microenvironment, limiting their usefulness in studying disease mechanisms and testing therapies. In contrast, three-dimensional (3D) in vitro models provide more realistic platforms that better mimic the architecture, mechanical features, and cellular interactions of HNSCC. This review explores the mechanical properties of 3D in vitro models developed for HNSCC research. It highlights key 3D culture techniques, such as spheroids, organoids, and bioprinted tissues, emphasizing their ability to simulate critical tumor characteristics like hypoxia, drug resistance, and metastasis. Particular attention is given to stiffness, elasticity, and dynamic behavior, highlighting how these models emulate native tumor tissues. By enhancing the physiological relevance of in vitro studies, 3D models offer significant potential to revolutionize HNSCC research and facilitate the development of effective, personalized therapeutic strategies. This review bridges the gap between preclinical and clinical applications by summarizing the mechanical properties of 3D models and providing guidance for developing systems that replicate both biological and mechanical characteristics of tumor tissues, advancing innovation in cancer research and therapy.

Tumor Spheroids, Tumor Organoids, Tumor Explants, and Tumoroids: What Are the Differences between Them?

Three-dimensional (3D) cell cultures that mimic tumor microenvironment have become an essential tool in cancer research and drug response analysis, significantly enhancing our understanding of tumor biology and advancing personalized medicine. Currently, the most widely mentioned 3D multicellular culture models include spheroids, organoids, tumor explants, and tumoroids. These 3D structures, exploited for various applications, are generated from cancer and non-cancer cells of different origin using multiple techniques. However, despite extensive research and numerous studies, consistent definitions of these 3D culture models are not clearly established. The manuscript provides a comprehensive overview of these models, detailing brief history of their research, unique biological characteristics, advantages, limitations, and specific applications.

Ex vivo therapeutic screening of metastatic cSCC: A review of methodological considerations for clinical implementation

Cutaneous squamous cell carcinoma (cSCC) is the second most common malignancy worldwide, with most deaths caused by locally advanced and metastatic disease. Treatment of resectable metastases is typically limited to invasive surgery with adjuvant radiotherapy; however, many patients fail to respond and there is minimal data to predict response or propose effective alternatives. Precision medicine could improve this, though genomic biomarkers remain elusive in the high mutational background and genomic complexity of cSCC. A phenotypic approach to precision medicine using patient-derived ex vivo tumour models is gaining favour for its capacity to directly assess biological responses to therapeutics as a functional, predictive biomarker. However, the use of ex vivo models for guiding therapeutic selection has yet to be employed for metastatic cSCC. This review will therefore evaluate the existing experimental models of metastatic cSCC and discuss how ex vivo methods could overcome the shortcomings of these existing models. Disease-specific considerations for a prospective methodological pipeline will also be discussed in the context of precision medicine.

Tumour organoids and assembloids: Patient-derived cancer avatars for immunotherapy

BACKGROUND

Organoid technology is an emerging and rapidly growing field that shows promise in studying organ development and screening therapeutic regimens. Although organoids have been proposed for a decade, concerns exist, including batch-to-batch variations, lack of the native microenvironment and clinical applicability.

MAIN BODY

The concept of organoids has derived patient-derived tumour organoids (PDTOs) for personalized drug screening and new drug discovery, mitigating the risks of medication misuse. The greater the similarity between the PDTOs and the primary tumours, the more influential the model will be. Recently, 'tumour assembloids' inspired by cell-coculture technology have attracted attention to complement the current PDTO technology. High-quality PDTOs must reassemble critical components, including multiple cell types, tumour matrix, paracrine factors, angiogenesis and microorganisms. This review begins with a brief overview of the history of organoids and PDTOs, followed by the current approaches for generating PDTOs and tumour assembloids. Personalized drug screening has been practised; however, it remains unclear whether PDTOs can predict immunotherapies, including immune drugs (e.g. immune checkpoint inhibitors) and immune cells (e.g. tumour-infiltrating lymphocyte, T cell receptor-engineered T cell and chimeric antigen receptor-T cell). PDTOs, as cancer avatars of the patients, can be expanded and stored to form a biobank.

CONCLUSION

Fundamental research and clinical trials are ongoing, and the intention is to use these models to replace animals. Pre-clinical immunotherapy screening using PDTOs will be beneficial to cancer patients.

KEY POINTS

The current PDTO models have not yet constructed key cellular and non-cellular components. PDTOs should be expandable and editable. PDTOs are promising preclinical models for immunotherapy unless mature PDTOs can be established. PDTO biobanks with consensual standards are urgently needed.

Bioinspired 3D microprinted cell scaffolds: Integration of graph theory to recapitulate complex network wiring in lymph nodes

Physical networks are ubiquitous in nature, but many of them possess a complex organizational structure that is difficult to recapitulate in artificial systems. This is especially the case in biomedical and tissue engineering, where the microstructural details of 3D cell scaffolds are important. Studies of biological networks-such as fibroblastic reticular cell (FRC) networks-have revealed the crucial role of network topology in a range of biological functions. However, cell scaffolds are rarely analyzed, or designed, using graph theory. To understand how networks affect adhered cells, 3D culture platforms capturing the complex topological properties of biologically relevant networks would be needed. In this work, we took inspiration from the small-world organization (high clustering and low path length) of FRC networks to design cell scaffolds. An algorithmic toolset was created to generate the networks and process them to improve their 3D printability. We employed tools from graph theory to show that the networks were small-world (omega factor, ω = -0.10 ± 0.02; small-world propensity, SWP = 0.74 ± 0.01). 3D microprinting was employed to physicalize networks as scaffolds, which supported the survival of FRCs. This work, therefore, represents a bioinspired, graph theory-driven approach to control the networks of microscale cell niches.

In Vitro Models of Head and Neck Cancer: From Primitive to Most Advanced

For several decades now, researchers have been trying to answer the demand of clinical oncologists to create an ideal preclinical model of head and neck squamous cell carcinoma (HNSCC) that is accessible, reproducible, and relevant. Over the past years, the development of cellular technologies has naturally allowed us to move from primitive short-lived primary 2D cell cultures to complex patient-derived 3D models that reproduce the cellular composition, architecture, mutational, or viral load of native tumor tissue. Depending on the tasks and capabilities, a scientific laboratory can choose from several types of models: primary cell cultures, immortalized cell lines, spheroids or heterospheroids, tissue engineering models, bioprinted models, organoids, tumor explants, and histocultures. HNSCC in vitro models make it possible to screen agents with potential antitumor activity, study the contribution of the tumor microenvironment to its progression and metastasis, determine the prognostic significance of individual biomarkers (including using genetic engineering methods), study the effect of viral infection on the pathogenesis of the disease, and adjust treatment tactics for a specific patient or groups of patients. Promising experimental results have created a scientific basis for the registration of several clinical studies using HNSCC in vitro models.