When it comes to communicating, cells perform better in crowds. When too many work together, though, the cells end up in a game of “telephone,” passing on increasingly unreliable signals.
Researchers from Yale, Emory, Purdue, and other universities looked at how cells sense the chemical and mechanical cues that determine cell behavior. Two studies with their results — which have potential implications ranging from breast cancer treatment to semiconductor manufacturing — appear the week of Jan. 18 in the journal Proceedings of the National Academy of Sciences.
Cells read these signals by sensing the concentration of a chemical and gravitating toward it, as if tracking a scent. “The cells want to find where there’s more of this molecule,” said Andre Levchenko, the John C. Malone Professor of Biomedical Engineering and director of the Yale Systems Biology Institute, one of the papers’ authors. “They use the gradients as directional cues.”
The studies focused on how well individual cells sense these cues compared to teams of cells. One study addressed this theoretically, while the other combined theory and experiments. The researchers placed together breast cells, which can self-organize into miniature breast tissue. The development of these small organ-like tissues, known as organoids, allowed the scientists to study how cell ensembles of different sizes sense the chemical signal’s gradients. Epidermal growth factor (EGF), a substance that stimulates cell growth, was the chemical used in the experiments.
When there were very weak gradients of EGF, with only slight differences in molecular concentration, the superiority of collective decision-making among cells became clear. “The single cells could not detect those differences; it was important for the cells to be together,” Levchenko said.
Page 1 of 2