Researchers at the German Research Center for Environmental Health have created the first ever three-dimensional human mammary gland outside of the human body. Using adult stem cells, the study examined how breast cancer cells can adopt aggressive traits and potentially become lethal. This innovative new technology has the ability to mimic normal human breast function, while also allowing researchers to examine types of breast cancers and how they develop.

How It Works

Led by Dr. Christina Scheel, a team of researchers cultured human breast epithelial cells to rebuild the three-dimensional tissue of a human mammary gland. To simulate the effects of puberty, a transparent gel was used to help the cells divide and spread; these cells then formed hollow ducts that branched off and ended in grape-like structures as they would in normal mammary gland development. Cells within the mammary gland are inherently regenerative, needing to remodel and reproduce constantly to create milk; because of this, the mammary glands are the site of many stem cells, which researchers sought to examine specifically to track potential tumor growth. When creating the human mammary gland outside of the body, researchers were able to mimic this regenerative environment.

The Potential for Cancer

Researchers believe that most malignant cell growth comes from mammary cell development and function, especially within these stem cells. As the human mammary gland has the potential to regenerate its entire self, the tissue harbors many stem cells for potential transitioning. Researchers theorize that aggressive breast cancer cells activate uncontrollable development in these cells, which then impacts progression of the tumor. The tumor then becomes, in a sense, its own organ. In order to prevent this, researchers examined how regenerative functions are carried out normally in their tissue model, to provide a basis for new strategies targeting abnormal development.

“A technological breakthrough”

Observing cells specifically with the ability to regenerate, researchers found that regenerative properties were dictated by the physical properties of the environment surrounding the cells.

“We were able to demonstrate that increasing the rigidity of the gel led to increased spreading of the cells, or, said differently, invasive growth. Similar behavior was already observed in breast cancer cells,” said Jelena Linnemann, author of the study, in a recent press release. “Our results suggest that invasive growth in response to physical rigidity represents a normal process during mammary gland development that is exploited during tumor progression.”

Author Lisa Meixner added that this new insight brings them one step closer to understanding how to stop breast cancer in its tracks. “With our [model], we can elucidate how such processes are controlled at the molecular level, which provides the basis for developing therapeutic strategies to inhibit them in breast cancer,” she said.

Among the model’s many advantages for study, researchers found that isolating the tissue from the human body allows for easier control of the environment. Using healthy tissue from women who have had breast reduction surgeries, researchers were able to start the regenerative process. “After the operation, the tissue is normally discarded. For us, it is an experimental treasure chest that enables us to tease out individual difference in the behavior of stem and other cells in the human mammary gland,” said co-author Haruko Miura.

Scheel also noted that their model will kick-start a new forum for cancer research that will allow us to understand the disease more than we ever had before. “This technological break-through provides the basis for many research projects, both those aimed to understand how breast cancer cells acquire traits, as well as to elucidate how adult stem cells function in normal regeneration,” she said.

And with this amazing petri dish-built breast, we are coming one step closer to defeating breast cancer for good. By allowing researchers to understand the nature of stem cells, and how regeneration can go awry, there is much potential for the future of breast cancer treatment.

Source: Linneman J, Scheel C, Meixner L, et al. Qualification of regenerative potential in primary human mammary epithelial cells. Development. 2015.