TMIC-32. TUMOR CELL CILIA ASSOCIATE WITH SPECIFIC IMMUNE CELL POPULATIONS IN HUMAN AND MOUSE MODELS OF GBM

Abstract INTRODUCTION Glioblastoma (GBM) typically recurs after standard of care therapies. A major obstacle is that GBMs employ various mechanisms to suppress the host immune system, preventing destruction and removal cancer cells. better understanding crosstalk between tumor cell types needed advance immunotherapeutic approaches against GBM. contain primary cilia, organelles likened both cellular ‘antennae’ transmitters, their presence associated with more aggressive treatment resistant tumors. OBJECTIVE To explore whether ciliated GBM cells associate infiltrating determine if these interactions are specific for certain populations. METHODS We immunostained patient specimens sections from syngeneic mouse models markers cilia (ARL13B gTub) together (CD45, CD11b, Ly-6B.1, CD3). Cilia were also examined in brain tumors generated CCR2+/rfp/CX3CR1+/gfp mice, evaluate proximity glioma CCR2- CX3CR1-expressing myeloid subpopulations (brain resident microglia as well peripheral-derived macrophages monocyctic- MDSCs (M-MDSCs). Proximity different or was quantified using nearest neighbor analyses. RESULTS In samples, CD45+ extended processes contacted tip. Similar observations made intracranial GBM-bearing mice where we detected juxtaposition recruited (i.e. CD45, CD11b Ly-6B.1). Notably, predominately immune-suppressive M-MDSCs. Further, CD3+ T rarely juxtaposed maintained greater distances away compared CONCLUSION Our data suggest select types, raising possibility immunologically cold may Ongoing studies examining how landscape develops depending on cilia.