A 3D fibrous scaffold inducing tumoroids: a platform for anticancer drug development

Nanostructured Biomaterials in 3D Tumor Tissue Engineering Scaffolds: Regenerative Medicine and Immunotherapies

The evaluation of nanostructured biomaterials and medicines is associated with 2D cultures that provide insight into biological mechanisms at the molecular level, while critical aspects of the tumor microenvironment (TME) are provided by the study of animal xenograft models. More realistic models that can histologically reproduce human tumors are provided by tissue engineering methods of co-culturing cells of varied phenotypes to provide 3D tumor spheroids that recapitulate the dynamic TME in 3D matrices. The novel approaches of creating 3D tumor models are combined with tumor tissue engineering (TTE) scaffolds including hydrogels, bioprinted materials, decellularized tissues, fibrous and nanostructured matrices. This review focuses on the use of nanostructured materials in cancer therapy and regeneration, and the development of realistic models for studying TME molecular and immune characteristics. Tissue regeneration is an important aspect of TTE scaffolds used for restoring the normal function of the tissues, while providing cancer treatment. Thus, this article reports recent advancements in the development of 3D TTE models for antitumor drug screening, studying tumor metastasis, and tissue regeneration. Also, this review identifies the significant opportunities of using 3D TTE scaffolds in the evaluation of the immunological mechanisms and processes involved in the application of immunotherapies.

Microsphere-Enabled Modular Formation of Miniaturized In Vitro Breast Cancer Models

In search of effective therapeutics for breast cancers, establishing physiologically relevant in vitro models is of great benefit to facilitate the clinical translation. Despite extensive progresses, it remains to develop the tumor models maximally recapturing the key pathophysiological attributes of their native counterparts. Therefore, the current study aimed to develop a microsphere-enabled modular approach toward the formation of in vitro breast tumor models with the capability of incorporating various selected cells while retaining spatial organization. Poly (lactic-co-glycolic acid) microspheres (150-200 mm) with tailorable pore size and surface topography are fabricated and used as carriers to respectively lade with breast tumor-associated cells. Culture of cell-laden microspheres assembled within a customized microfluidic chamber allowed to form 3D tumor models with spatially controlled cell distribution. The introduction of endothelial cell-laden microspheres into cancer-cell laden microspheres at different ratios would induce angiogenesis within the culture to yield vascularized tumor. Evaluation of anticancer drugs such as doxorubicin and Cediranib on the tumor models do demonstrate corresponding physiological responses. Clearly, with the ability to modulate microsphere morphology, cell composition and spatial distribution, microsphere-enabled 3D tumor tissue formation offers a high flexibility to satisfy the needs for pathophysiological study, anticancer drug screening or design of personalized treatment.

Artificial tumor matrices and bioengineered tools for tumoroid generation

The tumor microenvironment (TME) is critical for tumor growth and metastasis. The TME contains cancer-associated cells, tumor matrix, and tumor secretory factors. The fabrication of artificial tumors, so-called tumoroids, is of great significance for the understanding of tumorigenesis and clinical cancer therapy. The assembly of multiple tumor cells and matrix components through interdisciplinary techniques is necessary for the preparation of various tumoroids. This article discusses current methods for constructing tumoroids (tumor tissue slices and tumor cell co-culture) for pre-clinical use. This article focuses on the artificial matrix materials (natural and synthetic materials) and biofabrication techniques (cell assembly, bioengineered tools, bioprinting, and microfluidic devices) used in tumoroids. This article also points out the shortcomings of current tumoroids and potential solutions. This article aims to promotes the next-generation tumoroids and the potential of them in basic research and clinical application.

Recent Progress in Fabrication of Electrospun Nanofiber Membranes for Developing Physiological In Vitro Organ/Tissue Models

Nanofiber membranes (NFMs), which have an extracellular matrix-mimicking structure and unique physical properties, have garnered great attention as biomimetic materials for developing physiologically relevant in vitro organ/tissue models. Recent progress in NFM fabrication techniques immensely contributes to the development of NFM-based cell culture platforms for constructing physiological organ/tissue models. However, despite the significance of the NFM fabrication technique, an in-depth discussion of the fabrication technique and its future aspect is insufficient. This review provides an overview of the current state-of-the-art of NFM fabrication techniques from electrospinning techniques to postprocessing techniques for the fabrication of various types of NFM-based cell culture platforms. Moreover, the advantages of the NFM-based culture platforms in the construction of organ/tissue models are discussed especially for tissue barrier models, spheroids/organoids, and biomimetic organ/tissue constructs. Finally, the review concludes with perspectives on challenges and future directions for fabrication and utilization of NFMs.

Graphene oxide accelerates TGFβ-mediated epithelial-mesenchymal transition and stimulates pro-inflammatory immune response in amniotic epithelial cells

The application of biomaterials on immune regenerative strategies to deal with unsolved pathologies is getting attention in the field of tissue engineering. In this context, graphene oxide (GO) has been proposed as an immune-mimetic material largely used for developing stem cell-based regenerative therapies, since it has shown to influence stem cell behavior and modulate their immune response. Similarly, amniotic epithelial stem cells (AECs) are getting an increasing clinical interest as source of stem cells due to their great plasticity and immunomodulatory paracrine activities, even though GO bio-mimetic effects still remain unknown. To this aim, GO-functionalized glass coverslips have been used for AECs culture. The results demonstrated how GO-coating is able to induce and accelerate the Epithelial-Mesenchymal Transition (EMT), in a process mediated by the intracellular activation of TGFβ1-SMAD2/3 signaling pathway. The trans-differentiation towards mesenchymal phenotype provides AECs of migratory ability and substantially changes the pattern of cytokines secretion upon inflammatory stimulus. Indeed, GO-exposed AECs enhance their pro-inflammatory interleukins production thus inducing a more efficient activation of macrophages and, at the same time, by slightly reducing their inhibitory action on peripheral blood mononuclear cells proliferation. Therefore, the adhesion of AECs on GO-functionalized surfaces might contribute to the generation of a tailored microenvironment useful to face both the phases of the inflammation, thereby fostering the regenerative process.

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.

Replacement, Reduction, and Refinement of Animal Experiments in Anticancer Drug Development: The Contribution of 3D In Vitro Cancer Models in the Drug Efficacy Assessment

In the last decades three-dimensional (3D) in vitro cancer models have been proposed as a bridge between bidimensional (2D) cell cultures and in vivo animal models, the gold standards in the preclinical assessment of anticancer drug efficacy. 3D in vitro cancer models can be generated through a multitude of techniques, from both immortalized cancer cell lines and primary patient-derived tumor tissue. Among them, spheroids and organoids represent the most versatile and promising models, as they faithfully recapitulate the complexity and heterogeneity of human cancers. Although their recent applications include drug screening programs and personalized medicine, 3D in vitro cancer models have not yet been established as preclinical tools for studying anticancer drug efficacy and supporting preclinical-to-clinical translation, which remains mainly based on animal experimentation. In this review, we describe the state-of-the-art of 3D in vitro cancer models for the efficacy evaluation of anticancer agents, focusing on their potential contribution to replace, reduce and refine animal experimentations, highlighting their strength and weakness, and discussing possible perspectives to overcome current challenges.

In Vitro Models of Ovarian Cancer: Bridging the Gap between Pathophysiology and Mechanistic Models

Ovarian cancer (OC) is a disease of major concern with a survival rate of about 40% at five years. This is attributed to the lack of visible and reliable symptoms during the onset of the disease, which leads over 80% of patients to be diagnosed at advanced stages. This implies that metastatic activity has advanced to the peritoneal cavity. It is associated with both genetic and phenotypic heterogeneity, which considerably increase the risks of relapse and reduce the survival rate. To understand ovarian cancer pathophysiology and strengthen the ability for drug screening, further development of relevant in vitro models that recapitulate the complexity of OC microenvironment and dynamics of OC cell population is required. In this line, the recent advances of tridimensional (3D) cell culture and microfluidics have allowed the development of highly innovative models that could bridge the gap between pathophysiology and mechanistic models for clinical research. This review first describes the pathophysiology of OC before detailing the engineering strategies developed to recapitulate those main biological features.

The Development of a Three-Dimensional Platform for Patient-Derived Ovarian Cancer Tissue Models: A Systematic Literature Review

There is an unmet biomedical need for ex vivo tumour models that would predict drug responses and in turn help determine treatment regimens and potentially predict resistance before clinical studies. Research has shown that three dimensional models of ovarian cancer (OvCa) are more realistic than two dimensional in vitro systems as they are able to capture patient in vivo conditions in more accurate manner. The vast majority of studies aiming to recapitulate the ovarian tumour morphology, behaviors, and study chemotherapy responses have been using ovarian cancer cell lines. However, despite the advantages of utilising cancer cell lines to set up a platform, they are not as informative as systems applying patient derived cells, as cell lines are not able to recapitulate differences between each individual patient characteristics. In this review we discussed the most recent advances in the creation of 3D ovarian cancer models that have used patient derived material, the challenges to overcome and future applications.

Bench to Bedside: New Therapeutic Approaches with Extracellular Vesicles and Engineered Biomaterials for Targeting Therapeutic Resistance of Cancer Stem Cells

Cancer has recently been the second leading cause of death worldwide, trailing only cardiovascular disease. Cancer stem cells (CSCs), represented as tumor-initiating cells (TICs), are mainly liable for chemoresistance and disease relapse due to their self-renewal capability and differentiating capacity into different types of tumor cells. The intricate molecular mechanism is necessary to elucidate CSC's chemoresistance properties and cancer recurrence. Establishing efficient strategies for CSC maintenance and enrichment is essential to elucidate the mechanisms and properties of CSCs and CSC-related therapeutic measures. Current approaches are insufficient to mimic the in vivo chemical and physical conditions for the maintenance and growth of CSC and yield unreliable research results. Biomaterials are now widely used for simulating the bone marrow microenvironment. Biomaterial-based three-dimensional (3D) approaches for the enrichment of CSC provide an excellent promise for future drug discovery and elucidation of molecular mechanisms. In the future, the biomaterial-based model will contribute to a more operative and predictive CSC model for cancer therapy. Design strategies for materials, physicochemical cues, and morphology will offer a new direction for future modification and new methods for studying the CSC microenvironment and its chemoresistance property. This review highlights the critical roles of the microenvironmental cues that regulate CSC function and endow them with drug resistance properties. This review also explores the latest advancement and challenges in biomaterial-based scaffold structure for therapeutic approaches against CSC chemoresistance. Since the recent entry of extracellular vesicles (EVs), cell-derived nanostructures, have opened new avenues of investigation into this field, which, together with other more conventionally studied signaling pathways, play an important role in cell-to-cell communication. Thus, this review further explores the subject of EVs in-depth. This review also discusses possible future biomaterial and biomaterial-EV-based models that could be used to study the tumor microenvironment (TME) and will provide possible therapeutic approaches. Finally, this review concludes with potential perspectives and conclusions in this area.

Three-dimensional in vitro culture models in oncology research

Cancer is a multifactorial disease that is responsible for 10 million deaths per year. The intra- and inter-heterogeneity of malignant tumors make it difficult to develop single targeted approaches. Similarly, their diversity requires various models to investigate the mechanisms involved in cancer initiation, progression, drug resistance and recurrence. Of the in vitro cell-based models, monolayer adherent (also known as 2D culture) cell cultures have been used for the longest time. However, it appears that they are often less appropriate than the three-dimensional (3D) cell culture approach for mimicking the biological behavior of tumor cells, in particular the mechanisms leading to therapeutic escape and drug resistance. Multicellular tumor spheroids are widely used to study cancers in 3D, and can be generated by a multiplicity of techniques, such as liquid-based and scaffold-based 3D cultures, microfluidics and bioprinting. Organoids are more complex 3D models than multicellular tumor spheroids because they are generated from stem cells isolated from patients and are considered as powerful tools to reproduce the disease development in vitro. The present review provides an overview of the various 3D culture models that have been set up to study cancer development and drug response. The advantages of 3D models compared to 2D cell cultures, the limitations, and the fields of application of these models and their techniques of production are also discussed.

Autochthonous nutrient recycling driven by soil microbiota could be sustaining high coconut productivity in Lakshadweep Islands sans external fertilizer application

The soils of Lakshadweep Islands are formed as a result of the fragmentation of coral limestone, that is carbonate-rich, with neutral pH, but poor in plant nutrients. Coconut palm (Cocos nucifera L.) is the main crop cultivated, supporting the life and livelihood of the islanders. No external fertilizer application or major plant protection measures are adopted for their cultivation as the Islands were declared to go organic decades back. Yet, Lakshadweep has one of the highest productivity of coconut compared with other coconut growing areas in India. Therefore, a question arises: how is such a high coconut productivity sustained? We try to answer by estimating in three main islands (i) the nutrients added to the soil via the litter generated by coconut palms and (ii) the role of soil microbiota, including arbuscular mycorrhizae, for the high productivity. Our results indicated that, besides adding a substantial quantum of organic carbon, twice the needed amount of nitrogen, extra 20% phosphorus to the already P-rich soils, 43-45% of potassium required by palms could be easily met by the total coconut biomass residues returned to the soil. Principal Component Analysis showed that soil organic carbon %, potassium, and organic carbon added via the palm litter and AM spore load scored >± 0.95 in PC1, whereas, available K in the soil, bacteria, actinomycetes, phosphate solubilizers and fluorescent pseudomonads scored above >± 0.95 in PC2. Based on our analysis, we suggest that the autochthonous nutrients added via the coconut biomass residues, recycled by the soil microbial communities, could be one of the main reasons for sustaining a high productivity of the coconut palms in Lakshadweep Islands, in the absence of any external fertilizer application, mimicking a semi-closed-loop forest ecosystem.

Recent Fabrication Methods to Produce Polymer-Based Drug Delivery Matrices (Experimental and In Silico Approaches)

The study of novel drug delivery systems represents one of the frontiers of the biomedical research area. Multi-disciplinary scientific approaches combining traditional or engineered technologies are used to provide major advances in improving drug bioavailability, rate of release, cell/tissue specificity and therapeutic index. Biodegradable and bio-absorbable polymers are usually the building blocks of these systems, and their copolymers are employed to create delivery components. For example, poly (lactic acid) or poly (glycolic acid) are often used as bricks for the production drug-based delivery systems as polymeric microparticles (MPs) or micron-scale needles. To avoid time-consuming empirical approaches for the optimization of these formulations, in silico-supported models have been developed. These methods can predict and tune the release of different drugs starting from designed combinations. Starting from these considerations, this review has the aim of investigating recent approaches to the production of polymeric carriers and the combination of in silico and experimental methods as promising platforms in the biomedical field.

A Systematic Comparative Assessment of the Response of Ovarian Cancer Cells to the Chemotherapeutic Cisplatin in 3D Models of Various Structural and Biochemical Configurations-Does One Model Type Fit All?

Simple Summary

Epithelial Ovarian Cancer is considered to be a ‘silent killer’ and a challenge for gynaecological health across the world due to its asymptotic nature in the early stages, its late-stage diagnosis, high recurrence rate and resistance to currently available treatment methods (chemotherapy). These disheartening figures highlight the need for extensive in vitro studies to better understand this disease. A number of in vitro 3D models are currently available to aid in the study of ovarian cancer and its response to therapeutic methods. In this work, we report, for the first time, a comprehensive comparative study of three widely used 3D in vitro models for ovarian cancer, along with chemotherapy assessment of primary and metastatic cells. Our study highlights the importance of selecting an appropriate 3D in vitro platform, which is based on multiple factors including the origin of cells used, experimental time period and experimental design, even for one specific disease.

Abstract

Epithelial Ovarian Cancer (EOC) is a silent, deadly and aggressive gynaecological disease with a relatively low survival rate. This has been attributed, to some extent, to EOC’s high recurrence rate and resistance to currently available platinum-based chemotherapeutic treatment methods. Multiple groups have studied and reported the effect of chemotherapeutic agents on various EOC 3D in vitro models. However, there are very few studies wherein a direct comparative study has been carried out between the different in vitro 3D models of EOC and the effect of chemotherapy within them. Herein, we report, for the first time, a direct comprehensive systematic comparative study of three different 3D in vitro platforms, namely (i) spheroids, (ii) synthetic PeptiGels/hydrogels of various chemical configurations and (iii) polymeric scaffolds with coatings of various extracellular matrices (ECMs) on the cell growth and response to the chemotherapeutic (Cisplatin) for ovary-derived (A2780) and metastatic (SK-OV-3) EOC cell lines. We report that all three 3D models are able to support the growth of EOC, but for different time periods (varying from 7 days to 4 weeks). We have also reported that chemoresistance to Cisplatin, in vitro, observed especially for metastatic EOC cells, is platform-dependent, in terms of both the structural and biochemical composition of the model/platform. Our study highlights the importance of selecting an appropriate 3D platform for in vitro tumour model development. We have demonstrated that the selection of the best platform for producing in vitro tumour models depends on the cancer/cell type, the experimental time period and the application for which the model is intended.

Spontaneous Formation of 3D Breast Cancer Tissues on Electrospun Chitosan/Poly(ethylene oxide) Nanofibrous Scaffolds

Three-dimensional (3D) tissue culture has attracted a great deal of attention as a result of the need to replace the conventional two-dimensional cell cultures with more meaningful methods, especially for understanding the sophisticated nature of native tumor microenvironments. However, most techniques for 3D tissue culture are laborious, expensive, and limited to spheroid formation. In this study, a low-cost and highly effective nanofibrous scaffold is presented for spontaneous formation of reproducible 3D breast cancer microtissues. Experimentally, aligned and non-aligned chitosan/poly(ethylene oxide) nanofibrous scaffolds were prepared at one of two chitosan concentrations (2 and 4 wt %) and various electrospinning parameters. The resulting fabricated scaffolds (C2P1 and C4P1) were structurally and morphologically characterized, as well as analyzed in silico. The obtained data suggest that the fiber diameter, surface roughness, and scaffold wettability are tunable and can be influenced based on the chitosan concentration, electrospinning conditions, and alignment mode. To test the usefulness of the fabricated scaffolds for 3D cell culture, a breast cancer cell line (MCF-7) was cultured on their surfaces and evaluated morphologically and biochemically. The obtained data showed a higher proliferation rate for cells grown on scaffolds compared to cells grown on two-dimensional adherent plates (tissue culture plate). The MTT assay revealed that the rate of cell proliferation on nanofibrous scaffolds is statistically significantly higher compared to tissue culture plate (P ≤ 0.001) after 14 days of culture. The formation of spheroids within the first few days of culture shows that the scaffolds effectively support 3D tissue culture from the outset of the experiment. Furthermore, 3D breast cancer tissues were spontaneously formed within 10 days of culture on aligned and non-aligned nanofibrous scaffolds, which suggests that the scaffolds imitate the in vivo extracellular matrix in the tumor microenvironment. Detailed mechanisms for the spontaneous formation of the 3D microtissues have been proposed. Our results suggest that scaffold surface topography significantly influences tissue formation and behavior of the cells.

Recent Advances in Multicellular Tumor Spheroid Generation for Drug Screening

Multicellular tumor spheroids (MCTs) have been employed in biomedical fields owing to their advantage in designing a three-dimensional (3D) solid tumor model. For controlling multicellular cancer spheroids, mimicking the tumor extracellular matrix (ECM) microenvironment is important to understand cell-cell and cell-matrix interactions. In drug cytotoxicity assessments, MCTs provide better mimicry of conventional solid tumors that can precisely represent anticancer drug candidates' effects. To generate incubate multicellular spheroids, researchers have developed several 3D multicellular spheroid culture technologies to establish a research background and a platform using tumor modelingvia advanced materials science, and biosensing techniques for drug-screening. In application, drug screening was performed in both invasive and non-invasive manners, according to their impact on the spheroids. Here, we review the trend of 3D spheroid culture technology and culture platforms, and their combination with various biosensing techniques for drug screening in the biomedical field.

3D Cell Culture Systems: Tumor Application, Advantages, and Disadvantages

The traditional two-dimensional (2D) in vitro cell culture system (on a flat support) has long been used in cancer research. However, this system cannot be fully translated into clinical trials to ideally represent physiological conditions. This culture cannot mimic the natural tumor microenvironment due to the lack of cellular communication (cell-cell) and interaction (cell-cell and cell-matrix). To overcome these limitations, three-dimensional (3D) culture systems are increasingly developed in research and have become essential for tumor research, tissue engineering, and basic biology research. 3D culture has received much attention in the field of biomedicine due to its ability to mimic tissue structure and function. The 3D matrix presents a highly dynamic framework where its components are deposited, degraded, or modified to delineate functions and provide a platform where cells attach to perform their specific functions, including adhesion, proliferation, communication, and apoptosis. So far, various types of models belong to this culture: either the culture based on natural or synthetic adherent matrices used to design 3D scaffolds as biomaterials to form a 3D matrix or based on non-adherent and/or matrix-free matrices to form the spheroids. In this review, we first summarize a comparison between 2D and 3D cultures. Then, we focus on the different components of the natural extracellular matrix that can be used as supports in 3D culture. Then we detail different types of natural supports such as matrigel, hydrogels, hard supports, and different synthetic strategies of 3D matrices such as lyophilization, electrospiding, stereolithography, microfluid by citing the advantages and disadvantages of each of them. Finally, we summarize the different methods of generating normal and tumor spheroids, citing their respective advantages and disadvantages in order to obtain an ideal 3D model (matrix) that retains the following characteristics: better biocompatibility, good mechanical properties corresponding to the tumor tissue, degradability, controllable microstructure and chemical components like the tumor tissue, favorable nutrient exchange and easy separation of the cells from the matrix.

Understanding the Role of Fibroblasts following a 3D Tumoroid Implantation for Breast Tumor Formation

An understanding of the participation and modulation of fibroblasts during tumor formation and growth is still unclear. Among many speculates, one might be the technical challenge to reveal the versatile function of fibroblasts in tissue complexity, and another is the dynamics in tissue physiology and cell activity. The histology of most solid tumors shows a predominant presence of fibroblasts, suggesting that tumor cells recruit fibroblasts for breast tumor growth. In this review paper, therefore, the migration, activation, differentiation, secretion, and signaling systems that are associated with fibroblasts and cancer-associated fibroblasts (CAFs) after implantation of a breast tumoroid, i.e., a lab-generated tumor tissue into an animal, are discussed.

Analysis of Actin and Focal Adhesion Organisation in U2OS Cells on Polymer Nanostructures

BACKGROUND

In this work, we explore how U2OS cells are affected by arrays of polymer nanopillars fabricated on flat glass surfaces. We focus on describing changes to the organisation of the actin cytoskeleton and in the location, number and shape of focal adhesions. From our findings we identify that the cells can be categorised into different regimes based on their spreading and adhesion behaviour on nanopillars. A quantitative analysis suggests that cells seeded on dense nanopillar arrays are suspended on top of the pillars with focal adhesions forming closer to the cell periphery compared to flat surfaces or sparse pillar arrays. This change is analogous to similar responses for cells seeded on soft substrates.

RESULTS

In this work, we explore how U2OS cells are affected by arrays of polymer nanopillars fabricated on flat glass surfaces. We focus on describing changes to the organisation of the actin cytoskeleton and in the location, number and shape of focal adhesions. From our findings we identify that the cells can be categorised into different regimes based on their spreading and adhesion behaviour on nanopillars. A quantitative analysis suggests that cells seeded on dense nanopillar arrays are suspended on top of the pillars with focal adhesions forming closer to the cell periphery compared to flat surfaces or sparse pillar arrays. This change is analogous to similar responses for cells seeded on soft substrates.

CONCLUSION

Overall, we show that the combination of high throughput nanofabrication, advanced optical microscopy, molecular biology tools to visualise cellular processes and data analysis can be used to investigate how cells interact with nanostructured surfaces and will in the future help to create culture substrates that induce particular cell function.

Electrospun polyvinyl-alcohol/gum arabic nanofibers: Biomimetic platform for in vitro cell growth and cancer nanomedicine delivery

The design of powerful in vitro cell culture platforms to support precision medicine can contribute to predict therapeutic success of cancer patients. Electrospun nanofibers applied to cell culture can mimic extracellular matrix and improve in vitro cell behavior. Here, we describe biocompatible blended polyvinyl-alcohol (PVA)/gum arabic (GA) extracellular matrix (ECM)-like nanofibers for in vitro cell cultures capable of delivering nanocomposite for desired biomedical application. Therefore, PVA/GA ECM-like electrospun nanofibers were developed and characterized. Heat treatment was used to crosslink the nanofibers and biocompatibility was evaluated, which demonstrated the ability of developed platform to provide a cell culture-friendly environment. Previous work demonstrated that GA-gold nanoparticles (GA-AuNPs) in non-cytotoxic concentrations can reduce key metastatic cellular events such as invasion and colony formation of metastatic melanoma cells. Thus, crosslinked nanofibers were functionalized with GA-AuNPs and its cellular delivery was evaluated. GA-AuNPs were efficiently adsorbed onto the PVA/GA nanofibers surface and the system effectively delivered the nanocomposites to metastatic melanoma cells. In conclusion, the described biocompatible system could be prospected as a valuable in vitro tool for precision medicine.

Enhanced radiotherapy efficacy of breast cancer multi cellular tumor spheroids through in-situ fabricated chitosan-zinc oxide bio-nanocomposites as radio-sensitizing agents

Overwhelming evidence has shown that three-dimensional multicellular tumor spheroids (MCTSs) as a mimic of in-vivo tumor can accurately exhibit cellular responses to treatments. So, we compared the capability of pure zinc oxide nanoparticles (ZnO-NPs) and chitosan-ZnO bio-nanocomposites (CS-ZnO BNCs) for enhancing the radiosensitization of MDA-MB-231 breast cancer cells (BCCs) in the 3D-MCTSs model. ZnO-NPs and CS-ZnO BNCs were synthesized by a facile co-precipitation method. FE-SEM images revealed that the uniform spherical ZnO-NPs with an average diameter of 35 nm were successfully dispersed on chitosan. MDA-MB-231 MCTSs which were formed in a non-adherent culture plate, possessed functional features of in-vivo tumor. The priority of such culture method to conventionally used 2D monolayer (or parental) cell culture is the mimicking of tumor microenvironment. The toxicity of CS-ZnO BNCs and ZnO-NPs against the MDA-M-231 BCCs was evaluated using MTT-colorimetric assay, which demonstrated superior biocompatibility of CS-ZnO BNCs compared to pure ZnO-NPs (even at high concentration of 100 μg/mL). Survival fraction analysis of cells under clinical X-ray irradiation (6 MV) showed that MCTSs had a higher radioresistance compared to parental cells. Besides, the clonogenic potential of irradiated MCTSs was significantly decreased by the addition of CS-ZnO BNCs similar to that of monolayer cells. The sensitivity enhancement ratios (SER) for MCTSs and monolayer cells were calculated 1.5 and 1.63, respectively. Further, tracking of radiobiological properties and apoptosis induction of MCTSs showed that CS-ZnO BNCs not only could lead to the creation of higher radiation-induced complex DNA break and apoptosis death in MCTSs, but also weakened DNA repair mechanisms. It was found that non-toxic concentration of CS-ZnO BNCs has promising potential to enhance radiosensitivity of resistant-MCTSs as a superior in-vitro tumor model. So, CS-ZnO BNCs can be a prominent candidate for overcoming the resistance of BCCs to radiotherapy.

Pulmonary tissue-mimetic hydrogel niches for small cell lung cancer cell culture

Although small cell lung cancer (SCLC) is characterized by early metastasis and high resistance to most anti-cancer therapeutics, resulting in poor prognosis, surgical treatment is unavailable for most patients. Instead, clinical treatment for SCLC patients relies largely on chemotherapy. Therefore, an analysis platform supporting research into the physiology of SCLC cells and novel anti-cancer drugs is strongly needed. Decellularized extracellular matrix (dECM) hydrogel is a promising candidate cell-culture system that could provide a tissue-specific environment. However, dECM-based hydrogels have limited property control, poor mechanical properties, and loss of components during decellularization. In this study, porcine decellularized lung tissue and hyaluronic acid (HA) were hybridized via photopolymerization to form a pulmonary tissue-mimetic hydrogel. dECM solution was obtained by decellularization and pepsin digestion. The dECM and HA were then modified with methacrylic moieties, which produced dECM-methacrylate (dECM-MA) and HA methacrylate (HA-MA). dECM-MA/HA-MA hydrogels were fabricated by photopolymerization using a photoinitiator under UV light irradiation. The mechanical properties of the dECM-based hydrogel were compared with those of native tissue. SCLC cells (NCI-H69) were encapsulated in multiple types of dECM-based hydrogels, and they exhibited higher cell proliferation, drug resistance, and CD44 expression in the presence of dECM-MA and HA-MA than in the control condition.

The epithelial-mesenchymal transition and the cytoskeleton in bioengineered systems

The epithelial-mesenchymal transition (EMT) is intrinsically linked to alterations of the intracellular cytoskeleton and the extracellular matrix. After EMT, cells acquire an elongated morphology with front/back polarity, which can be attributed to actin-driven protrusion formation as well as the gain of vimentin expression. Consequently, cells can deform and remodel the surrounding matrix in order to facilitate local invasion. In this review, we highlight recent bioengineering approaches to elucidate EMT and functional changes in the cytoskeleton. First, we review transitions between multicellular clusters and dispersed individuals on planar surfaces, which often exhibit coordinated behaviors driven by leader cells and EMT. Second, we consider the functional role of vimentin, which can be probed at subcellular length scales and within confined spaces. Third, we discuss the role of topographical patterning and EMT via a contact guidance like mechanism. Finally, we address how multicellular clusters disorganize and disseminate in 3D matrix. These new technologies enable controlled physical microenvironments and higher-resolution spatiotemporal measurements of EMT at the single cell level. In closing, we consider future directions for the field and outstanding questions regarding EMT and the cytoskeleton for human cancer progression. Video Abstract.

Development of a stacked, porous silk scaffold neuroblastoma model for investigating spatial differences in cell and drug responsiveness

Development of in vitro, preclinical cancer models that contain cell-driven microenvironments remains a challenge. Engineering of millimeter-scale, in vitro tumor models with spatially distinct regions that can be independently assessed to study tumor microenvironments has been limited. Here, we report the use of porous silk scaffolds to generate a high cell density neuroblastoma (NB) model that can spatially recapitulate changes resulting from cell and diffusion driven changes. Using COMSOL modeling, a scaffold holder design that facilitates stacking of thin, 200 μm silk scaffolds into a thick, bulk millimeter-scale tumor model (2, 4, 6, and 8 stacked scaffolds) and supports cell-driven oxygen gradients was developed. Cell-driven oxygen gradients were confirmed through pimonidazole staining. Post-culture, the stacked scaffolds were separated for analysis on a layer-by-layer basis. The analysis of each scaffold layer demonstrated decreasing DNA and increasing expression of hypoxia related genes (VEGF, CAIX, and GLUT1) from the exterior scaffolds to the interior scaffolds. Furthermore, the expression of hypoxia related genes at the interior of the stacks was comparable to that of a single scaffold cultured under 1% O₂ and at the exterior of the stacks was comparable to that of a single scaffold cultured under 21% O₂. The four-stack scaffold model underwent further evaluation to determine if a hypoxia activated drug, tirapazamine, induced reduced cell viability within the internal stacks (region of reduced oxygen) as compared with the external stacks. Decreased DNA content was observed in the internal stacks as compared to the external stacks when treated with tirapazamine, which suggests the internal scaffold stacks had higher levels of hypoxia than the external scaffolds. This stacked silk scaffold system presents a method for creating a single culture model capable of generating controllable cell-driven microenvironments through different stacks that can be individually assessed and used for drug screening.

Mechanobiological evaluation of prostate cancer metastasis to bone using an in vitro prostate cancer testbed

Prostate cancer exhibits a propensity to metastasize to the bone, which often leads to fatality. Bone metastasis is characterized by complex biochemical, morphological, pathophysiological, and genetic changes to cancer cells as they colonize at bone sites. In this study, we report the evaluation of MDA PCa2b prostate cancer cells' nanomechanical properties during the mesenchymal-to-epithelial transition (MET) and during disease progression at the metastatic site. Bone-mimetic tissue-engineered 3D nanoclay scaffolds have been used to create in vitro metastatic site for prostate cancer. A significant softening of the prostate cancer cells during MET and further softening as disease progression occurs at metastasis is also reported. The significant reduction in elastic modulus of prostate cancer cells during MET was attributed to actin reorganization and depolymerization. This study provides input towards direct nanomechanical measurements to evaluate the time evolution of cells' mechanical behavior in tumors at bone metastasis site.

Batch Effect Adjustment to Lower the Drug Attrition Rate of MCF-7 Breast Cancer Cells Exposed to Silica Nanomaterial-Derived Scaffolds

Drug attrition rate is the calculation or measure of the clinical efficacy of a candidate drug on a screen platform for a specific period. Determining the attrition rate of a prospective cancer drug is a reliable way of testing the clinical efficacy. A low attrition rate in the last phase of a preclinical trial increases the success of a drug discovery process. It has been reported that the attrition rates of antineoplastic drugs are much higher than for other therapeutic drugs. Among the factors identified for the high attrition rates in antineoplastic drugs are the nature of the screen-based platforms involving human-derived xenografts, extracellular matrix-derived scaffold systems, and the synthetic scaffolds, which all have propensity to proliferate tumor cells at faster rates than in vivo primary tumors. Other factors that affect the high attrition rates are induced scaffold toxicity and the use of assays that are irrelevant, yet affect data processing. These factors contribute to the wide variation in data and systematic errors. As a result, it becomes imperative to filter batch variations and to standardize the data. Importantly, understanding the interplay between the biological milieu and scaffold connections is also crucial. Here the cell viability of MCF-7 (breast cancer cell line) cells exposed to different scaffolds were screened before cisplatin dosing using the calculated p-values. The statistical significance (p-value) of data was calculated using the one-way analysis of variance, with the p-value set as: 0 < p < 0.06. In addition, the half-maximal inhibitory concentration (IC₅₀) of the different scaffolds exposed to MCF-7 cells were calculated with the probit extension model and cumulative distribution (%) of the extension data. The chemotherapeutic dose (cisplatin, 56 mg/m²) reduced the cell viability of MCF-7 cells to 5% within 24 h on the scaffold developed from silica nanoparticles (SNPs) and polyethylene glycol (PEG) formulation (SNP:PEG) mixtures with a ratio of 1:10, respectively.

Repurposing nano-enabled polymeric scaffolds for tumor-wound management and 3D tumor engineering

The main challenges of cancer drugs are toxicity, effect on wound healing/patient outcome and in vivo instability. Polymeric scaffolds have been used separately for tissue regeneration in wound healing and as anticancer drug releasing devices. Bringing these two together in bifunctional scaffolds can provide a tool for postoperative local tumor management by promoting healthy tissue regrowth and to deliver anticancer drugs. Another addition to the versatility of polymeric scaffold is its recently discovered ability to act as 3D cell culture models for in vitro isolation and amplification of cancer cells for personalized drug screening and to recapitulate the tumor microenvironment. This review focuses on the repurposing of 3D polymeric scaffolds for local tumor-wound management and development of in vitro cell culture models.

One-Step Dip-Coating-Fabricated Core-Shell Silk Fibroin Rice Paper Fibrous Scaffolds for 3D Tumor Spheroid Formation

Bioscaffolds are important substrates for supporting three-dimensional (3D) cell cultures. Silk fibroin (SF) is an attractive biomaterial in tissue engineering because of its good biocompatibility and mechanical properties. Electrospinning is one of the most often used approaches to fabricate SF fibrous scaffolds; yet, this technique still faces many challenges, such as low yield, residual organic solvents, limited extensibility of fibers, and a lack of spatial control over pore size. To circumvent these limitations, a core-shell SF on rice paper (SF@RP) fibrous scaffold was fabricated using a mild one-step dip-coating method. The cellulose fiber matrix of RP is the physical basis of the 3D scaffold, whereas the SF coating on the cellulose fiber controls the adhesion/spreading of the cells. The results indicated that by tuning the secondary structure of SF on the surface of a SF@RP scaffold, the cell behavior on SF@RP could be tuned. Tumor spheroids can be formed on SF@RP scaffolds with a dominant random secondary structure, in contrast to cells adhering and spreading on SF@RP scaffolds with a higher ratio of β-sheet secondary structures. Direct culturing of breast cancer MDA-MB-231 and MCF-7, lung cancer A549, prostate cancer DU145, and liver cancer HepG2 cells could spontaneously lead to corresponding tumor spheroids on SF@RP. In addition, the physiological characteristics of HepG2 tumor spheroids were investigated, and the results showed that compared with HepG2 monolayer cells, CYP3A4, CYP1A1, and albumin gene expression levels in HepG2 cell spheres formed on SF@RP scaffolds were significantly higher. Moreover, these spheroids showed higher drug resistance. In summary, these SF@RP scaffolds prepared by the dip-coating method are biocompatible substrates for cell culture, especially for tumor cell spheroid formation.

Three-Dimensional Culture System of Cancer Cells Combined with Biomaterials for Drug Screening

Simple Summary

For the research and development of drug discovery, it is of prime importance to construct the three-dimensional (3D) tissue models in vitro. To this end, the enhancement design of cell function and activity by making use of biomaterials is essential. In this review, 3D culture systems of cancer cells combined with several biomaterials for anticancer drug screening are introduced.

Abstract

Anticancer drug screening is one of the most important research and development processes to develop new drugs for cancer treatment. However, there is a problem resulting in gaps between the in vitro drug screening and preclinical or clinical study. This is mainly because the condition of cancer cell culture is quite different from that in vivo. As a trial to mimic the in vivo cancer environment, there has been some research on a three-dimensional (3D) culture system by making use of biomaterials. The 3D culture technologies enable us to give cancer cells an in vitro environment close to the in vivo condition. Cancer cells modified to replicate the in vivo cancer environment will promote the biological research or drug discovery of cancers. This review introduces the in vitro research of 3D cell culture systems with biomaterials in addition to a brief summary of the cancer environment.

Organoids in Translational Oncology

Translational medicine aims to translate the most promising preclinical research into clinical practice. Oncology is a continuously growing medical field: the scientific research on cancer biology is currently based on in vitro experiments, carried out on tissue culture plates (TCPs) and other 2D samples. In this context, 3D printing has greatly improved the biofabrication of new biological matrices that mimic the extracellular environments, which may characterize healthy from cancerous tissues. Organoids have recently been described in several reports on scientific literature. The term that better describes such organoids-based tumoral tissues is "tumoroids". Tumoroids are substantially "tumor-like organoids", typically deriving from primary tumors harvested from patients. This topical review aims to give an update on organoids applied in translational medicine, paying specific attention to their use in the investigation of the main molecular mechanisms of cancer onset and growth, and on the most impacting strategies for effective targeted therapies.

Electrospun nanofibers in cancer research: from engineering of in vitro 3D cancer models to therapy

Electrospinning is historically related to tissue engineering due to its ability to produce nano-/microscale fibrous materials with mechanical and functional properties that are extremely similar to those of the extracellular matrix of living tissues. The general interest in electrospun fibrous matrices has recently expanded to cancer research both as scaffolds for in vitro cancer modelling and as patches for in vivo therapeutic delivery. In this review, we examine electrospinning by providing a brief description of the process and overview of most materials used in this process, discussing the effect of changing the process parameters on fiber conformations and assemblies. Then, we describe two different applications of electrospinning in service of cancer research: firstly, as three-dimensional (3D) fibrous materials for generating in vitro pre-clinical cancer models; and secondly, as patches encapsulating anticancer agents for in vivo delivery.

Antibacterial activity of iron oxide, iron nitride, and tobramycin conjugated nanoparticles against Pseudomonas aeruginosa biofilms

BACKGROUND

Novel methods are necessary to reduce morbidity and mortality of patients suffering from infections with Pseudomonas aeruginosa. Being the most common infectious species of the Pseudomonas genus, P. aeruginosa is the primary Gram-negative etiology responsible for nosocomial infections. Due to the ubiquity and high adaptability of this species, an effective universal treatment method for P. aeruginosa infection still eludes investigators, despite the extensive research in this area.

RESULTS

We report bacterial inhibition by iron-oxide (nominally magnetite) nanoparticles (NPs) alone, having a mean hydrodynamic diameter of ~ 16 nm, as well as alginate-capped iron-oxide NPs. Alginate capping increased the average hydrodynamic diameter to ~ 230 nm. We also investigated alginate-capped iron-oxide NP-drug conjugates, with a practically unchanged hydrodynamic diameter of ~ 232 nm. Susceptibility and minimum inhibitory concentration (MIC) of the NPs, NP-tobramycin conjugates, and tobramycin alone were determined in the PAO1 bacterial colonies. Investigations into susceptibility using the disk diffusion method were done after 3 days of biofilm growth and after 60 days of growth. MIC of all compounds of interest was determined after 60-days of growth, to ensure thorough establishment of biofilm colonies.

CONCLUSIONS

Positive inhibition is reported for uncapped and alginate-capped iron-oxide NPs, and the corresponding MICs are presented. We report zero susceptibility to iron-oxide NPs capped with polyethylene glycol, suggesting that the capping agent plays a major role in enabling bactericidal ability in of the nanocomposite. Our findings suggest that the alginate-coated nanocomposites investigated in this study have the potential to overcome the bacterial biofilm barrier. Magnetic field application increases the action, likely via enhanced diffusion of the iron-oxide NPs and NP-drug conjugates through mucin and alginate barriers, which are characteristic of cystic-fibrosis respiratory infections. We demonstrate that iron-oxide NPs coated with alginate, as well as alginate-coated magnetite-tobramycin conjugates inhibit P. aeruginosa growth and biofilm formation in established colonies. We have also determined that susceptibility to tobramycin decreases for longer culture times. However, susceptibility to the iron-oxide NP compounds did not demonstrate any comparable decrease with increasing culture time. These findings imply that iron-oxide NPs are promising lower-cost alternatives to silver NPs in antibacterial coatings, solutions, and drugs, as well as other applications in which microbial abolition or infestation prevention is sought.

Lung cancer cells survive epidermal growth factor receptor tyrosine kinase inhibitor exposure through upregulation of cholesterol synthesis

Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) provide clinical benefits over chemotherapy for lung cancer patients with EGFR activating mutations. Despite initial clinical responses, long-term efficacy is not possible because of acquired resistance to these therapies. We have developed EGFR TKI drug-tolerant (DT) human lung cancer cell lines as a model for de novo resistance. Mass spectroscopic analysis revealed that the cytochrome P450 protein, CYP51A1 (Lanosterol 14α-demethylase), which is directly involved with cholesterol synthesis, was significantly upregulated in the DT cells. Total cellular cholesterol, and more specifically, mitochondrial cholesterol, were found to be upregulated in DT cells. We then used the CYP51A1 inhibitor, ketoconazole, to downregulate cholesterol synthesis. In both parental and DT cells, ketoconazole and EGFR TKIs acted synergistically to induce apoptosis and overcome the development of EGFR tolerance. Lastly, this combination therapy was shown to shrink the growth of tumors in an in vivo mouse model of EGFR TKI resistance. Thus, our study demonstrates for the first time that ketoconazole treatment inhibits upregulation of mitochondrial cholesterol and thereby overcomes EGFR-TKI resistance in lung cancer cells.

Advances in Translational Nanotechnology: Challenges and Opportunities

The burgeoning field of nanotechnology aims to create and deploy nanoscale structures, devices, and systems with novel, size-dependent properties and functions. The nanotechnology revolution has sparked radically new technologies and strategies across all scientific disciplines, with nanotechnology now applied to virtually every area of research and development in the US and globally. NanoFlorida was founded to create a forum for scientific exchange, promote networking among nanoscientists, encourage collaborative research efforts across institutions, forge strong industry-academia partnerships in nanoscience, and showcase the contributions of students and trainees in nanotechnology fields. The 2019 NanoFlorida International Conference expanded this vision to emphasize national and international participation, with a focus on advances made in translating nanotechnology. This review highlights notable research in the areas of engineering especially in optics, photonics and plasmonics and electronics; biomedical devices, nano-biotechnology, nanotherapeutics including both experimental nanotherapies and nanovaccines; nano-diagnostics and -theranostics; nano-enabled drug discovery platforms; tissue engineering, bioprinting, and environmental nanotechnology, as well as challenges and directions for future research.

Actinomycin D and Telmisartan Combination Targets Lung Cancer Stem Cells Through the Wnt/Beta Catenin Pathway

The failure of lung cancer treatments has been attributed mostly to the development of drug resistance, however the underlying cellular and molecular mechanisms are poorly understood. Cancer initiating stem cells (CSCs), present in tumors in a small percentage, play critical roles in the development of drug resistance, metastasis, and cancer relapse. Hence, novel treatments targeting both bulk cancer cells and CSCs are under intense investigation. Herein, we report that lung cancer cells grown on a 3D fibrous scaffold form tumoroids that resemble in vivo tumors, expand CSCs, and provide a platform to identify anti-CSC drugs. The screening of an NCI library of FDA-approved drugs using tumoroid cultures led to identification of Actinomycin D (AD) as a top CSC inhibitor. Since CSCs are mostly resident in the tumor's inner core, AD was combined with an angiotensin receptor antagonist, Telmisartan (TS), which is known to increase drug permeability in tumors and was shown to have anti-CSC activity. Our results showed that AD + TS administered intra-tumorally was significantly more effective than either drug alone in both syngeneic and xenograft mouse models. The results of mechanistic studies revealed that CSC expansion in tumoroids was associated with activation of β catenin signaling and that AD + TS treatment reduced active β catenin levels in tumors. Together, these results establish the utility of the tumoroid culture system to expand CSCs ex vivo for targeted drug screening, to identify promising novel treatments with both anti-CSC and anti-cancer effects, and to individualize treatments for metastatic drug resistant lung cancer patients.

Epinephrine Infiltration of Adipose Tissue Impacts MCF7 Breast Cancer Cells and Total Lipid Content

BACKGROUND

Considering the positive or negative potential effects of adipocytes, depending on their lipid composition, on breast tumor progression, it is important to evaluate whether adipose tissue (AT) harvesting procedures, including epinephrine infiltration, may influence breast cancer progression.

METHODS

Culture medium conditioned with epinephrine-infiltrated adipose tissue was tested on human Michigan Cancer Foundation-7 (MCF7) breast cancer cells, cultured in monolayer or in oncospheres. Lipid composition was evaluated depending on epinephrine-infiltration for five patients. Epinephrine-infiltrated adipose tissue (EI-AT) or corresponding conditioned medium (EI-CM) were injected into orthotopic breast carcinoma induced in athymic mouse.

RESULTS

EI-CM significantly increased the proliferation rate of MCF7 cells Moreover EI-CM induced an output of the quiescent state of MCF7 cells, but it could be either an activator or inhibitor of the epithelial mesenchymal transition as indicated by gene expression changes. EI-CM presented a significantly higher lipid total weight compared with the conditioned medium obtained from non-infiltrated-AT of paired-patients. In vivo, neither the EI-CM or EI-AT injection significantly promoted MCF7-induced tumor growth.

CONCLUSIONS

Even though conditioned media are widely used to mimic the secretome of cells or tissues, they may produce different effects on tumor progression, which may explain some of the discrepancy observed between in vitro, preclinical and clinical data using AT samples.

Mithramycin A Inhibits Colorectal Cancer Growth by Targeting Cancer Stem Cells

The pivotal role of cancer initiating stem cells (CSCs) in tumor initiation, growth, metastasis and drug resistance has led to the postulation of a 'total cancer therapy' paradigm, which involves targeting both cancer cells and CSCs for effective therapy. However, the progress in identifying drugs for total cancer therapy has been limited. Herein, we show for the first time that mithramycin A (Mit-A) can successfully inhibit CSC proliferation, in addition to inhibiting bulk cancer cells in a model of colorectal cancer (CRC), the second leading cause of death among men and women in the United States. To this end, a polymeric nanofiber scaffold culture system was established to develop 3D tumor organoids (tumoroids) from CRC cell lines such as HT29, HCT116, KM12, CT26 and MC38 as well as ex vivo mouse tumors. These tumoroids possessed increased expression of CSC markers and transcription factors, expanded the number of CSCs in culture and increased CSC functional properties measured by aldehyde dehydrogenase activity. Screening of an NCI library of FDA approved drugs led to the identification of Mit-A as a potential total cancer therapy drug. In both sphere and tumoroid culture, Mit-A inhibits cancer growth by reducing the expression of cancer stemness markers. In addition, Mit-A inhibits the expression of SP1, a previously known target in CRCs. Moreover, Mit-A significantly reduces growth of tumoroids in ex vivo cultures and CRC tumor growth in vivo. Finally, a dose-dependent treatment on CRC cells indicate that Mit-A significantly induces the cell death and PARP-cleavage of both CSC and non-CSC cells. Taken together the results of these in vitro, ex vivo and in vivo studies lead to the inference that Mit-A is a promising drug candidate for total cancer therapy of CRCs.

Epithelial-mesenchymal transition of cancer cells using bioengineered hybrid scaffold composed of hydrogel/3D-fibrous framework

Cancer cells undergoing epithelial-mesenchymal transition (EMT) acquire stem cell-like phenotype associated with malignant behaviour, chemoresistance, and relapse. Current two-dimensional (2D) in-vitro culture models of tumorigenesis are inadequate to replicate the complexity of in-vivo microenvironment. Therefore, the generation of functional three-dimensional (3D) constructs is a fundamental prerequisite to form multi-cellular tumour spheroids for studying basic pathological mechanisms. In this study, we focused on two major points (i) designing and fabrication of 3D hybrid scaffolds comprising electrospun fibers with cancer cells embedded within hydrogels, and (ii) determining the potential roles of 3D hybrid scaffolds associated with EMT in cancer progression and metastasis. Our findings revealed that 3D hybrid scaffold enhances cell proliferation and induces cancer cells to undergo EMT, as demonstrated by significant up-regulation of EMT associated transcriptional factors including Snail1, Zeb1, and Twist2; and mesenchymal markers whereas epithelial marker, E-Cadherin was downregulated. Remarkably, this induction is independent of cancer cell-type as similar results were obtained for breast cancer cells, MDA-MB-231 and gastric cancer cells, MKN74. Moreover, the hybrid scaffolds enrich aggressive cancer cells with stem cell properties. We showed that our 3D scaffolds could trigger EMT of cancer cells which could provide a useful model for studying anticancer therapeutics against metastasis.

Ex vivo Dynamics of Human Glioblastoma Cells in a Microvasculature-on-a-Chip System Correlates with Tumor Heterogeneity and Subtypes

The perivascular niche (PVN) plays an essential role in brain tumor stem-like cell (BTSC) fate control, tumor invasion, and therapeutic resistance. Here, a microvasculature-on-a-chip system as a PVN model is used to evaluate the ex vivo dynamics of BTSCs from ten glioblastoma patients. BTSCs are found to preferentially localize in the perivascular zone, where they exhibit either the lowest motility, as in quiescent cells, or the highest motility, as in the invasive phenotype, with migration over long distance. These results indicate that PVN is a niche for BTSCs, while the microvascular tracks may serve as a path for tumor cell migration. The degree of colocalization between tumor cells and microvessels varies significantly across patients. To validate these results, single-cell transcriptome sequencing (10 patients and 21 750 single cells in total) is performed to identify tumor cell subtypes. The colocalization coefficient is found to positively correlate with proneural (stem-like) or mesenchymal (invasive) but not classical (proliferative) tumor cells. Furthermore, a gene signature profile including PDGFRA correlates strongly with the "homing" of tumor cells to the PVN. These findings demonstrate that the model can recapitulate in vivo tumor cell dynamics and heterogeneity, representing a new route to study patient-specific tumor cell functions.

Ex vivo Dynamics of Human Glioblastoma Cells in a Microvasculature-on-a-Chip System Correlates with Tumor Heterogeneity and Subtypes

The perivascular niche (PVN) plays an essential role in brain tumor stem-like cell (BTSC) fate control, tumor invasion, and therapeutic resistance. Here, a microvasculature-on-a-chip system as a PVN model is used to evaluate the ex vivo dynamics of BTSCs from ten glioblastoma patients. BTSCs are found to preferentially localize in the perivascular zone, where they exhibit either the lowest motility, as in quiescent cells, or the highest motility, as in the invasive phenotype, with migration over long distance. These results indicate that PVN is a niche for BTSCs, while the microvascular tracks may serve as a path for tumor cell migration. The degree of colocalization between tumor cells and microvessels varies significantly across patients. To validate these results, single-cell transcriptome sequencing (10 patients and 21 750 single cells in total) is performed to identify tumor cell subtypes. The colocalization coefficient is found to positively correlate with proneural (stem-like) or mesenchymal (invasive) but not classical (proliferative) tumor cells. Furthermore, a gene signature profile including PDGFRA correlates strongly with the "homing" of tumor cells to the PVN. These findings demonstrate that the model can recapitulate in vivo tumor cell dynamics and heterogeneity, representing a new route to study patient-specific tumor cell functions.

PLLA scaffolds with controlled architecture as potential microenvironment for in vitro tumor model

The "microenvironment" where a tumor develops plays a fundamental role in determining its progression, the onset of metastasis and, eventually, its resistance to therapies. Tumor cells can be considered more or less invasive depending both on the nature of the cells and on the site where they are located. Commonly adopted laboratory culture protocols for the investigation of tumor cells take usually place on standard two-dimensional supports. However, such cultures do not allow for reproduction of the biophysical properties of the tumor's microenvironment, thus causing the cells to lose most of their relevant characteristics. In this work MDA-MB 231 breast cancer cells were cultivated within Poly-l-Lactic Acid (PLLA) scaffolds produced via Thermally Induced Phase Separation (TIPS). Starting from a ternary solution (polymer-solvent-nonsolvent) we produced scaffolds with different morphologies, porosities and pore architectures. The influence of porosity and average pore size upon cell adhesion and growth were investigated by using Cell Counting Kit-8 (CCK-8) as cell viability test, a fluorescence assay staining cell with DAPI and Scanning Electron Microscopy (SEM). Our study demonstrates that the average pore size of the polymeric scaffolds influences both the cell adhesion and resulting morphology of the growing breast cancer cells. In particular, the reported data corroborate the evidence that an average pore size ranging from 40 to 50 μm induces tumor cell aggregation and the formation of the irregular tumor masses typically observed in-vivo. In addition, TIPS proved to be a suitable manufacturing technique for finely tuning the scaffolds' architecture, relevant to developing the most effective microenvironment for an in-vitro tumor cells growth closely mimicking in-vivo conditions.