SYST-24 PROPOFOL EXERTS ANTI-TUMOR EFFECTS IN GLIOMA AND THE TUMOR MICROENVIRONMENT VIA NON-CODING RNAS AND SECRETED EXOSOMES

BACKGROUND: Glioblastoma (GBM), is the most common primary brain tumor. GBM contains a small subpopulation of glioma stem cells (GSCs) that are implicated in tumor recurrence and treatment resistance and therefore represent important therapeutic targets. Recent clinical studies suggest propofol impacts subsequent tumor response to treatments and patient prognosis. The effects of propofol on patient derived GSCs alone and in combination with radiation and temozolomide, (TMZ) have not been reported. Objectives: The molecular mechanisms underlying propofol’s anti-tumor effects on GSCs and its effect on cellular communication with microglia was studied. Using GSC spheroids, differentiated glioma and tumor cells on a microfluid chip, effects of propofol alone and together with radiation and TMZ on the self-renewal and stemness of GSCs, their mesenchymal transit and the proliferation and apoptosis of differentiated glioma cells was analyzed. Using transwell plates, the effects of propofol on the cross-talk of GSCs with human microglia cells was examined. RESULTS: Propofol exerted a dose-dependent inhibitory effect on the self-renewal, expression of mesenchymal markers and migration of GSCs and sensitized them to both temozolomide (TMZ) and radiation. At higher concentrations propofol induced a large degree of cell death as demonstrated using microfluid chip. Propofol increased the expression of the lncRNA BDNF-AS, which acts as a tumor suppressor in GBM and silencing of this lncRNA partially abrogated propofol’s anti-tumor effects. Propofol also inhibited the pro-tumorigenic GSC-microglia cross talk via extracellular vesicles (EVs) and delivery of BDNF-AS. CONCLUSIONS: Propofol exerted anti-tumor effects on GSCs and differentiated glioma cells by inhibiting cell renewal, proliferation, and mesenchymal transition and by inducing cell death at higher concentration. Propofol also sensitized GSCs to radiation and TMZ. Propofol, which is widely used in GBM surgeries, should be further explored as a potential repurposed drug during resection and an effective adjunct to radiation and TMZ.