Targeting Kinase Signaling in Glioblastoma: Structural Optimization, Blood–Brain Barrier Dynamics and Combinatorial Translational Strategies

Small-molecule kinase inhibitors offer a compelling therapeutic strategy for glioblastoma, yet their clinical efficacy remains severely limited by blood–brain barrier penetration and active efflux transporter extrusion. This review evaluates current medicinal chemistry approaches and translational paradigms to overcome these drug delivery and biological constraints. A critical analysis of the literature reveals that direct structural optimization faces a multidimensional balancing act; next-generation design must prioritize macrocyclization, structural rigidification, and bioisosteric capping to lower polar surface area and evade P-glycoprotein and BCRP efflux. Furthermore, carrier-mediated prodrugs targeting the LAT1 transporter provide a viable rescue strategy for highly potent scaffolds. Reviewing recent clinical failures, such as paxalisib and osimertinib, underscores that single-node monotherapies fail due to compensatory pathway hyperactivation and clonal heterogeneity, whereas multi-targeted agents or rational dual-node combinations prevent rapid tumor adaptation. Additionally, combining kinase inhibitors with DNA damage repair inhibitors, immune checkpoint modulation, or MR-guided focused ultrasound could provide powerful synergistic networks. Finally, bridging the translational gap requires complementing conventional serum-cultured cell lines with patient-derived glioma stem cells and orthotopic xenografts to better recapitulate the cellular architecture of the disease. Ultimately, overcoming the therapeutic challenges in glioblastoma demands a fundamental pivot toward rigorous neuro-pharmacological design and multi-lineage network oncology.