Role and mechanisms of a three-dimensional bioprinted microtissue model in promoting proliferation and invasion of growth-hormone-secreting pituitary adenoma cells

Application of three-dimensional (3D) bioprinting in anti-cancer therapy

Three-dimensional (3D) bioprinting is a novel technology that enables the creation of 3D structures with bioinks, the biomaterials containing living cells. 3D bioprinted structures can mimic human tissue at different levels of complexity from cells to organs. Currently, 3D bioprinting is a promising method in regenerative medicine and tissue engineering applications, as well as in anti-cancer therapy research. Cancer, a type of complex and multifaceted disease, presents significant challenges regarding diagnosis, treatment, and drug development. 3D bioprinted models of cancer have been used to investigate the molecular mechanisms of oncogenesis, the development of cancers, and the responses to treatment. Conventional 2D cancer models have limitations in predicting human clinical outcomes and drug responses, while 3D bioprinting offers an innovative technique for creating 3D tissue structures that closely mimic the natural characteristics of cancers in terms of morphology, composition, structure, and function. By precise manipulation of the spatial arrangement of different cell types, extracellular matrix components, and vascular networks, 3D bioprinting facilitates the development of cancer models that are more accurate and representative, emulating intricate interactions between cancer cells and their surrounding microenvironment. Moreover, the technology of 3D bioprinting enables the creation of personalized cancer models using patient-derived cells and biomarkers, thereby advancing the fields of precision medicine and immunotherapy. The integration of 3D cell models with 3D bioprinting technology holds the potential to revolutionize cancer research, offering extensive flexibility, precision, and adaptability in crafting customized 3D structures with desired attributes and functionalities. In conclusion, 3D bioprinting exhibits significant potential in cancer research, providing opportunities for identifying therapeutic targets, reducing reliance on animal experiments, and potentially lowering the overall cost of cancer treatment. Further investigation and development are necessary to address challenges such as cell viability, printing resolution, material characteristics, and cost-effectiveness. With ongoing progress, 3D bioprinting can significantly impact the field of cancer research and improve patient outcomes.

Mechanical confinement promotes heat resistance of hepatocellular carcinoma via SP1/IL4I1/AHR axis

Mechanical stress can modulate the fate of cells in both physiological and extreme conditions. Recurrence of tumors after thermal ablation, a radical therapy for many cancers, indicates that some tumor cells can endure temperatures far beyond physiological ones. This unusual heat resistance with unknown mechanisms remains a key obstacle to fully realizing the clinical potential of thermal ablation. By developing a 3D bioprinting-based thermal ablation system, we demonstrate that hepatocellular carcinoma (HCC) cells in this 3D model exhibit enhanced heat resistance as compared with cells on plates. Mechanistically, the activation of transcription factor SP1 under mechanical confinement enhances the transcription of Interleukin-4-Induced-1, which catalyzes tryptophan metabolites to activate the aryl hydrocarbon receptor (AHR), leading to heat resistance. Encouragingly, the AHR inhibitor prevents HCC recurrence after thermal ablation. These findings reveal a previously unknown role of mechanical confinement in heat resistance and provide a rationale for AHR inhibitors as neoadjuvant therapy.

Organoid models of the pituitary gland in health and disease

The pituitary gland represents the hub of our endocrine system. Its cells produce specific hormones that direct multiple vital physiological processes such as body growth, fertility, and stress. The gland also contains a population of stem cells which are still enigmatic in phenotype and function. Appropriate research models are needed to advance our knowledge on pituitary (stem cell) biology. Over the last decade, 3D organoid models have been established, either derived from the pituitary stem cells or from pluripotent stem cells, covering both healthy and diseased conditions. Here, we summarize the state-of-the-art of pituitary-allied organoid models and discuss applications of these powerful in vitro research and translational tools to study pituitary development, biology, and disease.

3D bioprinted cancer models: from basic biology to drug development

Effort invested in the development of new drugs often fails to be translated into meaningful clinical benefits for patients with cancer. The development of more effective anticancer therapeutics and accurate prediction of their clinical merit remain urgent unmet medical needs. As solid cancers have complex and heterogeneous structures composed of different cell types and extracellular matrices, three-dimensional (3D) cancer models hold great potential for advancing our understanding of cancer biology, which has been historically investigated in tumour cell cultures on rigid plastic plates. Advanced 3D bioprinted cancer models have the potential to revolutionize the way we discover therapeutic targets, develop new drugs and personalize anticancer therapies in an accurate, reproducible, clinically translatable and robust manner. These ex vivo cancer models are already replacing existing in vitro systems and could, in the future, diminish or even replace the use of animal models. Therefore, profound understanding of the differences in tumorigenesis between 2D, 3D and animal models of cancer is essential. This Review presents the state of the art of 3D bioprinted cancer modelling, focusing on the biological processes that underlie the molecular mechanisms involved in cancer progression and treatment response as well as on proteomic and genomic signatures.

3D bioprinted tumor model with extracellular matrix enhanced bioinks for nanoparticle evaluation

The traditional evaluation of nanoparticles (NPs) is mainly based on 2D cell culture and animal models. However, these models are difficult to accurately represent human tumor microenvironment (TME) and fail to systematically study the complex transportation of NPs, thus limiting the translation of nano-drug formulations to clinical studies. This study reports a tumor model fabricated via 3D bioprinting with decellularized extracellular matrix (adECM) enhanced hybrid bioink. Compared with 2D cultured cells, the 3D printed tumor models with multicellular spheroids formation are closer to real tumor in protein, gene expression and tumorigenicity both in vitro and in vivo. Two characteristics of TME, ECM remodeling and epithelial-mesenchymal transition (EMT), are tracked simultaneously under 3D conditions. Furthermore, the cellular uptake efficiency of two different NPs is significantly lower in the printed 3D tumor model than the 2D individual cells, and higher drug resistance is observed in 3D group, which suggest the ECM barrier of tumor can significantly affect the permeability of NPs. These results suggest that this 3D printed tumor model is capable of mimicking the multiple TME, potentially providing a more accurate platform for the design and development of NPs before moving into animal and clinical trials.

Cell Heterogeneity Uncovered by Single-Cell RNA Sequencing Offers Potential Therapeutic Targets for Ischemic Stroke

Ischemic stroke is a detrimental neurological disease characterized by an irreversible infarct core surrounded by an ischemic penumbra, a salvageable region of brain tissue. Unique roles of distinct brain cell subpopulations within the neurovascular unit and peripheral immune cells during ischemic stroke remain elusive due to the heterogeneity of cells in the brain. Single-cell RNA sequencing (scRNA-seq) allows for an unbiased determination of cellular heterogeneity at high-resolution and identification of cell markers, thereby unveiling the principal brain clusters within the cell-type-specific gene expression patterns as well as cell-specific subclusters and their functions in different pathways underlying ischemic stroke. In this review, we have summarized the changes in differentiation trajectories of distinct cell types and highlighted the specific pathways and genes in brain cells that are impacted by stroke. This review is expected to inspire new research and provide directions for investigating the potential pathological mechanisms and novel treatment strategies for ischemic stroke at the level of a single cell.

Three Dimensional Cell Culturing for Modeling Adrenal and Pituitary Tumors

In vitro monolayer conditions are not able to reproduce the complexity of solid tumors, still, there is scarce information about the 3D cell culture models of endocrine tumor types. Therefore, our aim was to develop in vitro 3D tumor models by different methodologies for adrenocortical carcinoma (H295R), pituitary neuroendocrine tumor (RC-4B/C and GH3) and pheochromocytoma (PC-12). Various methodologies were tested. Cell biological assays (cell viability, proliferation and live cell ratio) and steroid hormone production by HPLC-MS/MS method were applied to monitor cellular well-being. Cells in hanging drops and embedded in matrigel formed multicellular aggregates but they were difficult to handle and propagate for further experiments. The most widely used methods: ultra-low attachment plate (ULA) and spheroid inducing media (SFDM) were not the most viable 3D model of RC-4B/C and GH3 cells that would be suitable for further experiments. Combining spheroid generation with matrigel scaffold H295R 3D models were viable for 7 days, RC-4B/C and GH3 3D models for 7–10 days. ULA and SFDM 3D models of PC-12 cells could be used for further experiments up to 4 days. Higher steroid production in 3D models compared to conventional monolayer culture was detected. Endocrine tumor cells require extracellular matrix as scaffold for viable 3D models that can be one reason behind the lack of the usage of endocrine 3D cultures. Our models help understanding the pathogenesis of endocrine tumors and revealing potential biomarkers and therapeutic targets. They could also serve as an excellent platform for preclinical drug test screening.

3D Bioprinting a human iPSC-derived MSC-loaded scaffold for repair of the uterine endometrium

Common events in the clinic, such as uterine curettage or inflammation, may lead to irreversible endometrial damage, often resulting in infertility in women of childbearing age. Currently, tissue engineering has the potential to achieve tissue manipulation, regeneration, and growth, but personalization and precision remain challenges. The application of "3D cell printing" is more in line with the clinical requirements of tissue repair. In this study, a porous grid-type human induced pluripotent stem cell-derived mesenchymal stem cell (hiMSC)-loaded hydrogel scaffold was constructed using a 3D bioprinting device. The 3D-printed hydrogel scaffold provided a permissive in vitro living environment for hiMSCs and significantly increased the survival duration of transplanted hiMSCs when compared with hiMSCs administered locally in vivo. Using an endometrial injury model, we found that hiMSC transplantation can cause early host immune responses (the serological immune response continued for more than 1 month, and the local immune response continued for approximately 1 week). Compared with the sham group, although the regenerative endometrium failed to show full restoration of the normal structure and function of the lining, implantation of the 3D-printed hiMSC-loaded scaffold not only promoted the recovery of the endometrial histomorphology (endometrial tissue and gland regeneration) and the regeneration of endometrial cells (stromal cells and epithelial cells) and endothelial cells but also improved endometrial receptivity functional indicators, namely, pinopode formation and leukemia inhibitory factor and αvβ3 expression, which partly restored the embryo implantation and pregnancy maintenance functions of the injured endometrium. These indicators were significantly better in the 3D-printed hiMSC-loaded scaffold group than in the unrepaired (empty) group, the hiMSCs alone group and the 3D scaffold group, and the empty group showed the worst repair results. Our study confirm that the 3D-printed hiMSC-loaded hydrogel scaffold may be a promising material for endometrial repair.

Emerging Biomimetic Materials for Studying Tumor and Immune Cell Behavior

Cancer is one of the leading causes of death both in the United States and worldwide. The dynamic microenvironment in which tumors grow consists of fibroblasts, immune cells, extracellular matrix (ECM), and cytokines that enable progression and metastasis. Novel biomaterials that mimic these complex surroundings give insight into the biological, chemical, and physical environment that cause cancer cells to metastasize and invade into other tissues. Two-dimensional (2D) cultures are useful for gaining limited information about cancer cell behavior; however, they do not accurately represent the environments that cells experience in vivo. Recent advances in the design and tunability of diverse three-dimensional (3D) biomaterials complement biological knowledge and allow for improved recapitulation of in vivo conditions. Understanding cell-ECM and cell-cell interactions that facilitate tumor survival will accelerate the design of more effective therapies. This review discusses innovative materials currently being used to study tumor and immune cell behavior and interactions, including materials that mimic the ECM composition, mechanical stiffness, and integrin binding sites of the tumor microenvironment.

Moving Electrospun Nanofibers and Bioprinted Scaffolds toward Translational Applications

Over the past two decades, electrospun nanofibers have been actively explored for a range of applications, including those related to biomedicine, environmental science, energy harvesting, catalysis, photonics, and electronics. Regarding biomedical applications, one can readily produce nanofiber-based scaffolds with controlled compositions, structures, alignments, and functions by varying the material, design of collector, number of spinnerets, and electrospinning parameters. This report highlights both preclinical and translational applications of electrospun nanofibers and bioprinted constructs presented at the 2019 International Conference on Electrospinning, together with some perspectives on their future development.

Biomaterials Based on Marine Resources for 3D Bioprinting Applications

Three-dimensional (3D) bioprinting has become a flexible tool in regenerative medicine with potential for various applications. Further development of the new 3D bioprinting field lies in suitable bioink materials with satisfied printability, mechanical integrity, and biocompatibility. Natural polymers from marine resources have been attracting increasing attention in recent years, as they are biologically active and abundant when comparing to polymers from other resources. This review focuses on research and applications of marine biomaterials for 3D bioprinting. Special attention is paid to the mechanisms, material requirements, and applications of commonly used 3D bioprinting technologies based on marine-derived resources. Commonly used marine materials for 3D bioprinting including alginate, carrageenan, chitosan, hyaluronic acid, collagen, and gelatin are also discussed, especially in regards to their advantages and applications.