Membrane proteomic profiling to identify candidate therapy targets for glioblastoma infiltration.

Background: Glioblastoma (GBM) is an aggressive brain tumor characterized by rapid growth and infiltration. New therapies are desperately needed to improve GBM patient outcomes. Intra-tumoral heterogeneity is a common driver of failure for novel GBM treatments, and many preclinical studies rely on cell lines established from the tumor core. As a result, they fail to characterize the infiltrative tumor cells, which remain post-surgery and ultimately drive tumor recurrence. Methods: This study characterizes the membrane proteome of 3 patient-derived GBM cell lines isolated from the tumor invasive margin (GIN8, GIN28, and GIN31), which is a proxy for residual disease post-surgery. We combined plasma membrane protein analysis with total protein analysis using liquid chromatography-mass spectrometry to uncover therapeutic targets most amenable for drug repurposing. Molecular docking analysis predicted specific binding pockets on the surface of key membrane proteins against which the top 10 approved drug candidates were screened based on their binding energy scores. Results: Membrane proteins such as EDIL3, DYSF, ROBO1, SERPINE2, LOXL1, and CD70 were consistently significantly upregulated across GBM cell lines relative to healthy astrocyte controls, indicating potential functional roles in GBM progression. Molecular docking identified nilotinib (targeting LOXL1) and darifenacin (targeting SH3KBP1) as candidate drugs that can bind to identified membrane proteins. Nilotinib and darifenacin produced average IC Conclusions: These findings suggest that targeting membrane proteins offers promise for developing effective GBM therapies predicated on the most prognostically relevant intra-tumor region.