Ferroptosis Enhances T Lymphocyte Infiltration into Glioblastoma Spheroids.

Glioblastoma is one of the most aggressive and therapeutically challenging brain tumors. It is characterized by a highly immunosuppressive tumor microenvironment and poor prognosis, requiring novel treatment strategies. Along this line, ferroptosis has been proposed. To study the impact of ferroptosis on glioblastoma cells and immune cell infiltration, we established a spheroid model using LN229 glioblastoma cells and verified ferroptosis by measuring lipid peroxidation and RNA expression of ferroptosis-related genes. We then co-cultured spheroids with human peripheral blood mononuclear cells to follow the infiltration of distinct immune cell subsets by flow cytometry and immunohistochemistry. T lymphocyte infiltration into ferroptotic spheroids compared to control spheroids became apparent with the notion that ferroptotic cells attracted T cells more efficiently compared to apoptotic or necrotic cells. Mechanistically, ferroptotic glioblastoma spheroids released high amounts of ATP, which caused T cell attraction, while ATP deprivation reduced this effect. Ferroptosis appears to be an interesting therapy approach but might need co-treatments to ensure proper T cell activation.