Organoids, Volume 4, Issue 2 (June 2025) – 8 articles

The current treatment for refractory BRAF-V600E mutant metastatic colorectal cancer (mCRC) involves combined inhibition of BRAF and the epidermal growth factor receptor (EGFR). However, tumour responses are often short-lived due to a rebound in mitogen-activated protein kinase (MAPK) activity. In this study, we combined short-term cell viability assays with long-term regrowth assays following drug removal over a period of three weeks. This allowed assessment of regrowth after therapy discontinuation. We tested the effect of combined BRAF inhibition (encorafenib) and EGFR inhibition (afatinib) on BRAF-V600E mutant CRC patient-derived organoids (PDOs). Combined EGFR/BRAF inhibition initially caused a major reduction in PDO growth capacity in BRAF-V600E mutant PDOs. This was followed by rapid regrowth after drug removal, mirroring clinical outcomes. EGFR inhibition in BRAF-V600E mutant PDOs led to activation of the insulin receptor (IR) and insulin-like growth factor-1 receptor (IGF1R). The IGF1R/IR inhibitor linsitinib prevented the rebound in MAPK activity following removal of afatinib and encorafenib, prevented regrowth of CRC PDOs, and improved the anti-tumour response in an in vivo model. PDO regrowth assays allow the identification of pathways driving tumour recurrence. IR/IGF1R-inhibition prevents regrowth following golden standard MAPK pathway-targeted therapy and provides a strategy to improve the treatment of BRAF-V600E mutant CRC Full article

Improved in vitro models are needed to reduce costs and delays in central nervous system (CNS) drug discovery. The FDA Modernization Acts 2.0 and 3.0 require human-centered alternative testing methods to mitigate animal-based experiments and discovery delays, and to ensure human safety. Developing cost-efficient, flexible microfluidic chips is essential to advance organ-on-chip (OoC) technology for drug discovery and disease modeling. While CNC micromilling shows promise for fabricating microfluidic devices, it remains underutilized due to limited accessibility. We present a simple CNC-milled flexible microfluidic chip fabricated from thermoplastic poly (methyl methacrylate) (PMMA). The structure of the microplate included drilled openings for connecting the wells. The chip’s biocompatibility was evaluated with isolated primary neuronal cultures from postnatal Wistar rat pups (p1). Primary cells cultured in the device showed high viability, differentiation, and 3D neurosphere formation, similar to conventional well-plate cultures. Neuronal cultures showed neurite growth and functional markers. Although cleanroom-based methods provide higher accuracy, the chip effectively promotes cell viability, differentiation, and alignment, offering an ideal platform for tissue modeling and OoC applications. It allows cell biologists to quickly create prototypes at lower cost and in less time than required for soft lithography and is a viable alternative to the current manufacturing methods. Full article

Tumour-associated angiogenesis plays a key role at all stages of cancer development and progression by providing a nutrient supply, promoting the creation of protective niches for therapy-resistant cancer stem cells, and supporting the metastatic cascade. Therapeutic strategies aimed at vascular targeting, including vessel disruption and/or normalisation, have yielded promising but inconsistent results, pointing to the need to set up reliable models dissecting the steps of the angiogenic process, as well as the ways to interfere with them, to improve patients’ outcomes while limiting side effects. Murine models have successfully contributed to both translational and pre-clinical cancer research, but they are time-consuming, expensive, and cannot recapitulate the genetic heterogeneity of cancer inside its native microenvironment. Non-animal technologies (NATs) are rapidly emerging as invaluable human-centric tools to reproduce the complex and dynamic tumour ecosystem, particularly the tumour-associated vasculature. In the present review, we summarise the currently available NATs able to mimic the vascular structure and functions with progressively increasing complexity, starting from two-dimensional static cultures to the more sophisticated tri-dimensional dynamic ones, patient-derived cultures, the perfused engineered microvasculature, and in silico models. We emphasise the added value of a “one health” approach to cancer research, including studies on spontaneously occurring tumours in companion animals devoid of the ethical concerns associated with traditional animal studies. The limitations of the present tools regarding broader use in pre-clinical oncology, and their translational potential in terms of new target identification, drug development, and personalised therapy, are also discussed. Full article

The extracellular matrix (ECM) provides structural support to cells, thereby forming a functional tissue. In cancer, the growth of the tumor creates internal mechanical stress, which, together with the remodeling activity of tumor cells and fibroblasts, alters the ECM structure, leading to an increased stiffness of the pathological ECM. The enhanced ECM stiffness, in turn, stimulates tumor growth and activates tumor-promoting fibroblasts and tumor cell migration, leading to metastasis and increased therapy resistance. While the relationship between matrix stiffness and migration has been studied before, their connection to internal tumor stress remains unresolved. Here we used 3D ECM-embedded spheroids and hydrogel particle stress sensors to quantify and correlate internal tumor spheroid pressure, ECM stiffness, ECM remodeling, and tumor cell migration. We note that 4T1 breast cancer spheroids and SV80 fibroblast spheroids showed increased invasion—described by area, complexity, number of branches, and branch area—in a stiffer, cross-linked ECM. On the other hand, changing ECM stiffness only minimally changed the radial alignment of fibers but highly changed the amount of fibers. For both cell types, the pressure measured in spheroids gradually decreased as the distance into the ECM increased. For 4T1 spheroids, increased ECM stiffness resulted in a further reach of mechanical stress into the ECM, which, together with the invasive phenotype, was reduced by inhibition of ROCK-mediated contractility. By contrast, such correlation between ECM stiffness and stress-reach was not observed for SV80 spheroids. Our findings connect ECM stiffness with tumor invasion, ECM remodeling, and the reach of tumor-induced mechanical stress into the ECM. Such mechanical connections between tumor and ECM are expected to drive early steps in cancer metastasis. Full article

Basic and translational cancer biology research requires model systems that recapitulate the features of human tumors. While two-dimensional (2D) cell cultures have been foundational and allowed critical advances, they lack the organizational complexity, cellular interactions, and extracellular matrix present in vivo. Mouse models have thus remained the gold standard for studying cancer. In addition to high cost and low throughput, mouse models can also suffer from reduced tumor heterogeneity and species-specific differences. Three-dimensional (3D) culture models have emerged as a key intermediary between 2D cell lines and mouse models, with lower cost and greater flexibility than mouse models and a more accurate representation of the tumor microenvironment than 2D cell lines. In neuroblastoma, an aggressive childhood cancer, 3D models have been applied to study drug responses, cell motility, and tumor–matrix interactions. Recent advances include the integration of immune cells for immunotherapy studies, mesenchymal stromal cells for tumor–stroma interactions, and bioprinted systems to manipulate matrix properties. This review examines the use of 3D culture systems in neuroblastoma, highlighting their advantages and limitations while emphasizing their potential to bridge gaps between in vitro, preclinical, and clinical applications. By improving our understanding of neuroblastoma biology, 3D models hold promise for advancing therapeutic strategies and outcomes in this childhood cancer. Full article

The development of brain organoids from human-induced pluripotent stem cells (iPSCs) has expanded research into neurodevelopment, disease modeling, and drug testing. More recently, the concept of organoid intelligence (OI) has emerged, proposing that these constructs could evolve to support learning, memory, or even sentience. While this perspective has driven enthusiasm in the field of organoid research and suggested new applications in fields such as neuromorphic computing, it also introduces significant scientific and conceptual concerns. Current brain organoids lack the anatomical complexity, network organization, and sensorimotor integration necessary for intelligence or sentience. Despite this, claims surrounding OI often rely on oversimplified interpretations of neural activity, fueled by neurorealist and reification biases that misattribute neurophysiological properties to biologically limited systems. Beyond scientific limitations, the framing of OI risks imposing ethical and regulatory challenges based on speculative concerns rather than empirical evidence. The assumption that organoids might possess sentience, or could develop it over time, could lead to unnecessary restrictions on legitimate research while misrepresenting their actual capabilities. Additionally, comparing biological systems to silicon-based computing overlooks fundamental differences in scalability, efficiency, and predictability, raising questions about whether organoids can meaningfully contribute to computational advancements. The field must recognize the limitations of these models rather than prematurely defining OI as a distinct research domain. A more cautious, evidence-driven approach is necessary to ensure that brain organoids remain valuable tools for neuroscience without overstating their potential. To maintain scientific credibility and public trust, it is essential to separate speculative narratives from grounded research, thus allowing for continued progress in organoid studies without reinforcing misconceptions about intelligence or sentience. Full article

Recent research works have shown the effect of nutrient concentration on cell activity, such as proliferation and differentiation. In 3D cell culture, the impact of scaffold geometry, including pore size, strut diameter, and pore shape, on the concentration gradient within scaffolds under two different loading conditions—constant fluid perfusion and non-fluid perfusion—in a perfusion bioreactor is investigated by developing an in silico model of scaffolds. In this study, both triply periodic minimal surface (TPMS) (with gyroid struts) and non-TPMS (with cubic and spherical pores) scaffolds were investigated. Two types of criteria are applied to the scaffolds: static and perfusion culture conditions. In a static environment, the scaffold in a perfusion bioreactor is loaded with a fluid velocity of $0 \mathrm{m}\mathrm{m}/\mathrm{s}$, whereas in a dynamic environment, perfusion flow with a velocity of 1 mm/s is applied. The results of in silico simulation indicate that the concentration gradient within the scaffold is significantly influenced by pore size, strut diameter, pore shape, and fluid flow, which in turn affects the diffusion rate during drug delivery. Full article

Lymphoid organs are critical for organizing the development of the immune system, generating immune tolerance, and orchestrating the adaptive immune response to foreign antigens. Defects in their structure and function can lead to immunodeficiency, hypersensitivity, cancer, or autoimmune diseases. To better understand these diseases and assess potential therapies, complex models that recapitulate the anatomy and physiology of these tissues are required. Organoid models possess a number of advantages, including complex 3D microarchitecture, scalability, and personalization, which make them ideal for modelling lymphoid organs and related pathologies. Organoids have been developed for both primary and secondary lymphoid tissues; however, these models possess several limitations, including immature phenotypes and incomplete stromal cell populations. Furthermore, these organoids are often heterogeneous in both structure and function. Several lymphoid organs, such as the spleen, do not yet have robust organoid models, offering opportunities for breakthroughs in the field. Overall, development of lymphoid organoids will pave the way for the rapid development and testing of novel therapies, organ modelling, and personalized medicine. This review summarizes current advances in models for the primary lymphoid organ—bone marrow and thymus—as well as the secondary lymphoid organs of the lymph node and spleen. Full article