In addition to competing for resources, living cells actively kill and eat each other. New explorations of these “cell-in-cell” phenomena show they are not restricted to cancer cells but are a common facet of living organisms, across the tree of life. Credit: Jason Drees for the Biodesign Institute at Arizona State University
The widespread occurrence of such interactions in non-cancer cells suggests that these events are not inherently “selfish” or “cancerous” behaviors. Rather, the researchers propose that cell-in-cell phenomena may play crucial roles in normal development, homeostasis, and stress response across a wide range of organisms.
Carlo Maley is a researcher with the Biodesign Center for Biocomputing, Security and Society; professor in the School of Life Sciences at ASU; and director of the Arizona Cancer Evolution Center. Credit: The Biodesign Institute at Arizona State University The study was conducted in collaboration with first author Stefania E. Kapsetaki, formerly with ASU and now a researcher at Tufts University, and Luis Cisneros, formerly with ASU and currently a researcher at Mayo Clinic.Cell-in-cell events have long been observed but remain poorly understood, especially outside the context of immune responses or cancer.
A spectrum of cell-in-cell behaviors are highlighted in the study, ranging from completely selfish acts, where one cell kills and consumes another, to more cooperative interactions, where both cells remain alive. For example, the researchers found evidence of “heterospecific killing,” where a cell engulfs and kills a cell of a different, across a wide range of unicellular, facultatively multicellular, and obligate multicellular organisms.
“Our categorization of cell-in-cell phenomena across the tree of life is important for better understanding the evolution and mechanism of these phenomena,” Kapsetaki says. “Why and how exactly do they happen? This is a question that requires further investigation across millions of living organisms, including organisms where cell-in-cell phenomena may not yet have been searched for.