Matrigel: from discovery and ECM mimicry to assays and models for cancer research

Rationally designed β-cyclodextrin-crosslinked polyacrylamide hydrogels for cell spheroid formation and 3D tumor model construction

In vitro tumor models are essential for understanding tumor behavior and evaluating tumor biological properties. Hydrogels that can mimic the tumor extracellular matrix have become popular for creating 3D in vitro tumor models. However, designing biocompatible hydrogels with appropriate chemical and physical properties for constructing tumor models is still a challenge. In this study, we synthesized a series of β-cyclodextrin (β-CD)-crosslinked polyacrylamide hydrogels with different β-CD densities and mechanical properties and evaluated their potential for use in 3D in vitro tumor model construction, including cell capture and spheroid formation. By utilizing a combination of β-CD-methacrylate (CD-MA) and a small amount of N,N'-methylene bisacrylamide (BIS) as hydrogel crosslinkers and optimizing the CD-MA/BIS ratio, the hydrogels performed excellently for tumor cell 3D culture and spheroid formation. Notably, when we co-cultured L929 fibroblasts with HeLa tumor cells on the hydrogel surface, co-cultured spheroids were formed, showing that the hydrogel can mimic the complexity of the tumor extracellular matrix. This comprehensive investigation of the relationship between hydrogel mechanical properties and biocompatibility provides important insights for hydrogel-based in vitro tumor modeling and advances our understanding of the mechanisms underlying tumor growth and progression.

An Endothelial Cell Is Not Simply an Endothelial Cell

Endothelial cells (ECs) are a multifaceted component of the vascular system with roles in immunity, maintaining tissue fluid balance, and vascular tone. Dysregulation or dysfunction of ECs can have far-reaching implications, leading pathologies ranging from cardiovascular diseases, such as hypertension and atherosclerosis, ischemia, chronic kidney disease, blood-brain barrier integrity, dementia, and tumor metastasis. Recent advancements in regenerative medicine have highlighted the potential of stem cell-derived ECs, particularly from induced pluripotent stem cells, to treat ischemic tissues, as well as models of vascular integrity. This review summarizes what is known in the generation of ECs with an emphasis on tissue-specific ECs and EC subphenotypes important in the development of targeted cell-based therapies for patient treatment.

Exploring the Therapeutic Potential of Extracellular Vesicles Derived from Human Immature Dental Pulp Cells on Papillary Thyroid Cancer

Mesenchymal stem-cell-derived extracellular vesicles (MSC-EVs) have been increasingly investigated for cancer therapy and drug delivery, and they offer an advanced cell-free therapeutic option. However, their overall effects and efficacy depend on various factors, including the MSC source and cargo content. In this study, we isolated EVs from the conditioned medium of human immature dental pulp stem cells (hIDPSC-EVs) and investigated their effects on two papillary thyroid cancer (PTC) cell lines (BCPAP and TPC1). We observed efficient uptake of hIDPSC-EVs by both PTC cell lines, with a notable impact on gene regulation, particularly in the Wnt signaling pathway in BCPAP cells. However, no significant effects on cell proliferation were observed. Conversely, hIDPSC-EVs significantly reduced the invasive capacity of both PTC cell lines after 120 h of treatment. These in vitro findings suggest the therapeutic potential of hIDPSC-EVs in cancer management and emphasize the need for further research to develop novel and effective treatment strategies. Furthermore, the successful internalization of hIDPSC-EVs by PTC cell lines underscores their potential use as nanocarriers for anti-cancer agents.

Identification and characterization of TM4SF1+ tumor self-seeded cells

Tumor self-seeding is a process whereby circulating tumor cells (CTCs) recolonize the primary tumor, which promotes tumor growth, angiogenesis, and invasion. However, the detailed nature and functions of tumor self-seeded cells (TSCs) have not been well defined due to challenges in tracking and isolating TSCs. Here, we report an accurate animal model using photoconvertible tagging to recapitulate the spontaneous process of tumor self-seeding and identify TSCs as a subpopulation of primary tumor cells with enhanced invasiveness and survival. We demonstrate transmembrane-4-L-six-family-1 (TM4SF1) as a marker of TSCs, which promotes migration, invasion, and anchorage-independent survival in cancer cells. By analyzing single-cell RNA sequencing datasets, we identify a potential TSC population with a metastatic profile in patients with cancer, which is detectable in early-stage disease and expands during cancer progression. In summary, we establish a framework to study TSCs and identify emerging cell targets with diagnostic, prognostic, or therapeutic potential in cancers.

Biofabrication and Monitoring of a 3D Printed Skin Model for Melanoma

There is an unmet need for in vitro cancer models that emulate the complexity of human tissues. 3D-printed solid tumor micromodels based on decellularized extracellular matrices (dECMs) recreate the biomolecule-rich matrix of native tissue. Herein a 3D in vitro metastatic melanoma model that is amenable for drug screening purposes and recapitulates features of both the tumor and the skin microenvironment is described. Epidermal, basement membrane, and dermal biocompatible inks are prepared by means of combined chemical, mechanical, and enzymatic processes. Bioink printability is confirmed by rheological assessment and bioprinting, and bioinks are subsequently combined with melanoma cells and dermal fibroblasts to build complex 3D melanoma models. Cells are tracked by confocal microscopy and surface-enhanced Raman spectroscopy (SERS) mapping. Printed dECMs and cell tracking allow modeling of the initial steps of metastatic disease, and may be used to better understand melanoma cell behavior and response to drugs.

Bottlenose dolphin (Tursiops truncatus) immortalized fibroblasts on novel 3D in vitro collagen-free scaffolds

Dolphins, as apex predators, can be considered relevant sentinels of the health of marine ecosystems. The creation of 3D cell models to assess in vitro cell-to-cell and cell-to-matrix interactions in environmental-mimicking conditions, is of considerable interest. However, to date the establishment of cetacean 3D culture systems has not yet been accomplished. Thus, in this study, different 3D systems of bottlenose dolphin (Tursiops truncatus) skin fibroblasts have been analyzed. Particularly, novel scaffolds based on hyaluronic acid and ionic-complementary self-assembling peptides such as RGD-EAbuK and EAbuK-IKVAV have been compared to Matrigel. Histological and fluorescent staining, electron microscopy (TEM) analyses and viability assays have been performed and RT-PCR has been used to detect extracellular matrix (ECM) components produced by cells. Results showed that Matrigel induced cells to form aggregates with lower viability and no ECM production compared to the novel scaffolds. Moreover, scaffolds allowed dispersed cells to produce a collagenous ECM containing collagen1a1, laminin B1 and elastin. The HA-EAbuK-IKVAV scaffold resulted in the most suitable 3D model in terms of cell quantity and viability. The development of this innovative approach is the first step towards the possibility to create 3D in vitro models for this protected species.

Intracellular pH dynamics respond to microenvironment stiffening and mediate vasculogenic mimicry through β-catenin

Dysregulated intracellular pH (pHi) dynamics and an altered tumor microenvironment have emerged as drivers of cancer cell phenotypes. However, the molecular integration between the physical properties of the microenvironment and dynamic intracellular signaling responses remains unclear. Here, we use two metastatic cell models, one breast and one lung, to assess pHi response to varying extracellular matrix (ECM) stiffness. To experimentally model ECM stiffening, we use two tunable-stiffness hydrogel systems: Matrigel and hyaluronic acid (HA) gels, which mimic the increased protein secretion and crosslinking associated with ECM stiffening. We find that single-cell pHi decreases with increased ECM stiffness in both hydrogel systems and both metastatic cell types. We also observed that stiff ECM promotes vasculogenic mimicry (VM), a phenotype associated with metastasis and resistance. Importantly, we show that decreased pHi is both a necessary and sufficient mediator of VM, as raising pHi on stiff ECM reduces VM phenotypes and lowering pHi on soft ECM drives VM. We characterize β-catenin as a pH-dependent molecular mediator of pH-dependent VM, where stiffness-driven changes in β-catenin abundance can be overridden by increased pHi. We uncover a dynamic relationship between matrix stiffness and pHi, thus suggesting pHi dynamics can override mechanosensitive cell responses to the extracellular microenvironment.

Plant-Based Decellularization: A Novel Approach for Perfusion-Compatible Tissue Engineering Structures

This study explores the potential of plant-based decellularization in regenerative medicine, a pivotal development in tissue engineering focusing on scaffold development, modification, and vascularization. Plant decellularization involves removing cellular components from plant structures, offering an eco-friendly and cost-effective alternative to traditional scaffold materials. The use of plant-derived polymers is critical, presenting both benefits and challenges, notably in mechanical properties. Integration of plant vascular networks represents a significant bioengineering breakthrough, aligning with natural design principles. The paper provides an in-depth analysis of development protocols, scaffold fabrication considerations, and illustrative case studies showcasing plant-based decellularization applications. This technique is transformative, offering sustainable scaffold design solutions with readily available plant materials capable of forming perfusable structures. Ongoing research aims to refine protocols, assess long-term implications, and adapt the process for clinical use, indicating a path toward widespread adoption. Plant-based decellularization holds promise for regenerative medicine, bridging biological sciences with engineering through eco-friendly approaches. Future perspectives include protocol optimization, understanding long-term impacts, clinical scalability, addressing mechanical limitations, fostering collaboration, exploring new research areas, and enhancing education. Collectively, these efforts envision a regenerative future where nature and scientific innovation converge to create sustainable solutions, offering hope for generations to come.

Efficient hepatocyte differentiation of primary human hepatocyte-derived organoids using three dimensional nanofibers (HYDROX) and their possible application in hepatotoxicity research

Human liver organoids are in vitro three dimensionally (3D) cultured cells that have a bipotent stem cell phenotype. Translational research of human liver organoids for drug discovery has been limited by the challenge of their low hepatic function compared to primary human hepatocytes (PHHs). Various attempts have been made to develop functional hepatocyte-like cells from human liver organoids. However, none have achieved the same level of hepatic functions as PHHs. We here attempted to culture human liver organoids established from cryopreserved PHHs (PHH-derived organoids), using HYDROX, a chemically defined 3D nanofiber. While the proliferative capacity of PHH-derived organoids was lost by HYDROX-culture, the gene expression levels of drug-metabolizing enzymes were significantly improved. Enzymatic activities of cytochrome P450 3A4 (CYP3A4), CYP2C19, and CYP1A2 in HYDROX-cultured PHH-derived organoids (Org-HYDROX) were comparable to those in PHHs. When treated with hepatotoxic drugs such as troglitazone, amiodarone and acetaminophen, Org-HYDROX showed similar cell viability to PHHs, suggesting that Org-HYDROX could be applied to drug-induced hepatotoxicity tests. Furthermore, Org-HYDROX maintained its functions for up to 35 days and could be applied to chronic drug-induced hepatotoxicity tests using fialuridine. Our findings demonstrated that HYDROX could possibly be a novel biomaterial for differentiating human liver organoids towards hepatocytes applicable to pharmaceutical research.

Assessing drug uptake and response differences in 2D and 3D cellular environments using stimulated Raman scattering microscopy

The architecture of cell culture-two-dimensional (2D) versus three-dimensional (3D)-significantly impacts various cellular factors, including cell-cell interactions, nutrient and oxygen gradients, metabolic activity, and gene expression profiles. This can result in different cellular responses during cancer drug treatment, with 3D-cultured cells often exhibiting higher resistance to chemotherapeutic drugs. While various genetic and proteomic analyses have been employed to investigate the underlying mechanisms of this increased resistance, complementary techniques that provide experimental evidence of spatial molecular profiling data are limited. Stimulated Raman scattering (SRS) microscopy has demonstrated its capability to measure both intracellular drug uptake and growth inhibition. In this work, we applied three-band SRS imaging to 2D and 3D cell cultures and provided a comparative analysis of drug uptake and response with the goal of understanding whether the difference in drug uptake explains the drug resistance in 3D culture compared to 2D. Our investigations revealed that despite similar intracellular drug levels in 2D and 3D A549 cells during lapatinib treatment, the growth of 3D spheroids is less impacted, supporting an enhanced drug tolerance in the 3D microenvironment. We further elucidated drug penetration patterns and the resulting heterogeneous cellular responses across different spheroid layers. Additionally, we investigated the role of the extracellular matrix in modulating drug delivery and cell response, and we discovered that limited drug penetration in 3D could also contribute to lower drug response. Our study provides valuable insights into the intricate mechanisms of increased drug resistance in 3D tumor models during cancer drug treatments.

An Extracellular Matrix Overlay Model for Bioluminescence Microscopy to Measure Single-Cell Heterogeneous Responses to Antiandrogens in Prostate Cancer Cells

Prostate cancer (PCa) displays diverse intra-tumoral traits, impacting its progression and treatment outcomes. This study aimed to refine PCa cell culture conditions for dynamic monitoring of androgen receptor (AR) activity at the single-cell level. We introduced an extracellular matrix-Matrigel (ECM-M) culture model, enhancing cellular tracking during bioluminescence single-cell imaging while improving cell viability. ECM-M notably tripled the traceability of poorly adherent PCa cells, facilitating robust single-cell tracking, without impeding substrate permeability or AR response. This model effectively monitored AR modulation by antiandrogens across various PCa cell lines. Single-cell imaging unveiled heterogeneous antiandrogen responses within populations, correlating non-responsive cell proportions with drug IC50 values. Integrating ECM-M culture with the PSEBC-TSTA biosensor enabled precise characterization of ARi responsiveness within diverse cell populations. Our ECM-M model stands as a promising tool to assess heterogeneous single-cell treatment responses in cancer, offering insights to link drug responses to intracellular signaling dynamics. This approach enhances our comprehension of the nuanced and dynamic nature of PCa treatment responses.

Zeaxanthin impairs angiogenesis and tumor growth of glioblastoma: An in vitro and in vivo study

OBJECTIVES

To investigate the therapeutic effects of Zeaxanthin (Zea), one of the oxidized xanthophyll carotenoids belonging to the isoprenoids, on inhibiting the angiogenesis and tumor growth of glioblastoma (GBM) via an in vitro and in vivo study.

METHODS

The effects of Zea on the proliferation, adhesion, migration and invasion of human GBM cell lines were detected by cell proliferation assay, cell adhesion assay and Transwell assay. The effect of Zea on angiogenesis was detected by rat aortic ring assay and human umbilical vein endothelial cells (HUVEC) in vitro tube formation assay. The effects of Zea on PARP, Caspase 3 and VEGFR2 phosphorylation as well as VEGFR2's downstream signaling pathway were detected by Western blot. The in vivo human GBM xenograft mouse model was employed to study the therapeutic efficacy of Zea.

RESULTS

Zea impaired the proliferation, adhesion, migration and invasion of U87 and U251 cells as well as HUVECs. Rat aortic ring experiments displayed Zea significantly inhibited angiogenesis during VEGF-induced microvascular germination. In vitro and in vivo vascular experiments verified that Zea inhibited VEGF-induced HUVEC proliferation and capillary-like tube formation. Additionally, Zea induced GBM cells apoptosis via increasing the expression of cleaved PARP and Caspase 3. In HUVECs and U251 GBM cells, Zea down-regulated VEGF-induced activation of the VEGFR2 kinase pathway. Meanwhile the expression of p-AKT, p-ERK, p-STAT3 and FAK were all attenuated in U251 cells. Moreover, the effects of Zea on GBM cells proliferation could be blocked by VEGFR2 kinase inhibitor SU5408. These results suggest that Zea may hinder GBM angiogenesis and tumor growth through down-regulating a cascade of oncogenic signaling pathways, both through the inhibition of angiogenesis and the anti-tumor mechanism of a direct cytotoxic effect. Besides, Zea inhibits GBM angiogenesis and tumor growth exemplified through a xenograft mouse model in vivo.

CONCLUSION

Zea impairs angiogenesis and tumor growth of GBM both in vitro and in vivo. It can be declared that Zea is a potential valuable anticancer candidate for the future treatment strategy of GBM.

Toward reproducible tumor organoid culture: focusing on primary liver cancer

Organoids present substantial potential for pushing forward preclinical research and personalized medicine by accurately recapitulating tissue and tumor heterogeneity in vitro. However, the lack of standardized protocols for cancer organoid culture has hindered reproducibility. This paper comprehensively reviews the current challenges associated with cancer organoid culture and highlights recent multidisciplinary advancements in the field with a specific focus on standardizing liver cancer organoid culture. We discuss the non-standardized aspects, including tissue sources, processing techniques, medium formulations, and matrix materials, that contribute to technical variability. Furthermore, we emphasize the need to establish reproducible platforms that accurately preserve the genetic, proteomic, morphological, and pharmacotypic features of the parent tumor. At the end of each section, our focus shifts to organoid culture standardization in primary liver cancer. By addressing these challenges, we can enhance the reproducibility and clinical translation of cancer organoid systems, enabling their potential applications in precision medicine, drug screening, and preclinical research.

Insight into the differential toxicity of PFOA and PFBA based on a 3D-cultured MDA-MB-231 cell model

Perfluoroalkyl substances (PFASs) are a category of high-concerned emerging contaminants which are suspected to correlate with various human adverse health outcomes including tumors. It is also a question whether short-chain PFASs are qualified alternatives under the regulation of long-chain PFASs. In this study, a three-dimensional (3D) culture system based on Gelatin methacrylate (GelMA) hydrogel matrix was used to investigate the impacts of 120-h perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA) exposure of MDA-MB-231 cells. The results showed that PFOA exposure promoted the proliferation, migration, and invasion of MDA-MB-231 cells in an environmentally relevant concentration range (0.1 to 10 μM), exhibiting a clear malignant-promoting risk. In contrast, PFBA only showed a trend to induce non-invasive cell migration. Hippo/YAP signaling pathway was identified as the contributor to the differences between the two PFASs. PFOA but PFBA reduced YAP phosphorylation and increased the nuclear content of YAP, which further facilitated abundant key factors of epithelial-mesenchymal transition (EMT) process. Our results provided a new idea for the carcinogenicity of PFOA using a 3D-based paradigm. Although the effects by PFBA were much milder than PFOA in the current test duration, the cell model suitable for longer exposure is still necessary to better assess the safety of alternative short-chain PFASs.

Intestinal organoid modeling: bridging the gap from experimental model to clinical translation

The 3D culture of intestinal organoids entails embedding isolated intestinal crypts and bone marrow mesenchymal stem cells within a growth factor-enriched matrix gel. This process leads to the formation of hollow microspheres with structures resembling intestinal epithelial cells, which are referred to as intestinal organoids. These structures encompass various functional epithelial cell types found in the small intestine and closely mimic the organizational patterns of the small intestine, earning them the name "mini-intestines". Intestinal tumors are prevalent within the digestive system and represent a significant menace to human health. Through the application of 3D culture technology, miniature colorectal organs can be cultivated to retain the genetic characteristics of the primary tumor. This innovation offers novel prospects for individualized treatments among patients with intestinal tumors. Presently established libraries of patient-derived organoids serve as potent tools for conducting comprehensive investigations into tissue functionality, developmental processes, tumorigenesis, and the pathobiology of cancer. This review explores the origins of intestinal organoids, their culturing environments, and their advancements in the realm of precision medicine. It also addresses the current challenges and outlines future prospects for development.

Reversible Intracellular Gelation of MCF10A Cells Enables Programmable Control Over 3D Spheroid Growth

In nature, some organisms survive extreme environments by inducing a biostatic state wherein cellular contents are effectively vitrified. Recently, a synthetic biostatic state in mammalian cells is achieved via intracellular network formation using bio-orthogonal strain-promoted azide-alkyne cycloaddition (SPAAC) reactions between functionalized poly(ethylene glycol) (PEG) macromers. In this work, the effects of intracellular network formation on a 3D epithelial MCF10A spheroid model are explored. Macromer-transfected cells are encapsulated in Matrigel, and spheroid area is reduced by ≈50% compared to controls. The intracellular hydrogel network increases the quiescent cell population, as indicated by increased p21 expression. Additionally, bioenergetics (ATP/ADP ratio) and functional metabolic rates are reduced. To enable reversibility of the biostasis effect, a photosensitive nitrobenzyl-containing macromer is incorporated into the PEG network, allowing for light-induced degradation. Following light exposure, cell state, and proliferation return to control levels, while SPAAC-treated spheroids without light exposure (i.e., containing intact intracellular networks) remain smaller and less proliferative through this same period. These results demonstrate that photodegradable intracellular hydrogels can induce a reversible slow-growing state in 3D spheroid culture.

Inflammatory breast cancer biomarkers and biology

Inflammatory breast cancer (IBC) is a unique breast cancer with a highly virulent course and low 5- and 10-year survival rates. Even though it only accounts for 1-5% of breast cancers it is estimated to account for 10% of breast cancer deaths annually in the United States. The accuracy of diagnosis and classification of this unique cancer is a major concern within the medical community. Early molecular and biological studies incidentally included IBC samples with other conventional breast cancers and were not informative as to the unique nature of the disease. Subsequent molecular studies that focused specifically on IBC demonstrated that IBC has a unique biology different from other forms of breast cancer. Additionally, a handful of unique signature genes that are hallmarks of IBC have also been suggested. Further understanding of IBC biology can help with diagnosis and treatment of the disease. The current article reviews the history and highlights of IBC studies.

Enhancement of lacrimal gland cell function by decellularized lacrimal gland derived hydrogel

Sustainable treatment of aqueous deficient dry eye (ADDE) represents an unmet medical need and therefore requires new curative and regenerative approaches based on appropriatein vitromodels. Tissue specific hydrogels retain the individual biochemical composition of the extracellular matrix and thus promote the inherent cell´s physiological function. Hence, we created a decellularized lacrimal gland (LG) hydrogel (dLG-HG) meeting the requirements for a bioink as the basis of a LG model with potential forin vitroADDE studies. Varying hydrolysis durations were compared to obtain dLG-HG with best possible physical and ultrastructural properties while preserving the original biochemical composition. A particular focus was placed on dLG-HG´s impact on viability and functionality of LG associated cell types with relevance for a futurein vitromodel in comparison to the unspecific single component hydrogel collagen type-I (Col) and the common cell culture substrate Matrigel. Proliferation of LG epithelial cells (EpC), LG mesenchymal stem cells, and endothelial cells cultured on dLG-HG was enhanced compared to culture on Matrigel. Most importantly with respect to a functionalin vitromodel, the secretion capacity of EpC cultured on dLG-HG was higher than that of EpC cultured on Col or Matrigel. In addition to these promising cell related properties, a rapid matrix metalloproteinase-dependent biodegradation was observed, which on the one hand suggests a lively cell-matrix interaction, but on the other hand limits the cultivation period. Concluding, dLG-HG possesses decisive properties for the tissue engineering of a LGin vitromodel such as cytocompatibility and promotion of secretion, making it superior to unspecific cell culture substrates. However, deceleration of biodegradation should be addressed in future experiments.

Efficacy of EDTA-NS irrigation in eradicating Staphylococcus aureus biofilm-associated infection

Aims

To investigate the efficacy of ethylenediaminetetraacetic acid-normal saline (EDTA-NS) in dispersing biofilms and reducing bacterial infections.

Methods

EDTA-NS solutions were irrigated at different durations (1, 5, 10, and 30 minutes) and concentrations (1, 2, 5, 10, and 50 mM) to disrupt Staphylococcus aureus biofilms on Matrigel-coated glass and two materials widely used in orthopaedic implants (Ti-6Al-4V and highly cross-linked polyethylene (HXLPE)). To assess the efficacy of biofilm dispersion, crystal violet staining biofilm assay and colony counting after sonification and culturing were performed. The results were further confirmed and visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). We then investigated the efficacies of EDTA-NS irrigation in vivo in rat and pig models of biofilm-associated infection.

Results

When 10 mM or higher EDTA-NS concentrations were used for ten minutes, over 99% of S. aureus biofilm formed on all three types of materials was eradicated in terms of absorbance measured at 595 nm and colony-forming units (CFUs) after culturing. Consistently, SEM and CSLM scanning demonstrated that less adherence of S. aureus could be observed on all three types of materials after 10 mM EDTA-NS irrigation for ten minutes. In the rat model, compared with NS irrigation combined with rifampin (Ti-6Al-4V wire-implanted rats: 60% bacteria survived; HXLPE particle-implanted rats: 63.3% bacteria survived), EDTA-NS irrigation combined with rifampin produced the highest removal rate (Ti-6Al-4V wire-implanted rats: 3.33% bacteria survived; HXLPE particle-implanted rats: 6.67% bacteria survived). In the pig model, compared with NS irrigation combined with rifampin (Ti-6Al-4V plates: 75% bacteria survived; HXLPE bearings: 87.5% bacteria survived), we observed a similar level of biofilm disruption on Ti-6Al-4V plates (25% bacteria survived) and HXLPE bearings (37.5% bacteria survived) after EDTA-NS irrigation combined with rifampin. The in vivo study revealed that the biomass of S. aureus biofilm was significantly reduced when treated with rifampin following irrigation and debridement, as indicated by both the biofilm bacterial burden and crystal violet staining. EDTA-NS irrigation (10 mM/10 min) combined with rifampin effectively removes S. aureus biofilm-associated infections both in vitro and in vivo.

Conclusion

EDTA-NS irrigation with or without antibiotics is effective in eradicating S. aureus biofilm-associated infection both ex and in vivo.

Optimization of Xenografting Methods for Generating Human Skeletal Muscle in Mice

Xenografts of human skeletal muscle generated in mice can be used to study muscle pathology and to test drugs designed to treat myopathies and muscular dystrophies for their efficacy and specificity in human tissue. We previously developed methods to generate mature human skeletal muscles in immunocompromised mice starting with human myogenic precursor cells (hMPCs) from healthy individuals and individuals with facioscapulohumeral muscular dystrophy (FSHD). Here, we examine a series of alternative treatments at each stage in order to optimize engraftment. We show that (i) X-irradiation at 25Gy is optimal in preventing regeneration of murine muscle while supporting robust engraftment and the formation of human fibers without significant murine contamination; (ii) hMPC lines differ in their capacity to engraft; (iii) some hMPC lines yield grafts that respond better to intermittent neuromuscular electrical stimulation (iNMES) than others; (iv) some lines engraft better in male than in female mice; (v) coinjection of hMPCs with laminin, gelatin, Matrigel, or Growdex does not improve engraftment; (vi) BaCl2 is an acceptable replacement for cardiotoxin, but other snake venom preparations and toxins, including the major component of cardiotoxin, cytotoxin 5, are not; and (vii) generating grafts in both hindlimbs followed by iNMES of each limb yields more robust grafts than housing mice in cages with running wheels. Our results suggest that replacing cardiotoxin with BaCl2 and engrafting both tibialis anterior muscles generates robust grafts of adult human muscle tissue in mice.

Human induced pluripotent stem cell-derived planar neural organoids assembled on synthetic hydrogels

The tailorable properties of synthetic polyethylene glycol (PEG) hydrogels make them an attractive substrate for human organoid assembly. Here, we formed human neural organoids from iPSC-derived progenitor cells in two distinct formats: (i) cells seeded on a Matrigel surface; and (ii) cells seeded on a synthetic PEG hydrogel surface. Tissue assembly on synthetic PEG hydrogels resulted in three dimensional (3D) planar neural organoids with greater neuronal diversity, greater expression of neurovascular and neuroinflammatory genes, and reduced variability when compared with tissues assembled upon Matrigel. Further, our 3D human tissue assembly approach occurred in an open cell culture format and created a tissue that was sufficiently translucent to allow for continuous imaging. Planar neural organoids formed on PEG hydrogels also showed higher expression of neural, vascular, and neuroinflammatory genes when compared to traditional brain organoids grown in Matrigel suspensions. Further, planar neural organoids contained functional microglia that responded to pro-inflammatory stimuli, and were responsive to anti-inflammatory drugs. These results demonstrate that the PEG hydrogel neural organoids can be used as a physiologically relevant in vitro model of neuro-inflammation.

An Overview of Current Glaucomatous Trabecular Meshwork Models

PURPOSE

To provide an overview of the existing alternative models for studying trabecular meshwork (TM).

METHODS

Literature review.

RESULTS

The TM is a complex tissue that regulates aqueous humor outflow from the eye. Dysfunction of the TM is a major contributor to the pathogenesis of open-angle glaucoma, a leading cause of irreversible blindness worldwide. The TM is a porous structure composed of trabecular meshwork cells (TMC) within a multi-layered extracellular matrix (ECM). Although dysregulation of the outflow throughout the TM represents the first step in the disease process, the underlying mechanisms of TM degeneration associate cell loss and accumulation of ECM, but remain incompletely understood, and drugs targeting the TM are limited. Therefore, experimental models of glaucomatous trabeculopathy are necessary for preclinical screening, to advance research on this disease's pathophysiology, and to develop new therapeutic strategies targeting the TM. Traditional animal models have been used extensively, albeit with inherent limitations, including ethical concerns and limited translatability to humans. Consequently, there has been an increasing focus on developing alternative in vitro models to study the TM. Recent advancements in three-dimensional cell culture and tissue engineering are still in their early stages and do not yet fully reflect the complexity of the outflow pathway. However, they have shown promise in reducing reliance on animal experimentation in certain aspects of glaucoma research.

CONCLUSION

This review provides an overview of the existing alternative models for studying TM and their potential for advancing research on the pathophysiology of open-angle glaucoma and developing new therapeutic strategies.

Engineered organoids for biomedical applications

As miniaturized and simplified stem cell-derived 3D organ-like structures, organoids are rapidly emerging as powerful tools for biomedical applications. With their potential for personalized therapeutic interventions and high-throughput drug screening, organoids have gained significant attention recently. In this review, we discuss the latest developments in engineering organoids and using materials engineering, biochemical modifications, and advanced manufacturing technologies to improve organoid culture and replicate vital anatomical structures and functions of human tissues. We then explore the diverse biomedical applications of organoids, including drug development and disease modeling, and highlight the tools and analytical techniques used to investigate organoids and their microenvironments. We also examine the latest clinical trials and patents related to organoids that show promise for future clinical translation. Finally, we discuss the challenges and future perspectives of using organoids to advance biomedical research and potentially transform personalized medicine.

Overcoming biological barriers by virus-like drug particles for drug delivery

Virus-like particles (VLPs) have natural structural antigens similar to those found in viruses, making them valuable in vaccine immunization. Furthermore, VLPs have demonstrated significant potential in drug delivery, and emerged as promising vectors for transporting chemical drug, genetic drug, peptide/protein, and even nanoparticle drug. With virus-like permeability and strong retention, they can effectively target specific organs, tissues or cells, facilitating efficient intracellular drug release. Further modifications allow VLPs to transfer across various physiological barriers, thus acting the purpose of efficient drug delivery and accurate therapy. This article provides an overview of VLPs, covering their structural classifications, deliverable drugs, potential physiological barriers in drug delivery, strategies for overcoming these barriers, and future prospects.

Effect of collagen endometrial patch loaded with adipose-derived mesenchymal stem cells on endometrial regeneration in rats with a thin endometrium

Background

This study aimed to investigate the effects of a collagen endometrial patch (EM patch) loaded with adipose-derived mesenchymal stem cells (ADSCs) on endometrial regeneration in a rat model with thin endometrium.

Materials and methods

Thin endometrium was induced in female rats and divided into treatment groups as outlined: control, group 1(G1), local injection of ADSCs into the uterus, group 2 (G2), an EM patch without ADSCs, group 3 (G3), and an EM patch loaded with ADSCs, group 4 (G4). The rats were euthanized at either two weeks or four weeks after modeling and treatment followed by histological and biochemical analyses to examine the regenerative effects on the injured endometrium.

Results

Transplantation of the ADSC-loaded EM patch significantly promoted endometrial proliferation and increased the luminal epithelial area. Two weeks after treatment, the mean number of von Villebrand factor (vWF)+ or cluster of differentiation (CD) 31+-stained blood vessels was significantly higher in G4 than in G1 and G2. The mRNA and protein expression levels of TGF-β and FGF2 were significantly upregulated in G4 compared to those in the control. G4 exhibited significantly increased LIF mRNA levels and immunoreactivity compared with the other groups at both two weeks and four weeks after treatment. Cell tracking after ADSCs treatment revealed the presence of a substantial number of ADSCs grafted in the uterine tissues of G4, whereas a low number of ADSCs that were focally clustered were present in G2.

Conclusion

Transplantation of EM patches loaded with ADSCs resulted in the histological and biochemical restoration of an injured endometrium. The strategic integration of EM patches and ADSCs holds significant promise as an innovative therapeutic approach for effectively treating impaired endometrial conditions.

Tailoring biomaterials for biomimetic organs-on-chips

Organs-on-chips are microengineered microfluidic living cell culture devices with continuously perfused chambers penetrating to cells. By mimicking the biological features of the multicellular constructions, interactions among organs, vascular perfusion, physicochemical microenvironments, and so on, these devices are imparted with some key pathophysiological function levels of living organs that are difficult to be achieved in conventional 2D or 3D culture systems. In this technology, biomaterials are extremely important because they affect the microstructures and functionalities of the organ cells and the development of the organs-on-chip functions. Thus, herein, we provide an overview on the advances of biomaterials for the construction of organs-on-chips. After introducing the general components, structures, and fabrication techniques of the biomaterials, we focus on the studies of the functions and applications of these biomaterials in the organs-on-chips systems. Applications of the biomaterial-based organs-on-chips as alternative animal models for pharmaceutical, chemical, and environmental tests are described and highlighted. The prospects for exciting future directions and the challenges of biomaterials for realizing the further functionalization of organs-on-chips are also presented.

Successes and challenges in modeling heterogeneous BRAFV600E mutated central nervous system neoplasms

Central nervous system (CNS) neoplasms are difficult to treat due to their sensitive location. Over the past two decades, the availability of patient tumor materials facilitated large scale genomic and epigenomic profiling studies, which have resulted in detailed insights into the molecular underpinnings of CNS tumorigenesis. Based on results from these studies, CNS tumors have high molecular and cellular intra-tumoral and inter-tumoral heterogeneity. CNS cancer models have yet to reflect the broad diversity of CNS tumors and patients and the lack of such faithful cancer models represents a major bottleneck to urgently needed innovations in CNS cancer treatment. Pediatric cancer model development is lagging behind adult tumor model development, which is why we focus this review on CNS tumors mutated for BRAFV600E which are more prevalent in the pediatric patient population. BRAFV600E-mutated CNS tumors exhibit high inter-tumoral heterogeneity, encompassing clinically and histopathological diverse tumor types. Moreover, BRAFV600E is the second most common alteration in pediatric low-grade CNS tumors, and low-grade tumors are notoriously difficult to recapitulate in vitro and in vivo. Although the mutation predominates in low-grade CNS tumors, when combined with other mutations, most commonly CDKN2A deletion, BRAFV600E-mutated CNS tumors are prone to develop high-grade features, and therefore BRAFV600E-mutated CNS are a paradigm for tumor progression. Here, we describe existing in vitro and in vivo models of BRAFV600E-mutated CNS tumors, including patient-derived cell lines, patient-derived xenografts, syngeneic models, and genetically engineered mouse models, along with their advantages and shortcomings. We discuss which research gaps each model might be best suited to answer, and identify those areas in model development that need to be strengthened further. We highlight areas of potential research focus that will lead to the heightened predictive capacity of preclinical studies, allow for appropriate validation, and ultimately improve the success of "bench to bedside" translational research.

Elastin-like Recombinamer Hydrogels as Platforms for Breast Cancer Modeling

The involvement of the extracellular matrix (ECM) in tumor progression has motivated the development of biomaterials mimicking the tumor ECM to develop more predictive cancer models. Particularly, polypeptides based on elastin could be an interesting approach to mimic the ECM due to their tunable properties. Here, we demonstrated that elastin-like recombinamer (ELR) hydrogels can be suitable biomaterials to develop breast cancer models. This hydrogel was formed by two ELR polypeptides, one containing sequences biodegradable by matrix metalloproteinase and cyclooctyne and the other carrying arginylglycylaspartic acid and azide groups to allow cell adhesion, biodegradability, and suitable stiffness through "click-chemistry" cross-linking. Our findings show that breast cancer or nontumorigenic breast cells showed high viability and cell proliferation for up to 7 days. MCF7 and MCF10A formed spheroids whereas MDA-MB-231 formed cell networks, with the expression of ECM and high drug resistance in all cases, evidencing that ELR hydrogels are a promising biomaterial for breast cancer modeling.

Regorafenib inhibits growth, survival and angiogenesis in nasopharyngeal carcinoma and is synergistic with Mcl-1 inhibitor

OBJECTIVES

Regorafenib is an oral multi-kinase inhibitor approved for various metastatic/advanced cancers, and has been investigated in clinical trials in many other tumour entities. The purpose of this study was to evaluate the therapeutic potential of regorafenib for nasopharyngeal carcinoma (NPC).

METHODS

Cellular proliferation, survival, apoptosis and colony formation assays were performed and combination index was determined. NPC xenograft tumour models were established. In vitro and In vivo angiogenesis assays were performed.

KEY FINDINGS

Regorafenib is effective against a panel of NPC cell lines regardless of cellular origin and genetic profiling while sparing normal nasal epithelial cells. The predominant inhibitory effects of regorafenib in NPC are anchorage-dependent and anchorage-independent growth rather than survival. Apart from tumour cells, regorafenib potently inhibits angiogenesis. Mechanistically, regorafenib inhibits multiple oncogenic pathways including Raf/Erk/Mek and PI3K/Akt/mTOR. Regorafenib decreases Bcl-2 but not Mcl-1 level in NPC cells. The in vitro observations are evident in in vivo NPC xenograft mouse model. The combination of Mcl-1 inhibitor with regorafenib is synergistic in inhibiting NPC growth without causing systemic toxicity in mice.

CONCLUSIONS

Our findings also support further clinical investigation of regorafenib and Mcl-1 inhibitor for NPC treatment.

Organoid-on-a-chip: Current challenges, trends, and future scope toward medicine

In vitro organoid models, typically defined as 3D multicellular aggregates, have been extensively used as a promising tool in drug screening, disease progression research, and precision medicine. Combined with advanced microfluidics technique, organoid-on-a-chip can flexibly replicate in vivo organs within the biomimetic physiological microenvironment by accurately regulating different parameters, such as fluid conditions and concentration gradients of biochemical factors. Since engineered organ reconstruction has opened a new paradigm in biomedicine, innovative approaches are increasingly required in micro-nano fabrication, tissue construction, and development of pharmaceutical products. In this Perspective review, the advantages and characteristics of organoid-on-a-chip are first introduced. Challenges in current organoid culture, extracellular matrix building, and device manufacturing techniques are subsequently demonstrated, followed by potential alternative approaches, respectively. The future directions and emerging application scenarios of organoid-on-a-chip are finally prospected to further satisfy the clinical demands.

Flourishing tumor organoids: History, emerging technology, and application

Malignant tumors are one of the leading causes of death which impose an increasingly heavy burden on all countries. Therefore, the establishment of research models that closely resemble original tumor characteristics is crucial to further understanding the mechanisms of malignant tumor development, developing safer and more effective drugs, and formulating personalized treatment plans. Recently, organoids have been widely used in tumor research owing to their advantages including preserving the structure, heterogeneity, and cellular functions of the original tumor, together with the ease of manipulation. This review describes the history and characteristics of tumor organoids and the synergistic combination of three-dimensional (3D) culture approaches for tumor organoids with emerging technologies, including tissue-engineered cell scaffolds, microfluidic devices, 3D bioprinting, rotating wall vessels, and clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR-Cas9). Additionally, the progress in research and the applications in basic and clinical research of tumor organoid models are summarized. This includes studies of the mechanism of tumor development, drug development and screening, precision medicine, immunotherapy, and simulation of the tumor microenvironment. Finally, the existing shortcomings of tumor organoids and possible future directions are discussed.

From Non-Alcoholic Fatty Liver Disease to Liver Cancer: Microbiota and Inflammation as Key Players

It is estimated that 25% of the world's population has non-alcoholic fatty liver disease. This disease can advance to a more severe form, non-alcoholic steatohepatitis (NASH), a disease with a greater probability of progression to cirrhosis and hepatocellular carcinoma (HCC). NASH could be characterized as a necro-inflammatory complication of chronic hepatic steatosis. The combination of factors that lead to NASH and its progression to HCC in the setting of inflammation is not clearly understood. The portal vein is the main route of communication between the intestine and the liver. This allows the transfer of products derived from the intestine to the liver and the hepatic response pathway of bile and antibody secretion to the intestine. The intestinal microbiota performs a fundamental role in the regulation of immune function, but it can undergo changes that alter its functionality. These changes can also contribute to cancer by disrupting the immune system and causing chronic inflammation and immune dysfunction, both of which are implicated in cancer development. In this article, we address the link between inflammation, microbiota and HCC. We also review the different in vitro models, as well as recent clinical trials addressing liver cancer and microbiota.

Antibody-dependent cellular cytotoxicity-inducing antibodies enhance the natural killer cell anti-cancer response against patient-derived pancreatic cancer organoids

Introduction

Pancreatic cancer is associated with poor prognosis, and limited treatment options are available for the majority of patients. Natural killer (NK) cells in combination with antibodies inducing antibody-dependent cell-mediated cytotoxicity (ADCC) could be a highly effective new therapeutic option in pancreatic cancer. Accurate predictive preclinical models are needed to develop successful NK cell immunotherapy. Tumor organoids, in vitro 3D organ-like structures that retain important pathophysiological characteristics of the in vivo tumor, may provide such a model. In the current study, we assessed the cytotoxic potential of adoptive NK cells against human pancreatic cancer organoids. We hypothesized that NK cell anti-tumor responses could be enhanced by including ADCC-triggering antibodies.

Methods

We performed cytotoxicity assays with healthy donor-derived IL-2-activated NK cells and pancreatic cancer organoids from four patients. A 3D cytotoxicity assay using live-cell-imaging was developed and enabled real-time assessment of the response.

Results

We show that NK cells migrate to and target pancreatic cancer organoids, resulting in an increased organoid death, compared to the no NK cell controls (reaching an average fold change from baseline of 2.1±0.8 vs 1.4±0.6). After 24-hours of co-culture, organoid 2D growth increased. Organoids from 2 out of 4 patients were sensitive to NK cells, while organoids from the other two patients were relatively resistant, indicating patient-specific heterogeneity among organoid cultures. The ADCC-inducing antibodies avelumab (anti-PD-L1) and trastuzumab (anti-HER2) increased NK cell-induced organoid cell death (reaching an average fold change from baseline of 3.5±1.0 and 4.5±1.8, respectively). Moreover, combination therapy with avelumab or trastuzumab resulted in complete disintegration of organoids. Finally, inclusion of ADCC-inducing antibodies was able to overcome resistance in NK-organoid combinations with low or no kill.

Discussion

These results support the use of organoids as a relevant and personalized model to study the anti-tumor response of NK cells in vitro and the potential of ADCC-inducing antibodies to enhance NK cell effector function.

Tissue-specific cancer stem/progenitor cells: Therapeutic implications

Surgical resection, chemotherapy, and radiation are the standard therapeutic modalities for treating cancer. These approaches are intended to target the more mature and rapidly dividing cancer cells. However, they spare the relatively quiescent and intrinsically resistant cancer stem cells (CSCs) subpopulation residing within the tumor tissue. Thus, a temporary eradication is achieved and the tumor bulk tends to revert supported by CSCs' resistant features. Based on their unique expression profile, the identification, isolation, and selective targeting of CSCs hold great promise for challenging treatment failure and reducing the risk of cancer recurrence. Yet, targeting CSCs is limited mainly by the irrelevance of the utilized cancer models. A new era of targeted and personalized anti-cancer therapies has been developed with cancer patient-derived organoids (PDOs) as a tool for establishing pre-clinical tumor models. Herein, we discuss the updated and presently available tissue-specific CSC markers in five highly occurring solid tumors. Additionally, we highlight the advantage and relevance of the three-dimensional PDOs culture model as a platform for modeling cancer, evaluating the efficacy of CSC-based therapeutics, and predicting drug response in cancer patients.

Optimization strategies of mesenchymal stem cell-based therapy for acute kidney injury

Considering the high prevalence and the lack of targeted pharmacological management of acute kidney injury (AKI), the search for new therapeutic approaches for it is in urgent demand. Mesenchymal stem cells (MSCs) have been increasingly recognized as a promising candidate for the treatment of AKI. However, clinical translation of MSCs-based therapies is hindered due to the poor retention and survival rates as well as the impaired paracrine ability of MSCs post-delivery. To address these issues, a series of strategies including local administration, three-dimensional culture, and preconditioning have been applied. Owing to the emergence and development of these novel biotechnologies, the effectiveness of MSCs in experimental AKI models is greatly improved. Here, we summarize the different approaches suggested to optimize the efficacy of MSCs therapy, aiming at promoting the therapeutic effects of MSCs on AKI patients.

Animal-derived products in science and current alternatives

More than fifty years after the 3Rs definition and despite the continuous implementation of regulatory measures, animals continue to be widely used in basic research. Their use comprises not only in vivo experiments with animal models, but also the production of a variety of supplements and products of animal origin for cell and tissue culture, cell-based assays, and therapeutics. The animal-derived products most used in basic research are fetal bovine serum (FBS), extracellular matrix proteins such as Matrigel™, and antibodies. However, their production raises several ethical issues regarding animal welfare. Additionally, their biological origin is associated with a high risk of contamination, resulting, frequently, in poor scientific data for clinical translation. These issues support the search for new animal-free products able to replace FBS, Matrigel™, and antibodies in basic research. In addition, in silico methodologies play an important role in the reduction of animal use in research by refining the data previously to in vitro and in vivo experiments. In this review, we depicted the current available animal-free alternatives in in vitro research.

Unsung versatility of elastin-like polypeptide inspired spheroid fabrication: A review

Lately, 3D cell culture technique has gained a lot of appreciation as a research model. Augmented with technological advancements, the area of 3D cell culture is growing rapidly with a diverse array of scaffolds being tested. This is especially the case for spheroid cultures. The culture of cells as spheroids provides opportunities for unanticipated vision into biological phenomena with its application to drug discovery, metabolic profiling, stem cell research as well as tumor, and disease biology. Spheroid fabrication techniques are broadly categorised into matrix-dependent and matrix-independent techniques. While there is a profusion of spheroid fabrication substrates with substantial biological relevance, an economical, modular, and bio-compatible substrate for high throughput production of spheroids is lacking. In this review, we posit the prospects of elastin-like polypeptides (ELPs) as a broad-spectrum spheroid fabrication platform. Elastin-like polypeptides are nature inspired, size-tunable genetically engineered polymers with wide applicability in various arena of biological considerations, has been employed for spheroid culture with profound utility. The technology offers a cheap, high-throughput, reproducible alternative for spheroid culture with exquisite adaptability. Here, we will brief the applicability of 3D cultures as compared to 2D cultures with spheroids being the focal point of the review. Common approaches to spheroid fabrication are discussed with existential limitations. Finally, the versatility of elastin-like polypeptide inspired substrates for spheroid culture has been discussed.

Drug-Delivery Nanoplatform with Synergistic Regulation of Angiogenesis-Osteogenesis Coupling for Promoting Vascularized Bone Regeneration

It has been confirmed that substantial vascularization is an effective strategy to heal large-scale bone defects in the field of bone tissue engineering. The local application of deferoxamine (DFO) is among the most common and effective methods for promoting the formation of blood vessels, although its short half-life in plasma, rapid clearance, and poor biocompatibility limit its therapeutic suitability. Herein, zeolitic imidazolate framework-8 (ZIF-8) was selected as a vehicle to extend the half-life of DFO. In the present study, a nano DFO-loaded ZIF-8 (DFO@ZIF-8) drug delivery system was established to promote angiogenesis-osteogenesis coupling. The nanoparticles were characterized, and their drug loading efficiency was examined to confirm the successful synthesis of nano DFO@ZIF-8. Additionally, due to the sustained release of DFO and Zn²⁺, DFO@ZIF-8 NPs were able to promote angiogenesis in human umbilical vein endothelial cells (HUVECs) culture and osteogenesis in bone marrow stem cells (BMSCs) in vitro. Furthermore, the DFO@ZIF-8 NPs promoted vascularization by enhancing the expression of type H vessels and a vascular network. The DFO@ZIF-8 NPs promoted bone regeneration in vivo by increasing the expression of OCN and BMP-2. RNA sequencing analysis revealed that the PI3K-AKT-MMP-2/9 and HIF-1α pathways were upregulated by DFO@ZIF-8 NPs in HUVECs, ultimately leading to the formation of new blood vessels. In addition, the mechanism by which DFO@ZIF-8 NPs promoted bone regeneration was potentially related to the synergistic effect of angiogenesis-osteogenesis coupling and Zn²⁺-mediation of the MAPK pathway. Taken together, DFO@ZIF-8 NPs, which were demonstrated to have low cytotoxicity and excellent coupling of angiogenesis and osteogenesis, represent a promising strategy for the reconstruction of critical-sized bone defects.

Synergistic Encapsulation of Paclitaxel and Sorafenib by Methoxy Poly(Ethylene Glycol)-b-Poly(Caprolactone) Polymeric Micelles for Ovarian Cancer Therapy

Ovarian cancer has a high mortality rate due to difficult detection at an early stage. It is necessary to develop a novel anticancer treatment that demonstrates improved efficacy while reducing toxicity. Here, using the freeze-drying method, micelles encapsulating paclitaxel (PTX) and sorafenib (SRF) with various polymers were prepared, and the optimal polymer (mPEG-b-PCL) was selected by measuring drug loading (%), encapsulation efficiency (%), particle size, polydispersity index, and zeta potential. The final formulation was selected based on a molar ratio (PTX:SRF = 1:2.3) with synergistic effects on two ovarian cancer cell lines (SKOV3-red-fluc, HeyA8). In the in vitro release assay, PTX/SRF micelles showed a slower release than PTX and SRF single micelles. In pharmacokinetic evaluation, PTX/SRF micelles showed improved bioavailability compared to PTX/SRF solution. In in vivo toxicity assays, no significant differences were observed in body weight between the micellar formulation and the control group. The anticancer effect of PTX/SRF combination therapy was improved compared to the use of a single drug. In the xenografted BALB/c mouse model, the tumor growth inhibition rate of PTX/SRF micelles was 90.44%. Accordingly, PTX/SRF micelles showed improved anticancer effects compared to single-drug therapy in ovarian cancer (SKOV3-red-fluc).

Towards a New 3Rs Era in the construction of 3D cell culture models simulating tumor microenvironment

Three-dimensional cell culture technology (3DCC) sits between two-dimensional cell culture (2DCC) and animal models and is widely used in oncology research. Compared to 2DCC, 3DCC allows cells to grow in a three-dimensional space, better simulating the in vivo growth environment of tumors, including hypoxia, nutrient concentration gradients, micro angiogenesis mimicism, and the interaction between tumor cells and the tumor microenvironment matrix. 3DCC has unparalleled advantages when compared to animal models, being more controllable, operable, and convenient. This review summarizes the comparison between 2DCC and 3DCC, as well as recent advances in different methods to obtain 3D models and their respective advantages and disadvantages.

The predictive capacity of in vitro preclinical models to evaluate drugs for the treatment of retinoblastoma

Retinoblastoma is a rare childhood cancer of the eye. Of the small number of drugs are used to treat retinoblastoma, all have been repurposed from drugs developed for other conditions. In order to find drugs or drug combinations better suited to the improved treatment of retinoblastoma, reliable predictive models are required, which facilitate the challenging transition from in vitro studies to clinical trials. In this review, the research performed to date on the development of 2D and 3D in vitro models for retinoblastoma is presented. Most of this research was undertaken with a view to better biological understanding of retinoblastoma, and we discuss the potential for these models to be applied to drug screening. Future research directions for streamlined drug discovery are considered and evaluated, and many promising avenues identified.

Tumor Spheroids as Model to Design Acoustically Mediated Drug Therapies: A Review

Tumor spheroids as well as multicellular tumor spheroids (MCTSs) are promising 3D in vitro tumor models for drug screening, drug design, drug targeting, drug toxicity, and validation of drug delivery methods. These models partly reflect the tridimensional architecture of tumors, their heterogeneity and their microenvironment, which can alter the intratumoral biodistribution, pharmacokinetics, and pharmacodynamics of drugs. The present review first focuses on current spheroid formation methods and then on in vitro investigations exploiting spheroids and MCTS for designing and validating acoustically mediated drug therapies. We discuss the limitations of the current studies and future perspectives. Various spheroid formation methods enable the easy and reproducible generation of spheroids and MCTSs. The development and assessment of acoustically mediated drug therapies have been mainly demonstrated in spheroids made up of tumor cells only. Despite the promising results obtained with these spheroids, the successful evaluation of these therapies will need to be addressed in more relevant 3D vascular MCTS models using MCTS-on-chip platforms. These MTCSs will be generated from patient-derived cancer cells and nontumor cells, such as fibroblasts, adipocytes, and immune cells.

Liver Organoids as an In Vitro Model to Study Primary Liver Cancer

Primary liver cancers (PLC), including hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), are among the leading causes of cancer-related mortality worldwide. Bi-dimensional in vitro models are unable to recapitulate the key features of PLC; consequently, recent advancements in three-dimensional in vitro systems, such as organoids, opened up new avenues for the development of innovative models for studying tumour's pathological mechanisms. Liver organoids show self-assembly and self-renewal capabilities, retaining essential aspects of their respective in vivo tissue and allowing modelling diseases and personalized treatment development. In this review, we will discuss the current advances in the field of liver organoids focusing on existing development protocols and possible applications in regenerative medicine and drug discovery.

Anti-Arthritic and Anti-Cancer Activities of Polyphenols: A Review of the Most Recent In Vitro Assays

Polyphenols have gained widespread attention as they are effective in the prevention and management of various diseases, including cancer diseases (CD) and rheumatoid arthritis (RA). They are natural organic substances present in fruits, vegetables, and spices. Polyphenols interact with various kinds of receptors and membranes. They modulate different signal cascades and interact with the enzymes responsible for CD and RA. These interactions involve cellular machinery, from cell membranes to major nuclear components, and provide information on their beneficial effects on health. These actions provide evidence for their pharmaceutical exploitation in the treatment of CD and RA. In this review, we discuss different pathways, modulated by polyphenols, which are involved in CD and RA. A search of the most recent relevant publications was carried out with the following criteria: publication date, 2012-2022; language, English; study design, in vitro; and the investigation of polyphenols present in extra virgin olive, grapes, and spices in the context of RA and CD, including, when available, the underlying molecular mechanisms. This review is valuable for clarifying the mechanisms of polyphenols targeting the pathways of senescence and leading to the development of CD and RA treatments. Herein, we focus on research reports that emphasize antioxidant properties.

Challenges and Opportunities Modeling the Dynamic Tumor Matrisome

We need novel strategies to target the complexity of cancer and, particularly, of metastatic disease. As an example of this complexity, certain tissues are particularly hospitable environments for metastases, whereas others do not contain fertile microenvironments to support cancer cell growth. Continuing evidence that the extracellular matrix (ECM) of tissues is one of a host of factors necessary to support cancer cell growth at both primary and secondary tissue sites is emerging. Research on cancer metastasis has largely been focused on the molecular adaptations of tumor cells in various cytokine and growth factor environments on 2-dimensional tissue culture polystyrene plates. Intravital imaging, conversely, has transformed our ability to watch, in real time, tumor cell invasion, intravasation, extravasation, and growth. Because the interstitial ECM that supports all cells in the tumor microenvironment changes over time scales outside the possible window of typical intravital imaging, bioengineers are continuously developing both simple and sophisticated in vitro controlled environments to study tumor (and other) cell interactions with this matrix. In this perspective, we focus on the cellular unit responsible for upholding the pathologic homeostasis of tumor-bearing organs, cancer-associated fibroblasts (CAFs), and their self-generated ECM. The latter, together with tumoral and other cell secreted factors, constitute the "tumor matrisome". We share the challenges and opportunities for modeling this dynamic CAF/ECM unit, the tools and techniques available, and how the tumor matrisome is remodeled (e.g., via ECM proteases). We posit that increasing information on tumor matrisome dynamics may lead the field to alternative strategies for personalized medicine outside genomics.

Optimization of extracellular matrix for primary human hepatocyte cultures using mixed collagen-Matrigel matrices

Loss of differentiation of primary human hepatocytes (PHHs) ex vivo is a known problem of in vitro liver models. Culture optimizations using collagen type I and Matrigel reduce the dedifferentiation process but are not able to prevent it. While neither of these extracellular matrices (ECMs) on their own correspond to the authentic hepatic ECM, a combination of them could more closely resemble the in vivo situation. Our study aimed to systematically analyze the influence of mixed matrices composed of collagen type I and Matrigel on the maintenance and reestablishment of hepatic functions. Therefore, PHHs were cultured on mixed collagen-Matrigel matrices in monolayer and sandwich cultures and viability, metabolic capacity, differentiation markers, cellular arrangement and the cells' ability to repolarize and form functional bile canaliculi were assessed by reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR), functional assays and immunofluorescence microscopy. Our results show that mixed matrices were superior to pure matrices in maintaining metabolic capacity and hepatic differentiation. In contrast, Matrigel supplementation can impair the development of a proper hepatocytic polarization. Our systematic study helps to compose an optimized ECM to maintain and reestablish hepatic differentiation on cellular and multicellular levels in human liver models.

Neural grafts containing exosomes derived from Schwann cell-like cells promote peripheral nerve regeneration in rats

Background

Schwann cell-like cells (SCLCs), differentiated from mesenchymal stem cells, have shown promising outcomes in the treatment of peripheral nerve injuries in preclinical studies. However, certain clinical obstacles limit their application. Hence, the primary aim of this study was to investigate the role of exosomes derived from SCLCs (SCLCs-exo) in peripheral nerve regeneration.

Methods

SCLCs were differentiated from human amniotic mesenchymal stem cells (hAMSCs) in vitro and validated by immunofluorescence, real-time quantitative PCR and western blot analysis. Exosomes derived from hAMSCs (hAMSCs-exo) and SCLCs were isolated by ultracentrifugation and validated by nanoparticle tracking analysis, WB analysis and electron microscopy. A prefabricated nerve graft was used to deliver hAMSCs-exo or SCLCs-exo in an injured sciatic nerve rat model. The effects of hAMSCs-exo or SCLCs-exo on rat peripheral nerve injury (PNI) regeneration were determined based on the recovery of neurological function and histomorphometric variation. The effects of hAMSCs-exo or SCLCs-exo on Schwann cells were also determined via cell proliferation and migration assessment.

Results

SCLCs significantly expressed the Schwann cell markers glial fibrillary acidic protein and S100. Compared to hAMSCs-exo, SCLCs-exo significantly enhanced motor function recovery, attenuated gastrocnemius muscle atrophy and facilitated axonal regrowth, myelin formation and angiogenesis in the rat model. Furthermore, hAMSCs-exo and SCLCs-exo were efficiently absorbed by Schwann cells. However, compared to hAMSCs-exo, SCLCs-exo significantly promoted the proliferation and migration of Schwann cells. SCLCs-exo also significantly upregulated the expression of a glial cell-derived neurotrophic factor, myelin positive regulators (SRY-box transcription factor 10, early growth response protein 2 and organic cation/carnitine transporter 6) and myelin proteins (myelin basic protein and myelin protein zero) in Schwann cells.

Conclusions

These findings suggest that SCLCs-exo can more efficiently promote PNI regeneration than hAMSCs-exo and are a potentially novel therapeutic approach for treating PNI.

Visualizing and Quantifying mRNA Localization at the Invasive Front of 3D Cancer Spheroids

Localization of mRNAs at the front of migrating cells is a widely used mechanism that functionally supports efficient cell movement. It is observed in single cells on two-dimensional surfaces, as well as in multicellular three-dimensional (3D) structures and in tissue in vivo. 3D multicellular cultures can reveal how the topology of the extracellular matrix and cell-cell contacts influence subcellular mRNA distributions. Here we describe a method for mRNA imaging in an inducible system of collective cancer cell invasion. MDA-MB-231 cancer cell spheroids are embedded in Matrigel, induced to invade, and processed to image mRNAs with single-molecule sensitivity. An analysis algorithm is used to quantify and compare mRNA distributions at the front of invasive leader cells. The approach can be easily adapted and applied to analyze RNA distributions in additional settings where cells polarize along a linear axis.

Biomimetic Strategy to Enhance Epithelial Cell Viability and Spreading on PEEK Implants

Polyetheretherketone (PEEK) is a biocompatible material widely used in spinal and craniofacial implants, with potential use in percutaneous implants. However, its inertness prevents it from forming a tight seal with the surrounding soft tissue, which can lead to infections and implant failure. Conversely, the surface chemistry of percutaneous organs (i.e., teeth) helps establish a strong interaction with the epithelial cells of the contacting soft tissues, and hence a tight seal, preventing infection. The seal is created by adsorption of basement membrane (BM) proteins, secreted by epithelial cells, onto the percutaneous organ surfaces. Here, we aim to create a tight seal between PEEK and epithelial tissues by mimicking the surface chemistry of teeth. Our hypothesis is that collagen I, the most abundant tooth protein, enables integration between the epithelial tissue and teeth by promoting adsorption of BM proteins. To test this, we immobilized collagen I via EDC/NHS coupling on a carboxylated PEEK surface modified using diazonium chemistry. We used titanium alloy (Ti-6Al-4V) for comparison, as titanium is the most widely used percutaneous biomaterial. Both collagen-modified PEEK and titanium showed a larger adsorption of key BM proteins (laminin, nidogen, and fibronectin) compared to controls. Keratinocyte epithelial cell viability on collagen-modified PEEK was twice that of control PEEK and ∼1.5 times that of control titanium after 3 days of cell seeding. Both keratinocytes and fibroblasts spread more on collagen-modified PEEK and titanium compared to controls. This work introduces a versatile and biomimetic surface modification technique that may enhance PEEK-epithelial tissue sealing with the potential of extending PEEK applications to percutaneous implants, making it competitive with titanium.

Neural Regeneration in Regenerative Endodontic Treatment: An Overview and Current Trends

Pulpal and periapical diseases are the most common dental diseases. The traditional treatment is root canal therapy, which achieves satisfactory therapeutic outcomes-especially for mature permanent teeth. Apexification, pulpotomy, and pulp revascularization are common techniques used for immature permanent teeth to accelerate the development of the root. However, there are obstacles to achieving functional pulp regeneration. Recently, two methods have been proposed based on tissue engineering: stem cell transplantation, and cell homing. One of the goals of functional pulp regeneration is to achieve innervation. Nerves play a vital role in dentin formation, nutrition, sensation, and defense in the pulp. Successful neural regeneration faces tough challenges in both animal studies and clinical trials. Investigation of the regeneration and repair of the nerves in the pulp has become a serious undertaking. In this review, we summarize the current understanding of the key stem cells, signaling molecules, and biomaterials that could promote neural regeneration as part of pulp regeneration. We also discuss the challenges in preclinical or clinical neural regeneration applications to guide deep research in the future.