Enhancing local glioblastoma treatment via in vitro synergistic pairing of Janus kinase/signal transducer and activator of transcription-3 inhibitor with antiepileptic drugs.

The heterogeneity and treatment resistance of glioblastoma (GBM) can be addressed through multidrug combination therapies that target multiple biological pathways simultaneously. In this study, we explored the repurposing of antiepileptic drugs with potential antitumor effects, combined with the Janus kinase/signal transducer and activator of transcription-3 (JAK/STAT3) inhibitor ruxolitinib (RUX), as an alternative local therapeutic approach for GBM. The cytotoxic effects of valproic acid (VPA), oxcarbazepine (OXC), and gabapentin (GBP) were evaluated on A172 and U251 GBM cells. Both VPA and OXC significantly reduced cell viability, prompting further investigation of their effects in combination with RUX. When tested in 3-dimensional multicellular tumorspheres, the combinations at their IC50 exhibited suboptimal effectiveness compared with single-agent treatment. Using a factorial experimental design based on a minimal combination approach to analyze dose-response data, followed by subsequent Bliss synergy analysis, synergistic interactions were revealed exclusively for RUX + VPA on A172 cells. Although the interaction between RUX and OXC was additive, GBM cells displayed increased sensitivity to this combination, suggesting potential therapeutic value. Ultimately, the most effective drug ratios were assessed using live/dead cell fluorescence staining in 3-dimensional multicellular tumorspheres. The variable treatment response observed among GBM cell lines underscores the need for personalized treatment strategies tailored to the specific molecular profile of individual tumors. SIGNIFICANCE STATEMENT: Given the unmet needs in glioblastoma treatment, the study explores novel combinations of Janus kinase/signal transducer and activator of transcription-3 inhibitor ruxolitinib and antiepileptics for local codelivery, aiming to overcome resistance and heterogeneity through synergistic effects and sustained release via molecularly imprinted reservoirs.