Organoids in Translational Oncology

The potential of hydrogel-free tumoroids in head and neck squamous cell carcinoma

BACKGROUND

Head and neck malignancy, and in particular squamous cell carcinoma (SCC), is responsible for a significant disease burden globally. The lack of an optimal in vitro model system to accurately recapitulate in vivo response to therapy in HNSCC remains a challenge. The development of patient-derived three-dimensional tumour cultures, or tumoroids, has enabled improved modelling of the tumour microenvironment through simulation of important characteristics such as tumour hypoxia, cell-cell interactions and nutrient diffusion characteristics.

METHODS

We performed a comprehensive English-language literature review of current methods of tumoroid development utilising Matrigel and Cultrex Basement Membrane Extract 2 (key terms: tumour organoids, tumoroids, hydrogels, Matrigel, Cultrex, squamous cell carcinoma, head and neck)-two common proprietary murine-derived hydrogels containing extracellular matrix proteins. Nascent literature on the establishment of a novel hydrogel-free platform for tumoroid development as distinct from these existing methods was also explored.

RESULTS

Whilst useful for facilitating cell-matrix interactions and providing a scaffold for three-dimensional cell growth and organisation, murine-derived cell matrix methods were noted to have notable limitations including temperature sensitivity and the medium forming a barrier to analysis of the supernatant. A novel hydrogel-free method of establishing in vitro tumoroid cultures has been subject to experimentation in colorectal but not head and neck malignancy. The absence of a hydrogel provides for the de novo synthesis of extracellular matrix native to the tumour and self-organisation of cells within this scaffold through the use of ultralow attachment plates. This model demonstrates similar structural and physiological properties to native tissue, whilst enabling more accurate biomimicry of the tumour microenvironment for drug testing.

CONCLUSIONS

In the absence of prior experimentation on a hydrogel-free method for establishing HNSCC tumoroids, and comparisons between hydrogel and hydrogel-free models, the future development of a comparative protocol encompassing recruitment, collection, processing and analysis represents a valuable opportunity.

Viscoelasticity in 3D Cell Culture and Regenerative Medicine: Measurement Techniques and Biological Relevance

The field of mechanobiology is gaining prominence due to recent findings that show cells sense and respond to the mechanical properties of their environment through a process called mechanotransduction. The mechanical properties of cells, cell organelles, and the extracellular matrix are understood to be viscoelastic. Various technologies have been researched and developed for measuring the viscoelasticity of biological materials, which may provide insight into both the cellular mechanisms and the biological functions of mechanotransduction. Here, we explain the concept of viscoelasticity and introduce the major techniques that have been used to measure the viscoelasticity of various soft materials in different length- and timescale frames. The topology of the material undergoing testing, the geometry of the probe, the magnitude of the exerted stress, and the resulting deformation should be carefully considered to choose a proper technique for each application. Lastly, we discuss several applications of viscoelasticity in 3D cell culture and tissue models for regenerative medicine, including organoids, organ-on-a-chip systems, engineered tissue constructs, and tunable viscoelastic hydrogels for 3D bioprinting and cell-based therapies.

Phenotypic Heterogeneity, Bidirectionality, Universal Cues, Plasticity, Mechanics, and the Tumor Microenvironment Drive Cancer Metastasis

Tumor diseases become a huge problem when they embark on a path that advances to malignancy, such as the process of metastasis. Cancer metastasis has been thoroughly investigated from a biological perspective in the past, whereas it has still been less explored from a physical perspective. Until now, the intraluminal pathway of cancer metastasis has received the most attention, while the interaction of cancer cells with macrophages has received little attention. Apart from the biochemical characteristics, tumor treatments also rely on the tumor microenvironment, which is recognized to be immunosuppressive and, as has recently been found, mechanically stimulates cancer cells and thus alters their functions. The review article highlights the interaction of cancer cells with other cells in the vascular metastatic route and discusses the impact of this intercellular interplay on the mechanical characteristics and subsequently on the functionality of cancer cells. For instance, macrophages can guide cancer cells on their intravascular route of cancer metastasis, whereby they can help to circumvent the adverse conditions within blood or lymphatic vessels. Macrophages induce microchannel tunneling that can possibly avoid mechanical forces during extra- and intravasation and reduce the forces within the vascular lumen due to vascular flow. The review article highlights the vascular route of cancer metastasis and discusses the key players in this traditional route. Moreover, the effects of flows during the process of metastasis are presented, and the effects of the microenvironment, such as mechanical influences, are characterized. Finally, the increased knowledge of cancer metastasis opens up new perspectives for cancer treatment.

Microfluidic printed 3D bioactive scaffolds for postoperative treatment of gastric cancer

Tumor recurrence and tissue regeneration are two major challenges in the postoperative treatment of cancer. Current research hotspots are focusing on developing novel scaffold materials that can simultaneously suppress tumor recurrence and promote tissue repair. Here, we propose a microfluidic 3D-printed methacrylate fish gelatin (F-GelMA@BBR) scaffold loaded with berberine (BBR) for the postoperative treatment of gastric cancer. The F-GelMA@BBR scaffold displayed a significant killing effect on gastric cancer MKN-45 cells in vitro and demonstrated excellent anti-recurrence efficiency in gastric cancer postoperative models. In vitro experiments have shown that F-GelMA@BBR exhibits significant cytotoxicity on gastric cancer cells while maintaining the cell viability of normal cells. The results of in vivo experiments show that F-GelMA@BBR can significantly suppress the tumor volume to 49.7 % of the control group. In addition, the scaffold has an ordered porous structure and good biocompatibility, which could support the attachment and proliferation of normal cells to promote tissue repair at the tumor resection site. These features indicated that such scaffold material is a promising candidate for postoperative tumor treatment in the practical application.

Cancer stem cells and their niche in cancer progression and therapy

High recurrence and metastasis rates and poor prognoses are the major challenges of current cancer therapy. Mounting evidence suggests that cancer stem cells (CSCs) play an important role in cancer development, chemoradiotherapy resistance, recurrence, and metastasis. Therefore, targeted CSC therapy has become a new strategy for solving the problems of cancer metastasis and recurrence. Since the properties of CSCs are regulated by the specific tumour microenvironment, the so-called CSC niche, which targets crosstalk between CSCs and their niches, is vital in our pursuit of new therapeutic opportunities to prevent cancer from recurring. In this review, we aim to highlight the factors within the CSC niche that have important roles in regulating CSC properties, including the extracellular matrix (ECM), stromal cells (e.g., associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), and mesenchymal stem cells (MSCs)), and physiological changes (e.g., inflammation, hypoxia, and angiogenesis). We also discuss recent progress regarding therapies targeting CSCs and their niche to elucidate developments of more effective therapeutic strategies to eliminate cancer.

Regulation of cell fate by cell imprinting approach in vitro

Cell culture-based technologies are widely utilized in various domains such as drug evaluation, toxicity assessment, vaccine and biopharmaceutical development, reproductive technology, and regenerative medicine. It has been demonstrated that pre-adsorption of extracellular matrix (ECM) proteins including collagen, laminin and fibronectin provide more degrees of support for cell adhesion. The purpose of cell imprinting is to imitate the natural topography of cell membranes by gels or polymers to create a reliable environment for the regulation of cell function. The results of recent studies show that cell imprinting is a tool to guide the behavior of cultured cells by controlling their adhesive interactions with surfaces. Therefore, in this review we aim to compare different cell cultures with the imprinting method and discuss different cell imprinting applications in regenerative medicine, personalized medicine, disease modeling, and cell therapy.

Advances in organoid technology for veterinary disease modeling

Organoids are in vitro organ-like structures that faithfully recapitulate many characteristics of a specific organ. During the past decades, major progress has been accomplished in establishing three-dimensional (3D) culture systems toward stem cell-derived organoids. As a significant technological breakthrough, these amazing 3D organoid constructs bridge the conventional 2D in vitro models and in vivo animal models and provide an unprecedented opportunity to investigate the complexities of veterinary diseases ranging from their pathogenesis to the prevention, therapy, or even future organ replacement strategies. In this review, we briefly discuss several definitions used in organoid research and highlight the currently known achievements in modeling veterinary diseases, including infectious and inflammatory diseases, cancers, and metabolic diseases. The applications of organoid technology in veterinary disease modeling are still in their infancy stage but the future is promising.

Organoids of the male reproductive system: Challenges, opportunities, and their potential use in fertility research

Organoids are units of function of a given organ able to reproduce, in culture, a biological structure similar in architecture and function to its counterpart in vivo. Today, it is possible to develop an organoid from a fragment of tissue, a stem cell located in an adult organ, an embryonic stem cell, or an induced pluripotent stem cell. In the past decade, many organoids have been developed which mimic stomach, pancreas, liver and brain tissues, optic cups, among many others. Additionally, different male reproductive system organs have already been developed as organoids, including the prostate and testis. These 3D cultures may be of great importance for urological cancer research and have the potential to be used in fertility research for the study of spermatozoa production and maturation, germ cells-somatic cells interactions, and mechanisms of disease. They also provide an accurate preclinical pipeline for drug testing and discovery, as well as for the study of drug resistance. In this work, we revise the current knowledge on organoid technology and its use in healthcare and research, describe the male reproductive system organoids and other biomaterials already developed, and discuss their current application. Finally, we highlight the research gaps, challenges, and opportunities in the field and propose strategies to improve the use of organoids for the study of male infertility situations. This article is categorized under: Reproductive System Diseases > Stem Cells and Development Reproductive System Diseases > Biomedical Engineering.

Pancreatic cancer derived 3D organoids as a clinical tool to evaluate the treatment response

Background and purpose

Pancreatic cancer (PC) is the fourth leading cause of cancer death in both men and women. The standard of care for patients with locally advanced PC of chemotherapy, stereotactic radiotherapy (RT), or chemo-radiation-therapy has shown highly variable and limited success rates. However, three-dimensional (3D) Pancreatic tumor organoids (PTOs) have shown promise to study tumor response to drugs, and emerging treatments under in vitro conditions. We investigated the potential for using 3D organoids to evaluate the precise radiation and drug dose responses of in vivo PC tumors.

Methods

PTOs were created from mouse pancreatic tumor tissues, and their microenvironment was compared to that of in vivo tumors using immunohistochemical and immunofluorescence staining. The organoids and in vivo PC tumors were treated with fractionated X-ray RT, 3-bromopyruvate (3BP) anti-tumor drug, and combination of 3BP + fractionated RT.

Results

Pancreatic tumor organoids (PTOs) exhibited a similar fibrotic microenvironment and molecular response (as seen by apoptosis biomarker expression) as in vivo tumors. Untreated tumor organoids and in vivo tumor both exhibited proliferative growth of 6 folds the original size after 10 days, whereas no growth was seen for organoids and in vivo tumors treated with 8 (Gray) Gy of fractionated RT. Tumor organoids showed reduced growth rates of 3.2x and 1.8x when treated with 4 and 6 Gy fractionated RT, respectively. Interestingly, combination of 100 µM of 3BP + 4 Gy of RT showed pronounced growth inhibition as compared to 3-BP alone or 4 Gy of radiation alone. Further, positive identification of SOX2, SOX10 and TGFβ indicated presence of cancer stem cells in tumor organoids which might have some role in resistance to therapies in pancreatic cancer.

Conclusions

PTOs produced a similar microenvironment and exhibited similar growth characteristics as in vivo tumors following treatment, indicating their potential for predicting in vivo tumor sensitivity and response to RT and combined chemo-RT treatments.

Liquid biopsy approaches and immunotherapy in colorectal cancer for precision medicine: Are we there yet?

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally, with nearly half of patients detected in the advanced stages. This is due to the fact that symptoms associated with CRC often do not appear until the cancer has reached an advanced stage. This suggests that CRC is a cancer with a slow progression, making it curable and preventive if detected in its early stage. Therefore, there is an urgent clinical need to improve CRC early detection and personalize therapy for patients with this cancer. Recently, liquid biopsy as a non-invasive or nominally invasive approach has attracted considerable interest for its real-time disease monitoring capability through repeated sample analysis. Several studies in CRC have revealed the potential for liquid biopsy application in a real clinical setting using circulating RNA/miRNA, circulating tumor cells (CTCs), exosomes, etc. However, Liquid biopsy still remains a challenge since there are currently no promising results with high specificity and specificity that might be employed as optimal circulatory biomarkers. Therefore, in this review, we conferred the plausible role of less explored liquid biopsy components like mitochondrial DNA (mtDNA), organoid model of CTCs, and circulating cancer-associated fibroblasts (cCAFs); which may allow researchers to develop improved strategies to unravel unfulfilled clinical requirements in CRC patients. Moreover, we have also discussed immunotherapy approaches to improve the prognosis of MSI (Microsatellite Instability) CRC patients using neoantigens and immune cells in the tumor microenvironment (TME) as a liquid biopsy approach in detail.

Advances in the application of 3D tumor models in precision oncology and drug screening

Traditional tumor models cannot perfectly simulate the real state of tumors in vivo, resulting in the termination of many clinical trials. 3D tumor models’ technology provides new in vitro models that bridge the gap between in vitro and in vivo findings, and organoids maintain the properties of the original tissue over a long period of culture, which enables extensive research in this area. In addition, they can be used as a substitute for animal and in vitro models, and organoids can be established from patients’ normal and malignant tissues, with unique advantages in clinical drug development and in guiding individualized therapies. 3D tumor models also provide a promising platform for high-throughput research, drug and toxicity testing, disease modeling, and regenerative medicine. This report summarizes the 3D tumor model, including evidence regarding the 3D tumor cell culture model, 3D tumor slice model, and organoid culture model. In addition, it provides evidence regarding the application of 3D tumor organoid models in precision oncology and drug screening. The aim of this report is to elucidate the value of 3D tumor models in cancer research and provide a preclinical reference for the precise treatment of cancer patients.

Patient-Derived Lung Tumoroids—An Emerging Technology in Drug Development and Precision Medicine

Synthetic 3D multicellular systems derived from patient tumors, or tumoroids, have been developed to complete the cancer research arsenal and overcome the limits of current preclinical models. They aim to represent the molecular and structural heterogeneity of the tumor micro-environment, and its complex network of interactions, with greater accuracy. They are more predictive of clinical outcomes, of adverse events, and of resistance mechanisms. Thus, they increase the success rate of drug development, and help clinicians in their decision-making process. Lung cancer remains amongst the deadliest of diseases, and still requires intensive research. In this review, we analyze the merits and drawbacks of the current preclinical models used in lung cancer research, and the position of tumoroids. The introduction of immune cells and healthy regulatory cells in autologous tumoroid models has enabled their application to most recent therapeutic concepts. The possibility of deriving tumoroids from primary tumors within reasonable time has opened a direct approach to patient-specific features, supporting their future role in precision medicine.

Tumor organoids: synergistic applications, current challenges, and future prospects in cancer therapy

Patient-derived cancer cells (PDCs) and patient-derived xenografts (PDXs) are often used as tumor models, but have many shortcomings. PDCs not only lack diversity in terms of cell type, spatial organization, and microenvironment but also have adverse effects in stem cell cultures, whereas PDX are expensive with a low transplantation success rate and require a long culture time. In recent years, advances in three-dimensional (3D) organoid culture technology have led to the development of novel physiological systems that model the tissues of origin more precisely than traditional culture methods. Patient-derived cancer organoids bridge the conventional gaps in PDC and PDX models and closely reflect the pathophysiological features of natural tumorigenesis and metastasis, and have led to new patient-specific drug screening techniques, development of individualized treatment regimens, and discovery of prognostic biomarkers and mechanisms of resistance. Synergistic combinations of cancer organoids with other technologies, for example, organ-on-a-chip, 3D bio-printing, and CRISPR-Cas9-mediated homology-independent organoid transgenesis, and with treatments, such as immunotherapy, have been useful in overcoming their limitations and led to the development of more suitable model systems that recapitulate the complex stroma of cancer, inter-organ and intra-organ communications, and potentially multiorgan metastasis. In this review, we discuss various methods for the creation of organ-specific cancer organoids and summarize organ-specific advances and applications, synergistic technologies, and treatments as well as current limitations and future prospects for cancer organoids. Further advances will bring this novel 3D organoid culture technique closer to clinical practice in the future.

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.

Using 3D in vitro cell culture models in anti-cancer drug discovery

INTRODUCTION

The high failure rate in drug discovery remains a costly and time-consuming challenge. Improving the odds of success in the early steps of drug development requires disease models with high biological relevance for biomarker discovery and drug development. The adoption of three-dimensional (3D) cell culture systems over traditional monolayers in cell-based assays is considered a promising step toward improving the success rate in drug discovery.

AREAS COVERED

In this article, the author focuses on new technologies for 3D cell culture and their applications in cancer drug discovery. Besides the most common 3D cell-culture systems for tumor cells, the article emphasizes the need for 3D cell culture technologies that can mimic the complex tumor microenvironment and cancer stem cell niche.

EXPERT OPINION

There has been a rapid increase in 3D cell culture technologies in recent years in an effort to more closely mimic in vivo physiology. Each 3D cell culture system has its own strengths and weaknesses with regard to in vivo tumor growth and the tumor microenvironment. This requires careful consideration of which 3D cell culture system is chosen for drug discovery and should be based on factors like drug target and tumor origin.

3D Culture Systems for Exploring Cancer Immunology

Simple Summary

To study any disease, researchers need convenient and relevant disease models. In cancer, the most commonly used models are two-dimensional (2D) culture models, which grow cells on hard, rigid, plastic surfaces, and mouse models. Cancer immunology is especially difficult to model because the immune system is exceedingly complex; it contains multiple types of cells, and each cell type has several subtypes and a spectrum of activation states. These many immune cell types interact with cancer cells and other components of the tumor, ultimately influencing disease outcomes. 2D culture methods fail to recapitulate these complex cellular interactions. Mouse models also suffer because the murine and human immune systems vary significantly. Three-dimensional (3D) culture systems therefore provide an alternative method to study cancer immunology and can fill the current gaps in available models. This review will describe common 3D culture models and how those models have been used to advance our understanding of cancer immunology.

Abstract

Cancer immunotherapy has revolutionized cancer treatment, spurring extensive investigation into cancer immunology and how to exploit this biology for therapeutic benefit. Current methods to investigate cancer-immune cell interactions and develop novel drug therapies rely on either two-dimensional (2D) culture systems or murine models. However, three-dimensional (3D) culture systems provide a potentially superior alternative model to both 2D and murine approaches. As opposed to 2D models, 3D models are more physiologically relevant and better replicate tumor complexities. Compared to murine models, 3D models are cheaper, faster, and can study the human immune system. In this review, we discuss the most common 3D culture systems—spheroids, organoids, and microfluidic chips—and detail how these systems have advanced our understanding of cancer immunology.

Organoids and Liquid Biopsy in Oral Cancer Research

To promote the newest discoveries in oral cancer research, a special issue "Frontiers in Oral Cancer-Basic and Clinical Sciences" in the Journal of Clinical Medicine (JCM) was opened from September 2019 to April 2020 [...].