The GPCR Connection: Linking Alzheimer's Disease and Glioblastoma.

Alzheimer's disease (AD) and glioblastoma multiforme (GBM) are biologically distinct age-related brain disorders with opposing clinical phenotypes. AD is characterised by progressive neurodegeneration and cognitive decline, whereas GBM is characterised by aggressive cellular proliferation and a poor prognosis. Despite these differences, converging evidence indicates that both conditions share molecular pathways and network-level dysfunction that emerge during brain ageing. Central to this convergence are G protein-coupled receptors (GPCRs), which act as integrative signalling hubs that regulate inflammation, metabolism, calcium (CA2+) homeostasis, and cell survival. In AD, GPCR signalling modulates amyloid-β production and clearance, Tau phosphorylation, intracellular CA2+ dynamics, and glial-driven neuroinflammation. In contrast, the same receptor families promote tumour growth, angiogenesis, immune evasion, and therapeutic resistance in patients with GBM. Core intracellular cascades, such as PI3K-AKT-mTOR and MAPK-ERK, are dysregulated in both diseases and function as shared signalling backbones, with outcomes dictated by cellular context rather than receptor identity. CXCR4, LPA₁, and FPR1 exemplify this duality, driving either oncogenic proliferation or neuronal dysfunction, depending on the biological environment. Recent advances in integrative multiomics, computational modelling, artificial intelligence, and organoid systems have revealed GPCR-centred regulatory nodes and accelerated the identification of druggable targets. Collectively, these findings suggest that AD and GBM, although pathologically antithetical, share a molecular fingerprint shaped by ageing-associated inflammation, metabolic disruption, cellular senescence and dysregulated GPCR networks. Deciphering this context-dependent duality may enable precision therapeutic strategies to either restore neuronal integrity in AD or suppress malignant programmes in GBM while fostering cross-fertilisation between neurodegeneration and neuro-oncology research.