A multi-cellular 3D model of human breast tissue to replace rodent xenograft models in breast cancer research

We aim to reduce the number of rodent models investigating the biology of the breast by developing a superior in vitro matrix incorporating bespoke human breast extracellular matrix (ECM) components, providing a robust culture model as the go-to platform for exploring the biology of the breast and breast cancer. Drs Merry and Meade have developed a simple peptide hydrogel system originally optimised for the culture of stem cells. In collaboration with Dr Farnie and Prof Howell, who provide expertise in primary breast cell culture, ductal carcinoma (DCIS) and breast ECM/density, we have pilot data demonstrating that the hydrogel is suitable for the growth of typical in vitro 3D normal and DCIS breast structures. As with the vast majority of cancers, the interaction of DCIS cells with their local microenvironment, the surrounding stroma and ECM, is fundamental in defining their proliferation, transformation to malignancy and invasion. Our hydrogel is well positioned to replicate aspects of the complex mixture of proteins and glycans that embeds and supports cells, and can also be manipulated to mimic ECM stiffness (breast density) which is a key predictor of DCIS recurrence and primary invasive breast cancer development. We will use a combination of proteomics and glycomics to identify the key ECM components defining dense and non-dense breast tissue in normal, DCIS and invasive breast cancer conditions. The proteins and glycans will then be combined to generate a panel of 6 bespoke hydrogel environments modelling the range of tissue types. We will validate the model using multicellular 3D culture and assay for ECM remodelling by encapsulated cells, directly assessing the ability of our in vitro model system to replicate human breast tissue. Finally, we will incorporate immune cells into the gels, thereby addressing a key feature of animal models that currently separates them from in vitro systems.