Mammary Intraductal Gene Electroporation (MIGE): A Novel Non-Viral Gene Delivery Method Targeting Murine Mammary Epithelial Cells

The mammary gland is a valuable model in cancer research and developmental biology. Gene delivery techniques are crucial for mammary tissue research to understand how genes function and study on diseases such as cancer. Viral vector-based approaches provide a high degree of transduction efficiency, but they raise safety and immunogenicity concerns, whereas non-viral vector-based approaches are considered safer and have lower immunogenicity than viral methods. Unfortunately, non-viral gene delivery has rarely been applied to the mammary glands because it is technically challenging. Here, we developed a novel method for in vivo transfection of epithelial cells lining murine mammary glands via intraductal injection of plasmid DNA using a breath-controlled glass capillary and subsequent electroporation (EP) of the injected area. Female mice were transfected with plasmids harboring the enhanced green fluorescent protein (EGFP) gene. Widespread EGFP fluorescence was observed in the mammary epithelial cells of the ducts and adipocytes adjacent to the ducts. As this in vivo gene delivery method is simple, safe, and efficient for gene transfer to the mammary glands, we named this technique “Mammary Intraductal Gene Electroporation” (MIGE). The MIGE method is a useful experimental tool for studies on mammary gland development and differentiation as well as breast cancer research.