Abstract B029: 3D magnetic gliomasphere modeling reveals CDK inhibitor mediated suppression of migration in newly diagnosed and recurrent glioblastoma under hypoxic conditions

Abstract Purpose: Glioblastoma (GBM) exhibits functional heterogeneity and therapeutic resistance across disease stages. We developed a 3D magnetic spheroid platform to assess invasion, stem cell plasticity, and therapeutic response in newly diagnosed and recurrent patient-derived gliomaspheres under physiologically relevant hypoxic conditions. Methods: Gliomasphere migration was monitored by live-cell imaging under hypoxia. Stem cell plasticity was assessed by CD44 expression using laser scanning confocal microscopy, while basal MCL-1 levels and CDK inhibitor targets were analysed by Western blotting. Cell viability and apoptosis were evaluated using WST-1 and Caspase-3/7 Glo assays. Invasion dynamics in response to Temozolomide (TMZ) and novel CKIs (CYC065 & THZ1) were assessed across disease stages. Results: Newly diagnosed gliomaspheres exhibited dynamic CD44 plasticity, whereas recurrent gliomaspheres maintained stable CD44 expression. In unmatched samples, newly diagnosed tumors were more invasive than recurrent tumors; this difference was not observed in patient-matched pairs. Across all stages and oxygen conditions, CDK inhibitors far more effectively suppressed invasion and induced apoptosis than TMZ, independent of CD44 status. CKI activity was associated with MCL-1 downregulation and inhibition of CDK2/7/9, and was maintained despite fluctuations in BCL-2 family proteins under hypoxia, confirmed by reduced viability and increased Caspase-3/7 activity. Conclusions: This 3D magnetic spheroid platform captures spatially resolved functional heterogeneity in glioblastoma and enables precise evaluation of invasion and therapeutic response. Novel CDK inhibitors robustly suppress invasion and induce apoptosis across disease stages and oxygen conditions, highlighting their potential as broadly effective therapeutics. This work demonstrates how spatial 3D modeling can uncover hypoxia driven plasticity and inform translational strategies in glioblastoma. Generative artificial intelligence was used to assist with language editing and clarity of the abstract; all scientific content and conclusions were determined by the authors. Citation Format: Niamh M. Scully, Brenton L. Cavanagh, Heiko Duessmann, Jochen H.M. Prehn, Brona M. Murphy. 3D magnetic gliomasphere modeling reveals CDK inhibitor mediated suppression of migration in newly diagnosed and recurrent glioblastoma under hypoxic conditions [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Brain Cancer; 2026 Mar 23-25; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2026;86(6_Suppl):Abstract nr B029.