Berkeley Lab scientist grows samples of living tissue to test chemicals for carcinogenicity

Dr. Paul Yaswen/Courtesy

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A team of researchers have developed a method to determine chemicals’ tendency to cause breast cancer.

Lawrence Berkeley National Laboratory staff scientist Paul Yaswen and his team — along with researchers at the Silent Spring Institute, the University of Florida and Stanford University — are using stem cells to grow samples of “living” tissue known as organoids, upon which chemicals can be tested. Once the researchers figure out how to best maintain the organoids, they plan to expose them to a series of 18 carcinogenic and noncarcinogenic chemicals to see if they exhibit tumorous growth in the presence of carcinogens.

The goal of their project is to make organoid testing a way to single out chemicals that could cause breast cancer.

In most labs, the carcinogenicity of chemicals is tested on mice or on cells in a Petri dish. But mice take time to breed and be maintained, and a chemical that is harmless to mice might affect humans quite differently. Furthermore, cells in a dish together do not communicate with one another in the way that cells in living tissue, which are differentiated from one another, do.

According to Yaswen, this is where stem cells can be helpful. Unlike with mice and clusters of identical cells, chemical testing on stem cell organoids should theoretically give scientists a better idea of how various environmental chemicals affect humans.

“We realized that at a very basic level, cancer is a disease of faulty cell-cell communication,” Yaswen said in an email. “To better understand how environmental chemicals contribute to cancer, we need a model that will allow cells to communicate with each other as they do in real tissues; this is not possible in conventional cell cultures in which one cell type usually predominates.”

According to Yaswen, understanding cell signaling is important when investigating cancer. When a cell becomes cancerous, it loses its ability to communicate with other cells.

By observing how organoid cells change the way they communicate in the presence of particular chemicals, the researchers can determine how carcinogenic these chemicals are.

“We can use the organoids to examine how chemicals affect the different cell types and their organization,” Yaswen said.

Regarding future applications of his project, Yaswen said his team hopes to generate an experimental system that can be used to quickly screen the more than 80,000 chemicals found in the home and workplace for possible breast carcinogenicity.

At the moment, however, Yaswen and his team are mainly focused on improving the process of generating and maintaining the organoids themselves.

“The most challenging aspect of using stem cells is to find incubation conditions and favor their survival and propagation without compromising their ability to form fully representative organoids,” Yaswen said.

Contact Rachel Lew at [email protected] and follow her on Twitter @Rlew12C.