Development of a Hybrid Nanoink for 3D Bioprinting of Heterogeneous Tumor Models

The progress and challenges in modeling colorectal cancer and the impact on novel drug discovery

INTRODUCTION

Colorectal cancer (CRC) remains one of the leading causes of cancer-related morbidity and mortality worldwide. This disease is complex and heterogeneous, influenced by a variety of genetic, epigenetic, and environmental factors that drive CRC initiation and progression. Despite advances in therapeutic strategies, the five-year survival rate for metastatic CRC is alarmingly low. Traditional two-dimensional (2D) cell culture systems have been the foundation of cancer research, but their inability to replicate the complex tumor microenvironment (TME) limits their effectiveness.

AREAS COVERED

This paper explores the evolution of CRC models, starting with the limitations of traditional 2D cell culture systems and the significant advancements offered by 3D models. Additionally, it highlights 3D bioprinting and on-chip CRC models, which have enhanced the ability to mimic in vivo conditions.

EXPERT OPINION

The transition to advanced 3D models represents a pivotal shift in CRC research, offering considerable improvements over the established 2D models. These models hold promise for the development of patient-specific models that better mimic in vivo conditions. However, the inherent complexity of CRC continues to pose challenges in developing models that can fully capture the disease's multifaceted nature. This complexity and high costs associated with these technologies, along with the need for standardized protocols, pose significant challenges to their widespread adoption.

Cellulose-based 3D printing bio-inks for biomedical applications: A review

Cellulose is the most ubiquitous polymer found in nature. In recent years, cellulose derivatives of various kinds, such as cellulose esters and ethers, and nanocelluloses, have become popular bioprintable materials used for making bio-inks because of their affordability, biocompatibility, biodegradability, and printability. Nevertheless, the potential uses of nanocellulose and cellulose derivative-based bio-inks have not been thoroughly explored. This review emphasizes advancements in the design of cellulose-based bio-inks for 3D bioprinting of diverse tissues as well as the physicochemical attributes of cellulose derivatives and nanocellulose that make them a viable choice for bio-inks in 3D bioprinting. Additionally, cellulose bio-inks' current benefits and drawbacks in 3D printing are thoroughly examined. Various cross-linking approaches are offered for multicomponent cellulose and nanocellulose-based bio-inks to control the fidelity of the ink and alter the mechanical stiffness in the printed hydrogel construct as a bioactive cue. By emphasizing the interactions involving cells and the matrix, it additionally examines the effect of functional groups and surface charge on nanocellulose on vital cellular functions (including cell survival, adhesion, and proliferation). Thus, this review aims to offer an integrated platform for 3D bioprinting with cellulose-based materials for the biomedical industry.

Recapitulating the Cancer-Immunity Cycle on a Chip

The cancer-immunity cycle is a fundamental framework for understanding how the immune system interacts with cancer cells, balancing T cell recognition and elimination of tumors while avoiding autoimmune reactions. Despite advancements in immunotherapy, there remains a critical need to dissect each phase of the cycle, particularly the interactions among the tumor, vasculature, and immune system within the tumor microenvironment (TME). Innovative platforms such as organ-on-a-chip, organoids, and bioprinting within microphysiological systems (MPS) are increasingly utilized to enhance the understanding of these interactions. These systems meticulously replicate crucial aspects of the TME and immune responses, providing robust platforms to study cancer progression, immune evasion, and therapeutic interventions with greater physiological relevance. This review explores the latest advancements in MPS technologies for modeling various stages of the cancer-immune cycle, critically evaluating their applications and limitations in advancing the understanding of cancer-immune dynamics and guiding the development of next-generation immunotherapeutic strategies.

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

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

Biomimetic Microenvironmental Stiffness Boosts Stemness of Pancreatic Ductal Adenocarcinoma via Augmented Autophagy

Pancreatic ductal adenocarcinoma (PDAC) features high recurrence rates and intensified lethality, accompanied by stiffening of the extracellular matrix (ECM) microenvironment, which is mainly due to the deposition, remodeling, and cross-linking of collagen. Boosted stemness plays an essential role during occurrence and progression, which indicates a poor prognosis. Therefore, it is of great importance to understand the effect of the underlying interaction of matrix stiffness and stemness on PDAC. For this purpose, a methacrylated gelatin (GelMA) hydrogel with tunable stiffness was applied for incubating MIA PaCa-2 and PANC-1 cells. The results demonstrated that compared to the soft group (5% GelMA, w/v), the expression of stemness-related genes (SOX2, OCT4, and NANOG) in the stiff group (10% GelMA, w/v) displayed pronounced elevation as well as sphere formation. Intriguingly, we also observed that matrix stiffness regulated autophagy of PDAC, which played a momentous role in stemness promotion. In order to clarify the underlying relationship between matrix stiffness-mediated cell autophagy and stemness, rescue experiments with rapamycin and chloroquine were conducted with transmission electron microscopy, immunofluorescence staining, sphere formation, and qRT-PCR assays to evaluate the level of stemness and autophagy. For exploring the molecular mechanism in depth, RNA-seq and differential expression of miRNAs were carried out, which may sensor and respond to matrix stiffness during the regulation of stemness and autophagy. In conclusion, we validated that blocking autophagy repressed the stemness induced by matrix stiffness in PDAC and provided a potential therapeutic strategy for this aggressive cancer.

3D Bioprinting as a Powerful Technique for Recreating the Tumor Microenvironment

In vitro three-dimensional models aim to reduce and replace animal testing and establish new tools for oncology research and the development and testing of new anticancer therapies. Among the various techniques to produce more complex and realistic cancer models is bioprinting, which allows the realization of spatially controlled hydrogel-based scaffolds, easily incorporating different types of cells in order to recreate the crosstalk between cancer and stromal components. Bioprinting exhibits other advantages, such as the production of large constructs, the repeatability and high resolution of the process, as well as the possibility of vascularization of the models through different approaches. Moreover, bioprinting allows the incorporation of multiple biomaterials and the creation of gradient structures to mimic the heterogeneity of the tumor microenvironment. The aim of this review is to report the main strategies and biomaterials used in cancer bioprinting. Moreover, the review discusses several bioprinted models of the most diffused and/or malignant tumors, highlighting the importance of this technique in establishing reliable biomimetic tissues aimed at improving disease biology understanding and high-throughput drug screening.

3D bioprinting tumor models mimic the tumor microenvironment for drug screening

Cancer is a severe threat to human life and health and represents the main cause of death globally. Drug therapy is one of the primary means of treating cancer; however, most anticancer medications do not proceed beyond preclinical testing because the conditions of actual human tumors are not effectively mimicked by traditional tumor models. Hence, bionic in vitro tumor models must be developed to screen for anticancer drugs. Three-dimensional (3D) bioprinting technology can produce structures with built-in spatial and chemical complexity and models with accurately controlled structures, a homogeneous size and morphology, less variation across batches, and a more realistic tumor microenvironment (TME). This technology can also rapidly produce such models for high-throughput anticancer medication testing. This review describes 3D bioprinting methods, the use of bioinks in tumor models, and in vitro tumor model design strategies for building complex tumor microenvironment features using biological 3D printing technology. Moreover, the application of 3D bioprinting in vitro tumor models in drug screening is also discussed.

3D bioprinted colorectal cancer models based on hyaluronic acid and signalling glycans

In cancer microenvironment, aberrant glycosylation events of ECM proteins and cell surface receptors occur. We developed a protocol to generate 3D bioprinted models of colorectal cancer (CRC) crosslinking hyaluronic acid and gelatin functionalized with three signalling glycans characterized in CRC, 3'-Sialylgalactose, 6'-Sialylgalactose and 2'-Fucosylgalactose. The crosslinking, performed exploiting azide functionalized gelatin and hyaluronic acid and 4arm-PEG-dibenzocyclooctyne, resulted in biocompatible hydrogels that were 3D bioprinted with commercial CRC cells HT-29 and patient derived CRC tumoroids. The glycosylated hydrogels showed good 3D printability, biocompatibility and stability over the time. SEM and synchrotron radiation SAXS/WAXS analysis revealed the influence of glycosylation in the construct morphology, whereas MALDI-MS imaging showed that protein profiles of tumoroid cells vary with glycosylation, indicating that sialylation and fucosylation of ECM proteins induce diverse alterations to the proteome of the tumoroid and surrounding cells.

Deployable extrusion bioprinting of compartmental tumoroids with cancer associated fibroblasts for immune cell interactions

Realizing the translational impacts of three-dimensional (3D) bioprinting for cancer research necessitates innovation in bioprinting workflows which integrate affordability, user-friendliness, and biological relevance. Herein, we demonstrate 'BioArm', a simple, yet highly effective extrusion bioprinting platform, which can be folded into a carry-on pack, and rapidly deployed between bio-facilities. BioArm enabled the reconstruction of compartmental tumoroids with cancer-associated fibroblasts (CAFs), forming the shell of each tumoroid. The 3D printed core-shell tumoroids showedde novosynthesized extracellular matrices, and enhanced cellular proliferation compared to the tumour alone 3D printed spheroid culture. Further, thein vivophenotypes of CAFs normally lost after conventional 2D co-culture re-emerged in the bioprinted model. Embedding the 3D printed tumoroids in an immune cell-laden collagen matrix permitted tracking of the interaction between immune cells and tumoroids, and subsequent simulated immunotherapy treatments. Our deployable extrusion bioprinting workflow could significantly widen the accessibility of 3D bioprinting for replicating multi-compartmental architectures of tumour microenvironment, and for developing strategies in cancer drug testing in the future.

A rapid high throughput bioprinted colorectal cancer spheroid platform forin vitrodrug- and radiation-response

We describe the development of a high-throughput bioprinted colorectal cancer (CRC) spheroid platform with high levels of automation, information content, and low cell number requirement. This is achieved via the formulation of a hydrogel bioink with a compressive Young's modulus that is commensurate with that of colonic tissue (1-3 kPa), which supports exponential growth of spheroids from a wide range of CRC cell lines. The resulting spheroids display tight cell-cell junctions, bioink matrix-cell interactions and necrotic hypoxic cores. By combining high content light microscopy imaging and processing with rapid multiwell plate bioprinting, dose-response profiles are generated from CRC spheroids challenged with oxaliplatin (OX) and fluorouracil (5FU), as well as radiotherapy. Bioprinted CRC spheroids are shown to exhibit high levels of chemoresistance relative to cell monolayers, and OX was found to be significantly less effective against tumour spheroids than in monolayer culture, when compared to 5FU.

Progress in Gelatin as Biomaterial for Tissue Engineering

Tissue engineering has become a medical alternative in this society with an ever-increasing lifespan. Advances in the areas of technology and biomaterials have facilitated the use of engineered constructs for medical issues. This review discusses on-going concerns and the latest developments in a widely employed biomaterial in the field of tissue engineering: gelatin. Emerging techniques including 3D bioprinting and gelatin functionalization have demonstrated better mimicking of native tissue by reinforcing gelatin-based systems, among others. This breakthrough facilitates, on the one hand, the manufacturing process when it comes to practicality and cost-effectiveness, which plays a key role in the transition towards clinical application. On the other hand, it can be concluded that gelatin could be considered as one of the promising biomaterials in future trends, in which the focus might be on the detection and diagnosis of diseases rather than treatment.

Applications of Polymers for Organ-on-Chip Technology in Urology

Organ-on-chips (OOCs) are microfluidic devices used for creating physiological organ biomimetic systems. OOC technology brings numerous advantages in the current landscape of preclinical models, capable of recapitulating the multicellular assemblage, tissue-tissue interaction, and replicating numerous human pathologies. Moreover, in cancer research, OOCs emulate the 3D hierarchical complexity of in vivo tumors and mimic the tumor microenvironment, being a practical cost-efficient solution for tumor-growth investigation and anticancer drug screening. OOCs are compact and easy-to-use microphysiological functional units that recapitulate the native function and the mechanical strain that the cells experience in the human bodies, allowing the development of a wide range of applications such as disease modeling or even the development of diagnostic devices. In this context, the current work aims to review the scientific literature in the field of microfluidic devices designed for urology applications in terms of OOC fabrication (principles of manufacture and materials used), development of kidney-on-chip models for drug-toxicity screening and kidney tumors modeling, bladder-on-chip models for urinary tract infections and bladder cancer modeling and prostate-on-chip models for prostate cancer modeling.