The neural behavior of glioblastoma, including the formation of tumor microtubes and synaptic circuitry, is increasingly understood to be pivotal for disease manifestation (Osswald et al. 2015; Venkatesh et al. 2015; Weil et al. 2017; Venkataramani et al. 2019; Venkatesh et al. 2019; Alcantara Llaguno et al. 2019; Venkataramani et al. 2022). Nonetheless, the few approved treatments for glioblastoma target its oncological nature, while its neural vulnerabilities remain incompletely mapped and clinically unexploited. Here, we systematically survey the neural molecular dependencies and cellular heterogeneity across 27 glioblastoma patients and diverse model systems. In patient tumor samples taken directly after surgery, we identify a spectrum of neural stem cell morphologies indicative of poor prognosis, and discover a set of repurposable neuroactive drugs with unexpected and consistent anti-glioma efficacy. Glioblastoma cells exhibit functional dependencies on highly expressed drug targets including neurological ion channels and receptors, while interpretable molecular machine learning reveals downstream convergence on secondary drug targets (COSTAR) involving AP-1-driven tumor suppression. COSTAR enables in silico drug screening on >1 million compounds that are validated with high accuracy. Multi-omic profiling of drug-treated glioblastoma cells confirms rapid Ca2+-driven AP-1 pathway induction to represent a tumor-intrinsic vulnerability at the intersection of oncogenesis and neural activity-dependent signaling. Finally, the consistent anti-glioma activity across patients and model systems is epitomized by the antidepressant Vortioxetine, which synergizes in vivo with approved glioblastoma chemotherapies. In all, our global analysis reveals that the neural vulnerabilities of glioblastoma converge on an AP-1 mediated gene regulatory network with direct translatable potential.

Peptides were separated by reversed-phase chromatography on a 50 cm ES803 C18 column (Thermo Fisher Scientifc) that was connected to a Easy-nLC 1200 (Thermo Fisher Scientific).. Peptides were eluted at a constant flow rate of nl/min with a 90 min stepped gradient from 3–25% buffer B (80% ACN, 0.1% FA) and 25-50%B. Mass spectra were acquired in PRM mode on an Q Exactive HF-X Hybrid Quadrupole-Orbitrap MS system (Thermo Fisher Scientific). The MS1 mass range was 340–1,400 m/z at a resolution of 120,000. Spectra were acquired at 60,000 resolution (automatic gain control target value 2.0*10e5); Normalized HCD collision energy was set to 28 (+/-5)%, maximum injection time to 118 ms. Monitored peptides were analyzed in Skyline v20 and results were uploaded to PanoramaWeb.