Glioblastoma (GBM) is the most common primary brain tumor. Due to high resistance to treatment, local invasion, and high risk of recurrence, GBM patient prognoses are often dismal, with median survival around 15 months. The current standard of care is threefold: surgery, radiation therapy and chemotherapy with temozolomide (TMZ). However, patient survival has only marginally improved. Radioimmunotherapy (RIT) is a fourth modality under clinical trials and aims at combining immunotherapeutic agents with radiotherapy. Here, we develop in vitro assays for rapid evaluation of RIT strategies. Using a standard cell irradiator and an Electric Cell Impedance Sensor, we quantify cell migration following the combination of radiotherapy and chemotherapy with TMZ and RIT with durvalumab, a PD-L1 immune checkpoint inhibitor. We measure cell survival using a cloud-based clonogenic assay. Irradiated T98G and U87 GBM cells migrate significantly (p < 0.05) more than untreated cells in the first 20-40 hours post-treatment. Addition of TMZ increased migration rates for T98G at the 20 Gy (p < 0.01). Neither TMZ nor durvalumab significantly changed cell survival in 21 days post-treatment. Interestingly, durvalumab abolished the enhanced migration effect, indicating possible potency against local invasion. These results provide parameters for rapid supplementary evaluation of RIT against brain tumors.

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.

Nanoparticle-mediated radiation therapy (NPRT) is an emerging modality for radiosensitization of highly resistant cancers such as brain cancers. This is due to the ability of specific nanoparticles (NPs) to increase physical dose deposition and subsequent direct damage to cells and DNA within their local vicinity, through enhanced generation of reactive oxygen species, ROS. Here, we report the successful use of PEGylated (biocompatible) core-shell quantum dots (QDs) and carbon quantum dots (CQDs) to simultaneously enhance and assess ROS generation while radiosensitizing highly radioresistant brain cancer cell lines: T98G and U87 Glioblastoma cells. Relative peak fluorescence intensity ratio calculations and average intensity comparisons show highly significant (***p&lt;0.001) enhancement of ROS generation, for 5 Gy and 20 Gy irradiation, applied using a Faxitron Cell Irradiator. By quantifying post-radiotherapy cell attachment, proliferation, migration, cell survival and cell death using electric cell-substrate impedance sensing and clonogenic assays, we demonstrate potentially improved in vitro radiotherapeutic outcomes for brain cancer cells radiosensitized using PEGylated CdSe/ZnS QDs and CQDs.