Cas9 mediated in vitro gene editing in primary mammary epithelial cells

Breast cancer affects one in eight women in the UK and is the responsible for the death of 1000 women every month. One of the major challenges for the treatment of breast cancer is the heterogeneous nature of the disease. There is evidence that tumour heterogeneity could be attributed to the cell of origin of these tumours. For example, luminal breast cancer is thought to arise from differentiated cells, while basal-like breast cancer (BLBC) is thought to arise from undifferentiated progenitor and stem like cells. This would necessitate the expression and function of cell type specific factors, which determine the cells’ fate. Therefore, understanding the developmental hierarchy of normal mammary epithelial cells could pave way for the development of effective subtype specific treatments for breast cancer. 

The mouse provides an excellent model to study how different cell fate regulators are involved in mammary epithelial development and breast cancer development. However, with the advances in DNA sequencing and cancer genomics the number of candidate genes, which need to be investigated in the mouse, has increased. This lead to an increase in demand for genetically modified (GM) mice to perform these studies. In this project we aim to circumvent the need for the generation of new GM mice for breast cancer and mammary gland studies by capitalising on recent technical advances to generate a fast, cost effective and flexible approach to tag genes of interest directly in primary mammary epithelial cells. We will utilise the Crispr/Cas9 technology to delete or tag genes of interest in primary mammary epithelial cells in vitro and re-introduce them directly back into the mammary fatpad of recipient mice ready for downstream analysis.

Our new approach will enable us to study novel genes of interest in the mammary gland without the need for generating new GM mice which will dramatically reduce the number of animals needed to perform breast cancer and mammary gland studies.