Multicellular tumor spheroids: an underestimated tool is catching up again. J Biotechnol. 2010;148:3-15. [PMID: 20097238 DOI: 10.1016/j.jbiotec.2010.01.012]

Exploring oncology treatment strategies with tyrosine kinase inhibitors through advanced 3D models (Review)

The limitations of two-dimensional (2D) models in cancer research have hindered progress in fully understanding the complexities of drug resistance and therapeutic failures. However, three-dimensional (3D) models provide a more accurate representation of in vivo environments, capturing critical cellular interactions and dynamics that are essential in evaluating the efficacy and toxicity of tyrosine kinase inhibitors (TKIs). These advanced models enable researchers to explore drug resistance mechanisms with greater precision, optimizing treatment strategies and improving the predictive accuracy of clinical outcomes. By leveraging 3D models, it will be possible to deepen the current understanding of TKIs and drive forward innovations in cancer treatment. The present review discusses the limitations of 2D models and the transformative impact of 3D models on oncology research, highlighting their roles in addressing the challenges of 2D systems and advancing TKI studies.

Lipid nanoparticles as nano-Trojan-horses for siRNA delivery and gene-knockdown

The therapeutic messenger RNA strategies, such as those using small interfering RNAs, take several advantages (versatility, efficiency and selectivity) over plasmid DNA-based strategies. However, the challenge remains to find nanovectors capable of properly loading the genetic material, transporting it through troublesome environments, like a tumoral site, and delivering it into the cytoplasm of target cells. Here, lipid nanoparticles, consisting of a gemini cationic/neutral helper lipid mixture, are proposed as siRNA nanovector. Cells from cervical and brain cancer overexpressing the green fluorescent protein (GFP) were chosen to analyse the biological response as well as the efficiency and safety of the siRNA-loaded nanovector according to the cell phenotype. Flow cytometry and epifluorescence or confocal microscopy were used to follow the gene knockdown in these overexpressed cells. The effect of the nanovector on cellular proliferation was evaluated with cytotoxicity assays while their potential oxidative stress generation was determined by quantifying the generation of reactive oxygen species. To explore the mechanism of cellular uptake, different inhibitors of endocytic pathways were used during incubation with cells. Finally, nanovectors were incubated in 3D-grown cells (spheroids) to see whether they can penetrate the complex tumoral microenvironments, their efficiency to knockdown GFP expression being monitored by confocal microscopy.

MAPK14/p38α shapes the molecular landscape of endometrial cancer and promotes tumorigenic characteristics

The molecular underpinnings of high-grade endometrial carcinoma (HGEC) metastatic growth and survival are poorly understood. Here, we show that ascites-derived and primary tumor HGEC cell lines in 3D spheroid culture faithfully recapitulate key features of malignant peritoneal effusion and exhibit fundamentally distinct transcriptomic, proteomic, and metabolomic landscapes compared with conventional 2D monolayers. Using a genetic screening platform, we identify MAPK14 (which encodes the protein kinase p38α) as a specific requirement for HGEC in spheroid culture. MAPK14/p38α has broad roles in programming the phosphoproteome, transcriptome, and metabolome of HGEC spheroids, yet has negligible impact on monolayer cultures. MAPK14 promotes tumorigenicity in vivo and is specifically required to sustain a sub-population of spheroid cells that is enriched in cancer stemness markers. Therefore, spheroid growth of HGEC activates unique biological programs, including p38α signaling, that cannot be captured using 2D culture models and are highly relevant to malignant disease pathology.

Environmental Exposure to Bisphenol A Enhances Invasiveness in Papillary Thyroid Cancer

Bisphenol A (BPA) is a prevalent environmental contaminant found in plastics and known for its endocrine-disrupting properties, posing risks to both human health and the environment. Despite its widespread presence, the impact of BPA on papillary thyroid cancer (PTC) progression, especially under realistic environmental conditions, is not well understood. This study examined the effects of BPA on PTC using a 3D thyroid papillary tumor spheroid model, which better mimicked the complex interactions within human tissues compared to traditional 2D models. Our findings demonstrated that BPA, at environmentally relevant concentrations, could induce significant changes in PTC cells, including a decrease in E-cadherin expression, an increase in vimentin expression, and reduced thyroglobulin (TG) secretion. These changes suggest that BPA exposure may promote epithelial-mesenchymal transition (EMT), enhance invasiveness, and reduce cell differentiation, potentially complicating treatment, including by increasing resistance to radioiodine therapy. This research highlights BPA's hazardous nature as an environmental contaminant and emphasizes the need for advanced in vitro models, like 3D tumor spheroids, to better assess the risks posed by such chemicals. It provides valuable insights into the environmental implications of BPA and its role in thyroid cancer progression, enhancing our understanding of endocrine-disrupting chemicals.

Synergistic Effects of Mistletoe Lectin and Cisplatin on Triple-Negative Breast Cancer Cells: Insights from 2D and 3D In Vitro Models

Triple-negative breast cancer (TNBC) remains a challenging subtype due to its aggressive nature and limited treatment options. This study investigated the potential synergistic effects of Korean mistletoe lectin (Viscum album L. var. coloratum agglutinin, VCA) and cisplatin on MDA-MB-231 TNBC cells using both 2D and 3D culture models. In 2D cultures, the combination of VCA and cisplatin synergistically inhibited cell proliferation, induced apoptosis, and arrested the cell cycle at the G2/M phase. Also, the combination treatment significantly reduced cell migration and invasion. Gene expression analysis showed significant changes in specific genes related to apoptosis (Bax, Bcl-2), metastasis (MMP-2, MMP-9), and EMT (E-cadherin, N-cadherin). Three-dimensional spheroid models corroborated these findings, demonstrating enhanced cytotoxicity and reduced invasion with the combination treatment. Significantly, the 3D models exhibited differential drug sensitivity compared to 2D cultures, emphasizing the importance of utilizing physiologically relevant models in preclinical studies. The combination treatment also reduced the expression of angiogenesis-related factors VEGF-A and HIF-1α. This comprehensive study provides substantial evidence for the potential of VCA and cisplatin combination therapy in TNBC treatment and underscores the significance of integrating 2D and 3D models in preclinical cancer research.

Application and progress of 3D tumor models in breast cancer

Due to its high heterogeneity and significant impact on women's health globally, breast cancer necessitates robust preclinical models to understand tumor biology and guide personalized treatment strategies. Three-dimensional (3D) in vitro tumor models hold immense promise in this regard. These tumor models not only mimic the spatial structure and growth environment of tumors in vivo, but also retain the pathological and genetic characteristics of solid tumors. This fidelity makes them powerful tools for accelerating advancements in fundamental research and translational medicine. The diversity, modularity, and efficacy of 3D tumor models are driving a biotechnological revolution. As these technologies become increasingly sophisticated, 3D tumor models are poised to become powerful weapons in the fight against breast cancer. This article expounds on the progress made in utilizing 3D tumor models for breast cancer research.

A Review on Patient-derived 3D Micro Cancer Approach for Drug Screen in Personalized Cancer Medicine

Precision medicine in oncology aims to identify an individualized treatment plan based on genomic alterations in a patient's tumor. It helps to select the most beneficial therapy for an individual patient. As it is now known that no patient's cancer is the same, and therefore, different patients may respond differently to conventional treatments, precision medicine, which replaces the one-size-fits-all approach, supports the development of tailored treatments for specific cancers of different patients. Patient-specific organoid or spheroid models as 3D cell culture models are very promising for predicting resistance to anti-cancer drugs and for identifying the most effective cancer therapy for high-throughput drug screening combined with genomic analysis in personalized medicine. Because tumor spheroids incorporate many features of solid tumors and reflect resistance to drugs and radiation, as in human cancers, they are widely used in drug screening studies. Testing patient-derived 3D cancer spheroids with some anticancer drugs based on information from molecular profiling can reveal the sensitivity of tumor cells to drugs and provide the right compounds to be effective against resistant cells. Given that many patients do not respond to standard treatments, patient-specific treatments will be more effective, less toxic. They will affect survival better compared to the standard approach used for all patients.

The present and future of the Cancer Dependency Map

Despite tremendous progress in the past decade, the complex and heterogeneous nature of cancer complicates efforts to identify new therapies and therapeutic combinations that achieve durable responses in most patients. Further advances in cancer therapy will rely, in part, on the development of targeted therapeutics matched with the genetic and molecular characteristics of cancer. The Cancer Dependency Map (DepMap) is a large-scale data repository and research platform, aiming to systematically reveal the landscape of cancer vulnerabilities in thousands of genetically and molecularly annotated cancer models. DepMap is used routinely by cancer researchers and translational scientists and has facilitated the identification of several novel and selective therapeutic strategies for multiple cancer types that are being tested in the clinic. However, it is also clear that the current version of DepMap is not yet comprehensive. In this Perspective, we review (1) the impact and current uses of DepMap, (2) the opportunities to enhance DepMap to overcome its current limitations, and (3) the ongoing efforts to further improve and expand DepMap.

The use of patient-derived xenografts and patient-derived organoids in the search for new therapeutic regimens for pancreatic carcinoma. A review

Patient-derived organoids (PDOs) and xenografts (PDXs) are powerful tools for personalized medicine in pancreatic cancer (PC) research. This study explores the complementary strengths of PDOs and PDXs in terms of practicality, genetic fidelity, cost, and labor considerations. Among other models like 2D cell cultures, spheroids, cancer-on-chip systems, cell line-derived xenografts (CDX), and genetically engineered mouse models (GEMMs), PDOs and PDXs uniquely balance genetic fidelity and personalized medicine potential, offering distinct advantages over the simplicity of 2D cultures and the advanced, but often resource-intensive, GEMMs and cancer-on-chip systems. PDOs excel in high-throughput drug screening due to their ease of use, lower cost, and shorter experimental timelines. However, they lack a complete tumor microenvironment. Conversely, PDXs offer a more complex microenvironment that closely reflects patient tumors, potentially leading to more clinically relevant results. Despite limitations in size, number of specimens, and engraftment success, PDXs demonstrate significant concordance with patient responses to treatment, highlighting their value in personalized medicine. Both models exhibit significant genetic fidelity, making them suitable for drug sensitivity testing. The choice between PDOs and PDXs depends on the research focus, resource availability, and desired level of microenvironment complexity. PDOs are advantageous for high-throughput screening of a diverse array of potential therapeutic agents due to their relative ease of culture and scalability. PDXs, on the other hand, offer a more physiologically relevant model, allowing for a comprehensive evaluation of drug efficacy and mechanisms of action.

Are 3D Tumor Cell Spheroids a Utile System for the In Vitro Evaluation of Diagnostic Radiotracers?

By possibly bridging the gap between 2D in vitro cell assays and in vivo applications, tumor cell spheroid cultures offer promising avenues for advancing innovation in nuclear medicine. Regarding the in vitro evaluation of therapeutic radioligands, tumor cell spheroids have been successfully used to assess the therapeutic efficacy against human tumors. However, studies employing spheroids for testing diagnostic tracers are missing. The present work investigated the receptor interaction of a diagnostic radioligand with different tumor cell spheroids and compared the results to those received from a standard 2D cell assay to validate the usefulness of 3D cell systems for diagnostic radiotracer testing. For this purpose, a new agent-[68Ga]Ga-NODAGA-PEG5-c(RGDfK)-was developed. In competitive displacement assays against [125I]I-echistatin in human U87MG glioblastoma cell monolayers, NODAGA-PEG5-c(RGDfK) demonstrated specific binding and IC50 values of 3.08 ± 0.12 and 10.39 ± 0.89 μM in the absence and presence of basal membrane extract (BME), respectively. Compared to cell monolayers, the 3D cell aggregates yielded considerably higher IC50 values of 16.46 ± 2.88, 20.52 ± 4.41, and 18.44 ± 6.06 μM in spheroids generated without additive, collagen-1, and BME supplementation and showed considerable unspecific binding. The obtained data were contextualized by investigating differences in morphology, cell viability, and integrin content per cell of the 2D and 3D cell models as well as the influence of ECM composition. Integrin expression per cell was stable, while spheroid density and the associated radioligand uptake were varying, depending on the culture conditions. This suggests a correlation between the NODAGA-PEG5-c(RGDfK)-integrin αvβ3-interaction and cell model compactness. Further, a considerable influence of matrix components on ligand-receptor interaction could be demonstrated. Overall, the results showed profound differences between the 2D and 3D radiotracer assays investigated, and further work is warranted to verify the expected added value of 3D tumor cell spheroids for the evaluation of diagnostic radioligands.

Modeling intratumor heterogeneity in breast cancer

Reduced therapy response in breast cancer has been correlated with heterogeneity in biomarker composition, expression level, and spatial distribution of cancer cells within a patient tumor. Thus, there is a need for models to replicate cell-cell, cell-stromal, and cell-microenvironment interactions during cancer progression. Traditional two-dimensional (2D) cell culture models are convenient but cannot adequately represent tumor microenvironment histological organization,in vivo3D spatial/cellular context, and physiological relevance. Recently, three-dimensional (3D)in vitrotumor models have been shown to provide an improved platform for incorporating compositional and spatial heterogeneity and to better mimic the biological characteristics of patient tumors to assess drug response. Advances in 3D bioprinting have allowed the creation of more complex models with improved physiologic representation while controlling for reproducibility and accuracy. This review aims to summarize the advantages and challenges of current 3Din vitromodels for evaluating therapy response in breast cancer, with a particular emphasis on 3D bioprinting, and addresses several key issues for future model development as well as their application to other cancers.

A spheroid whole mount drug testing pipeline with machine-learning based image analysis identifies cell-type specific differences in drug efficacy on a single-cell level

BACKGROUND

The growth and drug response of tumors are influenced by their stromal composition, both in vivo and 3D-cell culture models. Cell-type inherent features as well as mutual relationships between the different cell types in a tumor might affect drug susceptibility of the tumor as a whole and/or of its cell populations. However, a lack of single-cell procedures with sufficient detail has hampered the automated observation of cell-type-specific effects in three-dimensional stroma-tumor cell co-cultures.

METHODS

Here, we developed a high-content pipeline ranging from the setup of novel tumor-fibroblast spheroid co-cultures over optical tissue clearing, whole mount staining, and 3D confocal microscopy to optimized 3D-image segmentation and a 3D-deep-learning model to automate the analysis of a range of cell-type-specific processes, such as cell proliferation, apoptosis, necrosis, drug susceptibility, nuclear morphology, and cell density.

RESULTS

This demonstrated that co-cultures of KP-4 tumor cells with CCD-1137Sk fibroblasts exhibited a growth advantage compared to tumor cell mono-cultures, resulting in higher cell counts following cytostatic treatments with paclitaxel and doxorubicin. However, cell-type-specific single-cell analysis revealed that this apparent benefit of co-cultures was due to a higher resilience of fibroblasts against the drugs and did not indicate a higher drug resistance of the KP-4 cancer cells during co-culture. Conversely, cancer cells were partially even more susceptible in the presence of fibroblasts than in mono-cultures.

CONCLUSION

In summary, this underlines that a novel cell-type-specific single-cell analysis method can reveal critical insights regarding the mechanism of action of drug substances in three-dimensional cell culture models.

Pelophen B is a non-taxoid binding microtubule-stabilizing agent with promising preclinical anticancer properties

Taxanes, such as paclitaxel (PTX), stabilize microtubules and are used as a first-line therapy in multiple cancer types. Disruption of microtubule equilibrium, which plays an essential role in mitosis and cell homeostasis, ultimately results in cell death. Even though PTX is a very potent chemotherapy, its use is associated with major side effects and therapy resistance. Pelophen B (PPH), a synthetic analog of peloruside A, stabilizes microtubules through interaction with a non-taxoid binding site of β-tubulin. We evaluated the anticancer effect of PPH in a variety of tumor types by using established cell lines, early-passage cultures and ex vivo tumor-derived cultures that preserve the 3D architecture of the tumor microenvironment. PPH significantly blocks colony formation capacity, reduces viability and exerts additivity with PTX. Interestingly, PPH overcomes resistance to PTX. Mechanistically, PPH induces a G2/M cell cycle arrest and increases the presence of tubulin polymerization promoting protein (TPPP), inducing lysine 40 acetylation of α-tubulin. Although, results induced by paclitaxel or PPH are concordant, PPH's unique microtubule binding mechanism enables PTX additivity and ensures overcoming PTX-induced resistance. In conclusion, PPH results in remarkable anti-cancer activity in a range of preclinical models supporting further clinical investigation of PPH as a therapeutic anticancer agent.

Multicellular tumor spheroids: A convenient in vitro model for translational cancer research

In the attempts to mitigate uncertainties in the results of monolayer culture for the identification of cancer therapeutic targets and compounds, there has been a growing interest in using 3D cancer spheroid models, which include tumorospheres (TSs), tissue-derived tumor spheres (TDTSs), organotypic multicellular tumor spheroids (OMSs), and multicellular tumor spheroids (MCTSs). The MCTSs, either Mono-MCTSs or Hetero-MCTSs, with or without scaffold, in particular, offer numerous advantages over other spheroid models, including easy cultivation, high reproducibility, accessibility, high throughput, controllable size, well-rounded shape, simplicity of genetic manipulation, economical and availability of various biological methods for their development. In this review, we have attempted to discuss the role of MCTSs concerning various aspects of translational cancer research, such as drug response and penetration, cell-cell interaction, and invasion and metastasis. However, the Mono-MCTSs, either scaffold-free or scaffold-based, may not adequately represent the cellular heterogeneity and complexity of clinical tumors, limiting their utility in translational cancer research. Conversely, Hetero-MCTS models, both scaffold-free and scaffold-based, show better suitability due to the presence of a similar in vivo type tumor microenvironment. Nonetheless, scaffold-based Hetero-MCTS models show batch variability and challenges in performing quantitative assays due to difficulties extracting spheroids and cells from scaffolds. Further, incorporating stromal cells with cancer cells in a more precise ratio to develop Hetero-MCTSs can enhance the model's relevance, yielding more clinically reliable outcomes for drug candidates and improving insights into tumor biology.

Breaking the mold: 3D cell cultures reshaping the future of cancer research

Despite extensive efforts to unravel tumor behavior and develop anticancer therapies, most treatments fail when advanced to clinical trials. The main challenge in cancer research has been the absence of predictive cancer models, accurately mimicking the tumoral processes and response to treatments. The tumor microenvironment (TME) shows several human-specific physical and chemical properties, which cannot be fully recapitulated by the conventional 2D cell cultures or the in vivo animal models. These limitations have driven the development of novel in vitro cancer models, that get one step closer to the typical features of in vivo systems while showing better species relevance. This review introduces the main considerations required for developing and exploiting tumor spheroids and organoids as cancer models. We also detailed their applications in drug screening and personalized medicine. Further, we show the transition of these models into novel microfluidic platforms, for improved control over physiological parameters and high-throughput screening. 3D culture models have provided key insights into tumor biology, more closely resembling the in vivo TME and tumor characteristics, while enabling the development of more reliable and precise anticancer therapies.

A Population-Based Tumor-Volume Model for Head and Neck Cancer During Radiation Therapy With a Dynamic Oxygenated Compartment

PURPOSE

With the coming era of digital medicine and healthcare technology, mathematical modeling of tumors has become a key step to optimize and realize precision radiation therapy. The purpose of this study was to develop a mathematical model for simulating the change of head and neck (HN) tumor volume during radiation therapy.

METHODS AND MATERIALS

A formula was developed to describe the dynamic change of oxygenated compartment within a tumor, which was combined with the lethal lesions model to describe various cell processes during radiation therapy, including potentially lethal lesion repair and misrepair, cell proliferation/loss, and tumor reoxygenation. Parameter sensitivity analysis was performed to evaluate the impacts of lesion- and repair-related biological factors on radiation therapy outcomes.

RESULTS

We tested our model on 14 available patients with HN cancer and compared the performance with 3 other models. The mean error of our model for the 12 good fit cases was 12.2%, which is considerably smaller than that of the linear quadratic model (19.7%), the generalized linear quadratic model (19.1%), and a 4-level cell population model (16.6%). Correlation analysis results revealed that for small tumors, there was a positive correlation (correlation coefficient r=0.9416) between hypoxic fraction (hf) and tumor volume, whereas the correlation became negative and not significant (r=-0.4365) for large tumors. It is demonstrated from sensitivity analysis that the production rate of lethal lesions (ηl) has a far greater impact on tumor volume than other parameters. The hf had an insignificant impact on tumor volume but had a notable influence on the volume of surviving cells. The final volume of surviving cells athf=0.5 was almost 8 ×102 times that of hf=0.01. The potentially lethal lesion-related parameters (the production rate of potentially lethal lessions per unit dose ηpl, the rate of correct repair per unit time εpl, and the rate of binary misrepair per unit time ε2pl) had rather small impacts (<1%) on both tumor volume and the volume of surviving cells, which indicates that the repaired and misrepaired sublethal cells only take up a small portion of the total cancer cell population.

CONCLUSIONS

A population-based tumor-volume model for HN cancer during radiation therapy with a dynamic oxygenated compartment was developed in this study. Comprehensively considering the damage process of tumor cells caused by radiation therapy, the accurate prediction of the volume change of HN tumors during treatment was revealed. Meanwhile, various cell activities and their principles in the process of antitumor treatment were reflected, which has positive clinical reference significance for radiobiology.

Advancing osteosarcoma 3D modeling in vitro for novel tumor microenvironment-targeted therapies development

Osteosarcoma (OS) represents one of the most common primary bone cancers affecting children and young adults. The available treatments have remained unimproved for the past decades, hampered by the poor knowledge of OS etiology/pathophysiology and the lack of innovative, predictive and biologically relevant in vitro models, that can recapitulate the 3D OS tumor microenvironment (TME). Here, we report the development and characterization of an innovative 3D model of OS, composed of OS tumor cells, immune cells (macrophages) and mesenchymal stem cells (MSCs), that formed a multicellular tissue spheroid (MCTS). This fully humanized 3D model was shown to accurately mimic the native histological features of OS, while innately leading to the polarization of macrophages towards an M2-like phenotype, highly aggressive and pro-tumor profile. Upon the exposure to immunomodulatory molecules, the MCTS were shown to be responsive by shifting macrophages polarization, and dramatically altering the TME secretome. In agreement, when treated with immunomodulatory/stimulatory nanoparticles (NPSs), we were able to revert the TME secretome towards an anti-inflammatory profile. This study establishes an advanced 3D OS model capable of shedding light on macrophages and MSCs contributions to disease progression, paving the way for the development of innovative therapeutic approaches targeting the OS TME, while providing a biologically relevant in vitro tool for the efficacy screening of novel OS therapeutic approaches.

Reproducible 3D culture of multicellular tumor spheroids in supramolecular hydrogel from cancer stem cells sorted by sedimentation field-flow fractionation

Three-dimensional (3D) cancer models, such as multicellular tumor spheroids (MCTS), are biological supports used for research in oncology, drug development and nanotoxicity assays. However, due to various analytical and biological challenges, the main recurring problem faced when developing this type of 3D model is the lack of reproducibility. When using a 3D support to assess the effect of biologics, small molecules or nanoparticles, it is essential that the support remains constant over time and multiples productions. This constancy ensures that any effect observed following molecule exposure can be attributed to the molecule itself and not to the heterogeneous properties of the 3D support. In this study, we address these analytical challenges by evaluating for the first time the 3D culture of a sub-population of cancer stem cells (CSCs) from a glioblastoma cancer cell line (U87-MG), produced by a SdFFF (sedimentation field-flow fractionation) cell sorting, in a supramolecular hydrogel composed of single, well-defined molecule (bis-amide bola amphiphile 0.25% w/v) with a stiffness of 0.4 kPa. CSCs were chosen for their ability of self-renewal and multipotency that allow them to generate fully-grown tumors from a small number of cells. The results demonstrate that CSCs cultured in the hydrogel formed spheroids with a mean diameter of 336.67 ± 38.70 µm by Day 35, indicating reproducible growth kinetics. This uniformity is in contrast with spheroids derived from unsorted cells, which displayed a more heterogeneous growth pattern, with a mean diameter of 203.20 ± 102.93 µm by Day 35. Statistical analysis using an unpaired t-test with unequal variances confirmed that this difference in spheroid size is significant, with a p-value of 0.0417 (p < 0.05). These findings demonstrate that CSC-derived spheroids, when cultured in a well-defined hydrogel, exhibit highly reproducible growth patterns compared to spheroids derived from unsorted cells, making them a more reliable 3D model for biological research and drug testing applications.

Recapitulating Glioma Stem Cell Niches Using 3D Spheroid Models for Glioblastoma Research

Glioblastoma multiforme (GBM) is among the most aggressive brain cancers, and it contains glioma stem cells (GSCs) that drive tumor initiation, progression, and recurrence. These cells resist conventional therapies, contributing to high recurrence rates in GBM patients. Developing in vitro models that mimic the tumor microenvironment (TME), particularly the GSC niche, is crucial for understanding GBM growth and therapeutic resistance. Three-dimensional (3D) spheroid models provide a more physiologically relevant approach than traditional two-dimensional (2D) cultures, recapitulating key tumor features like hypoxia, cell heterogeneity, and drug resistance. This review examines scaffold-free and scaffold-based methods for generating 3D GBM spheroids, focusing on their applications in studying the cancer stem cell niche. The discussion encompasses methods such as the hanging drop, low-adhesion plates, and magnetic levitation, alongside advancements in embedding spheroids within extracellular matrix-based hydrogels and employing 3D bioprinting to fabricate more intricate tumor models. These 3D culture systems offer substantial potential for enhancing our understanding of GBM biology and devising more effective targeted therapies.

Photodynamic therapy using hybrid nanoparticles comprising of upconversion nanoparticles and chlorin e6-bearing pullulan

With its minimal invasiveness, photodynamic therapy (PDT) is considered one of the most elegant modalities in cancer treatment. In this study, a facile hybrid nanoparticle was developed, composed of upconversion nanoparticles and chlorin e6-bearing pullulan, which can serve as a photosensitizer activated by a near-infrared red laser. Cell death induction in cancer cells was achieved through energy transfer from the near-infrared red laser emitted by the upconversion nanoparticles to chlorin e6. The therapeutic efficacy of our hybrid system surpassed that of the clinically available photosensitizer, Photofrin, and hybrid liposomes comprising upconversion nanoparticles and chlorin e6 were employed as control. Accumulation of our system in tumor tissue in tumor xenograft mice was primarily achieved through the enhanced permeability and retention (EPR) effect. The administered hybrids were excreted from each organ within 21 days after administration, minimizing the risk of undesirable side effects. Notably, our system exhibited 400 times higher PDT activity in tumor-bearing mice compared to the control groups. It also effectively inhibited metastasis.

The water channels aquaporin-1 and aquaporin-3 interact with and affect the cell polarity protein Scribble in 3D in vitro models of breast cancer

Cellular changes in carcinomas include alterations in cell proliferation, cell migration, cell-cell adhesion, and cellular polarity. In vitro studies have revealed that the water channels, aquaporin-1 (AQP1) and AQP3, can influence cell migration and cell-cell adhesion. Of note, we previously showed that AQP1 overexpression reduced levels of cell-cell adhesion proteins, whereas AQP3 increased levels when overexpressed in normal epithelial cells. Expression of AQP1 and AQP3 in breast carcinoma is associated with lymph node metastasis, recurrence, and poor survival of patients with breast cancer. In this study, we investigated if AQP1 and AQP3 affected cell polarity in breast cancer by studying the relationship between the major polarity protein Scribble and AQP1 and AQP3. In breast cancer tissue samples, the protein expression of AQP1, AQP3, and Scribble did not show an obvious correlation. However, in a GST pull-down assay, AQP1 and AQP3 interacted with Scribble. AQP1 overexpression reduced the size of 3D spheroids as well as reduced Scribble levels at cell-cell contacts, whereas AQP3 overexpression showed no significant change in spheroid size compared with control, AQP3 overexpression also reduced Scribble levels at cell-cell contacts. Of note, AQP1 overexpression increased cell migration and induced cell detachment and dissemination from migrating breast cancer cell sheets, whereas AQP3 overexpression did not. Thus, AQP1 and AQP3 differentially affect 3D-grown breast cancer spheroids, and especially AQP1 may contribute to cancer development and spread via negatively affecting cellular junctions and cell polarity proteins as well as increasing cell migration and cell detachment.NEW & NOTEWORTHY Overexpression of the water channels aquaporin-1 and aquaporin-3 reduced levels of the key polarity protein Scribble at cell-cell junctions, suggesting potential implications in breast cancer progression and metastasis.

Using microfluidic and conventional platforms to evaluate the effects of lanthanides on spheroid formation

Metastasis contributes to the increased mortality rate of cancer, but the intricate mechanisms remain unclear. Cancer cells from a primary tumor invade nearby tissues and access the lymphatic or circulatory system. If these cells manage to survive and extravasate from the vasculature into distant tissues and ultimately adapt to survive, they will proliferate and facilitate malignant tumor formation. Traditional two-dimensional (2D) cell cultures offer a rapid and convenient method for validating the efficacy of anticancer drugs within a reasonable cost range, but their utility is limited because of tumors' high heterogeneity in vivo and spatial complexities. Three-dimensional (3D) cell cultures that mimic the physiological conditions of cancer cells in vivo have gained considerable interest. In these cultures, cells assemble into spheroids through gravity, magnetic forces, or their low-adhesion to the plates. Although these approaches address some of the limitations of 2D cultures, they often require a considerable amount of time and cost. Therefore, this study aims to enhance the effectiveness of 3D culture techniques by using microfluidic systems to provide a high-throughput and sensitive pipeline for drug screening. Using these systems, we studied the effects of lanthanide elements, which have garnered interest in cancer treatment, on spheroid formation and cell spreading. Our findings suggest that these elements alter the compactness of cell spheroids and decrease cell mobility.

Synthetic and natural polymer hydrogels: A review of 3D spheroids and drug delivery

This review centers on the synthesis and characterization of both natural and synthetic hydrogels, highlighting their diverse applications across various fields. We will delve into the evolution of hydrogels, focusing on the importance of polysaccharide-based and synthetic variants, which have been particularly chosen for 3D spheroid development in cancer research and drug delivery. A detailed background on the research and specific methodologies, including the in-situ free radical polymerization used for synthesizing these hydrogels, will be extensively discussed. Additionally, the review will explore various applications of these hydrogels, such as their self-healing properties, swelling ratios, pH responsiveness, and cell viability. A comprehensive literature review will support this investigation. Ultimately, this review aims to clearly outline the objectives and significance of hydrogel synthesis and their applications.

The Functional Role of the Long Non-Coding RNA LINCMD1 in Leiomyoma Pathogenesis

Existing evidence indicates that LINCMD1 regulates muscle differentiation-related gene expression in skeletal muscle by acting as a miRNA sponge, though its role in leiomyoma development is still unknown. This study investigated LINCMD1's involvement in leiomyoma by analyzing paired myometrium and leiomyoma tissue samples (n = 34) from patients who had not received hormonal treatments for at least three months prior to surgery. Myometrium smooth muscle cells (MSMCs) were isolated, and gene expression of LINCMD1 and miR-135b was assessed via qRT-PCR, while luciferase assays determined the interaction between LINCMD1 and miR-135b. To examine the effects of LINCMD1 knockdown, siRNA transfection was applied to a 3D MSMC spheroid culture, followed by qRT-PCR and Western blot analyses of miR-135b, APC, β-Catenin and COL1A1 expression. The results showed that leiomyoma tissues had significantly reduced LINCMD1 mRNA levels, regardless of patient race or MED12 mutation status, while miR-135b levels were elevated compared to matched myometrium samples. Luciferase assays confirmed LINCMD1's role as a sponge for miR-135b. LINCMD1 knockdown in MSMC spheroids increased miR-135b levels, reduced APC expression, and led to β-Catenin accumulation and higher COL1A1 expression. These findings highlight LINCMD1 as a potential therapeutic target to modulate aberrant Wnt/β-Catenin signaling in leiomyoma.

Mimicking and analyzing the tumor microenvironment

The tumor microenvironment (TME) is increasingly appreciated to play a decisive role in cancer development and response to therapy in all solid tumors. Hypoxia, acidosis, high interstitial pressure, nutrient-poor conditions, and high cellular heterogeneity of the TME arise from interactions between cancer cells and their environment. These properties, in turn, play key roles in the aggressiveness and therapy resistance of the disease, through complex reciprocal interactions between the cancer cell genotype and phenotype, and the physicochemical and cellular environment. Understanding this complexity requires the combination of sophisticated cancer models and high-resolution analysis tools. Models must allow both control and analysis of cellular and acellular TME properties, and analyses must be able to capture the complexity at high depth and spatial resolution. Here, we review the advantages and limitations of key models and methods in order to guide further TME research and outline future challenges.

Combined PET Radiotracer Approach Reveals Insights into Stromal Cell-Induced Metabolic Changes in Pancreatic Cancer In Vitro and In Vivo

Background/Objective Pancreatic stellate cells (PSCs) in pancreatic adenocarcinoma (PDAC) are producing extracellular matrix, which promotes the formation of a dense fibrotic microenvironment. This makes PDAC a highly heterogeneous tumor-stroma-driven entity, associated with reduced perfusion, limited oxygen supply, high interstitial fluid pressure, and limited bioavailability of therapeutic agents. Methods In this study, spheroid and tumor xenograft models of human PSCs and PanC-1 cells were characterized radiopharmacologically using a combined positron emission tomography (PET) radiotracer approach. [18F]FDG, [18F]FMISO, and [18F]FAPI-74 were employed to monitor metabolic activity, hypoxic metabolic state, and functional expression of fibroblast activation protein alpha (FAPα), a marker of activated PSCs. Results In vitro, PanC-1 and multi-cellular tumor spheroids demonstrated comparable glucose uptake and hypoxia, whereas FAPα expression was significantly higher in PSC spheroids. In vivo, glucose uptake as well as the transition to hypoxia were comparable in PanC-1 and multi-cellular xenograft models. In mice injected with PSCs, FAPα expression decreased over a period of four weeks post-injection, which was attributed to the successive death of PSCs. In contrast, FAPα expression increased in both PanC-1 and multi-cellular xenograft models over time due to invasion of mouse fibroblasts. Conclusion The presented models are suitable for subsequently characterizing stromal cell-induced metabolic changes in tumors using noninvasive molecular imaging techniques.

Diffusion-based culture and real-time impedance monitoring of tumor spheroids in hydrogel microwells of a suspended membrane under microfluidic conditions

Tumor spheroids are widely studied for in vitro modeling of tumor growth and responses to anticancer drugs. However, current methods are mostly limited to static and perfusion-based cultures, which can be improved by more accurately mimicking pathological conditions. Here, we developed a diffusion-based dynamic culture system for tumor spheroids studies using a thin membrane of hydrogel microwells and a microfluidic device. This allows for effective exchange of nutrients and metabolites between the tumors and the culture medium flowing underneath, resulting in uniform tumor spheroids. To monitor the growth and drug response of the spheroids in real-time, we performed spectroscopic analyses of the system's impedance, demonstrating a close correlation between the tumor size and the resistance and capacitance of the system. Our results also indicate an enhanced drug effect on the tumor spheroids in the presence of a low AC electric field, suggesting a weakening mechanism of the spheroids induced by external perturbation.

Senescence-associated secretory phenotype regulation by dual drug delivery biomimetic nanoplatform for enhanced tumor chemotherapy

Many chemotherapies, which are still the main clinical treatment for primary tumors, will induce persistent DNA damage in non-tumor stromal cells, especially cancer-associated fibroblasts (CAFs), and activate them to secrete senescence-associated secretory phenotype (SASP). The transition could further result in the formation of tumor immunosuppressive microenvironment and cause drug resistance of neighboring tumor cells. To solve this dilemma, a multi-functional biomimetic drug delivery system (named mPtP@Lipo) was rationally developed by combining CAFs reshaper ginsenoside 20(S)-protopanaxadiol (PPD) and cisplatin prodrug (PtLA) to inhibit tumor progression and the formation of SASP. To achieve effective delivery of these molecules deep into the desmoplastic tumor, fibroblast membrane was fused with liposomes as a targeting carrier. In vitro and in vivo results showed that mPtP@Lipo could penetrate deep into the tumor, reverse CAFs phenotype and inhibit SASP formation, which then blocked the immunosuppressive progress and thus reinforced anti-tumor immune response. The combination of chemotherapeutics and CAFs regulator could achieve both tumor inhibition and tumor immune microenvironment remodeling. In conclusion, mPtP@Lipo provides a promising strategy for the comprehensive stromal-desmoplastic tumor treatment.

Supported gel slab scaffolds as a three-dimensional cell-based assay platform

Cell-based assays are heavily relied on in the drug discovery pipeline, quickly pairing down large compound libraries to a manageable number of drug candidates for further characterization and evaluation. Monolayer cultures in which cells are deposited onto the bottom of well plates are the workhorse of many of these screens despite continued evidence of their inability to predict in vivo responses. Three-dimensional (3D) culture platforms can generate tissue-like environments with more representative cellular phenotypes than monolayers but have proven challenging to incorporate into already-developed workflows. Scaffold-based approaches are a tractable means of generating tissue-like environments, supporting cell-laden gels whose preparation is analogous to depositing cells in a well plate. Here, we describe supported gel slab (SGS) scaffolds prepared from commercially available materials, an adhesive spray, and a laser cutter. These cell-containing scaffolds can readily fit into well plates, providing a format compatible with current liquid handlers and analytical instrumentation. The scaffolds enable the evaluation of cellular responses in individual or stacked structures, which contain extracellular matrix-rich microenvironments. With a series of demonstrations, we highlight the utility of the readily assembled SGS scaffolds to quantify cellular responses. These readouts include confocal microscopy, quantifying cellular invasion in Transwell-like and stacked formats, generating multilayered spheroid-on-demand structures capable of providing spatially resolved maps of drug responses, and identifying potential chemotherapies in a screening application.

Gradient-induced instability in tumour spheroids unveils the impact of microenvironmental nutrient changes

Tumours often display invasive behaviours that induce fingering, branching and fragmentation processes. The phenomenon, known as diffusional instability, is driven by differential cell proliferation, migration, and death due to the presence of metabolite and catabolite concentration gradients. An understanding of the intricate dynamics of this spatially heterogeneous process plays a key role in the investigation of tumour growth and invasion. In this study, we developed an in vitro tumour invasion assay to investigate cell invasiveness in tumour spheroids under a chemotactic stimulus. Our method, employing tumour spheroids seeded in a 3D collagen gel within a microfluidic chemotaxis chamber, focuses on the role of diffusive gradients. Using Time-Lapse Microscopy, the dynamic evolution of tumour spheroids was monitored in real-time, providing a comprehensive view of the morphological changes and cell migration patterns under different chemotactic conditions. Specifically, we explored the impact of fetal bovine serum (FBS) gradients on the behaviour of CT26 mouse colon carcinoma cells and compared the effects of varying FBS concentrations to two isotropic control conditions. Furthermore, a finite element in silico model was developed to quantify the diffusive flow of nutrients in the chemotaxis chamber and obtain a detailed understanding of tumour dynamics. Our findings reveal that the presence of a chemotactic gradient significantly influences tumour invasiveness, with higher concentrations of nutrients associated with increased cancer growth and cell migration.

Conditioned Medium From Reactive Astrocytes Inhibits Proliferation, Resistance, and Migration of p53-Mutant Glioblastoma Spheroid Through GLI-1 Downregulation

Glioblastoma (GBM) aggressiveness is partly driven by the reactivation of signaling pathways such as Sonic hedgehog (SHH) and the interaction with its microenvironment. SHH pathway activation is one of the phenomena behind the glial transformation in response to tumor growth. The reactivation of the SHH signaling cascade during GBM-astrocyte interaction is highly relevant to understanding the mechanisms used by the tumor to modulate the adjacent stroma. The role of reactive astrocytes considering SHH signaling during GBM progression is investigated using a 3D in vitro model. T98G GBM spheroids displayed significant downregulation of SHH (61.4 ± 9.3%), GLI-1 (6.5 ± 3.7%), Ki-67 (33.7 ± 8.1%), and mutant MTp53 (21.3 ± 10.6%) compared to the CONTROL group when incubated with conditioned medium of reactive astrocytes (CM-AST). The SHH pathway inhibitor, GANT-61, significantly reduced previous markers (SHH = 43.0 ± 12.1%; GLI-1 = 9.5 ± 3.4%; Ki-67 = 31.9 ± 4.6%; MTp53 = 6.5 ± 7.5%) compared to the CONTROL, and a synergistic effect could be observed between GANT-61 and CM-AST. The volume (2.0 ± 0.2 × 107 µm³), cell viability (80.4 ± 3.2%), and migration (41 ± 10%) of GBM spheroids were significantly reduced in the presence of GANT-61 and CM-AST when compared to CM-AST after 72 h (volume = 2.3 ± 0.4 × 107 µm³; viability = 92.2 ± 6.5%; migration = 102.5 ± 14.6%). Results demonstrated that factors released by reactive astrocytes promoted a neuroprotective effect preventing GBM progression using a 3D in vitro model potentiated by SHH pathway inhibition.

Bidirectional in-silico clearing approach for deep refractive-index tomography using a sparsely sampled transmission matrix

Optical diffraction tomography (ODT) enables the label-free volumetric imaging of biological specimens by mapping their three-dimensional refractive index (RI) distribution. However, the depth of imaging achievable is restricted due to spatially inhomogeneous RI distributions that induce multiple scattering. In this study, we introduce a novel ODT technique named bidirectional in-silico clearing RI tomography. This method incorporates both forward and reversed in-silico clearing. For the reversed in-silico clearing, we have integrated an ODT reconstruction framework with a transmission matrix approach, which enables RI reconstruction and wave backpropagation from the illumination side without necessitating modifications to the conventional ODT setup. Furthermore, the framework employs a sparsely sampled transmission matrix, significantly reducing the requisite number of measurements and computational expenses. Employing this proposed technique, we successfully imaged a spheroid with a thickness of 263 µm, corresponding to 11.4 scattering mean free paths. This method was successfully applied to various biological specimens, including liver and colon spheroids, demonstrating consistent imaging performance across samples with varied morphologies.

Spatiotemporal analysis of multi-scale cell structure in spheroid culture reveals hypertrophic chondrocyte differentiation

3D cell culture has emerged as a promising approach to replicate the complex behaviors of cells within living organisms. This study aims to analyze spatiotemporal behavior of the morphological characteristics of cell structure at multiscale in 3D scaffold-free spheroids using chondrogenic progenitor ATDC5 cells. Over a 14-day culture period, it exhibited cell hypertrophy in the spheroids regarding cellular and nuclear size as well as changes in morphology. Moreover, biological analysis indicated a signification up-regulation of normal chondrocyte as well as hypertrophic chondrocyte markers, suggesting early hypertrophic chondrocyte differentiation. Cell nuclei underwent changes in volume, sphericity, and distribution in spheroid over time, indicating alterations in chromatin organization. The ratio of chromatin condensation volume to cell nuclear volume decreased as the cell nuclei enlarged, potentially signifying changes in chromatin state during hypertrophic chondrocyte differentiation. Our image analysis techniques in this present study enabled detailed morphological measurement of cell structure at multi-scale, which can be applied to various 3D culture models for in-depth investigation.

Reconfigurable Hanging Drop Microarray Platform for On-Demand Preparation and Analysis of Spheroid Array

In response to the increasing demand for spheroid-based cancer research, the importance of developing integrated platforms that can simultaneously facilitate high-throughput spheroid production and multiplexed analysis is emphasized. In addition, the understanding of how the size and cellular composition of tumors directly influence their internal structures and functionalities underlines the critical need to produce spheroids of diverse sizes and compositions on a large scale. To address this rising demand, this work presents a configurable and linkable in vitro three-dimensional (3D) cell culture kit (CLiCK) for spheroids, termed CLiCK-Spheroid. This platform consists of three primary components: a hanging drop microarray (HDMA), a concave pillar microarray (CPMA), and gradient blocks. The HDMA alone produces a homogeneous spheroid array, while its combination with the gradient block enables one-step generation of a size-gradient spheroid array. Using the size-gradient spheroid arrays, the occurrence of necrotic cores based on spheroid size is demonstrated. Additionally, spheroids in a single batch can be conveniently compartmentalized and regrouped using a CPMA, enhancing the versatility of spheroid arrays and enabling multiplexed drug treatments. By combining the different assembly methods, this work has achieved high-throughput production of cell composition-gradient spheroid arrays, with noticeable variations in morphology and vascularization based on cell compositions.

A three-zone hypoxia chamber capable of regulating unique oxygen and carbon dioxide partial pressures simultaneously

Oxygen is a vital but often overlooked variable in tissue culture experiments. Physiologically relevant oxygen tensions range from partial pressures of 100 mmHg at the alveolar-capillary interface in the lung to less than 7.6 mmHg in the hypoxic regions of solid tumors. These values are markedly lower than the partial oxygen pressure of ambient air, which is standard experimental practice. Physiologically relevant culture environments are needed to better predict cellular and tissue-level responses to drugs or potential toxins. Three commonly used methods to regulate in vitro oxygen tension involve placing cells in 1) a hypoxia chamber, 2) setups that rely on mass transport-limited microenvironments, and 3) microfabricated devices. Hypoxia chambers have the lowest barrier to entry, as they do not require laboratories to change their tissue culture setups. Here, we present a gas-regulation system for a three-zone hypoxia chamber. Each zone can maintain independent environments, with partial pressure compositions of 1-21 % O2 and 1-10 % CO2. The design incorporates small-scale fabrication techniques (e.g., laser cutting and 3D printing) and off-the-shelf electronic components for simple assembly. The hypoxia chambers are significantly lower in cost than the commercial counterparts: $1,400 for the control system or $4,100 for a complete three-zone chamber system.

Continuous flow delivery system for the perfusion of scaffold-based 3D cultures

The paper-based culture platform developed by Whitesides readily incorporates tissue-like structures into laboratories with established workflows that rely on monolayer cultures. Cell-laden hydrogels are deposited in these porous scaffolds with micropipettes; these scaffolds support the thin gel slabs, allowing them to be evaluated individually or stacked into thick constructs. The paper-based culture platform has inspired many basic and translational studies, each exploring how readily accessible materials can generate complex structures that mimic aspects of tissues in vivo. Many of these examples have relied on static culture conditions, which result in diffusion-limited environments and cells experiencing pericellular hypoxia. Perfusion-based systems can alleviate pericellular hypoxia and other cell stresses by continually exposing the cells to fresh medium. These perfusion systems are common in microfluidic and organ-on-chip devices supporting cells as monolayer cultures or as 3D constructs. Here, we introduce a continuous flow delivery system, which uses parts readily produced with 3D printing to provide a self-contained culture platform in which cells in paper or other scaffolds are exposed to fresh (flowing) medium. We demonstrate the utility of this device with examples of cells maintained in single cell-laden scaffolds, stacks of cell-laden scaffolds, and scaffolds that contain monolayers of endothelial cells. These demonstrations highlight some possible experimental questions that can be enabled with readily accessible culture materials and a perfusion-based device that can be readily fabricated.

Exploiting Matrix Stiffness to Overcome Drug Resistance

Drug resistance is arguably one of the biggest challenges facing cancer research today. Understanding the underlying mechanisms of drug resistance in tumor progression and metastasis are essential in developing better treatment modalities. Given the matrix stiffness affecting the mechanotransduction capabilities of cancer cells, characterization of the related signal transduction pathways can provide a better understanding for developing novel therapeutic strategies. In this review, we aimed to summarize the recent advancements in tumor matrix biology in parallel to therapeutic approaches targeting matrix stiffness and its consequences in cellular processes in tumor progression and metastasis. The cellular processes governed by signal transduction pathways and their aberrant activation may result in activating the epithelial-to-mesenchymal transition, cancer stemness, and autophagy, which can be attributed to drug resistance. Developing therapeutic strategies to target these cellular processes in cancer biology will offer novel therapeutic approaches to tailor better personalized treatment modalities for clinical studies.

Novel 3D human trophoblast culture to explore T. cruzi infection in the placenta

Introduction

Human trophoblastic cell lines, such as BeWo, are commonly used in 2D models to study placental Trypanosoma cruzi infections. However, these models do not accurately represent natural infections. Three-dimensional (3D) microtissue cultures offer a more physiologically relevant in vitro model, mimicking tissue microarchitecture and providing an environment closer to natural infections. These 3D cultures exhibit functions such as cell proliferation, differentiation, morphogenesis, and gene expression that resemble in vivo conditions.

Methods

We developed a 3D culture model using the human trophoblastic cell line BeWo and nonadherent agarose molds from the MicroTissues® 3D Petri Dish® system. Both small (12-256) and large (12-81) models were tested with varying initial cell numbers. We measured the diameter of the 3D cultures and evaluated cell viability using Trypan Blue dye. Trophoblast functionality was assessed by measuring β-hCG production via ELISA. Cell fusion was evaluated using confocal microscopy, with Phalloidin or ZO-1 marking cell edges and DAPI staining nuclei. T. cruzi infection was assessed by microscopy and quantitative PCR, targeting the EF1-α gene for T. cruzi and GAPDH for BeWo cells, using three parasite strains: VD (isolated from a congenital Chagas disease infant and classified as Tc VI), and K98 and Pan4 (unrelated to congenital infection and classified as Tc I).

Results

Seeding 1000 BeWo cells per microwell in the large model resulted in comparable cellular viability to 2D cultures, with a theoretical diameter of 408.68 ± 12.65 μm observed at 5 days. Functionality, assessed through β-hCG production, exceeded levels in 2D cultures at both 3 and 5 days. T. cruzi infection was confirmed by qPCR and microscopy, showing parasite presence inside the cells for all three tested strains. The distribution and progression of the infection varied with each strain.

Discussion

This innovative 3D model offers a simple yet effective approach for generating viable and functional cultures susceptible to T. cruzi infection, presenting significant potential for studying the placental microenvironment.

3D Cell Migration Chip (3DCM-Chip): A New Tool toward the Modeling of 3D Cellular Complex Systems

3D hydrogel-based cell cultures provide models for studying cell behavior and can efficiently replicate the physiologic environment. Hydrogels can be tailored to mimic mechanical and biochemical properties of specific tissues and allow to produce gel-in-gel models. In this system, microspheres encapsulating cells are embedded in an outer hydrogel matrix, where cells are able to migrate. To enhance the efficiency of such studies, a lab-on-a-chip named 3D cell migration-chip (3DCM-chip) is designed, which offers substantial advantages over traditional methods. 3DCM-chip facilitates the analysis of biochemical and physical stimuli effects on cell migration/invasion in different cell types, including stem, normal, and tumor cells. 3DCM-chip provides a smart platform for developing more complex cell co-cultures systems. Herein the impact of human fibroblasts on MDA-MB 231 breast cancer cells' invasiveness is investigated. Moreover, how the presence of different cellular lines, including mesenchymal stem cells, normal human dermal fibroblasts, and human umbilical vein endothelial cells, affects the invasive behavior of cancer cells is investigated using 3DCM-chip. Therefore, predictive tumoroid models with a more complex network of interactions between cells and microenvironment are here produced. 3DCM-chip moves closer to the creation of in vitro systems that can potentially replicate key aspects of the physiological tumor microenvironment.

Overcoming resistance in small-cell lung cancer

INTRODUCTION

Small-cell lung cancer (SCLC) accounts for 15% of lung cancers and has a dismal prognosis due to early dissemination and acquired chemoresistance. The initial good response to chemotherapy is followed by refractory relapses within 1-2 years. Mechanisms leading to chemoresistance are not clear and progress is poor.

AREAS COVERED

This article reviews the current evidence of the resistance of SCLCs at the cellular level including alteration of key proteins and the possible presence of cancer stem cells (CSCs). Without compelling evidence for cellular mechanisms and clinical failures of novel approaches, the study of SCLC has advanced to the role of 3D tumor cell aggregates in chemoresistance.

EXPERT OPINION

The scarcity of viable tumor specimen from relapsed SCLC patients has hampered the investigations of acquired chemoresistance but a panel of nine SCLC circulating tumor cell (CTC) cell lines have revealed characteristics of SCLC in the advanced refractory states. The chemoresistance of relapsed SCLC seems to be linked to the spontaneous formation of large spheroids, termed tumorospheres, which contain resistant quiescent and hypoxic cells shielded by a physical barrier. So far, drugs to tackle large tumor spheroids are in preclinical and early clinical development.

Advancing cancer therapeutics: Integrating scalable 3D cancer models, extracellular vesicles, and omics for enhanced therapy efficacy

Cancer remains as one of the highest challenges to human health. However, anticancer drugs exhibit one of the highest attrition rates compared to other therapeutic interventions. In part, this can be attributed to a prevalent use of in vitro models with limited recapitulative potential of the in vivo settings. Three dimensional (3D) models, such as tumor spheroids and organoids, offer many research opportunities to address the urgent need in developing models capable to more accurately mimic cancer biology and drug resistance profiles. However, their wide adoption in high-throughput pre-clinical studies is dependent on scalable manufacturing to support large-scale therapeutic drug screenings and multi-omic approaches for their comprehensive cellular and molecular characterization. Extracellular vesicles (EVs), which have been emerging as promising drug delivery systems (DDS), stand to significantly benefit from such screenings conducted in realistic cancer models. Furthermore, the integration of these nanomedicines with 3D cancer models and omics profiling holds the potential to deepen our understanding of EV-mediated anticancer effects. In this chapter, we provide an overview of the existing 3D models used in cancer research, namely spheroids and organoids, the innovations in their scalable production and discuss how omics can facilitate the implementation of these models at different stages of drug testing. We also explore how EVs can advance drug delivery in cancer therapies and how the synergy between 3D cancer models and omics approaches can benefit in this process.

Single-Photon Deep-Red Light-Triggered Direct Release of an Anticancer Drug: An Investigative Tumor Regression Study on a Breast Cancer Spheroidal Tumor Model

Breast adenocarcinoma ranks high among the foremost lethal cancers affecting women globally, with its triple-negative subtype posing the greatest challenge due to its aggressiveness and resistance to treatment. To enhance survivorship and patients' quality of life, exploring advanced therapeutic approaches beyond conventional chemotherapies is imperative. To address this, innovative nanoscale drug delivery systems have been developed, offering precise, localized, and stimuli-triggered release of anticancer agents. Here, we present perylenemonoimide nanoparticle-based vehicles engineered for deep-red light activation, enabling direct chlorambucil release. Synthesized via the reprecipitation technique, these nanoparticles were thoroughly characterized. Light-induced drug release was monitored via spectroscopic and reverse-phase HPLC. The efficacy of the said drug delivery system was evaluated in both two-dimensional and three-dimensional spheroidal cancer models, demonstrating significant tumor regression attributed to apoptotic cell death induced by efficient drug release within cells and spheroids. This approach holds promise for advancing targeted breast cancer therapy, enhancing treatment efficacy and minimizing adverse effects.

Electroporation with Calcium or Bleomycin: First Application in an In Vivo Uveal Melanoma Patient-Derived Xenograft Model

Uveal melanoma (UM) represents a rare tumor of the uveal tract and is associated with a poor prognosis due to the high risk of metastasis. Despite advances in the treatment of UM, the mortality rate remains high, dictating an urgent need for novel therapeutic strategies. The current study introduces the first in vivo analysis of the therapeutic potential of calcium electroporation (CaEP) compared with electrochemotherapy (ECT) with bleomycin in a patient-derived xenograft (PDX) model based on the chorioallantoic membrane (CAM) assay. The experiments were conducted as monotherapy with either 5 or 10 mM calcium chloride or 1 or 2.5 µg/mL bleomycin in combination with EP or EP alone. CaEP and ECT induced a similar reduction in proliferative activity, neovascularization, and melanocytic expansion. A dose-dependent effect of CaEP triggered a significant induction of necrosis, whereas ECT application of 1 µg/mL bleomycin resulted in a significantly increased apoptotic response compared with untreated tumor grafts. Our results outline the prospective use of CaEP and ECT with bleomycin as an adjuvant treatment of UM, facilitating adequate local tumor control and potentially an improvement in metastatic and overall survival rates.

Caspase-9 suppresses metastatic behavior of MDA-MB-231 cells in an adaptive organoid model

Caspase-9, a cysteine-aspartate protease traditionally associated with intrinsic apoptosis, has recently emerged as having non-apoptotic roles, including influencing cell migration-an aspect that has received limited attention in existing studies. In our investigation, we aimed to explore the impact of caspase-9 on the migration and invasion behaviors of MDA-MB-231, a triple-negative breast cancer (TNBC) cell line known for its metastatic properties. We established a stable cell line expressing an inducible caspase-9 (iC9) in MDA-MB-231 and assessed their metastatic behavior using both monolayer and the 3D organotypic model in co-culture with human Foreskin fibroblasts (HFF). Our findings revealed that caspase-9 had an inhibitory effect on migration and invasion in both models. In monolayer culture, caspase-9 effectively suppressed the migration and invasion of MDA-MB-231 cells, comparable to the anti-metastatic agent panitumumab (Pan). Notably, the combination of caspase-9 and Pan exhibited a significant additional effect in reducing metastatic behavior. Interestingly, caspase-9 demonstrated superior efficacy compared to Pan in the organotypic model. Molecular analysis showed down regulation of epithelial-mesenchymal transition and migratory markers, in caspase-9 activated cells. Additionally, flow cytometry analysis indicated a cell cycle arrest. Moreover, pre-treatment with activated caspase-9 sensitized cells to the chemotherapy of doxorubicin, thereby enhancing its effectiveness. In conclusion, the anti-metastatic potential of caspase-9 presents avenues for the development of novel therapeutic approaches for TNBC/metastatic breast cancer. Although more studies need to figure out the exact involving mechanisms behind this behavior.

MAPK14 /p38α Shapes the Molecular Landscape of Endometrial Cancer and promotes Tumorigenic Characteristics

The molecular underpinnings of H igh G rade E ndometrial C arcinoma (HGEC) metastatic growth and survival are poorly understood. Here we show that ascites-derived and primary tumor HGEC cell lines in 3D spheroid culture faithfully recapitulate key features of malignant peritoneal effusion and exhibit fundamentally distinct transcriptomic, proteomic and metabolomic landscapes when compared with conventional 2D monolayers. Using genetic screening platform we identify MAPK14 (which encodes the protein kinase p38α) as a specific requirement for HGEC in spheroid culture. MAPK14 /p38α has broad roles in programing the phosphoproteome, transcriptome and metabolome of HGEC spheroids, yet has negligible impact on monolayer cultures. MAPK14 promotes tumorigenicity in vivo and is specifically required to sustain a sub-population of spheroid cells that is enriched in cancer stemness markers. Therefore, spheroid growth of HGEC activates unique biological programs, including p38α signaling, that cannot be captured using 2D culture models and are highly relevant to malignant disease pathology.

Mass Spectrometry Imaging Techniques: Non-Ambient and Ambient Ionization Approaches

Molecular information can be acquired from sample surfaces in real time using a revolutionary molecular imaging technique called mass spectrometry imaging (MSI). The technique can concurrently provide high spatial resolution information on the spatial distribution and relative proportion of many different compounds. Thus, many scientists have been drawn to the innovative capabilities of the MSI approach, leading to significant focus in various fields during the past few decades. This review describes the sampling protocol, working principle and applications of a few non-ambient and ambient ionization mass spectrometry imaging techniques. The non-ambient techniques include secondary ionization mass spectrometry and matrix-assisted laser desorption ionization, while the ambient techniques include desorption electrospray ionization, laser ablation electrospray ionization, probe electro-spray ionization, desorption atmospheric pressure photo-ionization and femtosecond laser desorption ionization. The review additionally addresses the advantages and disadvantages of ambient and non-ambient MSI techniques in relation to their suitability, particularly for biological samples used in tissue diagnostics. Last but not least, suggestions and conclusions are made regarding the challenges and future prospects of MSI.

Mechanical models and measurement methods of solid stress in tumors

In addition to genetic mutations, biomechanical factors also affect the structures and functions of the tumors during tumor growth, including solid stress, interstitial fluid pressure, stiffness, and microarchitecture. Solid stress affects tumors by compressing cancer and stromal cells and deforming blood and lymphatic vessels which reduce supply of oxygen, nutrients and drug delivery, making resistant to treatment. Researchers simulate the stress by creating mechanical models both in vitro and in vivo. Cell models in vitro are divided into two dimensions (2D) and three dimensions (3D). 2D models are simple to operate but exert pressure on apical surface of the cells. 3D models, the multicellular tumor spheres, are more consistent with the actual pathological state in human body. However, the models are more difficult to establish compared with the 2D models. Besides, the procedure of the animal models in vivo is even more complex and tougher to operate. Then, researchers challenged to quantify the solid stress through some measurement methods. We compared the advantages and limitations of these models and methods, which may help to explore new therapeutic targets for normalizing the tumor's physical microenvironment. KEY POINTS: •This is the first review to conclude the mechanical models and measurement methods in tumors. •The merit and demerit of these models and methods are compared. •Insights into further models are discussed.

Exploring Importance and Regulation of Autophagy in Cancer Stem Cells and Stem Cell-Based Therapies

Autophagy is a globally conserved cellular activity that plays a critical role in maintaining cellular homeostasis through the breakdown and recycling of cellular constituents. In recent years, there has been much emphasis given to its complex role in cancer stem cells (CSCs) and stem cell treatment. This study examines the molecular processes that support autophagy and how it is regulated in the context of CSCs and stem cell treatment. Although autophagy plays a dual role in the management of CSCs, affecting their removal as well as their maintenance, the intricate interaction between the several signaling channels that control cellular survival and death as part of the molecular mechanism of autophagy has not been well elucidated. Given that CSCs have a role in the development, progression, and resistance to treatment of tumors, it is imperative to comprehend their biological activities. CSCs are important for cancer biology because they also show a tissue regeneration model that helps with organoid regeneration. In other words, the manipulation of autophagy is a viable therapeutic approach in the treatment of cancer and stem cell therapy. Both synthetic and natural substances that target autophagy pathways have demonstrated promise in improving stem cell-based therapies and eliminating CSCs. Nevertheless, there are difficulties associated with the limitations of autophagy in CSC regulation, including resistance mechanisms and off-target effects. Thus, the regulation of autophagy offers a versatile strategy for focusing on CSCs and enhancing the results of stem cell therapy. Therefore, understanding the complex interactions between autophagy and CSC biology would be essential for creating therapeutic treatments that work in both regenerative medicine and cancer treatment.

Emerging In Vitro and In Vivo Models: Hope for the Better Understanding of Cancer Progression and Treatment

Various cancer models have been developed to aid the understanding of the underlying mechanisms of tumor development and evaluate the effectiveness of various anticancer drugs in preclinical studies. These models accurately reproduce the critical stages of tumor initiation and development to mimic the tumor microenvironment better. Using these models for target validation, tumor response evaluation, resistance modeling, and toxicity comprehension can significantly enhance the drug development process. Herein, various in vivo or animal models are presented, typically consisting of several mice and in vitro models ranging in complexity from transwell models to spheroids and CRISPR-Cas9 technologies. While in vitro models have been used for decades and dominate the early stages of drug development, they are still limited primary to simplistic tests based on testing on a single cell type cultivated in Petri dishes. Recent advancements in developing new cancer therapies necessitate the generation of complicated animal models that accurately mimic the tumor's complexity and microenvironment. Mice make effective tumor models as they are affordable, have a short reproductive cycle, exhibit rapid tumor growth, and are simple to manipulate genetically. Human cancer mouse models are crucial to understanding the neoplastic process and basic and clinical research improvements. The following review summarizes different in vitro and in vivo metastasis models, their advantages and disadvantages, and their ability to serve as a model for cancer research.

Cellular memory function from 3D to 2D: Three-dimensional high density collagen microfiber cultures induce their resistance to reactive oxygen species

Cell properties generally change when the culture condition is changed. However, mesenchymal stem cells cultured on a hard material surface maintain their differentiation characteristics even after being cultured on a soft material surface. This phenomenon suggests the possibility of a cell culture material to memorize stem cell function even in changing cell culture conditions. However, there are no reports about cell memory function in three-dimensional (3D) culture. In this study, colon cancer cells were cultured with collagen microfibers (CMF) in 3D to evaluate their resistance to reactive oxygen species (ROS) in comparison with a monolayer (2D) culture condition and to understand the effect of 3D-culture on cell memory function. The ratio of ROS-negative cancer cells in 3D culture increased with increasing amounts of CMF and the highest amount of CMF was revealed to be 35-fold higher than that of the 2D condition. The ROS-negative cells ratio was maintained for 7 days after re-seeding in a 2D culture condition, suggesting a 3D-memory function of ROS resistance. The findings of this study will open up new opportunities for 3D culture to induce cell memory function.