Cellular Biophysical Markers for Rapid Evaluation of Immune Checkpoint Inhibitors in Radioimmunotherapy Against Glioblastomas

Abstract

Cancers of the brain and nervous system account for 1 in every 100 cancer diagnoses in the United States and about 0.3 million diagnoses globally, every year. Surgery, radiotherapy, and chemo-therapy constitute the standard of care. Despite advancements in diagnosis and treatment delivery, mortality rate for these cancers have remained steady for over three decades. Immunotherapy is an emerging fourth treatment modality which has been effective against several cancers but not brain cancers, such as glioblastoma, GBM. Here, we develop in vitro assays to quantify molecular readouts of cell death, cell migration and clonogenicity, and synopsize these as biophysical markers for the rapid evaluation of immune checkpoint inhibitors (ICI), durvalumab and pembrolizumab, alone and in combination with radiotherapy (radioimmunotherapy). We find different trends in their direct action on two GBM cell lines (T98G and U87), even in the absence of immune cells. Radiation alone, and pembrolizumab with radiation, both reduced (p < 0.05) cell-cell adhesion. This reduction suggests increased potential for local invasion. Our assays offer additional insights regarding ICIs, may enable evaluation of their potential efficacy, and could set the stage for pa-tient-specific radioimmunotherapy against brain cancers, engendering improved treatment out-comes.