In a study published in Brain Communications, a new Open Access publication of the well-known journal Brain, the team led by Carlos Barcia, researcher at Institut de Neurociències of the Universitat Autònoma de Barcelona (INc), analyzed the role of immune cells in the expansion of glioblastoma, the most aggressive brain tumor. The study is a collaborative effort with the General Hospital in Valencia, and part of Elena Saavedra's doctoral thesis.
The research shows for the first time that microglia and macrophages, cells of the immune system, facilitate the invasive capacity of glioblastoma by clearing the necrotic areas of the tumor while ignoring tumor cells in its niche of invasion.
This invasive niche, which is the part of the tumor that comes into contact with the healthy tissue, is shaped like a pseudopalisade and is poorly irrigated by blood vessels. This results in a lack of oxygen -hypoxia-, which causes, on the one hand, that the tumor cells escape and invade healthy tissue, and on the other, the creation of a necrotic area inside the tumor. Researchers show, in this study, that microglia and macrophages travel to these hypoxic areas and only clean dying tumor cells, facilitating tumor growth and expansion.
The importance of this work is that we observed for the first time the presence of immune system cells in these particular tumor's invasive areas, and also that the phagocytic capacity of immune cells is not lost and could be trained to facilitate the removal of tumor instead of helping its growth."
Carlos Barcia, researcher at Institut de Neurociències, Universitat Autònoma de Barcelona
The next step, then, is to study how microglia cells and macrophages could be trained, through immunotherapy or other strategies, to not play in favour of the tumor, but to contribute to its elimination.
Saavedra-López, E., et al. (2020) Phagocytic glioblastoma-associated microglia and macrophages populate invading pseudopalisades. Brain Communications. doi.org/10.1093/braincomms/fcz043.