UC Davis

The human mammary gland is a pivotal organ within the human anatomy, serving as a paramount role in sustaining progeny through the synthesis of milk for nourishment during infancy and early childhood. However, this lactation system of the human mammary gland remains inadequately explored due to the challenge of replicating this process in vitro. Although several studies have utilized the human mammary gland for breast cancer research, the lactation function of the human mammary gland is understudied. Additionally, existing lactation studies predominantly rely on other cell lines such as mouse or bovine sources. The rise of developing lab-engineered meat and fish caused by up-and-coming food industry companies caused quite a stir in the cellular agriculture industry. At around the same time, the baby formula shortage revealed a need for an alternative source of breast milk, akin to the recent achievements in the cellular agriculture industry. Based on this background, my thesis aims to address these needs by using the human mammary cell line MCF10A, along with our novel 3D bioprinting system and developmental stage-specific culture media, to recapitulate the physiological environment of the human mammary gland in vivo. To this end, we confirm that our bioprinting setup consistently produces long, connected mammary mini-tissues from MCF10A which express differentiated luminal markers EpCAM and MUC-1, with evidence of milk proteins detected. These MCF10A mini-tissues also exhibit an appearance not documented before; cell swelling and cell transparency reveal the surface monolayer and interior tubular structures at around 25 days of culture.