Single-cell molecular characterization to partition the human glioblastoma tumor microenvironment (TME) genetic background

Abstract

Glioblastoma (GB) is a devastating primary brain malignancy. Recurrence of GB is inevitable despite the standard treatment of surgery, chemotherapy, and radiation, and the median survival is limited to around 15 months. Barriers to treatment include the complex interactions among the different cellular components inhabitant of the tumor microenvironment. These challenges are further compounded by extensive inter- and intra-tumor heterogeneity and by the dynamic plasticity of GB cells. The complex heterogeneous nature of GB cells is helped by the local inflammatory tumor microenvironment, which mostly induces tumor aggressiveness and drug resistance. More effective therapy development heavily depends on higher resolution molecular subtype signatures. All cellular components of a GB tumor are subjected to a continuous pressure inducing proliferation that might favor the accumulation of genetic mutations. Understanding the genetic background of several cellular component s belonging to a GB microenvironment could give insights into tumor behavior and progression. In the present study by using fluorescent multiple labeling and DEPArray cell separator, we recovered several single cells or groups of single cells from populations of different origins from IDH-WT GB samples. From each GB sample, we collected astrocytes (GFAP+), microglia (IBA+), stem cells (CD133+), and endothelial cells (CD105+) and performed Copy Number Aberration (CNA) analysis with a low sequencing depth. The same tumors were subjected to a bulk CNA analysis. The tumor partition in its single components allowed single-cell molecular subtyping which revealed new aspects of GB altered genetic background. Nowadays, single-cell approaches are leading to a new understanding of GB physiology and disease. Moreover, single-cell CNAs resource will permit new insights into genome heterogeneity, mutational processes, and clonal evolution in malignant tissues.