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非常低，因此迫切需要更准确的临床前疾病模型，将从基础癌症研究中获得的知识转化为患者的利益。在二维表面上培养的癌细胞不能再现复杂的三维肿瘤微环境，而动物模型不能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。细胞的微胶囊化，其中单个细胞类型或多种细胞类型被包裹在半透性或固体材料中形成微胶囊或微球，可以用作3D癌症模型，并适用于临床前药物测试。本项目旨在利用微囊化技术构建乳腺肿瘤微环境的生物工程模型，研究乳腺癌细胞与间充质干细胞（MSCs）之间的关系，MSCs的作用在文献中尚未得到充分阐明。膜乳化将用于生产单分散和可复制的生物相容性水凝胶微胶囊，用于包封两种细胞类型。膜乳化比其他可能的技术具有优势，因为它是可扩展的，颗粒均匀性可以严格控制，这将允许研究微胶囊大小对体内模型形成的影响。在基于微胶囊的癌症模型中，微胶囊刚度和粘弹性的重要性也尚未确定，因此水凝胶刚度将被调节以代表疾病进展的不同阶段，并将确定对细胞行为和迁移的影响。重要的是，学习如何制定具有这些特定参数（例如尺寸，材料刚度）的“理想”微胶囊将适用于其他体内模型的开发和基于水凝胶的微颗粒的其他用途。综上所述，膜乳化将用于生物工程体内样乳腺肿瘤微环境，允许研究癌细胞和间质干细胞之间的关系以及其他环境因素（如氧张力）的影响，这种微胶囊形式可以很容易地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.