OTME-12. Role of the transsulfuration pathway in glioblastoma invasion

Abstract Glioblastoma (GBM) is a primary malignant brain tumor with a median survival under two years. The poor prognosis GBM caries is largely due to cellular invasion, which enables escape from resection and drives inevitable recurrence. Numerous factors have been proposed as the primary driving forces behind GBM’s ability to invade adjacent tissues rapidly, including alterations in the tumor’s cellular metabolism. Though studies have investigated links between GBM’s metabolic profile and its invasive capability, these studies have had two notable limitations. First, while infiltrating GBM cells extending beyond the tumor edge utilize adaptive cellular machinery to overcome stressors in their microenvironment, these cells at the invasive front have not been the ones sampled in invasive studies, which have used cell lines or banked tumor tissue taken from the readily accessible tumor core. Second, studies of invasion have primarily used two-dimensional (2D) culture systems, which fail to capture the dimensionality, mechanics, and heterogeneity of GBM invasion. To address these limitations, our team has developed two parallel approaches: acquisition of site-directed biopsies from patient GBMs to define regional heterogeneity in invasiveness, and engineering of 3D platforms to study invasion in vitro. Through utilization of these platforms, and by taking advantage of the system-wide, unbiased screens of metabolite profile and gene expression available, our team looks to identify targetable metabolic factors which drive cellular invasion in GBM. Untargeted metabolomics revealed cystathionine to be selectively enriched in the invasive tumor front of both site directed biopsies (fold change 5.8), and 3D organoid models (fold change 14.2). RNA sequencing revealed 7/30(23%) metabolic genes upregulated in the invasive tumor front were involved in cysteine or glutathione metabolism. These results highlight a clear role of the transsulfuration pathway in GBM invasion that our team looks to investigate with further targeted assays.