TUMOR EDGE-DESTINED CELLS IN GBM CELLS IN A CELL-INTRINSIC MECHANISM

Abstract The highly infiltrative nature of glioblastoma (GBM) underscores limited response to current therapies and subsequent unfavorable clinical outcome. Despite the gross total resection of tumors located in the enhancing lesions, GBMs inevitably recur from the areas adjacent to the resection cavity that retains tumor cells with tumor-initiating capacity with therapy resistant nature (glioma-initiating cells: GICs). Here, we identified, in clinical GBM tumors, two mutually-exclusive glioma-initiating cell subpopulations in two different regions of GBM tumors, core- and edge-located glioma-initiating cells that co-exist in single tumors (Minata et al. Cell Reports. 2019). Following this observation, we further established patient-derived GBM clones from both tumor core and edge tissues, termed core-GICs and edge-GICs, and uncovered their distinct molecular signatures. Unexpectedly, we found that these two distinct GIC subpopulations retain the spatial identity, meaning that the core GICs locate themselves in the injected site, whereas the edge GICs initiated to form edge-like lesions, when xenografted into mouse brains. Through OMICs analyses, we identified CD38 as a key molecule to determine the edge phenotype both in vitro and in vivo. Collectively, our findings indicate, for the first time, that GBM cells are heterogeneous to be composed of tumor cells destined to be located in distinct regions of the tumors in a molecularly-defined manner.