Bioengineering a 3D microencapsulated model of breast cancer to reflect tumour microenvironment complexity and disease progression

癌症临床试验中的药物测试成功率极低，因此迫切需要更准确的临床前疾病模型，以将从基础癌症研究中获得的知识转化为患者利益。在2D表面上培养的癌细胞系无法重现有助于肿瘤发生的复杂3D肿瘤微环境，而动物模型无法完全复制人类肿瘤生理学。因此，需要设计新的3D临床前癌症模型，以弥合体外和体内癌症研究之间的差距。细胞的微囊化，其中单个细胞类型或多种细胞类型被截留在半渗透性或固体材料内以形成微胶囊或微球，可以用作3D癌症模型，并且适合于临床前药物测试中的应用。该项目旨在利用微囊化对乳腺肿瘤微环境进行生物工程改造，以研究乳腺癌细胞和间充质干细胞（MSC）之间的关系，其作用在文献中尚未完全阐明。将采用膜乳化来产生生物相容性水凝胶的单分散和可再现的微胶囊，其将用于包封两种细胞类型。膜乳化提供了优于其他可能技术的优点，因为它是可扩展的，并且可以严格控制颗粒均匀性，这将允许研究微胶囊尺寸对体内模型形成的影响。在基于微胶囊化的癌症模型中，微胶囊硬度和粘弹性的重要性也尚未确定，因此将调节水凝胶硬度以代表疾病进展的不同阶段，并确定对细胞行为和迁移的影响。重要的是，学习如何用这些特定参数配制“理想”微胶囊，这些参数（例如尺寸、材料刚度）将适用于其他体内模型的开发和基于水凝胶的微粒的其他用途。膜乳化将用于生物工程的体内-如乳腺肿瘤微环境允许研究癌细胞和MSC之间的关系以及其他环境因素如氧张力的影响，以微胶囊形式，可以容易地适用于高通量药物筛选。

Drug testing in cancer clinical trials has a drastically low success rate therefore more accurate pre-clinical disease models are urgently needed to translate knowledge gained from basic cancer research to patient benefit. Cancer cell lines cultured on a 2D surface fail to recapitulate the complex 3D tumour microenvironment that contributes to tumourigenesis whilst animal models cannot fully replicate human tumour physiology. Therefore, new 3D pre-clinical cancer models need to be engineered in order to bridge the gap between in vitro and in vivo cancer research. Microencapsulation of cells, where individual cell types or multiple cell types are entrapped within a semi-permeable or solid material to form microcapsules or microspheres, can be used as a 3D cancer model and is amenable for applications in pre-clinical drug testing. This project aims to bioengineer a model of the breast tumour microenvironment using microencapsulation to study the relationship between breast cancer cells and mesenchymal stem cells (MSCs), the role of which has not been fully elucidated in the literature. Membrane emulsification will be employed to produce monodisperse and reproducible microcapsules of biocompatible hydrogels that will be used to encapsulate the two cell types. Membrane emulsification offers advantages over other possible techniques as it is scalable and particle uniformity can be tightly controlled which will allow the study of the impact of microcapsule size on formation of the in vivo model. The importance of microcapsule stiffness and viscoelasticity has also not yet been determined in microencapsulation-based cancer models, therefore hydrogel stiffness will be modulated to represent different stages of disease progression and the effect on cell behaviour and migration will be determined. Importantly, the learning on how to formulate the 'ideal' microcapsule with these specific parameters (e.g. size, material stiffness) will be applicable to the development of other in vivo models and other uses of hydrogel-based microparticles.In summary, membrane emulsification will be used to bioengineer an in vivo-like breast tumour microenvironment that allows the study of the relationship between cancer cells and MSCs and the influence of other environmental factors such as oxygen tension, in a microcapsule format that can be easily adapted for high-throughput drug screening.